// Copyright 2011 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include "cc/trees/layer_tree_host_common.h" #include #include "base/debug/trace_event.h" #include "cc/base/math_util.h" #include "cc/layers/heads_up_display_layer_impl.h" #include "cc/layers/layer.h" #include "cc/layers/layer_impl.h" #include "cc/layers/layer_iterator.h" #include "cc/layers/render_surface.h" #include "cc/layers/render_surface_impl.h" #include "cc/trees/draw_property_utils.h" #include "cc/trees/layer_sorter.h" #include "cc/trees/layer_tree_host.h" #include "cc/trees/layer_tree_impl.h" #include "ui/gfx/geometry/rect_conversions.h" #include "ui/gfx/geometry/vector2d_conversions.h" #include "ui/gfx/transform.h" namespace cc { ScrollAndScaleSet::ScrollAndScaleSet() : page_scale_delta(1.f), top_controls_delta(0.f) { } ScrollAndScaleSet::~ScrollAndScaleSet() {} static void SortLayers(LayerList::iterator forst, LayerList::iterator end, void* layer_sorter) { NOTREACHED(); } static void SortLayers(LayerImplList::iterator first, LayerImplList::iterator end, LayerSorter* layer_sorter) { DCHECK(layer_sorter); TRACE_EVENT0("cc", "LayerTreeHostCommon::SortLayers"); layer_sorter->Sort(first, end); } template static gfx::Vector2dF GetEffectiveScrollDelta(LayerType* layer) { gfx::Vector2dF scroll_delta = layer->ScrollDelta(); // The scroll parent's scroll delta is the amount we've scrolled on the // compositor thread since the commit for this layer tree's source frame. // we last reported to the main thread. I.e., it's the discrepancy between // a scroll parent's scroll delta and offset, so we must add it here. if (layer->scroll_parent()) scroll_delta += layer->scroll_parent()->ScrollDelta(); return scroll_delta; } template static gfx::ScrollOffset GetEffectiveTotalScrollOffset(LayerType* layer) { gfx::ScrollOffset offset = layer->TotalScrollOffset(); // The scroll parent's total scroll offset (scroll offset + scroll delta) // can't be used because its scroll offset has already been applied to the // scroll children's positions by the main thread layer positioning code. if (layer->scroll_parent()) offset += gfx::ScrollOffset(layer->scroll_parent()->ScrollDelta()); return offset; } inline gfx::Rect CalculateVisibleRectWithCachedLayerRect( const gfx::Rect& target_surface_rect, const gfx::Rect& layer_bound_rect, const gfx::Rect& layer_rect_in_target_space, const gfx::Transform& transform) { if (layer_rect_in_target_space.IsEmpty()) return gfx::Rect(); // Is this layer fully contained within the target surface? if (target_surface_rect.Contains(layer_rect_in_target_space)) return layer_bound_rect; // If the layer doesn't fill up the entire surface, then find the part of // the surface rect where the layer could be visible. This avoids trying to // project surface rect points that are behind the projection point. gfx::Rect minimal_surface_rect = target_surface_rect; minimal_surface_rect.Intersect(layer_rect_in_target_space); if (minimal_surface_rect.IsEmpty()) return gfx::Rect(); // Project the corners of the target surface rect into the layer space. // This bounding rectangle may be larger than it needs to be (being // axis-aligned), but is a reasonable filter on the space to consider. // Non-invertible transforms will create an empty rect here. gfx::Transform surface_to_layer(gfx::Transform::kSkipInitialization); if (!transform.GetInverse(&surface_to_layer)) { // Because we cannot use the surface bounds to determine what portion of // the layer is visible, we must conservatively assume the full layer is // visible. return layer_bound_rect; } gfx::Rect layer_rect = MathUtil::ProjectEnclosingClippedRect( surface_to_layer, minimal_surface_rect); layer_rect.Intersect(layer_bound_rect); return layer_rect; } gfx::Rect LayerTreeHostCommon::CalculateVisibleRect( const gfx::Rect& target_surface_rect, const gfx::Rect& layer_bound_rect, const gfx::Transform& transform) { gfx::Rect layer_in_surface_space = MathUtil::MapEnclosingClippedRect(transform, layer_bound_rect); return CalculateVisibleRectWithCachedLayerRect( target_surface_rect, layer_bound_rect, layer_in_surface_space, transform); } template static LayerType* NextTargetSurface(LayerType* layer) { return layer->parent() ? layer->parent()->render_target() : 0; } // Given two layers, this function finds their respective render targets and, // computes a change of basis translation. It does this by accumulating the // translation components of the draw transforms of each target between the // ancestor and descendant. These transforms must be 2D translations, and this // requirement is enforced at every step. template static gfx::Vector2dF ComputeChangeOfBasisTranslation( const LayerType& ancestor_layer, const LayerType& descendant_layer) { DCHECK(descendant_layer.HasAncestor(&ancestor_layer)); const LayerType* descendant_target = descendant_layer.render_target(); DCHECK(descendant_target); const LayerType* ancestor_target = ancestor_layer.render_target(); DCHECK(ancestor_target); gfx::Vector2dF translation; for (const LayerType* target = descendant_target; target != ancestor_target; target = NextTargetSurface(target)) { const gfx::Transform& trans = target->render_surface()->draw_transform(); // Ensure that this translation is truly 2d. DCHECK(trans.IsIdentityOrTranslation()); DCHECK_EQ(0.f, trans.matrix().get(2, 3)); translation += trans.To2dTranslation(); } return translation; } enum TranslateRectDirection { TranslateRectDirectionToAncestor, TranslateRectDirectionToDescendant }; template static gfx::Rect TranslateRectToTargetSpace(const LayerType& ancestor_layer, const LayerType& descendant_layer, const gfx::Rect& rect, TranslateRectDirection direction) { gfx::Vector2dF translation = ComputeChangeOfBasisTranslation( ancestor_layer, descendant_layer); if (direction == TranslateRectDirectionToDescendant) translation.Scale(-1.f); return gfx::ToEnclosingRect( gfx::RectF(rect.origin() + translation, rect.size())); } // Attempts to update the clip rects for the given layer. If the layer has a // clip_parent, it may not inherit its immediate ancestor's clip. template static void UpdateClipRectsForClipChild( const LayerType* layer, gfx::Rect* clip_rect_in_parent_target_space, bool* subtree_should_be_clipped) { // If the layer has no clip_parent, or the ancestor is the same as its actual // parent, then we don't need special clip rects. Bail now and leave the out // parameters untouched. const LayerType* clip_parent = layer->scroll_parent(); if (!clip_parent) clip_parent = layer->clip_parent(); if (!clip_parent || clip_parent == layer->parent()) return; // The root layer is never a clip child. DCHECK(layer->parent()); // Grab the cached values. *clip_rect_in_parent_target_space = clip_parent->clip_rect(); *subtree_should_be_clipped = clip_parent->is_clipped(); // We may have to project the clip rect into our parent's target space. Note, // it must be our parent's target space, not ours. For one, we haven't // computed our transforms, so we couldn't put it in our space yet even if we // wanted to. But more importantly, this matches the expectations of // CalculateDrawPropertiesInternal. If we, say, create a render surface, these // clip rects will want to be in its target space, not ours. if (clip_parent == layer->clip_parent()) { *clip_rect_in_parent_target_space = TranslateRectToTargetSpace( *clip_parent, *layer->parent(), *clip_rect_in_parent_target_space, TranslateRectDirectionToDescendant); } else { // If we're being clipped by our scroll parent, we must translate through // our common ancestor. This happens to be our parent, so it is sufficent to // translate from our clip parent's space to the space of its ancestor (our // parent). *clip_rect_in_parent_target_space = TranslateRectToTargetSpace(*layer->parent(), *clip_parent, *clip_rect_in_parent_target_space, TranslateRectDirectionToAncestor); } } // We collect an accumulated drawable content rect per render surface. // Typically, a layer will contribute to only one surface, the surface // associated with its render target. Clip children, however, may affect // several surfaces since there may be several surfaces between the clip child // and its parent. // // NB: we accumulate the layer's *clipped* drawable content rect. template struct AccumulatedSurfaceState { explicit AccumulatedSurfaceState(LayerType* render_target) : render_target(render_target) {} // The accumulated drawable content rect for the surface associated with the // given |render_target|. gfx::Rect drawable_content_rect; // The target owning the surface. (We hang onto the target rather than the // surface so that we can DCHECK that the surface's draw transform is simply // a translation when |render_target| reports that it has no unclipped // descendants). LayerType* render_target; }; template void UpdateAccumulatedSurfaceState( LayerType* layer, const gfx::Rect& drawable_content_rect, std::vector>* accumulated_surface_state) { if (IsRootLayer(layer)) return; // We will apply our drawable content rect to the accumulated rects for all // surfaces between us and |render_target| (inclusive). This is either our // clip parent's target if we are a clip child, or else simply our parent's // target. We use our parent's target because we're either the owner of a // render surface and we'll want to add our rect to our *surface's* target, or // we're not and our target is the same as our parent's. In both cases, the // parent's target gives us what we want. LayerType* render_target = layer->clip_parent() ? layer->clip_parent()->render_target() : layer->parent()->render_target(); // If the layer owns a surface, then the content rect is in the wrong space. // Instead, we will use the surface's DrawableContentRect which is in target // space as required. gfx::Rect target_rect = drawable_content_rect; if (layer->render_surface()) { target_rect = gfx::ToEnclosedRect(layer->render_surface()->DrawableContentRect()); } if (render_target->is_clipped()) { gfx::Rect clip_rect = render_target->clip_rect(); // If the layer has a clip parent, the clip rect may be in the wrong space, // so we'll need to transform it before it is applied. if (layer->clip_parent()) { clip_rect = TranslateRectToTargetSpace( *layer->clip_parent(), *layer, clip_rect, TranslateRectDirectionToDescendant); } target_rect.Intersect(clip_rect); } // We must have at least one entry in the vector for the root. DCHECK_LT(0ul, accumulated_surface_state->size()); typedef typename std::vector> AccumulatedSurfaceStateVector; typedef typename AccumulatedSurfaceStateVector::reverse_iterator AccumulatedSurfaceStateIterator; AccumulatedSurfaceStateIterator current_state = accumulated_surface_state->rbegin(); // Add this rect to the accumulated content rect for all surfaces until we // reach the target surface. bool found_render_target = false; for (; current_state != accumulated_surface_state->rend(); ++current_state) { current_state->drawable_content_rect.Union(target_rect); // If we've reached |render_target| our work is done and we can bail. if (current_state->render_target == render_target) { found_render_target = true; break; } // Transform rect from the current target's space to the next. LayerType* current_target = current_state->render_target; DCHECK(current_target->render_surface()); const gfx::Transform& current_draw_transform = current_target->render_surface()->draw_transform(); // If we have unclipped descendants, the draw transform is a translation. DCHECK(current_target->num_unclipped_descendants() == 0 || current_draw_transform.IsIdentityOrTranslation()); target_rect = gfx::ToEnclosingRect( MathUtil::MapClippedRect(current_draw_transform, target_rect)); } // It is an error to not reach |render_target|. If this happens, it means that // either the clip parent is not an ancestor of the clip child or the surface // state vector is empty, both of which should be impossible. DCHECK(found_render_target); } template static inline bool IsRootLayer(LayerType* layer) { return !layer->parent(); } template static inline bool LayerIsInExisting3DRenderingContext(LayerType* layer) { return layer->Is3dSorted() && layer->parent() && layer->parent()->Is3dSorted(); } template