// 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/layers/heads_up_display_layer_impl.h"

#include <algorithm>
#include <vector>

#include "base/strings/stringprintf.h"
#include "base/trace_event/trace_event.h"
#include "base/trace_event/trace_event_argument.h"
#include "cc/debug/debug_colors.h"
#include "cc/debug/frame_rate_counter.h"
#include "cc/debug/paint_time_counter.h"
#include "cc/output/begin_frame_args.h"
#include "cc/output/renderer.h"
#include "cc/quads/texture_draw_quad.h"
#include "cc/resources/memory_history.h"
#include "cc/trees/layer_tree_host_impl.h"
#include "cc/trees/layer_tree_impl.h"
#include "skia/ext/platform_canvas.h"
#include "third_party/khronos/GLES2/gl2.h"
#include "third_party/khronos/GLES2/gl2ext.h"
#include "third_party/skia/include/core/SkBitmap.h"
#include "third_party/skia/include/core/SkPaint.h"
#include "third_party/skia/include/core/SkTypeface.h"
#include "third_party/skia/include/effects/SkColorMatrixFilter.h"
#include "ui/gfx/geometry/point.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/geometry/size_conversions.h"

namespace cc {

static inline SkPaint CreatePaint() {
  SkPaint paint;
#if (SK_R32_SHIFT || SK_B32_SHIFT != 16)
  // The SkCanvas is in RGBA but the shader is expecting BGRA, so we need to
  // swizzle our colors when drawing to the SkCanvas.
  SkColorMatrix swizzle_matrix;
  for (int i = 0; i < 20; ++i)
    swizzle_matrix.fMat[i] = 0;
  swizzle_matrix.fMat[0 + 5 * 2] = 1;
  swizzle_matrix.fMat[1 + 5 * 1] = 1;
  swizzle_matrix.fMat[2 + 5 * 0] = 1;
  swizzle_matrix.fMat[3 + 5 * 3] = 1;

  skia::RefPtr<SkColorMatrixFilter> filter =
      skia::AdoptRef(SkColorMatrixFilter::Create(swizzle_matrix));
  paint.setColorFilter(filter.get());
#endif
  return paint;
}

HeadsUpDisplayLayerImpl::Graph::Graph(double indicator_value,
                                      double start_upper_bound)
    : value(0.0),
      min(0.0),
      max(0.0),
      current_upper_bound(start_upper_bound),
      default_upper_bound(start_upper_bound),
      indicator(indicator_value) {}

double HeadsUpDisplayLayerImpl::Graph::UpdateUpperBound() {
  double target_upper_bound = std::max(max, default_upper_bound);
  current_upper_bound += (target_upper_bound - current_upper_bound) * 0.5;
  return current_upper_bound;
}

HeadsUpDisplayLayerImpl::HeadsUpDisplayLayerImpl(LayerTreeImpl* tree_impl,
                                                 int id)
    : LayerImpl(tree_impl, id),
      typeface_(skia::AdoptRef(
          SkTypeface::CreateFromName("monospace", SkTypeface::kBold))),
      internal_contents_scale_(1.f),
      fps_graph_(60.0, 80.0),
      paint_time_graph_(16.0, 48.0),
      fade_step_(0) {
}

HeadsUpDisplayLayerImpl::~HeadsUpDisplayLayerImpl() {}

scoped_ptr<LayerImpl> HeadsUpDisplayLayerImpl::CreateLayerImpl(
    LayerTreeImpl* tree_impl) {
  return HeadsUpDisplayLayerImpl::Create(tree_impl, id());
}

void HeadsUpDisplayLayerImpl::AcquireResource(
    ResourceProvider* resource_provider) {
  for (ScopedPtrVector<ScopedResource>::iterator it = resources_.begin();
       it != resources_.end();
       ++it) {
    if (!resource_provider->InUseByConsumer((*it)->id())) {
      resources_.swap(it, resources_.end() - 1);
      return;
    }
  }

  scoped_ptr<ScopedResource> resource =
      ScopedResource::Create(resource_provider);
  resource->Allocate(internal_content_bounds_,
                     ResourceProvider::TEXTURE_HINT_IMMUTABLE, RGBA_8888);
  resources_.push_back(resource.Pass());
}

