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// Copyright 2012 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/input/page_scale_animation.h"
#include <math.h>
#include "base/logging.h"
#include "cc/animation/timing_function.h"
#include "ui/gfx/geometry/point_f.h"
#include "ui/gfx/geometry/rect_f.h"
#include "ui/gfx/geometry/vector2d_conversions.h"
namespace {
// This takes a viewport-relative vector and returns a vector whose values are
// between 0 and 1, representing the percentage position within the viewport.
gfx::Vector2dF NormalizeFromViewport(const gfx::Vector2dF& denormalized,
const gfx::SizeF& viewport_size) {
return gfx::ScaleVector2d(denormalized,
1.f / viewport_size.width(),
1.f / viewport_size.height());
}
gfx::Vector2dF DenormalizeToViewport(const gfx::Vector2dF& normalized,
const gfx::SizeF& viewport_size) {
return gfx::ScaleVector2d(normalized,
viewport_size.width(),
viewport_size.height());
}
gfx::Vector2dF InterpolateBetween(const gfx::Vector2dF& start,
const gfx::Vector2dF& end,
float interp) {
return start + gfx::ScaleVector2d(end - start, interp);
}
} // namespace
namespace cc {
using base::TimeTicks;
using base::TimeDelta;
scoped_ptr<PageScaleAnimation> PageScaleAnimation::Create(
const gfx::Vector2dF& start_scroll_offset,
float start_page_scale_factor,
const gfx::SizeF& viewport_size,
const gfx::SizeF& root_layer_size,
scoped_ptr<TimingFunction> timing_function) {
return make_scoped_ptr(new PageScaleAnimation(start_scroll_offset,
start_page_scale_factor,
viewport_size,
root_layer_size,
timing_function.Pass()));
}
PageScaleAnimation::PageScaleAnimation(
const gfx::Vector2dF& start_scroll_offset,
float start_page_scale_factor,
const gfx::SizeF& viewport_size,
const gfx::SizeF& root_layer_size,
scoped_ptr<TimingFunction> timing_function)
: start_page_scale_factor_(start_page_scale_factor),
target_page_scale_factor_(0.f),
start_scroll_offset_(start_scroll_offset),
start_anchor_(),
target_anchor_(),
viewport_size_(viewport_size),
root_layer_size_(root_layer_size),
timing_function_(timing_function.Pass()) {
}
PageScaleAnimation::~PageScaleAnimation() {}
void PageScaleAnimation::ZoomTo(const gfx::Vector2dF& target_scroll_offset,
float target_page_scale_factor,
double duration) {
target_page_scale_factor_ = target_page_scale_factor;
target_scroll_offset_ = target_scroll_offset;
ClampTargetScrollOffset();
duration_ = TimeDelta::FromSecondsD(duration);
if (start_page_scale_factor_ == target_page_scale_factor) {
start_anchor_ = start_scroll_offset_;
target_anchor_ = target_scroll_offset;
return;
}
// For uniform-looking zooming, infer an anchor from the start and target
// viewport rects.
InferTargetAnchorFromScrollOffsets();
start_anchor_ = target_anchor_;
}
void PageScaleAnimation::ZoomWithAnchor(const gfx::Vector2dF& anchor,
float target_page_scale_factor,
double duration) {
start_anchor_ = anchor;
target_page_scale_factor_ = target_page_scale_factor;
duration_ = TimeDelta::FromSecondsD(duration);
// We start zooming out from the anchor tapped by the user. But if
// the target scale is impossible to attain without hitting the root layer
// edges, then infer an anchor that doesn't collide with the edges.
// We will interpolate between the two anchors during the animation.
