cc/layers/painted_scrollbar_layer.cc

   1 // Copyright 2013 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/layers/painted_scrollbar_layer.h"
   6
   7 #include "base/auto_reset.h"
   8 #include "base/basictypes.h"
   9 #include "base/debug/trace_event.h"
  10 #include "cc/layers/painted_scrollbar_layer_impl.h"
  11 #include "cc/resources/ui_resource_bitmap.h"
  12 #include "cc/trees/layer_tree_host.h"
  13 #include "cc/trees/layer_tree_impl.h"
  14 #include "skia/ext/platform_canvas.h"
  15 #include "skia/ext/refptr.h"
  16 #include "third_party/skia/include/core/SkBitmap.h"
  17 #include "third_party/skia/include/core/SkCanvas.h"
  18 #include "third_party/skia/include/core/SkSize.h"
  19 #include "ui/gfx/skia_util.h"
  20
  21 namespace cc {
  22
  23 scoped_ptr<LayerImpl> PaintedScrollbarLayer::CreateLayerImpl(
  24     LayerTreeImpl* tree_impl) {
  25   return PaintedScrollbarLayerImpl::Create(
  26       tree_impl, id(), scrollbar_->Orientation()).PassAs<LayerImpl>();
  27 }
  28
  29 scoped_refptr<PaintedScrollbarLayer> PaintedScrollbarLayer::Create(
  30     scoped_ptr<Scrollbar> scrollbar,
  31     int scroll_layer_id) {
  32   return make_scoped_refptr(
  33       new PaintedScrollbarLayer(scrollbar.Pass(), scroll_layer_id));
  34 }
  35
  36 PaintedScrollbarLayer::PaintedScrollbarLayer(
  37     scoped_ptr<Scrollbar> scrollbar,
  38     int scroll_layer_id)
  39     : scrollbar_(scrollbar.Pass()),
  40       scroll_layer_id_(scroll_layer_id),
  41       thumb_thickness_(scrollbar_->ThumbThickness()),
  42       thumb_length_(scrollbar_->ThumbLength()),
  43       is_overlay_(scrollbar_->IsOverlay()),
  44       has_thumb_(scrollbar_->HasThumb()) {
  45   if (!scrollbar_->IsOverlay())
  46     SetShouldScrollOnMainThread(true);
  47 }
  48
  49 PaintedScrollbarLayer::~PaintedScrollbarLayer() {}
  50
  51 int PaintedScrollbarLayer::ScrollLayerId() const {
  52   return scroll_layer_id_;
  53 }
  54
  55 void PaintedScrollbarLayer::SetScrollLayerId(int id) {
  56   if (id == scroll_layer_id_)
  57     return;
  58
  59   scroll_layer_id_ = id;
  60   SetNeedsFullTreeSync();
  61 }
  62
  63 bool PaintedScrollbarLayer::OpacityCanAnimateOnImplThread() const {
  64   return scrollbar_->IsOverlay();
  65 }
  66
  67 ScrollbarOrientation PaintedScrollbarLayer::orientation() const {
  68   return scrollbar_->Orientation();
  69 }
  70
  71 int PaintedScrollbarLayer::MaxTextureSize() {
  72   DCHECK(layer_tree_host());
  73   return layer_tree_host()->GetRendererCapabilities().max_texture_size;
  74 }
  75
  76 float PaintedScrollbarLayer::ClampScaleToMaxTextureSize(float scale) {
  77   // If the scaled content_bounds() is bigger than the max texture size of the
  78   // device, we need to clamp it by rescaling, since content_bounds() is used
  79   // below to set the texture size.