static bool IsRootLayerOfNewRenderingContext(LayerType* layer) { if (layer->parent()) return !layer->parent()->Is3dSorted() && layer->Is3dSorted(); return layer->Is3dSorted(); } template static bool IsLayerBackFaceVisible(LayerType* layer) { // The current W3C spec on CSS transforms says that backface visibility should // be determined differently depending on whether the layer is in a "3d // rendering context" or not. For Chromium code, we can determine whether we // are in a 3d rendering context by checking if the parent preserves 3d. if (LayerIsInExisting3DRenderingContext(layer)) return layer->draw_transform().IsBackFaceVisible(); // In this case, either the layer establishes a new 3d rendering context, or // is not in a 3d rendering context at all. return layer->transform().IsBackFaceVisible(); } template static bool IsSurfaceBackFaceVisible(LayerType* layer, const gfx::Transform& draw_transform) { if (LayerIsInExisting3DRenderingContext(layer)) return draw_transform.IsBackFaceVisible(); if (IsRootLayerOfNewRenderingContext(layer)) return layer->transform().IsBackFaceVisible(); // If the render_surface is not part of a new or existing rendering context, // then the layers that contribute to this surface will decide back-face // visibility for themselves. return false; } template static inline bool LayerClipsSubtree(LayerType* layer) { return layer->masks_to_bounds() || layer->mask_layer(); } template static gfx::Rect CalculateVisibleContentRect( LayerType* layer, const gfx::Rect& clip_rect_of_target_surface_in_target_space, const gfx::Rect& layer_rect_in_target_space) { DCHECK(layer->render_target()); // Nothing is visible if the layer bounds are empty. if (!layer->DrawsContent() || layer->content_bounds().IsEmpty() || layer->drawable_content_rect().IsEmpty()) return gfx::Rect(); // Compute visible bounds in target surface space. gfx::Rect visible_rect_in_target_surface_space = layer->drawable_content_rect(); if (layer->render_target()->render_surface()->is_clipped()) { // The |layer| L has a target T which owns a surface Ts. The surface Ts // has a target TsT. // // In this case the target surface Ts does clip the layer L that contributes // to it. So, we have to convert the clip rect of Ts from the target space // of Ts (that is the space of TsT), to the current render target's space // (that is the space of T). This conversion is done outside this function // so that it can be cached instead of computing it redundantly for every // layer. visible_rect_in_target_surface_space.Intersect( clip_rect_of_target_surface_in_target_space); } if (visible_rect_in_target_surface_space.IsEmpty()) return gfx::Rect(); return CalculateVisibleRectWithCachedLayerRect( visible_rect_in_target_surface_space, gfx::Rect(layer->content_bounds()), layer_rect_in_target_space, layer->draw_transform()); } static inline bool TransformToParentIsKnown(LayerImpl* layer) { return true; } static inline bool TransformToParentIsKnown(Layer* layer) { return !layer->TransformIsAnimating(); } static inline bool TransformToScreenIsKnown(LayerImpl* layer) { return true; } static inline bool TransformToScreenIsKnown(Layer* layer) { return !layer->screen_space_transform_is_animating(); } template static bool LayerShouldBeSkipped(LayerType* layer, bool layer_is_drawn) { // Layers can be skipped if any of these conditions are met. // - is not drawn due to it or one of its ancestors being hidden (or having // no copy requests). // - does not draw content. // - is transparent. // - has empty bounds // - the layer is not double-sided, but its back face is visible. // // Some additional conditions need to be computed at a later point after the // recursion is finished. // - the intersection of render_surface content and layer clip_rect is empty // - the visible_content_rect is empty // // Note, if the layer should not have been drawn due to being fully // transparent, we would have skipped the entire subtree and never made it // into this function, so it is safe to omit this check here. if (!layer_is_drawn) return true; if (!layer->DrawsContent() || layer->bounds().IsEmpty()) return true; LayerType* backface_test_layer = layer; if (layer->use_parent_backface_visibility()) { DCHECK(layer->parent()); DCHECK(!layer->parent()->use_parent_backface_visibility()); backface_test_layer = layer->parent(); } // The layer should not be drawn if (1) it is not double-sided and (2) the // back of the layer is known to be facing the screen. if (!backface_test_layer->double_sided() && TransformToScreenIsKnown(backface_test_layer) && IsLayerBackFaceVisible(backface_test_layer)) return true; return false; } template static bool HasInvertibleOrAnimatedTransform(LayerType* layer) { return layer->transform_is_invertible() || layer->TransformIsAnimating(); } static inline bool SubtreeShouldBeSkipped(LayerImpl* layer, bool layer_is_drawn) { // If the layer transform is not invertible, it should not be drawn. // TODO(ajuma): Correctly process subtrees with singular transform for the // case where we may animate to a non-singular transform and wish to // pre-raster. if (!HasInvertibleOrAnimatedTransform(layer)) return true; // When we need to do a readback/copy of a layer's output, we can not skip // it or any of its ancestors. if (layer->draw_properties().layer_or_descendant_has_copy_request) return false; // We cannot skip the the subtree if a descendant has a wheel or touch handler // or the hit testing code will break (it requires fresh transforms, etc). if (layer->draw_properties().layer_or_descendant_has_input_handler) return false; // If the layer is not drawn, then skip it and its subtree. if (!layer_is_drawn) return true; // If layer is on the pending tree and opacity is being animated then // this subtree can't be skipped as we need to create, prioritize and // include tiles for this layer when deciding if tree can be activated. if (layer->layer_tree_impl()->IsPendingTree() && layer->OpacityIsAnimating()) return false; // The opacity of a layer always applies to its children (either implicitly // via a render surface or explicitly if the parent preserves 3D), so the // entire subtree can be skipped if this layer is fully transparent. return !layer->opacity(); } static inline bool SubtreeShouldBeSkipped(Layer* layer, bool layer_is_drawn) { // If the layer transform is not invertible, it should not be drawn. if (!layer->transform_is_invertible() && !layer->TransformIsAnimating()) return true; // When we need to do a readback/copy of a layer's output, we can not skip // it or any of its ancestors. if (layer->draw_properties().layer_or_descendant_has_copy_request) return false; // We cannot skip the the subtree if a descendant has a wheel or touch handler // or the hit testing code will break (it requires fresh transforms, etc). if (layer->draw_properties().layer_or_descendant_has_input_handler) return false; // If the layer is not drawn, then skip it and its subtree. if (!layer_is_drawn) return true; // If the opacity is being animated then the opacity on the main thread is // unreliable (since the impl thread may be using a different opacity), so it // should not be trusted. // In particular, it should not cause the subtree to be skipped. // Similarly, for layers that might animate opacity using an impl-only // animation, their subtree should also not be skipped. return !layer->opacity() && !layer->OpacityIsAnimating() && !layer->OpacityCanAnimateOnImplThread(); } static inline void SavePaintPropertiesLayer(LayerImpl* layer) {} static inline void SavePaintPropertiesLayer(Layer* layer) { layer->SavePaintProperties(); if (layer->mask_layer()) layer->mask_layer()->SavePaintProperties(); if (layer->replica_layer() && layer->replica_layer()->mask_layer()) layer->replica_layer()->mask_layer()->SavePaintProperties(); } static bool SubtreeShouldRenderToSeparateSurface( Layer* layer, bool axis_aligned_with_respect_to_parent) { // // A layer and its descendants should render onto a new RenderSurfaceImpl if // any of these rules hold: // // The root layer owns a render surface, but it never acts as a contributing // surface to another render target. Compositor features that are applied via // a contributing surface can not be applied to the root layer. In order to // use these effects, another child of the root would need to be introduced // in order to act as a contributing surface to the root layer's surface. bool is_root = IsRootLayer(layer); // If the layer uses a mask. if (layer->mask_layer()) { DCHECK(!is_root); return true; } // If the layer has a reflection. if (layer->replica_layer()) { DCHECK(!is_root); return true; } // If the layer uses a CSS filter. if (!layer->filters().IsEmpty() || !layer->background_filters().IsEmpty()) { DCHECK(!is_root); return true; } int num_descendants_that_draw_content = layer->NumDescendantsThatDrawContent(); // If the layer flattens its subtree, but it is treated as a 3D object by its // parent (i.e. parent participates in a 3D rendering context). if (LayerIsInExisting3DRenderingContext(layer) && layer->should_flatten_transform() && num_descendants_that_draw_content > 0) { TRACE_EVENT_INSTANT0( "cc", "LayerTreeHostCommon::SubtreeShouldRenderToSeparateSurface flattening", TRACE_EVENT_SCOPE_THREAD); DCHECK(!is_root); return true; } // If the layer has blending. // TODO(rosca): this is temporary, until blending is implemented for other // types of quads than RenderPassDrawQuad. Layers having descendants that draw // content will still create a separate rendering surface. if (!layer->uses_default_blend_mode()) { TRACE_EVENT_INSTANT0( "cc", "LayerTreeHostCommon::SubtreeShouldRenderToSeparateSurface blending", TRACE_EVENT_SCOPE_THREAD); DCHECK(!is_root); return true; } // If the layer clips its descendants but it is not axis-aligned with respect // to its parent. bool layer_clips_external_content = LayerClipsSubtree(layer) || layer->HasDelegatedContent(); if (layer_clips_external_content && !axis_aligned_with_respect_to_parent && num_descendants_that_draw_content > 0) { TRACE_EVENT_INSTANT0( "cc", "LayerTreeHostCommon::SubtreeShouldRenderToSeparateSurface clipping", TRACE_EVENT_SCOPE_THREAD); DCHECK(!is_root); return true; } // If the layer has some translucency and does not have a preserves-3d // transform style. This condition only needs a render surface if two or more // layers in the subtree overlap. But checking layer overlaps is unnecessarily // costly so instead we conservatively create a surface whenever at least two // layers draw content for this subtree. bool at_least_two_layers_in_subtree_draw_content = num_descendants_that_draw_content > 0 && (layer->DrawsContent() || num_descendants_that_draw_content > 1); if (layer->opacity() != 1.f && layer->should_flatten_transform() && at_least_two_layers_in_subtree_draw_content) { TRACE_EVENT_INSTANT0( "cc", "LayerTreeHostCommon::SubtreeShouldRenderToSeparateSurface opacity", TRACE_EVENT_SCOPE_THREAD); DCHECK(!is_root); return true; } // The root layer should always have a render_surface. if (is_root) return true; // // These are allowed on the root surface, as they don't require the surface to // be used as a contributing surface in order to apply correctly. // // If the layer has isolation. // TODO(rosca): to be optimized - create separate rendering surface only when // the blending descendants might have access to the content behind this layer // (layer has transparent background or descendants overflow). // https://code.google.com/p/chromium/issues/detail?id=301738 if (layer->is_root_for_isolated_group()) { TRACE_EVENT_INSTANT0( "cc", "LayerTreeHostCommon::SubtreeShouldRenderToSeparateSurface isolation", TRACE_EVENT_SCOPE_THREAD); return true; } // If we force it. if (layer->force_render_surface()) return true; // If we'll make a copy of the layer's contents. if (layer->HasCopyRequest()) return true; return false; } // This function returns a translation matrix that can be applied on a vector // that's in the layer's target surface coordinate, while the position offset is // specified in some ancestor layer's coordinate. gfx::Transform ComputeSizeDeltaCompensation( LayerImpl* layer, LayerImpl* container, const