class ResourceSizeIsEqualTo {
 public:
  explicit ResourceSizeIsEqualTo(const gfx::Size& size_)
      : compare_size_(size_) {}

  bool operator()(const ScopedResource* resource) {
    return resource->size() == compare_size_;
  }

 private:
  const gfx::Size compare_size_;
};

void HeadsUpDisplayLayerImpl::ReleaseUnmatchedSizeResources(
    ResourceProvider* resource_provider) {
  ScopedPtrVector<ScopedResource>::iterator it_erase =
      resources_.partition(ResourceSizeIsEqualTo(internal_content_bounds_));
  resources_.erase(it_erase, resources_.end());
}

bool HeadsUpDisplayLayerImpl::WillDraw(DrawMode draw_mode,
                                       ResourceProvider* resource_provider) {
  if (draw_mode == DRAW_MODE_RESOURCELESS_SOFTWARE)
    return false;

  internal_contents_scale_ = draw_properties().ideal_contents_scale;
  internal_content_bounds_ =
      gfx::ToCeiledSize(gfx::ScaleSize(bounds(), internal_contents_scale_));

  ReleaseUnmatchedSizeResources(resource_provider);
  AcquireResource(resource_provider);
  return LayerImpl::WillDraw(draw_mode, resource_provider);
}

void HeadsUpDisplayLayerImpl::AppendQuads(
    RenderPass* render_pass,
    AppendQuadsData* append_quads_data) {
  if (!resources_.back()->id())
    return;

  SharedQuadState* shared_quad_state =
      render_pass->CreateAndAppendSharedQuadState();
  PopulateScaledSharedQuadState(shared_quad_state, internal_contents_scale_);

  gfx::Rect quad_rect(internal_content_bounds_);
  gfx::Rect opaque_rect(contents_opaque() ? quad_rect : gfx::Rect());
  gfx::Rect visible_quad_rect(quad_rect);
  bool premultiplied_alpha = true;
  gfx::PointF uv_top_left(0.f, 0.f);
  gfx::PointF uv_bottom_right(1.f, 1.f);
  const float vertex_opacity[] = { 1.f, 1.f, 1.f, 1.f };
  bool flipped = false;
  bool nearest_neighbor = false;
  TextureDrawQuad* quad =
      render_pass->CreateAndAppendDrawQuad<TextureDrawQuad>();
  quad->SetNew(shared_quad_state,
               quad_rect,
               opaque_rect,
               visible_quad_rect,
               resources_.back()->id(),
               premultiplied_alpha,
               uv_top_left,
               uv_bottom_right,
               SK_ColorTRANSPARENT,
               vertex_opacity,
               flipped,
               nearest_neighbor);
}

void HeadsUpDisplayLayerImpl::UpdateHudTexture(
    DrawMode draw_mode,
    ResourceProvider* resource_provider) {
  if (draw_mode == DRAW_MODE_RESOURCELESS_SOFTWARE || !resources_.back()->id())
    return;

  SkISize canvas_size;
  if (hud_canvas_)
    canvas_size = hud_canvas_->getDeviceSize();
  else
    canvas_size.set(0, 0);

  if (canvas_size.width() != internal_content_bounds_.width() ||
      canvas_size.height() != internal_content_bounds_.height() ||
      !hud_canvas_) {
    TRACE_EVENT0("cc", "ResizeHudCanvas");

    bool opaque = false;
    hud_canvas_ = make_scoped_ptr(
        skia::CreateBitmapCanvas(internal_content_bounds_.width(),
                                 internal_content_bounds_.height(), opaque));
  }

  UpdateHudContents();

  {
    TRACE_EVENT0("cc", "DrawHudContents");
    hud_canvas_->clear(SkColorSetARGB(0, 0, 0, 0));
    hud_canvas_->save();
    hud_canvas_->scale(internal_contents_scale_, internal_contents_scale_);

