src/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 device_scale_factor,
 102     float page_scale_factor,
 103     float maximum_animation_contents_scale,
 104     bool animating_transform_to_screen,
 105     float* contents_scale_x,
 106     float* contents_scale_y,
 107     gfx::Size* content_bounds) {
 108   ContentsScalingLayer::CalculateContentsScale(
 109       ClampScaleToMaxTextureSize(ideal_contents_scale),
 110       device_scale_factor,
 111       page_scale_factor,
 112       maximum_animation_contents_scale,
 113       animating_transform_to_screen,
 114       contents_scale_x,
 115       contents_scale_y,
 116       content_bounds);
 117 }
 118
 119 void PaintedScrollbarLayer::PushPropertiesTo(LayerImpl* layer) {
 120   ContentsScalingLayer::PushPropertiesTo(layer);
 121
 122   PushScrollClipPropertiesTo(layer);
 123
 124   PaintedScrollbarLayerImpl* scrollbar_layer =
 125       static_cast<PaintedScrollbarLayerImpl*>(layer);
 126
 127   scrollbar_layer->SetThumbThickness(thumb_thickness_);
 128   scrollbar_layer->SetThumbLength(thumb_length_);
 129   if (orientation() == HORIZONTAL) {
 130     scrollbar_layer->SetTrackStart(
 131         track_rect_.x() - location_.x());
 132     scrollbar_layer->SetTrackLength(track_rect_.width());
 133   } else {
 134     scrollbar_layer->SetTrackStart(
 135         track_rect_.y() - location_.y());
 136     scrollbar_layer->SetTrackLength(track_rect_.height());
 137   }
 138
 139   if (track_resource_.get())
 140     scrollbar_layer->set_track_ui_resource_id(track_resource_->id());
 141   if (thumb_resource_.get())
 142     scrollbar_layer->set_thumb_ui_resource_id(thumb_resource_->id());
 143
 144   scrollbar_layer->set_is_overlay_scrollbar(is_overlay_);
 145 }
 146
 147 ScrollbarLayerInterface* PaintedScrollbarLayer::ToScrollbarLayer() {
 148   return this;
 149 }
 150
 151 void PaintedScrollbarLayer::PushScrollClipPropertiesTo(LayerImpl* layer) {
 152   PaintedScrollbarLayerImpl* scrollbar_layer =
 153       static_cast<PaintedScrollbarLayerImpl*>(layer);
 154
 155   scrollbar_layer->SetScrollLayerById(scroll_layer_id_);
 156   scrollbar_layer->SetClipLayerById(clip_layer_id_);
 157 }
 158
 159 void PaintedScrollbarLayer::SetLayerTreeHost(LayerTreeHost* host) {
 160   // When the LTH is set to null or has changed, then this layer should remove
 161   // all of its associated resources.
 162   if (!host || host != layer_tree_host()) {
 163     track_resource_.reset();
 164     thumb_resource_.reset();
 165   }
 166
 167   ContentsScalingLayer::SetLayerTreeHost(host);
 168 }
 169
 170 gfx::Rect PaintedScrollbarLayer::ScrollbarLayerRectToContentRect(
 171     const gfx::Rect& layer_rect) const {
 172   // Don't intersect with the bounds as in LayerRectToContentRect() because
 173   // layer_rect here might be in coordinates of the containing layer.
 174   gfx::Rect expanded_rect = gfx::ScaleToEnclosingRect(
 175       layer_rect, contents_scale_x(), contents_scale_y());
 176   // We should never return a rect bigger than the content_bounds().