  80   gfx::Size scaled_bounds = ComputeContentBoundsForScale(scale, scale);
  81   if (scaled_bounds.width() > MaxTextureSize() ||
  82       scaled_bounds.height() > MaxTextureSize()) {
  83     if (scaled_bounds.width() > scaled_bounds.height())
  84       return (MaxTextureSize() - 1) / static_cast<float>(bounds().width());
  85     else
  86       return (MaxTextureSize() - 1) / static_cast<float>(bounds().height());
  87   }
  88   return scale;
  89 }
  90
  91 void PaintedScrollbarLayer::CalculateContentsScale(
  92     float ideal_contents_scale,
  93     float device_scale_factor,
  94     float page_scale_factor,
  95     bool animating_transform_to_screen,
  96     float* contents_scale_x,
  97     float* contents_scale_y,
  98     gfx::Size* content_bounds) {
  99   ContentsScalingLayer::CalculateContentsScale(
 100       ClampScaleToMaxTextureSize(ideal_contents_scale),
 101       device_scale_factor,
 102       page_scale_factor,
 103       animating_transform_to_screen,
 104       contents_scale_x,
 105       contents_scale_y,
 106       content_bounds);
 107 }
 108
 109 void PaintedScrollbarLayer::PushPropertiesTo(LayerImpl* layer) {
 110   ContentsScalingLayer::PushPropertiesTo(layer);
 111
 112   PaintedScrollbarLayerImpl* scrollbar_layer =
 113       static_cast<PaintedScrollbarLayerImpl*>(layer);
 114
 115   scrollbar_layer->SetThumbThickness(thumb_thickness_);
 116   scrollbar_layer->SetThumbLength(thumb_length_);
 117   if (orientation() == HORIZONTAL) {
 118     scrollbar_layer->SetTrackStart(
 119         track_rect_.x() - location_.x());
 120     scrollbar_layer->SetTrackLength(track_rect_.width());
 121   } else {
 122     scrollbar_layer->SetTrackStart(
 123         track_rect_.y() - location_.y());
 124     scrollbar_layer->SetTrackLength(track_rect_.height());
 125   }
 126
 127   if (track_resource_.get())
 128     scrollbar_layer->set_track_ui_resource_id(track_resource_->id());
 129   if (thumb_resource_.get())
 130     scrollbar_layer->set_thumb_ui_resource_id(thumb_resource_->id());
 131
 132   scrollbar_layer->set_is_overlay_scrollbar(is_overlay_);
 133 }
 134
 135 ScrollbarLayerInterface* PaintedScrollbarLayer::ToScrollbarLayer() {
 136   return this;
 137 }
 138
 139 void PaintedScrollbarLayer::SetLayerTreeHost(LayerTreeHost* host) {
 140   // When the LTH is set to null or has changed, then this layer should remove
 141   // all of its associated resources.
 142   if (!host || host != layer_tree_host()) {
 143     track_resource_.reset();
 144     thumb_resource_.reset();
 145   }
 146
 147   ContentsScalingLayer::SetLayerTreeHost(host);
 148 }
 149
 150 gfx::Rect PaintedScrollbarLayer::ScrollbarLayerRectToContentRect(
 151     gfx::Rect layer_rect) const {
 152   // Don't intersect with the bounds as in LayerRectToContentRect() because
 153   // layer_rect here might be in coordinates of the containing layer.
 154   gfx::Rect expanded_rect = gfx::ScaleToEnclosingRect(
 155       layer_rect, contents_scale_y(), contents_scale_y());
 156   // We should never return a rect bigger than the content_bounds().