    DrawHudContents(hud_canvas_.get());

    hud_canvas_->restore();
  }

  TRACE_EVENT0("cc", "UploadHudTexture");
  SkImageInfo info;
  size_t row_bytes = 0;
  const void* pixels = hud_canvas_->peekPixels(&info, &row_bytes);
  DCHECK(pixels);
  DCHECK(info.colorType() == kN32_SkColorType);
  resource_provider->CopyToResource(resources_.back()->id(),
                                    static_cast<const uint8_t*>(pixels),
                                    internal_content_bounds_);
}

void HeadsUpDisplayLayerImpl::ReleaseResources() {
  resources_.clear();
}

void HeadsUpDisplayLayerImpl::UpdateHudContents() {
  const LayerTreeDebugState& debug_state = layer_tree_impl()->debug_state();

  // Don't update numbers every frame so text is readable.
  base::TimeTicks now = layer_tree_impl()->CurrentBeginFrameArgs().frame_time;
  if (base::TimeDelta(now - time_of_last_graph_update_).InSecondsF() > 0.25f) {
    time_of_last_graph_update_ = now;

    if (debug_state.show_fps_counter) {
      FrameRateCounter* fps_counter = layer_tree_impl()->frame_rate_counter();
      fps_graph_.value = fps_counter->GetAverageFPS();
      fps_counter->GetMinAndMaxFPS(&fps_graph_.min, &fps_graph_.max);
    }

    if (debug_state.continuous_painting) {
      PaintTimeCounter* paint_time_counter =
          layer_tree_impl()->paint_time_counter();
      base::TimeDelta latest, min, max;

      if (paint_time_counter->End())
        latest = **paint_time_counter->End();
      paint_time_counter->GetMinAndMaxPaintTime(&min, &max);

      paint_time_graph_.value = latest.InMillisecondsF();
      paint_time_graph_.min = min.InMillisecondsF();
      paint_time_graph_.max = max.InMillisecondsF();
    }

    if (debug_state.ShowMemoryStats()) {
      MemoryHistory* memory_history = layer_tree_impl()->memory_history();
      if (memory_history->End())
        memory_entry_ = **memory_history->End();
      else
        memory_entry_ = MemoryHistory::Entry();
    }
  }

  fps_graph_.UpdateUpperBound();
  paint_time_graph_.UpdateUpperBound();
}

void HeadsUpDisplayLayerImpl::DrawHudContents(SkCanvas* canvas) {
  const LayerTreeDebugState& debug_state = layer_tree_impl()->debug_state();

  if (debug_state.ShowHudRects()) {
    DrawDebugRects(canvas, layer_tree_impl()->debug_rect_history());
    if (IsAnimatingHUDContents()) {
      layer_tree_impl()->SetNeedsRedraw();
    }
  }

  SkRect area = SkRect::MakeEmpty();
  if (debug_state.continuous_painting) {
    area = DrawPaintTimeDisplay(
        canvas, layer_tree_impl()->paint_time_counter(), 0, 0);
  } else if (debug_state.show_fps_counter) {
    // Don't show the FPS display when continuous painting is enabled, because
    // it would show misleading numbers.
    area =
        DrawFPSDisplay(canvas, layer_tree_impl()->frame_rate_counter(), 0, 0);
  }

  if (debug_state.show_fps_counter || debug_state.continuous_painting) {
    area = DrawGpuRasterizationStatus(canvas, 0, area.bottom(),
                                      SkMaxScalar(area.width(), 150));
  }

  if (debug_state.ShowMemoryStats())
    DrawMemoryDisplay(canvas, 0, area.bottom(), SkMaxScalar(area.width(), 150));
}

void HeadsUpDisplayLayerImpl::DrawText(SkCanvas* canvas,
                                       SkPaint* paint,
                                       const std::string& text,
                                       SkPaint::Align align,
                                       int size,
                                       int x,
                                       int y) const {
  const bool anti_alias = paint->isAntiAlias();
  paint->setAntiAlias(true);

  paint->setTextSize(size);
  paint->setTextAlign(align);
  paint->setTypeface(typeface_.get());
  canvas->drawText(text.c_str(), text.length(), x, y, *paint);