gfx::Vector2dF& position_offset) { gfx::Transform result_transform; // To apply a translate in the container's layer space, // the following steps need to be done: // Step 1a. transform from target surface space to the container's target // surface space // Step 1b. transform from container's target surface space to the // container's layer space // Step 2. apply the compensation // Step 3. transform back to target surface space gfx::Transform target_surface_space_to_container_layer_space; // Calculate step 1a LayerImpl* container_target_surface = container->render_target(); for (LayerImpl* current_target_surface = NextTargetSurface(layer); current_target_surface && current_target_surface != container_target_surface; current_target_surface = NextTargetSurface(current_target_surface)) { // Note: Concat is used here to convert the result coordinate space from // current render surface to the next render surface. target_surface_space_to_container_layer_space.ConcatTransform( current_target_surface->render_surface()->draw_transform()); } // Calculate step 1b gfx::Transform container_layer_space_to_container_target_surface_space = container->draw_transform(); container_layer_space_to_container_target_surface_space.Scale( container->contents_scale_x(), container->contents_scale_y()); gfx::Transform container_target_surface_space_to_container_layer_space; if (container_layer_space_to_container_target_surface_space.GetInverse( &container_target_surface_space_to_container_layer_space)) { // Note: Again, Concat is used to conver the result coordinate space from // the container render surface to the container layer. target_surface_space_to_container_layer_space.ConcatTransform( container_target_surface_space_to_container_layer_space); } // Apply step 3 gfx::Transform container_layer_space_to_target_surface_space; if (target_surface_space_to_container_layer_space.GetInverse( &container_layer_space_to_target_surface_space)) { result_transform.PreconcatTransform( container_layer_space_to_target_surface_space); } else { // TODO(shawnsingh): A non-invertible matrix could still make meaningful // projection. For example ScaleZ(0) is non-invertible but the layer is // still visible. return gfx::Transform(); } // Apply step 2 result_transform.Translate(position_offset.x(), position_offset.y()); // Apply step 1 result_transform.PreconcatTransform( target_surface_space_to_container_layer_space); return result_transform; } void ApplyPositionAdjustment( Layer* layer, Layer* container, const gfx::Transform& scroll_compensation, gfx::Transform* combined_transform) {} void ApplyPositionAdjustment( LayerImpl* layer, LayerImpl* container, const gfx::Transform& scroll_compensation, gfx::Transform* combined_transform) { if (!layer->position_constraint().is_fixed_position()) return; // Special case: this layer is a composited fixed-position layer; we need to // explicitly compensate for all ancestors' nonzero scroll_deltas to keep // this layer fixed correctly. // Note carefully: this is Concat, not Preconcat // (current_scroll_compensation * combined_transform). combined_transform->ConcatTransform(scroll_compensation); // For right-edge or bottom-edge anchored fixed position layers, // the layer should relocate itself if the container changes its size. bool fixed_to_right_edge = layer->position_constraint().is_fixed_to_right_edge(); bool fixed_to_bottom_edge = layer->position_constraint().is_fixed_to_bottom_edge(); gfx::Vector2dF position_offset = container->FixedContainerSizeDelta(); position_offset.set_x(fixed_to_right_edge ? position_offset.x() : 0); position_offset.set_y(fixed_to_bottom_edge ? position_offset.y() : 0); if (position_offset.IsZero()) return; // Note: Again, this is Concat. The compensation matrix will be applied on // the vector in target surface space. combined_transform->ConcatTransform( ComputeSizeDeltaCompensation(layer, container, position_offset)); } gfx::Transform ComputeScrollCompensationForThisLayer( LayerImpl* scrolling_layer, const gfx::Transform& parent_matrix, const gfx::Vector2dF& scroll_delta) { // For every layer that has non-zero scroll_delta, we have to compute a // transform that can undo the scroll_delta translation. In particular, we // want this matrix to premultiply a fixed-position layer's parent_matrix, so // we design this transform in three steps as follows. The steps described // here apply from right-to-left, so Step 1 would be the right-most matrix: // // Step 1. transform from target surface space to the exact space where // scroll_delta is actually applied. // -- this is inverse of parent_matrix // Step 2. undo the scroll_delta // -- this is just a translation by scroll_delta. // Step 3. transform back to target surface space. // -- this transform is the parent_matrix // // These steps create a matrix that both start and end in target surface // space. So this matrix can pre-multiply any fixed-position layer's // draw_transform to undo the scroll_deltas -- as long as that fixed position // layer is fixed onto the same render_target as this scrolling_layer. // gfx::Transform scroll_compensation_for_this_layer = parent_matrix; // Step 3 scroll_compensation_for_this_layer.Translate( scroll_delta.x(), scroll_delta.y()); // Step 2 gfx::Transform inverse_parent_matrix(gfx::Transform::kSkipInitialization); if (!parent_matrix.GetInverse(&inverse_parent_matrix)) { // TODO(shawnsingh): Either we need to handle uninvertible transforms // here, or DCHECK that the transform is invertible. } scroll_compensation_for_this_layer.PreconcatTransform( inverse_parent_matrix); // Step 1 return scroll_compensation_for_this_layer; } gfx::Transform ComputeScrollCompensationMatrixForChildren( Layer* current_layer, const gfx::Transform& current_parent_matrix, const gfx::Transform& current_scroll_compensation, const gfx::Vector2dF& scroll_delta) { // The main thread (i.e. Layer) does not need to worry about scroll // compensation. So we can just return an identity matrix here. return gfx::Transform(); } gfx::Transform ComputeScrollCompensationMatrixForChildren( LayerImpl* layer, const gfx::Transform& parent_matrix, const gfx::Transform& current_scroll_compensation_matrix, const gfx::Vector2dF& scroll_delta) { // "Total scroll compensation" is the transform needed to cancel out all // scroll_delta translations that occurred since the nearest container layer, // even if there are render_surfaces in-between. // // There are some edge cases to be aware of, that are not explicit in the // code: // - A layer that is both a fixed-position and container should not be its // own container, instead, that means it is fixed to an ancestor, and is a // container for any fixed-position descendants. // - A layer that is a fixed-position container and has a render_surface // should behave the same as a container without a render_surface, the // render_surface is irrelevant in that case. // - A layer that does not have an explicit container is simply fixed to the // viewport. (i.e. the root render_surface.) // - If the fixed-position layer has its own render_surface, then the // render_surface is the one who gets fixed. // // This function needs to be called AFTER layers create their own // render_surfaces. // // Scroll compensation restarts from identity under two possible conditions: // - the current layer is a container for fixed-position descendants // - the current layer is fixed-position itself, so any fixed-position // descendants are positioned with respect to this layer. Thus, any // fixed position descendants only need to compensate for scrollDeltas // that occur below this layer. bool current_layer_resets_scroll_compensation_for_descendants = layer->IsContainerForFixedPositionLayers() || layer->position_constraint().is_fixed_position(); // Avoid the overheads (including stack allocation and matrix // initialization/copy) if we know that the scroll compensation doesn't need // to be reset or adjusted. if (!current_layer_resets_scroll_compensation_for_descendants && scroll_delta.IsZero() && !layer->render_surface()) return current_scroll_compensation_matrix; // Start as identity matrix. gfx::Transform next_scroll_compensation_matrix; // If this layer does not reset scroll compensation, then it inherits the // existing scroll compensations. if (!current_layer_resets_scroll_compensation_for_descendants) next_scroll_compensation_matrix = current_scroll_compensation_matrix; // If the current layer has a non-zero scroll_delta, then we should compute // its local scroll compensation and accumulate it to the // next_scroll_compensation_matrix. if (!scroll_delta.IsZero()) { gfx::Transform scroll_compensation_for_this_layer = ComputeScrollCompensationForThisLayer( layer, parent_matrix, scroll_delta); next_scroll_compensation_matrix.PreconcatTransform( scroll_compensation_for_this_layer); } // If the layer created its own render_surface, we have to adjust // next_scroll_compensation_matrix. The adjustment allows us to continue // using the scroll compensation on the next surface. // Step 1 (right-most in the math): transform from the new surface to the // original ancestor surface // Step 2: apply the scroll compensation // Step 3: transform back to the new surface. if (layer->render_surface() && !next_scroll_compensation_matrix.IsIdentity()) { gfx::Transform inverse_surface_draw_transform( gfx::Transform::kSkipInitialization); if (!layer->render_surface()->draw_transform().GetInverse( &inverse_surface_draw_transform)) { // TODO(shawnsingh): Either we need to handle uninvertible transforms // here, or DCHECK that the transform is invertible. } next_scroll_compensation_matrix = inverse_surface_draw_transform * next_scroll_compensation_matrix * layer->render_surface()->draw_transform(); } return next_scroll_compensation_matrix; } template static inline void UpdateLayerScaleDrawProperties( LayerType* layer, float ideal_contents_scale, float maximum_animation_contents_scale, float page_scale_factor, float device_scale_factor) { layer->draw_properties().ideal_contents_scale = ideal_contents_scale; layer->draw_properties().maximum_animation_contents_scale = maximum_animation_contents_scale; layer->draw_properties().page_scale_factor = page_scale_factor; layer->draw_properties().device_scale_factor = device_scale_factor; } static inline void CalculateContentsScale(LayerImpl* layer, float contents_scale) { // LayerImpl has all of its content scales and bounds pushed from the Main // thread during commit and just uses those values as-is. } static inline void CalculateContentsScale(Layer* layer, float contents_scale) { layer->CalculateContentsScale(contents_scale, &layer->draw_properties().contents_scale_x, &layer->draw_properties().contents_scale_y, &layer->draw_properties().content_bounds); Layer* mask_layer = layer->mask_layer(); if (mask_layer) { mask_layer->CalculateContentsScale( contents_scale, &mask_layer->draw_properties().contents_scale_x, &mask_layer->draw_properties().contents_scale_y, &mask_layer->draw_properties().content_bounds); } Layer* replica_mask_layer = layer->replica_layer() ? layer->replica_layer()->mask_layer() : NULL; if (replica_mask_layer) { replica_mask_layer->CalculateContentsScale( contents_scale, &replica_mask_layer->draw_properties().contents_scale_x, &replica_mask_layer->draw_properties().contents_scale_y, &replica_mask_layer->draw_properties().content_bounds); } } static inline void UpdateLayerContentsScale( LayerImpl* layer, bool can_adjust_raster_scale, float ideal_contents_scale, float device_scale_factor, float page_scale_factor, bool animating_transform_to_screen) { CalculateContentsScale(layer, ideal_contents_scale); } static inline void UpdateLayerContentsScale( Layer* layer, bool can_adjust_raster_scale, float ideal_contents_scale, float device_scale_factor, float page_scale_factor, bool animating_transform_to_screen) { if (can_adjust_raster_scale) { float ideal_raster_scale = ideal_contents_scale / (device_scale_factor * page_scale_factor); bool need_to_set_raster_scale = layer->raster_scale_is_unknown(); // If we've previously saved a raster_scale but the ideal