 157   gfx::Size clamped_size = expanded_rect.size();
 158   clamped_size.SetToMin(content_bounds());
 159   expanded_rect.set_size(clamped_size);
 160   return expanded_rect;
 161 }
 162
 163 gfx::Rect PaintedScrollbarLayer::OriginThumbRect() const {
 164   gfx::Size thumb_size;
 165   if (orientation() == HORIZONTAL) {
 166     thumb_size =
 167         gfx::Size(scrollbar_->ThumbLength(), scrollbar_->ThumbThickness());
 168   } else {
 169     thumb_size =
 170         gfx::Size(scrollbar_->ThumbThickness(), scrollbar_->ThumbLength());
 171   }
 172   return ScrollbarLayerRectToContentRect(gfx::Rect(thumb_size));
 173 }
 174
 175 void PaintedScrollbarLayer::UpdateThumbAndTrackGeometry() {
 176   UpdateProperty(scrollbar_->TrackRect(), &track_rect_);
 177   UpdateProperty(scrollbar_->Location(), &location_);
 178   UpdateProperty(scrollbar_->IsOverlay(), &is_overlay_);
 179   UpdateProperty(scrollbar_->HasThumb(), &has_thumb_);
 180   if (has_thumb_) {
 181     UpdateProperty(scrollbar_->ThumbThickness(), &thumb_thickness_);
 182     UpdateProperty(scrollbar_->ThumbLength(), &thumb_length_);
 183   }
 184 }
 185
 186 bool PaintedScrollbarLayer::Update(ResourceUpdateQueue* queue,
 187                                    const OcclusionTracker* occlusion) {
 188   UpdateThumbAndTrackGeometry();
 189
 190   gfx::Rect scaled_track_rect = ScrollbarLayerRectToContentRect(
 191       gfx::Rect(location_, bounds()));
 192
 193   if (track_rect_.IsEmpty() || scaled_track_rect.IsEmpty())
 194     return false;
 195
 196   {
 197     base::AutoReset<bool> ignore_set_needs_commit(&ignore_set_needs_commit_,
 198                                                   true);
 199     ContentsScalingLayer::Update(queue, occlusion);
 200   }
 201
 202   if (update_rect_.IsEmpty() && track_resource_)
 203     return false;
 204
 205   track_resource_ = ScopedUIResource::Create(
 206       layer_tree_host(), RasterizeScrollbarPart(scaled_track_rect, TRACK));
 207
 208   gfx::Rect thumb_rect = OriginThumbRect();
 209   if (has_thumb_ && !thumb_rect.IsEmpty()) {
 210     thumb_resource_ = ScopedUIResource::Create(
 211         layer_tree_host(), RasterizeScrollbarPart(thumb_rect, THUMB));
 212   }
 213
 214   // UI resources changed so push properties is needed.
 215   SetNeedsPushProperties();
 216   return true;
 217 }
 218
 219 UIResourceBitmap PaintedScrollbarLayer::RasterizeScrollbarPart(
 220     gfx::Rect rect,
 221     ScrollbarPart part) {
 222   DCHECK(!rect.size().IsEmpty());
 223
 224   SkBitmap skbitmap;
 225   skbitmap.setConfig(SkBitmap::kARGB_8888_Config, rect.width(), rect.height());
 226   skbitmap.allocPixels();
 227
 228   SkCanvas skcanvas(skbitmap);
 229   skcanvas.translate(SkFloatToScalar(-rect.x()), SkFloatToScalar(-rect.y()));
 230   skcanvas.scale(SkFloatToScalar(contents_scale_x()),
 231                  SkFloatToScalar(contents_scale_y()));
 232
 233   gfx::Rect layer_rect = gfx::ScaleToEnclosingRect(
 234       rect, 1.f / contents_scale_x(), 1.f / contents_scale_y());
 235   SkRect layer_skrect = RectToSkRect(layer_rect);
 236   SkPaint paint;
 237   paint.setAntiAlias(false);
 238   paint.setXfermodeMode(SkXfermode::kClear_Mode);
 239   skcanvas.drawRect(layer_skrect, paint);
 240   skcanvas.clipRect(layer_skrect);
 241
 242   scrollbar_->PaintPart(&skcanvas, part, layer_rect);
 243   // Make sure that the pixels are no longer mutable to unavoid unnecessary
 244   // allocation and copying.
 245   skbitmap.setImmutable();
 246
 247   return UIResourceBitmap(skbitmap);
 248 }
 249
 250 }  // namespace cc