  paint->setAntiAlias(anti_alias);
}

void HeadsUpDisplayLayerImpl::DrawText(SkCanvas* canvas,
                                       SkPaint* paint,
                                       const std::string& text,
                                       SkPaint::Align align,
                                       int size,
                                       const SkPoint& pos) const {
  DrawText(canvas, paint, text, align, size, pos.x(), pos.y());
}

void HeadsUpDisplayLayerImpl::DrawGraphBackground(SkCanvas* canvas,
                                                  SkPaint* paint,
                                                  const SkRect& bounds) const {
  paint->setColor(DebugColors::HUDBackgroundColor());
  canvas->drawRect(bounds, *paint);
}

void HeadsUpDisplayLayerImpl::DrawGraphLines(SkCanvas* canvas,
                                             SkPaint* paint,
                                             const SkRect& bounds,
                                             const Graph& graph) const {
  // Draw top and bottom line.
  paint->setColor(DebugColors::HUDSeparatorLineColor());
  canvas->drawLine(bounds.left(),
                   bounds.top() - 1,
                   bounds.right(),
                   bounds.top() - 1,
                   *paint);
  canvas->drawLine(
      bounds.left(), bounds.bottom(), bounds.right(), bounds.bottom(), *paint);

  // Draw indicator line (additive blend mode to increase contrast when drawn on
  // top of graph).
  paint->setColor(DebugColors::HUDIndicatorLineColor());
  paint->setXfermodeMode(SkXfermode::kPlus_Mode);
  const double indicator_top =
      bounds.height() * (1.0 - graph.indicator / graph.current_upper_bound) -
      1.0;
  canvas->drawLine(bounds.left(),
                   bounds.top() + indicator_top,
                   bounds.right(),
                   bounds.top() + indicator_top,
                   *paint);
  paint->setXfermode(nullptr);
}

SkRect HeadsUpDisplayLayerImpl::DrawFPSDisplay(
    SkCanvas* canvas,
    const FrameRateCounter* fps_counter,
    int right,
    int top) const {
  const int kPadding = 4;
  const int kGap = 6;

  const int kFontHeight = 15;

  const int kGraphWidth = fps_counter->time_stamp_history_size() - 2;
  const int kGraphHeight = 40;

  const int kHistogramWidth = 37;

  int width = kGraphWidth + kHistogramWidth + 4 * kPadding;
  int height = kFontHeight + kGraphHeight + 4 * kPadding + 2;
  int left = bounds().width() - width - right;
  SkRect area = SkRect::MakeXYWH(left, top, width, height);

  SkPaint paint = CreatePaint();
  DrawGraphBackground(canvas, &paint, area);

  SkRect text_bounds =
      SkRect::MakeXYWH(left + kPadding,
                       top + kPadding,
                       kGraphWidth + kHistogramWidth + kGap + 2,
                       kFontHeight);
  SkRect graph_bounds = SkRect::MakeXYWH(left + kPadding,
                                         text_bounds.bottom() + 2 * kPadding,
                                         kGraphWidth,
                                         kGraphHeight);
  SkRect histogram_bounds = SkRect::MakeXYWH(graph_bounds.right() + kGap,
                                             graph_bounds.top(),
                                             kHistogramWidth,
                                             kGraphHeight);

  const std::string value_text =
      base::StringPrintf("FPS:%5.1f", fps_graph_.value);
  const std::string min_max_text =
      base::StringPrintf("%.0f-%.0f", fps_graph_.min, fps_graph_.max);

  VLOG(1) << value_text;

  paint.setColor(DebugColors::FPSDisplayTextAndGraphColor());
  DrawText(canvas,
           &paint,
           value_text,
           SkPaint::kLeft_Align,
           kFontHeight,
           text_bounds.left(),
           text_bounds.bottom());
  DrawText(canvas,
           &paint,
           min_max_text,
           SkPaint::kRight_Align,
           kFontHeight,
           text_bounds.right(),
           text_bounds.bottom());

  DrawGraphLines(canvas, &paint, graph_bounds, fps_graph_);