changes, things // are unpredictable and we should just use 1. if (!need_to_set_raster_scale && layer->raster_scale() != 1.f && ideal_raster_scale != layer->raster_scale()) { ideal_raster_scale = 1.f; need_to_set_raster_scale = true; } if (need_to_set_raster_scale) { bool use_and_save_ideal_scale = ideal_raster_scale >= 1.f && !animating_transform_to_screen; if (use_and_save_ideal_scale) layer->set_raster_scale(ideal_raster_scale); } } float raster_scale = 1.f; if (!layer->raster_scale_is_unknown()) raster_scale = layer->raster_scale(); gfx::Size old_content_bounds = layer->content_bounds(); float old_contents_scale_x = layer->contents_scale_x(); float old_contents_scale_y = layer->contents_scale_y(); float contents_scale = raster_scale * device_scale_factor * page_scale_factor; CalculateContentsScale(layer, contents_scale); if (layer->content_bounds() != old_content_bounds || layer->contents_scale_x() != old_contents_scale_x || layer->contents_scale_y() != old_contents_scale_y) layer->SetNeedsPushProperties(); } static inline void CalculateAnimationContentsScale( Layer* layer, bool ancestor_is_animating_scale, float ancestor_maximum_animation_contents_scale, const gfx::Transform& parent_transform, const gfx::Transform& combined_transform, bool* combined_is_animating_scale, float* combined_maximum_animation_contents_scale) { *combined_is_animating_scale = false; *combined_maximum_animation_contents_scale = 0.f; } static inline void CalculateAnimationContentsScale( LayerImpl* layer, bool ancestor_is_animating_scale, float ancestor_maximum_animation_contents_scale, const gfx::Transform& ancestor_transform, const gfx::Transform& combined_transform, bool* combined_is_animating_scale, float* combined_maximum_animation_contents_scale) { if (ancestor_is_animating_scale && ancestor_maximum_animation_contents_scale == 0.f) { // We've already failed to compute a maximum animated scale at an // ancestor, so we'll continue to fail. *combined_maximum_animation_contents_scale = 0.f; *combined_is_animating_scale = true; return; } if (!combined_transform.IsScaleOrTranslation()) { // Computing maximum animated scale in the presence of // non-scale/translation transforms isn't supported. *combined_maximum_animation_contents_scale = 0.f; *combined_is_animating_scale = true; return; } // We currently only support computing maximum scale for combinations of // scales and translations. We treat all non-translations as potentially // affecting scale. Animations that include non-translation/scale components // will cause the computation of MaximumScale below to fail. bool layer_is_animating_scale = !layer->layer_animation_controller()->HasOnlyTranslationTransforms(); if (!layer_is_animating_scale && !ancestor_is_animating_scale) { *combined_maximum_animation_contents_scale = 0.f; *combined_is_animating_scale = false; return; } // We don't attempt to accumulate animation scale from multiple nodes, // because of the risk of significant overestimation. For example, one node // may be increasing scale from 1 to 10 at the same time as a descendant is // decreasing scale from 10 to 1. Naively combining these scales would produce // a scale of 100. if (layer_is_animating_scale && ancestor_is_animating_scale) { *combined_maximum_animation_contents_scale = 0.f; *combined_is_animating_scale = true; return; } // At this point, we know either the layer or an ancestor, but not both, // is animating scale. *combined_is_animating_scale = true; if (!layer_is_animating_scale) { gfx::Vector2dF layer_transform_scales = MathUtil::ComputeTransform2dScaleComponents(layer->transform(), 0.f); *combined_maximum_animation_contents_scale = ancestor_maximum_animation_contents_scale * std::max(layer_transform_scales.x(), layer_transform_scales.y()); return; } float layer_maximum_animated_scale = 0.f; if (!layer->layer_animation_controller()->MaximumTargetScale( &layer_maximum_animated_scale)) { *combined_maximum_animation_contents_scale = 0.f; return; } gfx::Vector2dF ancestor_transform_scales = MathUtil::ComputeTransform2dScaleComponents(ancestor_transform, 0.f); *combined_maximum_animation_contents_scale = layer_maximum_animated_scale * std::max(ancestor_transform_scales.x(), ancestor_transform_scales.y()); } template static inline void MarkLayerWithRenderSurfaceLayerListId( LayerTypePtr layer, int current_render_surface_layer_list_id) { layer->draw_properties().last_drawn_render_surface_layer_list_id = current_render_surface_layer_list_id; } template static inline void MarkMasksWithRenderSurfaceLayerListId( LayerTypePtr layer, int current_render_surface_layer_list_id) { if (layer->mask_layer()) { MarkLayerWithRenderSurfaceLayerListId(layer->mask_layer(), current_render_surface_layer_list_id); } if (layer->replica_layer() && layer->replica_layer()->mask_layer()) { MarkLayerWithRenderSurfaceLayerListId(layer->replica_layer()->mask_layer(), current_render_surface_layer_list_id); } } template static inline void MarkLayerListWithRenderSurfaceLayerListId( LayerListType* layer_list, int current_render_surface_layer_list_id) { for (typename LayerListType::iterator it = layer_list->begin(); it != layer_list->end(); ++it) { MarkLayerWithRenderSurfaceLayerListId(*it, current_render_surface_layer_list_id); MarkMasksWithRenderSurfaceLayerListId(*it, current_render_surface_layer_list_id); } } template static inline void RemoveSurfaceForEarlyExit( LayerType* layer_to_remove, typename LayerType::RenderSurfaceListType* render_surface_layer_list) { DCHECK(layer_to_remove->render_surface()); // Technically, we know that the layer we want to remove should be // at the back of the render_surface_layer_list. However, we have had // bugs before that added unnecessary layers here // (https://bugs.webkit.org/show_bug.cgi?id=74147), but that causes // things to crash. So here we proactively remove any additional // layers from the end of the list. while (render_surface_layer_list->back() != layer_to_remove) { MarkLayerListWithRenderSurfaceLayerListId( &render_surface_layer_list->back()->render_surface()->layer_list(), 0); MarkLayerWithRenderSurfaceLayerListId(render_surface_layer_list->back(), 0); render_surface_layer_list->back()->ClearRenderSurfaceLayerList(); render_surface_layer_list->pop_back(); } DCHECK_EQ(render_surface_layer_list->back(), layer_to_remove); MarkLayerListWithRenderSurfaceLayerListId( &layer_to_remove->render_surface()->layer_list(), 0); MarkLayerWithRenderSurfaceLayerListId(layer_to_remove, 0); render_surface_layer_list->pop_back(); layer_to_remove->ClearRenderSurfaceLayerList(); } struct PreCalculateMetaInformationRecursiveData { bool layer_or_descendant_has_copy_request; bool layer_or_descendant_has_input_handler; int num_unclipped_descendants; PreCalculateMetaInformationRecursiveData() : layer_or_descendant_has_copy_request(false), layer_or_descendant_has_input_handler(false), num_unclipped_descendants(0) {} void Merge(const PreCalculateMetaInformationRecursiveData& data) { layer_or_descendant_has_copy_request |= data.layer_or_descendant_has_copy_request; layer_or_descendant_has_input_handler |= data.layer_or_descendant_has_input_handler; num_unclipped_descendants += data.num_unclipped_descendants; } }; static bool ValidateRenderSurface(LayerImpl* layer) { // There are a few cases in which it is incorrect to not have a // render_surface. if (layer->render_surface()) return true; return layer->filters().IsEmpty() && layer->background_filters().IsEmpty() && !layer->mask_layer() && !layer->replica_layer() && !IsRootLayer(layer) && !layer->is_root_for_isolated_group() && !layer->HasCopyRequest(); } static bool ValidateRenderSurface(Layer* layer) { return true; } // Recursively walks the layer tree to compute any information that is needed // before doing the main recursion. template static void PreCalculateMetaInformation( LayerType* layer, PreCalculateMetaInformationRecursiveData* recursive_data) { DCHECK(ValidateRenderSurface(layer)); layer->draw_properties().sorted_for_recursion = false; layer->draw_properties().has_child_with_a_scroll_parent = false; if (!HasInvertibleOrAnimatedTransform(layer)) { // Layers with singular transforms should not be drawn, the whole subtree // can be skipped. return; } if (layer->clip_parent()) recursive_data->num_unclipped_descendants++; for (size_t i = 0; i < layer->children().size(); ++i) { LayerType* child_layer = LayerTreeHostCommon::get_layer_as_raw_ptr(layer->children(), i); PreCalculateMetaInformationRecursiveData data_for_child; PreCalculateMetaInformation(child_layer, &data_for_child); if (child_layer->scroll_parent()) layer->draw_properties().has_child_with_a_scroll_parent = true; recursive_data->Merge(data_for_child); } if (layer->clip_children()) { int num_clip_children = layer->clip_children()->size(); DCHECK_GE(recursive_data->num_unclipped_descendants, num_clip_children); recursive_data->num_unclipped_descendants -= num_clip_children; } if (layer->HasCopyRequest()) recursive_data->layer_or_descendant_has_copy_request = true; if (!layer->touch_event_handler_region().IsEmpty() || layer->have_wheel_event_handlers()) recursive_data->layer_or_descendant_has_input_handler = true; layer->draw_properties().num_unclipped_descendants = recursive_data->num_unclipped_descendants; layer->draw_properties().layer_or_descendant_has_copy_request = recursive_data->layer_or_descendant_has_copy_request; layer->draw_properties().layer_or_descendant_has_input_handler = recursive_data->layer_or_descendant_has_input_handler; } static void RoundTranslationComponents(gfx::Transform* transform) { transform->matrix().set(0, 3, MathUtil::Round(transform->matrix().get(0, 3))); transform->matrix().set(1, 3, MathUtil::Round(transform->matrix().get(1, 3))); } template struct SubtreeGlobals { LayerSorter* layer_sorter; int max_texture_size; float device_scale_factor; float page_scale_factor; const LayerType* page_scale_application_layer; gfx::Vector2dF elastic_overscroll; const LayerType* elastic_overscroll_application_layer; bool can_adjust_raster_scales; bool can_render_to_separate_surface; bool layers_always_allowed_lcd_text; }; template struct DataForRecursion { // The accumulated sequence of transforms a layer will use to determine its // own draw transform. gfx::Transform parent_matrix; // The accumulated sequence of transforms a layer will use to determine its // own screen-space transform. gfx::Transform full_hierarchy_matrix; // The transform that removes all scrolling that may have occurred between a // fixed-position layer and its container, so that the layer actually does // remain fixed. gfx::Transform scroll_compensation_matrix; // The ancestor that would be the container for any fixed-position / sticky // layers. LayerType* fixed_container; // This is the normal clip rect that is propagated from parent to child. gfx::Rect clip_rect_in_target_space; // When the layer's children want to compute their visible content rect, they // want to know what their target surface's clip rect will be. BUT - they // want to know this clip rect represented in their own target space. This // requires inverse-projecting the surface's clip rect from the surface's // render target space down to the surface's own space. Instead of computing // this value redundantly for each child layer, it is computed only once // while dealing with the parent layer, and then this precomputed value is // passed down the recursion to the children that actually use it. gfx::Rect clip_rect_of_target_surface_in_target_space; // The maximum amount by which this layer will be scaled during the lifetime // of currently running animations. float maximum_animation_contents_scale; bool ancestor_is_animating_scale; bool ancestor_clips_subtree; typename LayerType::RenderSurfaceType* nearest_occlusion_immune_ancestor_surface; bool in_subtree_of_page_scale_application_layer; bool subtree_can_use_lcd_text; bool subtree_is_visible_from_ancestor; }; template static LayerType* GetChildContainingLayer(const LayerType& parent, LayerType* layer) { for (LayerType* ancestor = layer; ancestor; ancestor = ancestor->parent()) { if (ancestor->parent() == &parent) return ancestor; } NOTREACHED(); return 