1// Copyright 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "cc/resources/content_layer_updater.h"
6
7#include "base/debug/trace_event.h"
8#include "base/time/time.h"
9#include "cc/debug/rendering_stats_instrumentation.h"
10#include "cc/resources/layer_painter.h"
11#include "third_party/skia/include/core/SkCanvas.h"
12#include "third_party/skia/include/core/SkPaint.h"
13#include "third_party/skia/include/core/SkRect.h"
14#include "third_party/skia/include/core/SkScalar.h"
15#include "ui/gfx/rect_conversions.h"
16#include "ui/gfx/rect_f.h"
17#include "ui/gfx/skia_util.h"
18
19namespace cc {
20
21ContentLayerUpdater::ContentLayerUpdater(
22    scoped_ptr<LayerPainter> painter,
23    RenderingStatsInstrumentation* stats_instrumentation,
24    int layer_id)
25    : rendering_stats_instrumentation_(stats_instrumentation),
26      layer_id_(layer_id),
27      layer_is_opaque_(false),
28      layer_fills_bounds_completely_(false),
29      painter_(painter.Pass()),
30      background_color_(SK_ColorTRANSPARENT) {
31}
32
33ContentLayerUpdater::~ContentLayerUpdater() {}
34
35void ContentLayerUpdater::set_rendering_stats_instrumentation(
36    RenderingStatsInstrumentation* rsi) {
37  rendering_stats_instrumentation_ = rsi;
38}
39
40void ContentLayerUpdater::PaintContents(SkCanvas* canvas,
41                                        const gfx::Size& layer_content_size,
42                                        const gfx::Rect& paint_rect,
43                                        float contents_width_scale,
44                                        float contents_height_scale) {
45  TRACE_EVENT0("cc", "ContentLayerUpdater::PaintContents");
46  if (!canvas)
47    return;
48  canvas->save();
49  canvas->translate(SkIntToScalar(-paint_rect.x()),
50                    SkIntToScalar(-paint_rect.y()));
51
52  // The |canvas| backing should be sized to hold the |paint_rect|.
53  DCHECK_EQ(paint_rect.width(), canvas->getBaseLayerSize().width());
54  DCHECK_EQ(paint_rect.height(), canvas->getBaseLayerSize().height());
55
56  const bool is_scaled =
57      contents_width_scale != 1.f || contents_height_scale != 1.f;
58
59  if (is_scaled && (layer_is_opaque_ || layer_fills_bounds_completely_)) {
60    // Even if completely covered, for rasterizations that touch the edge of the
61    // layer, we also need to raster the background color underneath the last
62    // texel (since the paint won't cover it).
63    //
64    // The final texel of content may only be partially covered by a
65    // rasterization; this rect represents the content rect that is fully
66    // covered by content.
67    const gfx::Rect layer_content_rect = gfx::Rect(layer_content_size);
68    gfx::Rect deflated_layer_content_rect = layer_content_rect;
69    deflated_layer_content_rect.Inset(0, 0, 1, 1);
70
71    if (!layer_content_rect.Contains(deflated_layer_content_rect)) {
72      // Drawing at most 1 x 1 x (canvas width + canvas height) texels is 2-3X
73      // faster than clearing, so special case this.
74      DCHECK_LE(paint_rect.right(), layer_content_rect.right());
75      DCHECK_LE(paint_rect.bottom(), layer_content_rect.bottom());
76      canvas->save();
77      canvas->clipRect(gfx::RectToSkRect(layer_content_rect),
78                       SkRegion::kReplace_Op);
79      canvas->clipRect(gfx::RectToSkRect(deflated_layer_content_rect),
80                       SkRegion::kDifference_Op);
81      canvas->drawColor(background_color_, SkXfermode::kSrc_Mode);
82      canvas->restore();
83    }
84  }
85
86  gfx::Rect layer_rect;
87  if (is_scaled) {
88    canvas->scale(SkFloatToScalar(contents_width_scale),
89                  SkFloatToScalar(contents_height_scale));
90
91    // NOTE: this may go beyond the bounds of the layer, but that shouldn't
92    // cause problems (anything beyond the layer is clipped out).
93    layer_rect = gfx::ScaleToEnclosingRect(
94        paint_rect, 1.f / contents_width_scale, 1.f / contents_height_scale);
95  } else {
96    layer_rect = paint_rect;
97  }
98
99  SkRect layer_sk_rect = SkRect::MakeXYWH(
100      layer_rect.x(), layer_rect.y(), layer_rect.width(), layer_rect.height());
101
102  canvas->clipRect(layer_sk_rect);
103
104  // If the layer has opaque contents or will fill the bounds completely there
105  // is no need to clear the canvas before painting.
106  if (!layer_is_opaque_ && !layer_fills_bounds_completely_) {
107    TRACE_EVENT0("cc", "Clear");
108    canvas->drawColor(SK_ColorTRANSPARENT, SkXfermode::kSrc_Mode);
109  }
110
111  painter_->Paint(canvas, layer_rect);
112  canvas->restore();
113
114  paint_rect_ = paint_rect;
115}
116
117void ContentLayerUpdater::SetOpaque(bool opaque) {
118  layer_is_opaque_ = opaque;
119}
120
121void ContentLayerUpdater::SetFillsBoundsCompletely(bool fills_bounds) {
122  layer_fills_bounds_completely_ = fills_bounds;
123}
124
125void ContentLayerUpdater::SetBackgroundColor(SkColor background_color) {
126  background_color_ = background_color;
127}
128
129}  // namespace cc
130