  // Collect graph and histogram data.
  SkPath path;

  const int kHistogramSize = 20;
  double histogram[kHistogramSize] = { 1.0 };
  double max_bucket_value = 1.0;

  for (FrameRateCounter::RingBufferType::Iterator it = --fps_counter->end(); it;
       --it) {
    base::TimeDelta delta = fps_counter->RecentFrameInterval(it.index() + 1);

    // Skip this particular instantaneous frame rate if it is not likely to have
    // been valid.
    if (!fps_counter->IsBadFrameInterval(delta)) {
      double fps = 1.0 / delta.InSecondsF();

      // Clamp the FPS to the range we want to plot visually.
      double p = fps / fps_graph_.current_upper_bound;
      if (p > 1.0)
        p = 1.0;

      // Plot this data point.
      SkPoint cur =
          SkPoint::Make(graph_bounds.left() + it.index(),
                        graph_bounds.bottom() - p * graph_bounds.height());
      if (path.isEmpty())
        path.moveTo(cur);
      else
        path.lineTo(cur);

      // Use the fps value to find the right bucket in the histogram.
      int bucket_index = floor(p * (kHistogramSize - 1));

      // Add the delta time to take the time spent at that fps rate into
      // account.
      histogram[bucket_index] += delta.InSecondsF();
      max_bucket_value = std::max(histogram[bucket_index], max_bucket_value);
    }
  }

  // Draw FPS histogram.
  paint.setColor(DebugColors::HUDSeparatorLineColor());
  canvas->drawLine(histogram_bounds.left() - 1,
                   histogram_bounds.top() - 1,
                   histogram_bounds.left() - 1,
                   histogram_bounds.bottom() + 1,
                   paint);
  canvas->drawLine(histogram_bounds.right() + 1,
                   histogram_bounds.top() - 1,
                   histogram_bounds.right() + 1,
                   histogram_bounds.bottom() + 1,
                   paint);

  paint.setColor(DebugColors::FPSDisplayTextAndGraphColor());
  const double bar_height = histogram_bounds.height() / kHistogramSize;

  for (int i = kHistogramSize - 1; i >= 0; --i) {
    if (histogram[i] > 0) {
      double bar_width =
          histogram[i] / max_bucket_value * histogram_bounds.width();
      canvas->drawRect(
          SkRect::MakeXYWH(histogram_bounds.left(),
                           histogram_bounds.bottom() - (i + 1) * bar_height,
                           bar_width,
                           1),
          paint);
    }
  }

  // Draw FPS graph.
  paint.setAntiAlias(true);
  paint.setStyle(SkPaint::kStroke_Style);
  paint.setStrokeWidth(1);
  canvas->drawPath(path, paint);

  return area;
}

SkRect HeadsUpDisplayLayerImpl::DrawMemoryDisplay(SkCanvas* canvas,
                                                  int right,
                                                  int top,
                                                  int width) const {
  if (!memory_entry_.total_bytes_used)
    return SkRect::MakeEmpty();

  const int kPadding = 4;
  const int kFontHeight = 13;

  const int height = 3 * kFontHeight + 4 * kPadding;
  const int left = bounds().width() - width - right;
  const SkRect area = SkRect::MakeXYWH(left, top, width, height);

  const double kMegabyte = 1024.0 * 1024.0;

  SkPaint paint = CreatePaint();
  DrawGraphBackground(canvas, &paint, area);

  SkPoint title_pos = SkPoint::Make(left + kPadding, top + kFontHeight);
  SkPoint stat1_pos = SkPoint::Make(left + width - kPadding - 1,
                                    top + kPadding + 2 * kFontHeight);
  SkPoint stat2_pos = SkPoint::Make(left + width - kPadding - 1,
                                    top + 2 * kPadding + 3 * kFontHeight);

  paint.setColor(DebugColors::MemoryDisplayTextColor());
  DrawText(canvas,
           &paint,
           "GPU memory",
           SkPaint::kLeft_Align,
           kFontHeight,
           title_pos);

  std::string text = base::StringPrintf(
      "%6.1f MB used", memory_entry_.total_bytes_used / kMegabyte);
  DrawText(canvas, &paint, text, SkPaint::kRight_Align, kFontHeight, stat1_pos);