0; } template static void AddScrollParentChain(std::vector* out, const LayerType& parent, LayerType* layer) { // At a high level, this function walks up the chain of scroll parents // recursively, and once we reach the end of the chain, we add the child // of |parent| containing each scroll ancestor as we unwind. The result is // an ordering of parent's children that ensures that scroll parents are // visited before their descendants. // Take for example this layer tree: // // + stacking_context // + scroll_child (1) // + scroll_parent_graphics_layer (*) // | + scroll_parent_scrolling_layer // | + scroll_parent_scrolling_content_layer (2) // + scroll_grandparent_graphics_layer (**) // + scroll_grandparent_scrolling_layer // + scroll_grandparent_scrolling_content_layer (3) // // The scroll child is (1), its scroll parent is (2) and its scroll // grandparent is (3). Note, this doesn't mean that (2)'s scroll parent is // (3), it means that (*)'s scroll parent is (3). We don't want our list to // look like [ (3), (2), (1) ], even though that does have the ancestor chain // in the right order. Instead, we want [ (**), (*), (1) ]. That is, only want // (1)'s siblings in the list, but we want them to appear in such an order // that the scroll ancestors get visited in the correct order. // // So our first task at this step of the recursion is to determine the layer // that we will potentionally add to the list. That is, the child of parent // containing |layer|. LayerType* child = GetChildContainingLayer(parent, layer); if (child->draw_properties().sorted_for_recursion) return; if (LayerType* scroll_parent = child->scroll_parent()) AddScrollParentChain(out, parent, scroll_parent); out->push_back(child); child->draw_properties().sorted_for_recursion = true; } template static bool SortChildrenForRecursion(std::vector* out, const LayerType& parent) { out->reserve(parent.children().size()); bool order_changed = false; for (size_t i = 0; i < parent.children().size(); ++i) { LayerType* current = LayerTreeHostCommon::get_layer_as_raw_ptr(parent.children(), i); if (current->draw_properties().sorted_for_recursion) { order_changed = true; continue; } AddScrollParentChain(out, parent, current); } DCHECK_EQ(parent.children().size(), out->size()); return order_changed; } template static void GetNewDescendantsStartIndexAndCount(LayerType* layer, size_t* start_index, size_t* count) { *start_index = layer->draw_properties().index_of_first_descendants_addition; *count = layer->draw_properties().num_descendants_added; } template static void GetNewRenderSurfacesStartIndexAndCount(LayerType* layer, size_t* start_index, size_t* count) { *start_index = layer->draw_properties() .index_of_first_render_surface_layer_list_addition; *count = layer->draw_properties().num_render_surfaces_added; } // We need to extract a list from the the two flavors of RenderSurfaceListType // for use in the sorting function below. static LayerList* GetLayerListForSorting(RenderSurfaceLayerList* rsll) { return &rsll->AsLayerList(); } static LayerImplList* GetLayerListForSorting(LayerImplList* layer_list) { return layer_list; } static inline gfx::Vector2d BoundsDelta(Layer* layer) { return gfx::Vector2d(); } static inline gfx::Vector2d BoundsDelta(LayerImpl* layer) { return gfx::ToCeiledVector2d(layer->bounds_delta()); } template static void SortLayerListContributions( const LayerType& parent, typename LayerType::LayerListType* unsorted, size_t start_index_for_all_contributions, GetIndexAndCountType get_index_and_count) { typename LayerType::LayerListType buffer; for (size_t i = 0; i < parent.children().size(); ++i) { LayerType* child = LayerTreeHostCommon::get_layer_as_raw_ptr(parent.children(), i); size_t start_index = 0; size_t count = 0; get_index_and_count(child, &start_index, &count); for (size_t j = start_index; j < start_index + count; ++j) buffer.push_back(unsorted->at(j)); } DCHECK_EQ(buffer.size(), unsorted->size() - start_index_for_all_contributions); for (size_t i = 0; i < buffer.size(); ++i) (*unsorted)[i + start_index_for_all_contributions] = buffer[i]; } // Recursively walks the layer tree starting at the given node and computes all // the necessary transformations, clip rects, render surfaces, etc. template static void CalculateDrawPropertiesInternal( LayerType* layer, const SubtreeGlobals& globals, const DataForRecursion& data_from_ancestor, typename LayerType::RenderSurfaceListType* render_surface_layer_list, typename LayerType::LayerListType* layer_list, std::vector>* accumulated_surface_state, int current_render_surface_layer_list_id) { // This function computes the new matrix transformations recursively for this // layer and all its descendants. It also computes the appropriate render // surfaces. // Some important points to remember: // // 0. Here, transforms are notated in Matrix x Vector order, and in words we // describe what the transform does from left to right. // // 1. In our terminology, the "layer origin" refers to the top-left corner of // a layer, and the positive Y-axis points downwards. This interpretation is // valid because the orthographic projection applied at draw time flips the Y // axis appropriately. // // 2. The anchor point, when given as a PointF object, is specified in "unit // layer space", where the bounds of the layer map to [0, 1]. However, as a // Transform object, the transform to the anchor point is specified in "layer // space", where the bounds of the layer map to [bounds.width(), // bounds.height()]. // // 3. Definition of various transforms used: // M[parent] is the parent matrix, with respect to the nearest render // surface, passed down recursively. // // M[root] is the full hierarchy, with respect to the root, passed down // recursively. // // Tr[origin] is the translation matrix from the parent's origin to // this layer's origin. // // Tr[origin2anchor] is the translation from the layer's origin to its // anchor point // // Tr[origin2center] is the translation from the layer's origin to its // center // // M[layer] is the layer's matrix (applied at the anchor point) // // S[layer2content] is the ratio of a layer's content_bounds() to its // Bounds(). // // Some composite transforms can help in understanding the sequence of // transforms: // composite_layer_transform = Tr[origin2anchor] * M[layer] * // Tr[origin2anchor].inverse() // // 4. When a layer (or render surface) is drawn, it is drawn into a "target // render surface". Therefore the draw transform does not necessarily // transform from screen space to local layer space. Instead, the draw // transform is the transform between the "target render surface space" and // local layer space. Note that render surfaces, except for the root, also // draw themselves into a different target render surface, and so their draw // transform and origin transforms are also described with respect to the // target. // // Using these definitions, then: // // The draw transform for the layer is: // M[draw] = M[parent] * Tr[origin] * composite_layer_transform * // S[layer2content] = M[parent] * Tr[layer->position() + anchor] * // M[layer] * Tr[anchor2origin] * S[layer2content] // // Interpreting the math left-to-right, this transforms from the // layer's render surface to the origin of the layer in content space. // // The screen space transform is: // M[screenspace] = M[root] * Tr[origin] * composite_layer_transform * // S[layer2content] // = M[root] * Tr[layer->position() + anchor] * M[layer] // * Tr[anchor2origin] * S[layer2content] // // Interpreting the math left-to-right, this transforms from the root // render surface's content space to the origin of the layer in content // space. // // The transform hierarchy that is passed on to children (i.e. the child's // parent_matrix) is: // M[parent]_for_child = M[parent] * Tr[origin] * // composite_layer_transform // = M[parent] * Tr[layer->position() + anchor] * // M[layer] * Tr[anchor2origin] // // and a similar matrix for the full hierarchy with respect to the // root. // // Finally, note that the final matrix used by the shader for the layer is P * // M[draw] * S . This final product is computed in drawTexturedQuad(), where: // P is the projection matrix // S is the scale adjustment (to scale up a canonical quad to the // layer's size) // // When a render surface has a replica layer, that layer's transform is used // to draw a second copy of the surface. gfx::Transforms named here are // relative to the surface, unless they specify they are relative to the // replica layer. // // We will denote a scale by device scale S[deviceScale] // // The render surface draw transform to its target surface origin is: // M[surfaceDraw] = M[owningLayer->Draw] // // The render surface origin transform to its the root (screen space) origin // is: // M[surface2root] = M[owningLayer->screenspace] * // S[deviceScale].inverse() // // The replica draw transform to its target surface origin is: // M[replicaDraw] = S[deviceScale] * M[surfaceDraw] * // Tr[replica->position() + replica->anchor()] * Tr[replica] * // Tr[origin2anchor].inverse() * S[contents_scale].inverse() // // The replica draw transform to the root (screen space) origin is: // M[replica2root] = M[surface2root] * Tr[replica->position()] * // Tr[replica] * Tr[origin2anchor].inverse() // // It makes no sense to have a non-unit page_scale_factor without specifying // which layer roots the subtree the scale is applied to. DCHECK(globals.page_scale_application_layer || (globals.page_scale_factor == 1.f)); DataForRecursion data_for_children; typename LayerType::RenderSurfaceType* nearest_occlusion_immune_ancestor_surface = data_from_ancestor.nearest_occlusion_immune_ancestor_surface; data_for_children.in_subtree_of_page_scale_application_layer = data_from_ancestor.in_subtree_of_page_scale_application_layer; data_for_children.subtree_can_use_lcd_text = data_from_ancestor.subtree_can_use_lcd_text; // Layers that are marked as hidden will hide themselves and their subtree. // Exception: Layers with copy requests, whether hidden or not, must be drawn // anyway. In this case, we will inform their subtree they are visible to get // the right results. const bool layer_is_visible = data_from_ancestor.subtree_is_visible_from_ancestor && !layer->hide_layer_and_subtree(); const bool layer_is_drawn = layer_is_visible || layer->HasCopyRequest(); // The root layer cannot skip CalcDrawProperties. if (!IsRootLayer(layer) && SubtreeShouldBeSkipped(layer, layer_is_drawn)) { if (layer->render_surface()) layer->ClearRenderSurfaceLayerList(); layer->draw_properties().render_target = nullptr; return; } // We need to circumvent the normal recursive flow of information for clip // children (they don't inherit their direct ancestor's clip information). // This is unfortunate, and would be unnecessary if we were to formally // separate the clipping hierarchy from the layer hierarchy. bool ancestor_clips_subtree = data_from_ancestor.ancestor_clips_subtree; gfx::Rect ancestor_clip_rect_in_target_space = data_from_ancestor.clip_rect_in_target_space; // Update our clipping state. If we have a clip parent we will need to pull // from the clip state cache rather than using the clip state passed from our // immediate ancestor. UpdateClipRectsForClipChild( layer, &ancestor_clip_rect_in_target_space, &ancestor_clips_subtree); // As this function proceeds, these are the properties for the current // layer that actually get computed. To avoid unnecessary copies // (particularly for matrices), we do computations directly on these values // when possible. DrawProperties& layer_draw_properties = layer->draw_properties(); gfx::Rect clip_rect_in_target_space; bool layer_or_ancestor_clips_descendants = false; // This value is cached on the stack so that we don't have to inverse-project // the surface's clip rect redundantly for every layer. This value is the // same as the target surface's clip rect, except that instead of being // described in the target surface's target's space, it is described in the // current render target's space. gfx::Rect clip_rect_of_target_surface_in_target_space; float accumulated_draw_opacity = layer->opacity(); bool animating_opacity_to_target = layer->OpacityIsAnimating(); bool animating_opacity_to_screen = animating_opacity_to_target; if (layer->parent()) { accumulated_draw_opacity *= layer->parent()->draw_opacity(); animating_opacity_to_target |= layer->parent()->draw_opacity_is_animating(); animating_opacity_to_screen |= layer->parent()->screen_space_opacity_is_animating(); } bool animating_transform_to_target = layer->TransformIsAnimating(); bool animating_transform_to_screen = animating_transform_to_target; if (layer->parent()) { animating_transform_to_target |= layer->parent()->draw_transform_is_animating(); animating_transform_to_screen |= layer->parent()->screen_space_transform_is_animating(); } gfx::Point3F transform_origin = layer->transform_origin(); gfx::ScrollOffset scroll_offset = GetEffectiveTotalScrollOffset(layer); gfx::PointF position = layer->position() - ScrollOffsetToVector2dF(scroll_offset); gfx::Transform combined_transform = data_from_ancestor.parent_matrix; if (!layer->transform().IsIdentity()) { // LT = Tr[origin] * Tr[origin2transformOrigin] combined_transform.Translate3d(position.x() + transform_origin.x(), position.y() + transform_origin.y(), transform_origin.z()); // LT = Tr[origin] * Tr[origin2origin] * M[layer] combined_transform.PreconcatTransform(layer->transform()); // LT = Tr[origin] * Tr[origin2origin] * M[layer] * // Tr[transformOrigin2origin] combined_transform.Translate3d( -transform_origin.x(), -transform_origin.y(), -transform_origin.z()); } else { combined_transform.Translate(position.x(), position.y()); } gfx::Vector2dF effective_scroll_delta = GetEffectiveScrollDelta(layer); if (!animating_transform_to_target && layer->scrollable() && combined_transform.IsScaleOrTranslation()) { // Align the scrollable layer's position to screen space pixels to avoid // blurriness. To avoid side-effects, do this only if the transform is // simple. gfx::Vector2dF previous_translation = combined_transform.To2dTranslation(); RoundTranslationComponents(&combined_transform); gfx::Vector2dF current_translation = combined_transform.To2dTranslation(); // This rounding changes the scroll delta, and so must be included // in the scroll compensation matrix. The scaling converts from physical // coordinates to the scroll delta's CSS coordinates (using the parent // matrix instead of combined transform since scrolling is applied before // the layer's transform). For example, if we have a total scale factor of // 3.0, then 1 physical pixel is only 1/3 of a CSS pixel. gfx::Vector2dF parent_scales = MathUtil::ComputeTransform2dScaleComponents( data_from_ancestor.parent_matrix, 1.f); effective_scroll_delta -= gfx::ScaleVector2d(current_translation - previous_translation, 1.f / parent_scales.x(), 1.f / parent_scales.y()); } // Apply adjustment from position constraints. ApplyPositionAdjustment(layer, data_from_ancestor.fixed_container, data_from_ancestor.scroll_compensation_matrix, &combined_transform); bool combined_is_animating_scale = false; float combined_maximum_animation_contents_scale = 0.f; if (globals.can_adjust_raster_scales) { CalculateAnimationContentsScale( layer, data_from_ancestor.ancestor_is_animating_scale, data_from_ancestor.maximum_animation_contents_scale, data_from_ancestor.parent_matrix, combined_transform, &combined_is_animating_scale, &combined_maximum_animation_contents_scale); } data_for_children.ancestor_is_animating_scale = combined_is_animating_scale; data_for_children.maximum_animation_contents_scale = combined_maximum_animation_contents_scale; // Compute the 2d scale components of the transform hierarchy up to the target // surface. From there, we can decide on a contents scale for the layer. float layer_scale_factors = globals.device_scale_factor; if (data_from_ancestor.in_subtree_of_page_scale_application_layer) layer_scale_factors *= globals.page_scale_factor; gfx::Vector2dF combined_transform_scales = MathUtil::ComputeTransform2dScaleComponents( combined_transform, layer_scale_factors); float ideal_contents_scale = globals.can_adjust_raster_scales ? std::max(combined_transform_scales.x(), combined_transform_scales.y()) : layer_scale_factors; UpdateLayerContentsScale( layer, globals.can_adjust_raster_scales, ideal_contents_scale, globals.device_scale_factor, data_from_ancestor.in_subtree_of_page_scale_application_layer ? globals.page_scale_factor : 1.f, animating_transform_to_screen); UpdateLayerScaleDrawProperties( layer, ideal_contents_scale, combined_maximum_animation_contents_scale, data_from_ancestor.in_subtree_of_page_scale_application_layer ? globals.page_scale_factor : 1.f, globals.device_scale_factor); LayerType* mask_layer = layer->mask_layer(); if (mask_layer) { UpdateLayerScaleDrawProperties( mask_layer, ideal_contents_scale, combined_maximum_animation_contents_scale, data_from_ancestor.in_subtree_of_page_scale_application_layer ? globals.page_scale_factor : 1.f, globals.device_scale_factor); } LayerType* replica_mask_layer = layer->replica_layer() ? layer->replica_layer()->mask_layer() : NULL; if (replica_mask_layer) { UpdateLayerScaleDrawProperties( replica_mask_layer, ideal_contents_scale, combined_maximum_animation_contents_scale, data_from_ancestor.in_subtree_of_page_scale_application_layer ? globals.page_scale_factor : 1.f, globals.device_scale_factor); } // The draw_transform that gets computed below is effectively the layer's // draw_transform, unless the layer itself creates a render_surface. In that // case, the render_surface re-parents the transforms. layer_draw_properties.target_space_transform = combined_transform; // M[draw] = M[parent] * LT * S[layer2content] layer_draw_properties.target_space_transform.Scale( SK_MScalar1 / layer->contents_scale_x(), SK_MScalar1 / layer->contents_scale_y()); // The layer's screen_space_transform represents the transform between root // layer's "screen space" and local content space. layer_draw_properties.screen_space_transform = data_from_ancestor.full_hierarchy_matrix; if (layer->should_flatten_transform()) layer_draw_properties.screen_space_transform.FlattenTo2d(); layer_draw_properties.screen_space_transform.PreconcatTransform (layer_draw_properties.target_space_transform); // Adjusting text AA method during animation may cause repaints, which in-turn // causes jank. bool adjust_text_aa = !animating_opacity_to_screen && !animating_transform_to_screen; bool layer_can_use_lcd_text = true; bool subtree_can_use_lcd_text = true; if (!globals.layers_always_allowed_lcd_text) { // To avoid color fringing, LCD text should only be used on opaque layers // with just integral translation. subtree_can_use_lcd_text = data_from_ancestor.subtree_can_use_lcd_text && accumulated_draw_opacity == 1.f && layer_draw_properties.target_space_transform .IsIdentityOrIntegerTranslation(); // Also disable LCD text locally for non-opaque content. layer_can_use_lcd_text = subtree_can_use_lcd_text && layer->contents_opaque(); } // full_hierarchy_matrix is the matrix that transforms objects between screen // space (except projection matrix) and the most recent RenderSurfaceImpl's // space. next_hierarchy_matrix will only change if this layer uses a new // RenderSurfaceImpl, otherwise remains the same. data_for_children.full_hierarchy_matrix = data_from_ancestor.full_hierarchy_matrix; // If the subtree will scale layer contents by the transform hierarchy, then // we should scale things into the render surface by the transform hierarchy // to take advantage of that. gfx::Vector2dF render_surface_sublayer_scale = globals.can_adjust_raster_scales ? combined_transform_scales : gfx::Vector2dF(layer_scale_factors, layer_scale_factors); bool render_to_separate_surface = IsRootLayer(layer) || (globals.can_render_to_separate_surface && layer->render_surface()); if (render_to_separate_surface) { DCHECK(layer->render_surface()); // Check back-face visibility before continuing with this surface and its // subtree if (!layer->double_sided() && TransformToParentIsKnown(layer) && IsSurfaceBackFaceVisible(layer, combined_transform)) { layer->ClearRenderSurfaceLayerList(); layer->draw_properties().render_target = nullptr; return; } typename LayerType::RenderSurfaceType* render_surface = layer->render_surface(); layer->ClearRenderSurfaceLayerList(); layer_draw_properties.render_target = layer; if (IsRootLayer(layer)) { // The root layer's render surface size is predetermined and so the root // layer can't directly support non-identity transforms. It should just // forward top-level transforms to the rest of the tree. data_for_children.parent_matrix = combined_transform; // The root surface does not contribute to any other surface, it has no // target. layer->render_surface()->set_contributes_to_drawn_surface(false); } else { // The owning layer's draw transform has a scale from content to layer // space which we do not want; so here we use the combined_transform // instead of the draw_transform. However, we do need to add a different // scale factor that accounts for the surface's pixel dimensions. combined_transform.Scale(1.0 / render_surface_sublayer_scale.x(), 1.0 / render_surface_sublayer_scale.y()); render_surface->SetDrawTransform(combined_transform); // The owning layer's transform was re-parented by the surface, so the // layer's new draw_transform only needs to scale the layer to surface // space. layer_draw_properties.target_space_transform.MakeIdentity(); layer_draw_properties.target_space_transform. Scale(render_surface_sublayer_scale.x() / layer->contents_scale_x(), render_surface_sublayer_scale.y() / layer->contents_scale_y()); // Inside the surface's subtree, we scale everything to the owning layer's // scale. The sublayer matrix transforms layer rects into target surface // content space. Conceptually, all layers in the subtree inherit the // scale at the point of the render surface in the transform hierarchy, // but we apply it explicitly to the owning layer and the remainder of the // subtree independently. DCHECK(data_for_children.parent_matrix.IsIdentity()); data_for_children.parent_matrix.Scale(render_surface_sublayer_scale.x(), render_surface_sublayer_scale.y()); // Even if the |layer_is_drawn|, it only contributes to a drawn surface // when the |layer_is_visible|. layer->render_surface()->set_contributes_to_drawn_surface( layer_is_visible); } // The opacity value is moved from the layer to its surface, so that the // entire subtree properly inherits opacity. render_surface->SetDrawOpacity(accumulated_draw_opacity); render_surface->SetDrawOpacityIsAnimating(animating_opacity_to_target); animating_opacity_to_target = false; layer_draw_properties.opacity = 1.f; layer_draw_properties.blend_mode = SkXfermode::kSrcOver_Mode; layer_draw_properties.opacity_is_animating = animating_opacity_to_target; layer_draw_properties.screen_space_opacity_is_animating = animating_opacity_to_screen; render_surface->SetTargetSurfaceTransformsAreAnimating( animating_transform_to_target); render_surface->SetScreenSpaceTransformsAreAnimating( animating_transform_to_screen); animating_transform_to_target = false; layer_draw_properties.target_space_transform_is_animating = animating_transform_to_target; layer_draw_properties.screen_space_transform_is_animating = animating_transform_to_screen; // Update the aggregate hierarchy matrix to include the transform of the // newly created RenderSurfaceImpl. data_for_children.full_hierarchy_matrix.PreconcatTransform( render_surface->draw_transform()); if (layer->mask_layer()) { DrawProperties& mask_layer_draw_properties = layer->mask_layer()->draw_properties(); mask_layer_draw_properties.render_target = layer; mask_layer_draw_properties.visible_content_rect = gfx::Rect(layer->content_bounds()); } if (layer->replica_layer() && layer->replica_layer()->mask_layer()) { DrawProperties& replica_mask_draw_properties = layer->replica_layer()->mask_layer()->draw_properties(); replica_mask_draw_properties.render_target = layer; replica_mask_draw_properties.visible_content_rect = gfx::Rect(layer->content_bounds()); } // Ignore occlusion from outside the surface when surface contents need to // be fully drawn. Layers with copy-request