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(scoped_ptr<Scrollbar> scrollbar,
  37                                              int scroll_layer_id)
  38     : scrollbar_(scrollbar.Pass()),
  39       scroll_layer_id_(scroll_layer_id),
  40       clip_layer_id_(Layer::INVALID_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::SetScrollLayer(int layer_id) {
  56   if (layer_id == scroll_layer_id_)
  57     return;
  58
  59   scroll_layer_id_ = layer_id;
  60   SetNeedsFullTreeSync();
  61 }
  62
  63 void PaintedScrollbarLayer::SetClipLayer(int layer_id) {
  64   if (layer_id == clip_layer_id_)
  65     return;
  66
  67   clip_layer_id_ = layer_id;
  68   SetNeedsFullTreeSync();
  69 }
  70
  71 bool PaintedScrollbarLayer::OpacityCanAnimateOnImplThread() const {
  72   return scrollbar_->IsOverlay();
  73 }
  74
  75 ScrollbarOrientation PaintedScrollbarLayer::orientation() const {
  76   return scrollbar_->Orientation();
  77 }
  78
  79 int PaintedScrollbarLayer::MaxTextureSize() {
  80   DCHECK(layer_tree_host());
  81   return layer_tree_host()->GetRendererCapabilities().max_texture_size;
  82 }
  83
  84 float PaintedScrollbarLayer::ClampScaleToMaxTextureSize(float scale) {
  85   // If the scaled content_bounds() is bigger than the max texture size of the
  86   // device, we need to clamp it by rescaling, since content_bounds() is used
  87   // below to set the texture size.
  88   gfx::Size scaled_bounds = ComputeContentBoundsForScale(scale, scale);
  89   if (scaled_bounds.width() > MaxTextureSize() ||
  90       scaled_bounds.height() > MaxTextureSize()) {
  91     if (scaled_bounds.width() > scaled_bounds.height())
  92       return (MaxTextureSize() - 1) / static_cast<float>(bounds().width());
  93     else
  94       return (MaxTextureSize() - 1) / static_cast<float>(bounds().height());
  95   }
  96   return scale;
  97 }
  98
  99 void PaintedScrollbarLayer::CalculateContentsScale(
 100     float ideal_contents_scale,
 101     float* contents_scale_x,
 102     float* contents_scale_y,
 103     gfx::Size* content_bounds) {
 104   ContentsScalingLayer::CalculateContentsScale(
 105       ClampScaleToMaxTextureSize(ideal_contents_scale),
 106       contents_scale_x,
 107       contents_scale_y,
 108       content_bounds);
 109 }
 110
 111 void PaintedScrollbarLayer::PushPropertiesTo(LayerImpl* layer) {
 112   ContentsScalingLayer::PushPropertiesTo(layer);
 113
 114   PushScrollClipPropertiesTo(layer);
 115
 116   PaintedScrollbarLayerImpl* scrollbar_layer =
 117       static_cast<PaintedScrollbarLayerImpl*>(layer);
 118
 119   scrollbar_layer->SetThumbThickness(thumb_thickness_);
 120   scrollbar_layer->SetThumbLength(thumb_length_);
 121   if (orientation() == HORIZONTAL) {
 122     scrollbar_layer->SetTrackStart(
 123         track_rect_.x() - location_.x());
 124     scrollbar_layer->SetTrackLength(track_rect_.width());
 125   } else {
 126     scrollbar_layer->SetTrackStart(
 127         track_rect_.y() - location_.y());
 128     scrollbar_layer->SetTrackLength(track_rect_.height());
 129   }
 130
 131   if (track_resource_.get())
 132     scrollbar_layer->set_track_ui_resource_id(track_resource_->id());
 133   if (thumb_resource_.get())
 134     scrollbar_layer->set_thumb_ui_resource_id(thumb_resource_->id());
 135
 136   scrollbar_layer->set_is_overlay_scrollbar(is_overlay_);
 137 }
 138
 139 ScrollbarLayerInterface* PaintedScrollbarLayer::ToScrollbarLayer() {
 140   return this;
 141 }
 142
 143 void PaintedScrollbarLayer::PushScrollClipPropertiesTo(LayerImpl* layer) {
 144   PaintedScrollbarLayerImpl* scrollbar_layer =
 145       static_cast<PaintedScrollbarLayerImpl*>(layer);
 146
 147   scrollbar_layer->SetScrollLayerAndClipLayerByIds(scroll_layer_id_,
 148                                                    clip_layer_id_);
 149 }
 150
 151 void PaintedScrollbarLayer::SetLayerTreeHost(LayerTreeHost* host) {
 152   // When the LTH is set to null or has changed, then this layer should remove
 153   // all of its associated resources.
 154   if (!host || host != layer_tree_host()) {
 155     track_resource_.reset();
 156     thumb_resource_.reset();
 157   }
 158
 159   ContentsScalingLayer::SetLayerTreeHost(host);
 160 }
 161
 162 gfx::Rect PaintedScrollbarLayer::ScrollbarLayerRectToContentRect(
 163     const gfx::Rect& layer_rect) const {
 164   // Don't intersect with the bounds as in LayerRectToContentRect() because
 165   // layer_rect here might be in coordinates of the containing layer.