  if (!memory_entry_.had_enough_memory)
    paint.setColor(SK_ColorRED);
  text = base::StringPrintf("%6.1f MB max ",
                            memory_entry_.total_budget_in_bytes / kMegabyte);
  DrawText(canvas, &paint, text, SkPaint::kRight_Align, kFontHeight, stat2_pos);

  return area;
}

SkRect HeadsUpDisplayLayerImpl::DrawGpuRasterizationStatus(SkCanvas* canvas,
                                                           int right,
                                                           int top,
                                                           int width) const {
  std::string status;
  SkColor color = SK_ColorRED;
  switch (layer_tree_impl()->GetGpuRasterizationStatus()) {
    case GpuRasterizationStatus::ON:
      status = "GPU raster: on";
      color = SK_ColorGREEN;
      break;
    case GpuRasterizationStatus::ON_FORCED:
      status = "GPU raster: on (forced)";
      color = SK_ColorGREEN;
      break;
    case GpuRasterizationStatus::OFF_DEVICE:
      status = "GPU raster: off (device)";
      color = SK_ColorRED;
      break;
    case GpuRasterizationStatus::OFF_VIEWPORT:
      status = "GPU raster: off (viewport)";
      color = SK_ColorYELLOW;
      break;
    case GpuRasterizationStatus::OFF_CONTENT:
      status = "GPU raster: off (content)";
      color = SK_ColorYELLOW;
      break;
  }

  if (status.empty())
    return SkRect::MakeEmpty();

  const int kPadding = 4;
  const int kFontHeight = 13;

  const int height = kFontHeight + 2 * kPadding;
  const int left = bounds().width() - width - right;
  const SkRect area = SkRect::MakeXYWH(left, top, width, height);

  SkPaint paint = CreatePaint();
  DrawGraphBackground(canvas, &paint, area);

  SkPoint gpu_status_pos = SkPoint::Make(left + kPadding, top + kFontHeight);

  paint.setColor(color);
  DrawText(canvas, &paint, status, SkPaint::kLeft_Align, kFontHeight,
           gpu_status_pos);

  return area;
}

SkRect HeadsUpDisplayLayerImpl::DrawPaintTimeDisplay(
    SkCanvas* canvas,
    const PaintTimeCounter* paint_time_counter,
    int right,
    int top) const {
  const int kPadding = 4;
  const int kFontHeight = 15;

  const int kGraphWidth = paint_time_counter->HistorySize();
  const int kGraphHeight = 40;

  const int width = kGraphWidth + 2 * kPadding;
  const int height =
      kFontHeight + kGraphHeight + 4 * kPadding + 2 + kFontHeight + kPadding;
  const int left = bounds().width() - width - right;

  const SkRect area = SkRect::MakeXYWH(left, top, width, height);

  SkPaint paint = CreatePaint();
  DrawGraphBackground(canvas, &paint, area);

  SkRect text_bounds = SkRect::MakeXYWH(
      left + kPadding, top + kPadding, kGraphWidth, kFontHeight);
  SkRect text_bounds2 = SkRect::MakeXYWH(left + kPadding,
                                         text_bounds.bottom() + kPadding,
                                         kGraphWidth,
                                         kFontHeight);
  SkRect graph_bounds = SkRect::MakeXYWH(left + kPadding,
                                         text_bounds2.bottom() + 2 * kPadding,
                                         kGraphWidth,
                                         kGraphHeight);

  const std::string value_text =
      base::StringPrintf("%.1f", paint_time_graph_.value);
  const std::string min_max_text = base::StringPrintf(
      "%.1f-%.1f", paint_time_graph_.min, paint_time_graph_.max);

  paint.setColor(DebugColors::PaintTimeDisplayTextAndGraphColor());
  DrawText(canvas, &paint, "Compositor frame time (ms)", SkPaint::kLeft_Align,
           kFontHeight, text_bounds.left(), text_bounds.bottom());
  DrawText(canvas,
           &paint,
           value_text,
           SkPaint::kLeft_Align,
           kFontHeight,
           text_bounds2.left(),
           text_bounds2.bottom());
  DrawText(canvas,
           &paint,
           min_max_text,
           SkPaint::kRight_Align,
           kFontHeight,
           text_bounds2.right(),
           text_bounds2.bottom());