need to be complete. // We could be smarter about layers with replica and exclude regions // where both layer and the replica are occluded, but this seems like an // overkill. The same is true for layers with filters that move pixels. // TODO(senorblanco): make this smarter for the SkImageFilter case (check // for pixel-moving filters) if (layer->HasCopyRequest() || layer->has_replica() || layer->filters().HasReferenceFilter() || layer->filters().HasFilterThatMovesPixels()) { nearest_occlusion_immune_ancestor_surface = render_surface; } render_surface->SetNearestOcclusionImmuneAncestor( nearest_occlusion_immune_ancestor_surface); layer_or_ancestor_clips_descendants = false; bool subtree_is_clipped_by_surface_bounds = false; if (ancestor_clips_subtree) { // It may be the layer or the surface doing the clipping of the subtree, // but in either case, we'll be clipping to the projected clip rect of our // ancestor. gfx::Transform inverse_surface_draw_transform( gfx::Transform::kSkipInitialization); if (!render_surface->draw_transform().GetInverse( &inverse_surface_draw_transform)) { // TODO(shawnsingh): Either we need to handle uninvertible transforms // here, or DCHECK that the transform is invertible. } gfx::Rect surface_clip_rect_in_target_space = gfx::IntersectRects( data_from_ancestor.clip_rect_of_target_surface_in_target_space, ancestor_clip_rect_in_target_space); gfx::Rect projected_surface_rect = MathUtil::ProjectEnclosingClippedRect( inverse_surface_draw_transform, surface_clip_rect_in_target_space); if (layer_draw_properties.num_unclipped_descendants > 0) { // If we have unclipped descendants, we cannot count on the render // surface's bounds clipping our subtree: the unclipped descendants // could cause us to expand our bounds. In this case, we must rely on // layer clipping for correctess. NB: since we can only encounter // translations between a clip child and its clip parent, clipping is // guaranteed to be exact in this case. layer_or_ancestor_clips_descendants = true; clip_rect_in_target_space = projected_surface_rect; } else { // The new render_surface here will correctly clip the entire subtree. // So, we do not need to continue propagating the clipping state further // down the tree. This way, we can avoid transforming clip rects from // ancestor target surface space to current target surface space that // could cause more w < 0 headaches. The render surface clip rect is // expressed in the space where this surface draws, i.e. the same space // as clip_rect_from_ancestor_in_ancestor_target_space. render_surface->SetClipRect(ancestor_clip_rect_in_target_space); clip_rect_of_target_surface_in_target_space = projected_surface_rect; subtree_is_clipped_by_surface_bounds = true; } } DCHECK(layer->render_surface()); DCHECK(!layer->parent() || layer->parent()->render_target() == accumulated_surface_state->back().render_target); accumulated_surface_state->push_back( AccumulatedSurfaceState(layer)); render_surface->SetIsClipped(subtree_is_clipped_by_surface_bounds); if (!subtree_is_clipped_by_surface_bounds) { render_surface->SetClipRect(gfx::Rect()); clip_rect_of_target_surface_in_target_space = data_from_ancestor.clip_rect_of_target_surface_in_target_space; } // If the new render surface is drawn translucent or with a non-integral // translation then the subtree that gets drawn on this render surface // cannot use LCD text. data_for_children.subtree_can_use_lcd_text = subtree_can_use_lcd_text; render_surface_layer_list->push_back(layer); } else { DCHECK(layer->parent()); // Note: layer_draw_properties.target_space_transform is computed above, // before this if-else statement. layer_draw_properties.target_space_transform_is_animating = animating_transform_to_target; layer_draw_properties.screen_space_transform_is_animating = animating_transform_to_screen; layer_draw_properties.opacity = accumulated_draw_opacity; layer_draw_properties.blend_mode = layer->blend_mode(); layer_draw_properties.opacity_is_animating = animating_opacity_to_target; layer_draw_properties.screen_space_opacity_is_animating = animating_opacity_to_screen; data_for_children.parent_matrix = combined_transform; // Layers without render_surfaces directly inherit the ancestor's clip // status. layer_or_ancestor_clips_descendants = ancestor_clips_subtree; if (ancestor_clips_subtree) { clip_rect_in_target_space = ancestor_clip_rect_in_target_space; } // The surface's cached clip rect value propagates regardless of what // clipping goes on between layers here. clip_rect_of_target_surface_in_target_space = data_from_ancestor.clip_rect_of_target_surface_in_target_space; // Layers that are not their own render_target will render into the target // of their nearest ancestor. layer_draw_properties.render_target = layer->parent()->render_target(); } if (adjust_text_aa) layer_draw_properties.can_use_lcd_text = layer_can_use_lcd_text; gfx::Size content_size_affected_by_delta(layer->content_bounds()); // Non-zero BoundsDelta imply the contents_scale of 1.0 // because BoundsDela is only set on Android where // ContentScalingLayer is never used. DCHECK_IMPLIES(!BoundsDelta(layer).IsZero(), (layer->contents_scale_x() == 1.0 && layer->contents_scale_y() == 1.0)); // Thus we can omit contents scale in the following calculation. gfx::Vector2d bounds_delta = BoundsDelta(layer); content_size_affected_by_delta.Enlarge(bounds_delta.x(), bounds_delta.y()); gfx::Rect rect_in_target_space = MathUtil::MapEnclosingClippedRect( layer->draw_transform(), gfx::Rect(content_size_affected_by_delta)); if (LayerClipsSubtree(layer)) { layer_or_ancestor_clips_descendants = true; if (ancestor_clips_subtree && !render_to_separate_surface) { // A layer without render surface shares the same target as its ancestor. clip_rect_in_target_space = ancestor_clip_rect_in_target_space; clip_rect_in_target_space.Intersect(rect_in_target_space); } else { clip_rect_in_target_space = rect_in_target_space; } } // Tell the layer the rect that it's clipped by. In theory we could use a // tighter clip rect here (drawable_content_rect), but that actually does not // reduce how much would be drawn, and instead it would create unnecessary // changes to scissor state affecting GPU performance. Our clip information // is used in the recursion below, so we must set it beforehand. layer_draw_properties.is_clipped = layer_or_ancestor_clips_descendants; if (layer_or_ancestor_clips_descendants) { layer_draw_properties.clip_rect = clip_rect_in_target_space; } else { // Initialize the clip rect to a safe value that will not clip the // layer, just in case clipping is still accidentally used. layer_draw_properties.clip_rect = rect_in_target_space; } typename LayerType::LayerListType& descendants = (render_to_separate_surface ? layer->render_surface()->layer_list() : *layer_list); // Any layers that are appended after this point are in the layer's subtree // and should be included in the sorting process. size_t sorting_start_index = descendants.size(); if (!LayerShouldBeSkipped(layer, layer_is_drawn)) { MarkLayerWithRenderSurfaceLayerListId(layer, current_render_surface_layer_list_id); descendants.push_back(layer); } // Any layers that are appended after this point may need to be sorted if we // visit the children out of order. size_t render_surface_layer_list_child_sorting_start_index = render_surface_layer_list->size(); size_t layer_list_child_sorting_start_index = descendants.size(); if (!layer->children().empty()) { if (layer == globals.page_scale_application_layer) { data_for_children.parent_matrix.Scale( globals.page_scale_factor, globals.page_scale_factor); data_for_children.in_subtree_of_page_scale_application_layer = true; } if (layer == globals.elastic_overscroll_application_layer) { data_for_children.parent_matrix.Translate( -globals.elastic_overscroll.x(), -globals.elastic_overscroll.y()); } // Flatten to 2D if the layer doesn't preserve 3D. if (layer->should_flatten_transform()) data_for_children.parent_matrix.FlattenTo2d(); data_for_children.scroll_compensation_matrix = ComputeScrollCompensationMatrixForChildren( layer, data_from_ancestor.parent_matrix, data_from_ancestor.scroll_compensation_matrix, effective_scroll_delta); data_for_children.fixed_container = layer->IsContainerForFixedPositionLayers() ? layer : data_from_ancestor.fixed_container; data_for_children.clip_rect_in_target_space = clip_rect_in_target_space; data_for_children.clip_rect_of_target_surface_in_target_space = clip_rect_of_target_surface_in_target_space; data_for_children.ancestor_clips_subtree = layer_or_ancestor_clips_descendants; data_for_children.nearest_occlusion_immune_ancestor_surface = nearest_occlusion_immune_ancestor_surface; data_for_children.subtree_is_visible_from_ancestor = layer_is_drawn; } std::vector sorted_children; bool child_order_changed = false; if (layer_draw_properties.has_child_with_a_scroll_parent) child_order_changed = SortChildrenForRecursion(&sorted_children, *layer); for (size_t i = 0; i < layer->children().size(); ++i) { // If one of layer's children has a scroll parent, then we may have to // visit the children out of order. The new order is stored in // sorted_children. Otherwise, we'll grab the child directly from the // layer's list of children. LayerType* child = layer_draw_properties.has_child_with_a_scroll_parent ? sorted_children[i] : LayerTreeHostCommon::get_layer_as_raw_ptr(layer->children(), i); child->draw_properties().index_of_first_descendants_addition = descendants.size(); child->draw_properties().index_of_first_render_surface_layer_list_addition = render_surface_layer_list->size(); CalculateDrawPropertiesInternal( child, globals, data_for_children, render_surface_layer_list, &descendants, accumulated_surface_state, current_render_surface_layer_list_id); // If the child is its own render target, then it has a render surface. if (child->render_target() == child && !child->render_surface()->layer_list().empty() && !child->render_surface()->content_rect().IsEmpty()) { // This child will contribute its render surface, which means // we need to mark just the mask layer (and replica mask layer) // with the id. MarkMasksWithRenderSurfaceLayerListId( child, current_render_surface_layer_list_id); descendants.push_back(child); } child->draw_properties().num_descendants_added = descendants.size() - child->draw_properties().index_of_first_descendants_addition; child->draw_properties().num_render_surfaces_added = render_surface_layer_list->size() - child->draw_properties() .index_of_first_render_surface_layer_list_addition; } // Add the unsorted layer list contributions, if necessary. if (child_order_changed) { SortLayerListContributions( *layer, GetLayerListForSorting(render_surface_layer_list), render_surface_layer_list_child_sorting_start_index, &GetNewRenderSurfacesStartIndexAndCount); SortLayerListContributions( *layer, &descendants, layer_list_child_sorting_start_index, &GetNewDescendantsStartIndexAndCount); } // Compute the total drawable_content_rect for this subtree (the rect is in // target surface space). gfx::Rect local_drawable_content_rect_of_subtree = accumulated_surface_state->back().drawable_content_rect; if (render_to_separate_surface) { DCHECK(accumulated_surface_state->back().render_target == layer); accumulated_surface_state->pop_back(); } if (render_to_separate_surface && !IsRootLayer(layer) && layer->render_surface()->layer_list().empty()) { RemoveSurfaceForEarlyExit(layer, render_surface_layer_list); return; } // Compute the layer's drawable content rect (the rect is in target surface // space). layer_draw_properties.drawable_content_rect = rect_in_target_space; if (layer_or_ancestor_clips_descendants) { layer_draw_properties.drawable_content_rect.Intersect( clip_rect_in_target_space); } if (layer->DrawsContent()) { local_drawable_content_rect_of_subtree.Union( layer_draw_properties.drawable_content_rect); } // Compute the layer's visible content rect (the rect is in content space). layer_draw_properties.visible_content_rect = CalculateVisibleContentRect( layer, clip_rect_of_target_surface_in_target_space, rect_in_target_space); // Compute the remaining properties for