 166   gfx::Rect expanded_rect = gfx::ScaleToEnclosingRect(
 167       layer_rect, contents_scale_x(), contents_scale_y());
 168   // We should never return a rect bigger than the content_bounds().
 169   gfx::Size clamped_size = expanded_rect.size();
 170   clamped_size.SetToMin(content_bounds());
 171   expanded_rect.set_size(clamped_size);
 172   return expanded_rect;
 173 }
 174
 175 gfx::Rect PaintedScrollbarLayer::OriginThumbRect() const {
 176   gfx::Size thumb_size;
 177   if (orientation() == HORIZONTAL) {
 178     thumb_size =
 179         gfx::Size(scrollbar_->ThumbLength(), scrollbar_->ThumbThickness());
 180   } else {
 181     thumb_size =
 182         gfx::Size(scrollbar_->ThumbThickness(), scrollbar_->ThumbLength());
 183   }
 184   return gfx::Rect(thumb_size);
 185 }
 186
 187 void PaintedScrollbarLayer::UpdateThumbAndTrackGeometry() {
 188   UpdateProperty(scrollbar_->TrackRect(), &track_rect_);
 189   UpdateProperty(scrollbar_->Location(), &location_);
 190   UpdateProperty(scrollbar_->IsOverlay(), &is_overlay_);
 191   UpdateProperty(scrollbar_->HasThumb(), &has_thumb_);
 192   if (has_thumb_) {
 193     UpdateProperty(scrollbar_->ThumbThickness(), &thumb_thickness_);
 194     UpdateProperty(scrollbar_->ThumbLength(), &thumb_length_);
 195   } else {
 196     UpdateProperty(0, &thumb_thickness_);
 197     UpdateProperty(0, &thumb_length_);
 198   }
 199 }
 200
 201 bool PaintedScrollbarLayer::Update(ResourceUpdateQueue* queue,
 202                                    const OcclusionTracker<Layer>* occlusion) {
 203   UpdateThumbAndTrackGeometry();
 204
 205   gfx::Rect track_layer_rect = gfx::Rect(location_, bounds());
 206   gfx::Rect scaled_track_rect = ScrollbarLayerRectToContentRect(
 207       track_layer_rect);
 208
 209   if (track_rect_.IsEmpty() || scaled_track_rect.IsEmpty())
 210     return false;
 211
 212   {
 213     base::AutoReset<bool> ignore_set_needs_commit(&ignore_set_needs_commit_,
 214                                                   true);
 215     ContentsScalingLayer::Update(queue, occlusion);
 216   }
 217
 218   if (update_rect_.IsEmpty() && track_resource_)
 219     return false;
 220
 221   track_resource_ = ScopedUIResource::Create(
 222       layer_tree_host(),
 223       RasterizeScrollbarPart(track_layer_rect, scaled_track_rect, TRACK));
 224
 225   gfx::Rect thumb_layer_rect = OriginThumbRect();
 226   gfx::Rect scaled_thumb_rect =
 227       ScrollbarLayerRectToContentRect(thumb_layer_rect);
 228   if (has_thumb_ && !scaled_thumb_rect.IsEmpty()) {
 229     thumb_resource_ = ScopedUIResource::Create(
 230         layer_tree_host(),
 231         RasterizeScrollbarPart(thumb_layer_rect, scaled_thumb_rect, THUMB));
 232   }
 233
 234   // UI resources changed so push properties is needed.
 235   SetNeedsPushProperties();
 236   return true;
 237 }
 238
 239 UIResourceBitmap PaintedScrollbarLayer::RasterizeScrollbarPart(
 240     const gfx::Rect& layer_rect,
 241     const gfx::Rect& content_rect,
 242     ScrollbarPart part) {
 243   DCHECK(!content_rect.size().IsEmpty());
 244   DCHECK(!layer_rect.size().IsEmpty());
 245
 246   SkBitmap skbitmap;
 247   skbitmap.allocN32Pixels(content_rect.width(), content_rect.height());
 248   SkCanvas skcanvas(skbitmap);
 249
 250   float scale_x =
 251       content_rect.width() / static_cast<float>(layer_rect.width());
 252   float scale_y =
 253       content_rect.height() / static_cast<float>(layer_rect.height());
 254
 255   skcanvas.scale(SkFloatToScalar(scale_x),
 256                  SkFloatToScalar(scale_y));
 257   skcanvas.translate(SkFloatToScalar(-layer_rect.x()),
 258                      SkFloatToScalar(-layer_rect.y()));
 259
 260   SkRect layer_skrect = RectToSkRect(layer_rect);
 261   SkPaint paint;
 262   paint.setAntiAlias(false);
 263   paint.setXfermodeMode(SkXfermode::kClear_Mode);
 264   skcanvas.drawRect(layer_skrect, paint);
 265   skcanvas.clipRect(layer_skrect);
 266
 267   scrollbar_->PaintPart(&skcanvas, part, layer_rect);
 268   // Make sure that the pixels are no longer mutable to unavoid unnecessary
 269   // allocation and copying.
 270   skbitmap.setImmutable();
 271
 272   return UIResourceBitmap(skbitmap);
 273 }
 274
 275 }  // namespace cc