  paint.setColor(DebugColors::PaintTimeDisplayTextAndGraphColor());
  for (PaintTimeCounter::RingBufferType::Iterator it =
           paint_time_counter->End();
       it;
       --it) {
    double pt = it->InMillisecondsF();

    if (pt == 0.0)
      continue;

    double p = pt / paint_time_graph_.current_upper_bound;
    if (p > 1.0)
      p = 1.0;

    canvas->drawRect(
        SkRect::MakeXYWH(graph_bounds.left() + it.index(),
                         graph_bounds.bottom() - p * graph_bounds.height(),
                         1,
                         p * graph_bounds.height()),
        paint);
  }

  DrawGraphLines(canvas, &paint, graph_bounds, paint_time_graph_);

  return area;
}

void HeadsUpDisplayLayerImpl::DrawDebugRect(
    SkCanvas* canvas,
    SkPaint* paint,
    const DebugRect& rect,
    SkColor stroke_color,
    SkColor fill_color,
    float stroke_width,
    const std::string& label_text) const {
  gfx::Rect debug_layer_rect =
      gfx::ScaleToEnclosingRect(rect.rect, 1.0 / internal_contents_scale_,
                                1.0 / internal_contents_scale_);
  SkIRect sk_rect = RectToSkIRect(debug_layer_rect);
  paint->setColor(fill_color);
  paint->setStyle(SkPaint::kFill_Style);
  canvas->drawIRect(sk_rect, *paint);

  paint->setColor(stroke_color);
  paint->setStyle(SkPaint::kStroke_Style);
  paint->setStrokeWidth(SkFloatToScalar(stroke_width));
  canvas->drawIRect(sk_rect, *paint);

  if (label_text.length()) {
    const int kFontHeight = 12;
    const int kPadding = 3;

    // The debug_layer_rect may be huge, and converting to a floating point may
    // be lossy, so intersect with the HUD layer bounds first to prevent that.
    gfx::Rect clip_rect = debug_layer_rect;
    clip_rect.Intersect(gfx::Rect(internal_content_bounds_));
    SkRect sk_clip_rect = RectToSkRect(clip_rect);

    canvas->save();
    canvas->clipRect(sk_clip_rect);
    canvas->translate(sk_clip_rect.x(), sk_clip_rect.y());

    SkPaint label_paint = CreatePaint();
    label_paint.setTextSize(kFontHeight);
    label_paint.setTypeface(typeface_.get());
    label_paint.setColor(stroke_color);

    const SkScalar label_text_width =
        label_paint.measureText(label_text.c_str(), label_text.length());
    canvas->drawRect(SkRect::MakeWH(label_text_width + 2 * kPadding,
                                    kFontHeight + 2 * kPadding),
                     label_paint);

    label_paint.setAntiAlias(true);
    label_paint.setColor(SkColorSetARGB(255, 50, 50, 50));
    canvas->drawText(label_text.c_str(),
                     label_text.length(),
                     kPadding,
                     kFontHeight * 0.8f + kPadding,
                     label_paint);

    canvas->restore();
  }
}

void HeadsUpDisplayLayerImpl::DrawDebugRects(
    SkCanvas* canvas,
    DebugRectHistory* debug_rect_history) {
  SkPaint paint = CreatePaint();

  const std::vector<DebugRect>& debug_rects = debug_rect_history->debug_rects();
  std::vector<DebugRect> new_paint_rects;

  for (size_t i = 0; i < debug_rects.size(); ++i) {
    SkColor stroke_color = 0;
    SkColor fill_color = 0;
    float stroke_width = 0.f;
    std::string label_text;