the render surface, if the layer has // one. if (IsRootLayer(layer)) { // The root layer's surface's content_rect is always the entire viewport. DCHECK(render_to_separate_surface); layer->render_surface()->SetContentRect( ancestor_clip_rect_in_target_space); } else if (render_to_separate_surface) { typename LayerType::RenderSurfaceType* render_surface = layer->render_surface(); gfx::Rect clipped_content_rect = local_drawable_content_rect_of_subtree; // Don't clip if the layer is reflected as the reflection shouldn't be // clipped. If the layer is animating, then the surface's transform to // its target is not known on the main thread, and we should not use it // to clip. if (!layer->replica_layer() && TransformToParentIsKnown(layer)) { // Note, it is correct to use data_from_ancestor.ancestor_clips_subtree // here, because we are looking at this layer's render_surface, not the // layer itself. if (render_surface->is_clipped() && !clipped_content_rect.IsEmpty()) { gfx::Rect surface_clip_rect = LayerTreeHostCommon::CalculateVisibleRect( render_surface->clip_rect(), clipped_content_rect, render_surface->draw_transform()); clipped_content_rect.Intersect(surface_clip_rect); } } // The RenderSurfaceImpl backing texture cannot exceed the maximum supported // texture size. clipped_content_rect.set_width( std::min(clipped_content_rect.width(), globals.max_texture_size)); clipped_content_rect.set_height( std::min(clipped_content_rect.height(), globals.max_texture_size)); if (clipped_content_rect.IsEmpty()) { RemoveSurfaceForEarlyExit(layer, render_surface_layer_list); return; } // Layers having a non-default blend mode will blend with the content // inside its parent's render target. This render target should be // either root_for_isolated_group, or the root of the layer tree. // Otherwise, this layer will use an incomplete backdrop, limited to its // render target and the blending result will be incorrect. DCHECK(layer->uses_default_blend_mode() || IsRootLayer(layer) || !layer->parent()->render_target() || IsRootLayer(layer->parent()->render_target()) || layer->parent()->render_target()->is_root_for_isolated_group()); render_surface->SetContentRect(clipped_content_rect); // The owning layer's screen_space_transform has a scale from content to // layer space which we need to undo and replace with a scale from the // surface's subtree into layer space. gfx::Transform screen_space_transform = layer->screen_space_transform(); screen_space_transform.Scale( layer->contents_scale_x() / render_surface_sublayer_scale.x(), layer->contents_scale_y() / render_surface_sublayer_scale.y()); render_surface->SetScreenSpaceTransform(screen_space_transform); if (layer->replica_layer()) { gfx::Transform surface_origin_to_replica_origin_transform; surface_origin_to_replica_origin_transform.Scale( render_surface_sublayer_scale.x(), render_surface_sublayer_scale.y()); surface_origin_to_replica_origin_transform.Translate( layer->replica_layer()->position().x() + layer->replica_layer()->transform_origin().x(), layer->replica_layer()->position().y() + layer->replica_layer()->transform_origin().y()); surface_origin_to_replica_origin_transform.PreconcatTransform( layer->replica_layer()->transform()); surface_origin_to_replica_origin_transform.Translate( -layer->replica_layer()->transform_origin().x(), -layer->replica_layer()->transform_origin().y()); surface_origin_to_replica_origin_transform.Scale( 1.0 / render_surface_sublayer_scale.x(), 1.0 / render_surface_sublayer_scale.y()); // Compute the replica's "originTransform" that maps from the replica's // origin space to the target surface origin space. gfx::Transform replica_origin_transform = layer->render_surface()->draw_transform() * surface_origin_to_replica_origin_transform; render_surface->SetReplicaDrawTransform(replica_origin_transform); // Compute the replica's "screen_space_transform" that maps from the // replica's origin space to the screen's origin space. gfx::Transform replica_screen_space_transform = layer->render_surface()->screen_space_transform() * surface_origin_to_replica_origin_transform; render_surface->SetReplicaScreenSpaceTransform( replica_screen_space_transform); } } SavePaintPropertiesLayer(layer); // If neither this layer nor any of its children were added, early out. if (sorting_start_index == descendants.size()) { DCHECK(!render_to_separate_surface || IsRootLayer(layer)); return; } // If preserves-3d then sort all the descendants in 3D so that they can be // drawn from back to front. If the preserves-3d property is also set on the // parent then skip the sorting as the parent will sort all the descendants // anyway. if (globals.layer_sorter && descendants.size() && layer->Is3dSorted() && !LayerIsInExisting3DRenderingContext(layer)) { SortLayers(descendants.begin() + sorting_start_index, descendants.end(), globals.layer_sorter); } UpdateAccumulatedSurfaceState( layer, local_drawable_content_rect_of_subtree, accumulated_surface_state); if (layer->HasContributingDelegatedRenderPasses()) { layer->render_target()->render_surface()-> AddContributingDelegatedRenderPassLayer(layer); } } // NOLINT(readability/fn_size) template static void ProcessCalcDrawPropsInputs( const LayerTreeHostCommon::CalcDrawPropsInputs& inputs, SubtreeGlobals* globals, DataForRecursion* data_for_recursion) { DCHECK(inputs.root_layer); DCHECK(IsRootLayer(inputs.root_layer)); DCHECK(inputs.render_surface_layer_list); gfx::Transform identity_matrix; // The root layer's render_surface should receive the device viewport as the // initial clip rect. gfx::Rect device_viewport_rect(inputs.device_viewport_size); gfx::Vector2dF device_transform_scale_components = MathUtil::ComputeTransform2dScaleComponents(inputs.device_transform, 1.f); // Not handling the rare case of different x and y device scale. float device_transform_scale = std::max(device_transform_scale_components.x(), device_transform_scale_components.y()); gfx::Transform scaled_device_transform = inputs.device_transform; scaled_device_transform.Scale(inputs.device_scale_factor, inputs.device_scale_factor); globals->layer_sorter = NULL; globals->max_texture_size = inputs.max_texture_size; globals->device_scale_factor = inputs.device_scale_factor * device_transform_scale; globals->page_scale_factor = inputs.page_scale_factor; globals->page_scale_application_layer = inputs.page_scale_application_layer; globals->elastic_overscroll = inputs.elastic_overscroll; globals->elastic_overscroll_application_layer = inputs.elastic_overscroll_application_layer; globals->can_render_to_separate_surface = inputs.can_render_to_separate_surface; globals->can_adjust_raster_scales = inputs.can_adjust_raster_scales; globals->layers_always_allowed_lcd_text = inputs.layers_always_allowed_lcd_text; data_for_recursion->parent_matrix = scaled_device_transform; data_for_recursion->full_hierarchy_matrix = identity_matrix; data_for_recursion->scroll_compensation_matrix = identity_matrix; data_for_recursion->fixed_container = inputs.root_layer; data_for_recursion->clip_rect_in_target_space = device_viewport_rect; data_for_recursion->clip_rect_of_target_surface_in_target_space = device_viewport_rect; data_for_recursion->maximum_animation_contents_scale = 0.f; data_for_recursion->ancestor_is_animating_scale = false; data_for_recursion->ancestor_clips_subtree = true; data_for_recursion->nearest_occlusion_immune_ancestor_surface = NULL; data_for_recursion->in_subtree_of_page_scale_application_layer = false; data_for_recursion->subtree_can_use_lcd_text = inputs.can_use_lcd_text; data_for_recursion->subtree_is_visible_from_ancestor = true; } void LayerTreeHostCommon::UpdateRenderSurface( Layer* layer, bool can_render_to_separate_surface, gfx::Transform* transform, bool* draw_transform_is_axis_aligned) { bool preserves_2d_axis_alignment = transform->Preserves2dAxisAlignment() && *draw_transform_is_axis_aligned; if (IsRootLayer(layer) || (can_render_to_separate_surface && SubtreeShouldRenderToSeparateSurface( layer, preserves_2d_axis_alignment))) { // We reset the transform here so that any axis-changing transforms // will now be relative to this RenderSurface. transform->MakeIdentity(); *draw_transform_is_axis_aligned = true; if (!layer->render_surface()) { layer->CreateRenderSurface(); } layer->SetHasRenderSurface(true); return; } layer->SetHasRenderSurface(false); if (layer->render_surface()) layer->ClearRenderSurface(); } void LayerTreeHostCommon::UpdateRenderSurfaces( Layer* layer, bool can_render_to_separate_surface, const gfx::Transform& parent_transform, bool draw_transform_is_axis_aligned) { gfx::Transform transform_for_children = layer->transform(); transform_for_children *= parent_transform; draw_transform_is_axis_aligned &= layer->AnimationsPreserveAxisAlignment(); UpdateRenderSurface(layer, can_render_to_separate_surface, &transform_for_children, &draw_transform_is_axis_aligned); for (size_t i = 0; i < layer->children().size(); ++i) { UpdateRenderSurfaces(layer->children()[i].get(), can_render_to_separate_surface, transform_for_children, draw_transform_is_axis_aligned); } } static bool ApproximatelyEqual(const gfx::Rect& r1, const gfx::Rect& r2) { static const int tolerance = 1; return std::abs(r1.x() - r2.x()) <= tolerance && std::abs(r1.y() - r2.y()) <= tolerance && std::abs(r1.width() - r2.width()) <= tolerance && std::abs(r1.height() - r2.height()) <= tolerance; } void LayerTreeHostCommon::CalculateDrawProperties( CalcDrawPropsMainInputs* inputs) { UpdateRenderSurfaces(inputs->root_layer, inputs->can_render_to_separate_surface, gfx::Transform(), false); LayerList dummy_layer_list; SubtreeGlobals globals; DataForRecursion data_for_recursion; ProcessCalcDrawPropsInputs(*inputs, &globals, &data_for_recursion); PreCalculateMetaInformationRecursiveData recursive_data; PreCalculateMetaInformation(inputs->root_layer, &recursive_data); std::vector> accumulated_surface_state; CalculateDrawPropertiesInternal( inputs->root_layer, globals, data_for_recursion, inputs->render_surface_layer_list, &dummy_layer_list, &accumulated_surface_state, inputs->current_render_surface_layer_list_id); // The dummy layer list should not have been used. DCHECK_EQ(0u, dummy_layer_list.size()); // A root layer render_surface should always exist after // CalculateDrawProperties. DCHECK(inputs->root_layer->render_surface()); if (inputs->verify_property_trees) { // TODO(ajuma): Can we efficiently cache some of this rather than // starting from scratch every frame? TransformTree transform_tree; ClipTree clip_tree; ComputeVisibleRectsUsingPropertyTrees( inputs->root_layer, inputs->page_scale_application_layer, inputs->page_scale_factor, inputs->device_scale_factor, gfx::Rect(inputs->device_viewport_size), inputs->device_transform, &transform_tree, &clip_tree); bool failed = false; LayerIterator it, end; for (it = LayerIterator::Begin(inputs->render_surface_layer_list), end = LayerIterator::End(inputs->render_surface_layer_list); it != end; ++it) { Layer* current_layer = *it; if (it.represents_itself()) { if (!failed && current_layer->DrawsContent() && !ApproximatelyEqual( current_layer->visible_content_rect(), current_layer->visible_rect_from_property_trees())) { failed = true; } } } CHECK(!failed); } } void LayerTreeHostCommon::CalculateDrawProperties( CalcDrawPropsImplInputs* inputs) { LayerImplList dummy_layer_list; SubtreeGlobals globals; DataForRecursion data_for_recursion; ProcessCalcDrawPropsInputs(*inputs, &globals, &data_for_recursion); LayerSorter layer_sorter; globals.layer_sorter = &layer_sorter; PreCalculateMetaInformationRecursiveData recursive_data; PreCalculateMetaInformation(inputs->root_layer, &recursive_data); std::vector> accumulated_surface_state; CalculateDrawPropertiesInternal( inputs->root_layer, globals, data_for_recursion, inputs->render_surface_layer_list, &dummy_layer_list, &accumulated_surface_state, inputs->current_render_surface_layer_list_id); // The dummy layer list should not have been used. DCHECK_EQ(0u, dummy_layer_list.size()); // A root layer render_surface should always exist after // CalculateDrawProperties. DCHECK(inputs->root_layer->render_surface()); } } // namespace cc