 177   gfx::Size clamped_size = expanded_rect.size();
 178   clamped_size.SetToMin(content_bounds());
 179   expanded_rect.set_size(clamped_size);
 180   return expanded_rect;
 181 }
 182
 183 gfx::Rect PaintedScrollbarLayer::OriginThumbRect() const {
 184   gfx::Size thumb_size;
 185   if (orientation() == HORIZONTAL) {
 186     thumb_size =
 187         gfx::Size(scrollbar_->ThumbLength(), scrollbar_->ThumbThickness());
 188   } else {
 189     thumb_size =
 190         gfx::Size(scrollbar_->ThumbThickness(), scrollbar_->ThumbLength());
 191   }
 192   return gfx::Rect(thumb_size);
 193 }
 194
 195 void PaintedScrollbarLayer::UpdateThumbAndTrackGeometry() {
 196   UpdateProperty(scrollbar_->TrackRect(), &track_rect_);
 197   UpdateProperty(scrollbar_->Location(), &location_);
 198   UpdateProperty(scrollbar_->IsOverlay(), &is_overlay_);
 199   UpdateProperty(scrollbar_->HasThumb(), &has_thumb_);
 200   if (has_thumb_) {
 201     UpdateProperty(scrollbar_->ThumbThickness(), &thumb_thickness_);
 202     UpdateProperty(scrollbar_->ThumbLength(), &thumb_length_);
 203   }
 204 }
 205
 206 bool PaintedScrollbarLayer::Update(ResourceUpdateQueue* queue,
 207                                    const OcclusionTracker<Layer>* occlusion) {
 208   UpdateThumbAndTrackGeometry();
 209
 210   gfx::Rect track_layer_rect = gfx::Rect(location_, bounds());
 211   gfx::Rect scaled_track_rect = ScrollbarLayerRectToContentRect(
 212       track_layer_rect);
 213
 214   if (track_rect_.IsEmpty() || scaled_track_rect.IsEmpty())
 215     return false;
 216
 217   {
 218     base::AutoReset<bool> ignore_set_needs_commit(&ignore_set_needs_commit_,
 219                                                   true);
 220     ContentsScalingLayer::Update(queue, occlusion);
 221   }
 222
 223   if (update_rect_.IsEmpty() && track_resource_)
 224     return false;
 225
 226   track_resource_ = ScopedUIResource::Create(
 227       layer_tree_host(),
 228       RasterizeScrollbarPart(track_layer_rect, scaled_track_rect, TRACK));
 229
 230   gfx::Rect thumb_layer_rect = OriginThumbRect();
 231   gfx::Rect scaled_thumb_rect =
 232       ScrollbarLayerRectToContentRect(thumb_layer_rect);
 233   if (has_thumb_ && !scaled_thumb_rect.IsEmpty()) {
 234     thumb_resource_ = ScopedUIResource::Create(
 235         layer_tree_host(),
 236         RasterizeScrollbarPart(thumb_layer_rect, scaled_thumb_rect, THUMB));
 237   }
 238
 239   // UI resources changed so push properties is needed.
 240   SetNeedsPushProperties();
 241   return true;
 242 }
 243
 244 UIResourceBitmap PaintedScrollbarLayer::RasterizeScrollbarPart(
 245     const gfx::Rect& layer_rect,
 246     const gfx::Rect& content_rect,
 247     ScrollbarPart part) {
 248   DCHECK(!content_rect.size().IsEmpty());
 249   DCHECK(!layer_rect.size().IsEmpty());
 250
 251   SkBitmap skbitmap;
 252   skbitmap.allocN32Pixels(content_rect.width(), content_rect.height());
 253   SkCanvas skcanvas(skbitmap);
 254
 255   float scale_x =
 256       content_rect.width() / static_cast<float>(layer_rect.width());
 257   float scale_y =
 258       content_rect.height() / static_cast<float>(layer_rect.height());
 259
 260   skcanvas.scale(SkFloatToScalar(scale_x),
 261                  SkFloatToScalar(scale_y));
 262   skcanvas.translate(SkFloatToScalar(-layer_rect.x()),
 263                      SkFloatToScalar(-layer_rect.y()));
 264
 265   SkRect layer_skrect = RectToSkRect(layer_rect);
 266   SkPaint paint;
 267   paint.setAntiAlias(false);
 268   paint.setXfermodeMode(SkXfermode::kClear_Mode);
 269   skcanvas.drawRect(layer_skrect, paint);
 270   skcanvas.clipRect(layer_skrect);
 271
 272   scrollbar_->PaintPart(&skcanvas, part, layer_rect);
 273   // Make sure that the pixels are no longer mutable to unavoid unnecessary
 274   // allocation and copying.
 275   skbitmap.setImmutable();
 276
 277   return UIResourceBitmap(skbitmap);
 278 }
 279
 280 }  // namespace cc