    switch (debug_rects[i].type) {
      case PAINT_RECT_TYPE:
        new_paint_rects.push_back(debug_rects[i]);
        continue;
      case PROPERTY_CHANGED_RECT_TYPE:
        stroke_color = DebugColors::PropertyChangedRectBorderColor();
        fill_color = DebugColors::PropertyChangedRectFillColor();
        stroke_width = DebugColors::PropertyChangedRectBorderWidth();
        break;
      case SURFACE_DAMAGE_RECT_TYPE:
        stroke_color = DebugColors::SurfaceDamageRectBorderColor();
        fill_color = DebugColors::SurfaceDamageRectFillColor();
        stroke_width = DebugColors::SurfaceDamageRectBorderWidth();
        break;
      case REPLICA_SCREEN_SPACE_RECT_TYPE:
        stroke_color = DebugColors::ScreenSpaceSurfaceReplicaRectBorderColor();
        fill_color = DebugColors::ScreenSpaceSurfaceReplicaRectFillColor();
        stroke_width = DebugColors::ScreenSpaceSurfaceReplicaRectBorderWidth();
        break;
      case SCREEN_SPACE_RECT_TYPE:
        stroke_color = DebugColors::ScreenSpaceLayerRectBorderColor();
        fill_color = DebugColors::ScreenSpaceLayerRectFillColor();
        stroke_width = DebugColors::ScreenSpaceLayerRectBorderWidth();
        break;
      case TOUCH_EVENT_HANDLER_RECT_TYPE:
        stroke_color = DebugColors::TouchEventHandlerRectBorderColor();
        fill_color = DebugColors::TouchEventHandlerRectFillColor();
        stroke_width = DebugColors::TouchEventHandlerRectBorderWidth();
        label_text = "touch event listener";
        break;
      case WHEEL_EVENT_HANDLER_RECT_TYPE:
        stroke_color = DebugColors::WheelEventHandlerRectBorderColor();
        fill_color = DebugColors::WheelEventHandlerRectFillColor();
        stroke_width = DebugColors::WheelEventHandlerRectBorderWidth();
        label_text = "mousewheel event listener";
        break;
      case SCROLL_EVENT_HANDLER_RECT_TYPE:
        stroke_color = DebugColors::ScrollEventHandlerRectBorderColor();
        fill_color = DebugColors::ScrollEventHandlerRectFillColor();
        stroke_width = DebugColors::ScrollEventHandlerRectBorderWidth();
        label_text = "scroll event listener";
        break;
      case NON_FAST_SCROLLABLE_RECT_TYPE:
        stroke_color = DebugColors::NonFastScrollableRectBorderColor();
        fill_color = DebugColors::NonFastScrollableRectFillColor();
        stroke_width = DebugColors::NonFastScrollableRectBorderWidth();
        label_text = "repaints on scroll";
        break;
      case ANIMATION_BOUNDS_RECT_TYPE:
        stroke_color = DebugColors::LayerAnimationBoundsBorderColor();
        fill_color = DebugColors::LayerAnimationBoundsFillColor();
        stroke_width = DebugColors::LayerAnimationBoundsBorderWidth();
        label_text = "animation bounds";
        break;
    }

    DrawDebugRect(canvas,
                  &paint,
                  debug_rects[i],
                  stroke_color,
                  fill_color,
                  stroke_width,
                  label_text);
  }

  if (new_paint_rects.size()) {
    paint_rects_.swap(new_paint_rects);
    fade_step_ = DebugColors::kFadeSteps;
  }
  if (fade_step_ > 0) {
    fade_step_--;
    for (size_t i = 0; i < paint_rects_.size(); ++i) {
      DrawDebugRect(canvas,
                    &paint,
                    paint_rects_[i],
                    DebugColors::PaintRectBorderColor(fade_step_),
                    DebugColors::PaintRectFillColor(fade_step_),
                    DebugColors::PaintRectBorderWidth(),
                    "");
    }
  }
}

const char* HeadsUpDisplayLayerImpl::LayerTypeAsString() const {
  return "cc::HeadsUpDisplayLayerImpl";
}

void HeadsUpDisplayLayerImpl::AsValueInto(
    base::trace_event::TracedValue* dict) const {
  LayerImpl::AsValueInto(dict);
  dict->SetString("layer_name", "Heads Up Display Layer");
}

}  // namespace cc