InferTargetScrollOffsetFromStartAnchor();
ClampTargetScrollOffset();
if (start_page_scale_factor_ == target_page_scale_factor_) {
target_anchor_ = start_anchor_;
return;
}
InferTargetAnchorFromScrollOffsets();
}
void PageScaleAnimation::InferTargetScrollOffsetFromStartAnchor() {
gfx::Vector2dF normalized = NormalizeFromViewport(
start_anchor_ - start_scroll_offset_, StartViewportSize());
target_scroll_offset_ =
start_anchor_ - DenormalizeToViewport(normalized, TargetViewportSize());
}
void PageScaleAnimation::InferTargetAnchorFromScrollOffsets() {
// The anchor is the point which is at the same normalized relative position
// within both start viewport rect and target viewport rect. For example, a
// zoom-in double-tap to a perfectly centered rect will have normalized
// anchor (0.5, 0.5), while one to a rect touching the bottom-right of the
// screen will have normalized anchor (1.0, 1.0). In other words, it obeys
// the equations:
// anchor = start_size * normalized + start_offset
// anchor = target_size * normalized + target_offset
// where both anchor and normalized begin as unknowns. Solving
// for the normalized, we get the following:
float width_scale =
1.f / (TargetViewportSize().width() - StartViewportSize().width());
float height_scale =
1.f / (TargetViewportSize().height() - StartViewportSize().height());
gfx::Vector2dF normalized = gfx::ScaleVector2d(
start_scroll_offset_ - target_scroll_offset_, width_scale, height_scale);
target_anchor_ =
target_scroll_offset_ + DenormalizeToViewport(normalized,
TargetViewportSize());
}
void PageScaleAnimation::ClampTargetScrollOffset() {
gfx::Vector2dF max_scroll_offset =
gfx::RectF(root_layer_size_).bottom_right() -
gfx::RectF(gfx::SizeF(TargetViewportSize())).bottom_right();
target_scroll_offset_.SetToMax(gfx::Vector2dF());
target_scroll_offset_.SetToMin(max_scroll_offset);
}
gfx::SizeF PageScaleAnimation::StartViewportSize() const {
return gfx::ScaleSize(viewport_size_, 1.f / start_page_scale_factor_);
}
gfx::SizeF PageScaleAnimation::TargetViewportSize() const {
return gfx::ScaleSize(viewport_size_, 1.f / target_page_scale_factor_);
}
gfx::SizeF PageScaleAnimation::ViewportSizeAt(float interp) const {
return gfx::ScaleSize(viewport_size_, 1.f / PageScaleFactorAt(interp));
}
bool PageScaleAnimation::IsAnimationStarted() const {
return start_time_ > base::TimeTicks();
}
void PageScaleAnimation::StartAnimation(base::TimeTicks time) {
DCHECK(start_time_.is_null());
start_time_ = time;
}
gfx::Vector2dF PageScaleAnimation::ScrollOffsetAtTime(
base::TimeTicks time) const {
DCHECK(!start_time_.is_null());
return ScrollOffsetAt(InterpAtTime(time));
}
float PageScaleAnimation::PageScaleFactorAtTime(base::TimeTicks time) const {
DCHECK(!start_time_.is_null());
return PageScaleFactorAt(InterpAtTime(time));
}
bool PageScaleAnimation::IsAnimationCompleteAtTime(base::TimeTicks time) const {
DCHECK(!start_time_.is_null());
return time >= end_time();
}
float PageScaleAnimation::InterpAtTime(base::TimeTicks monotonic_time) const {
DCHECK(!start_time_.is_null());
DCHECK(monotonic_time >= start_time_);
if (IsAnimationCompleteAtTime(monotonic_time))
return 1.f;
const double normalized_time =
(monotonic_time - start_time_).InSecondsF() / duration_.InSecondsF();
return timing_function_->GetValue(normalized_time);
}
gfx::Vector2dF PageScaleAnimation::ScrollOffsetAt(float interp) const {
if (interp <= 0.f)
return start_scroll_offset_;
if (interp >= 1.f)
return target_scroll_offset_;
return AnchorAt(interp) - ViewportRelativeAnchorAt(interp);
}
gfx::Vector2dF PageScaleAnimation::AnchorAt(float interp) const {
// Interpolate from start to target anchor in absolute space.
return InterpolateBetween(start_anchor_, target_anchor_, interp);
}
gfx::Vector2dF PageScaleAnimation::ViewportRelativeAnchorAt(
float interp) const {
// Interpolate from start to target anchor in normalized space.
gfx::Vector2dF start_normalized =
NormalizeFromViewport(start_anchor_ - start_scroll_offset_,
StartViewportSize());
gfx::Vector2dF target_normalized =
NormalizeFromViewport(target_anchor_ - target_scroll_offset_,
TargetViewportSize());
gfx::Vector2dF interp_normalized =
InterpolateBetween(start_normalized, target_normalized, interp);
return DenormalizeToViewport(interp_normalized, ViewportSizeAt(interp));
}
float PageScaleAnimation::PageScaleFactorAt(float interp) const {
if (interp <= 0.f)
return start_page_scale_factor_;
if (interp >= 1.f)
return target_page_scale_factor_;
// Linearly interpolate the magnitude in log scale.
float diff = target_page_scale_factor_ / start_page_scale_factor_;
float log_diff = log(diff);
log_diff *= interp;
diff = exp(log_diff);
return start_page_scale_factor_ * diff;
}
} // namespace cc
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