UI Resource Manager

cc/layers/picture_scrollbar_layer_impl.cc

+// 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/picture_scrollbar_layer_impl.h"
+
+#if !USE_REGULAR_SCROLLBAR
+
+#include "cc/animation/scrollbar_animation_controller.h"
+#include "cc/layers/layer.h"
+#include "cc/layers/quad_sink.h"
+#include "cc/quads/solid_color_draw_quad.h"
+#include "cc/quads/texture_draw_quad.h"
+#include "cc/quads/tile_draw_quad.h"
+#include "cc/trees/layer_tree_impl.h"
+#include "cc/trees/layer_tree_settings.h"
+#include "ui/gfx/rect_conversions.h"
+
+namespace cc {
+
+scoped_ptr<ScrollbarLayerImpl> ScrollbarLayerImpl::Create(
+    LayerTreeImpl* tree_impl,
+    int id,
+    ScrollbarOrientation orientation) {
+  return make_scoped_ptr(new ScrollbarLayerImpl(tree_impl,
+                                                id,
+                                                orientation));
+}
+
+ScrollbarLayerImpl::ScrollbarLayerImpl(
+    LayerTreeImpl* tree_impl,
+    int id,
+    ScrollbarOrientation orientation)
+    : LayerImpl(tree_impl, id),
+      current_pos_(0.f),
+      maximum_(0),
+      thumb_thickness_(0),
+      thumb_length_(0),
+      track_start_(0),
+      track_length_(0),
+      orientation_(orientation),
+      vertical_adjust_(0.f),
+      visible_to_total_length_ratio_(1.f),
+      scroll_layer_id_(Layer::INVALID_ID),
+      track_ui_resource_id_(0),
+      thumb_ui_resource_id_(0),
+      is_scrollable_area_active_(false),
+      is_scroll_view_scrollbar_(false),
+      enabled_(false),
+      is_custom_scrollbar_(false),
+      is_overlay_scrollbar_(false) {}
+
+ScrollbarLayerImpl::~ScrollbarLayerImpl() {}
+
+ScrollbarLayerImpl* ScrollbarLayerImpl::ToScrollbarLayer() {
+  return this;
+}
+
+scoped_ptr<LayerImpl> ScrollbarLayerImpl::CreateLayerImpl(
+    LayerTreeImpl* tree_impl) {
+  return ScrollbarLayerImpl::Create(tree_impl,
+                                    id(),
+                                    orientation_).PassAs<LayerImpl>();
+}
+
+void ScrollbarLayerImpl::PushPropertiesTo(LayerImpl* layer) {
+  LayerImpl::PushPropertiesTo(layer);
+
+  ScrollbarLayerImpl* scrollbar_layer = static_cast<ScrollbarLayerImpl*>(layer);
+
+  scrollbar_layer->set_thumb_thickness(thumb_thickness_);
+  scrollbar_layer->set_thumb_length(thumb_length_);
+  scrollbar_layer->set_track_start(track_start_);
+  scrollbar_layer->set_track_length(track_length_);
+
+  if (scrollbar_layer->track_ui_resource_id_ != track_ui_resource_id_ ||
+      scrollbar_layer->thumb_ui_resource_id_ != thumb_ui_resource_id_) {
+    scrollbar_layer->set_track_ui_resource_id(track_ui_resource_id_);
+    scrollbar_layer->set_thumb_ui_resource_id(thumb_ui_resource_id_);
+
+    NoteLayerPropertyChanged();
+    scrollbar_layer->NoteLayerPropertyChanged();
+  }
+}
+
+bool ScrollbarLayerImpl::WillDraw(DrawMode draw_mode,
+                                  ResourceProvider* resource_provider) {
+  LayerImpl::WillDraw(draw_mode, resource_provider);
+  return draw_mode != DRAW_MODE_RESOURCELESS_SOFTWARE ||
+         layer_tree_impl()->settings().solid_color_scrollbars;
+}
+
+void ScrollbarLayerImpl::AppendQuads(QuadSink* quad_sink,
+                                     AppendQuadsData* append_quads_data) {
+  gfx::Rect bounds_rect(bounds());
+  gfx::Rect content_bounds_rect(content_bounds());
+
+  SharedQuadState* shared_quad_state =
+      quad_sink->UseSharedQuadState(CreateSharedQuadState());
+  AppendDebugBorderQuad(quad_sink, shared_quad_state, append_quads_data);
+
+  gfx::Rect thumb_quad_rect = ComputeThumbQuadRect();
+
+  if (layer_tree_impl()->settings().solid_color_scrollbars) {
+    scoped_ptr<SolidColorDrawQuad> quad = SolidColorDrawQuad::Create();
+    quad->SetNew(shared_quad_state,
+                 thumb_quad_rect,
+                 layer_tree_impl()->settings().solid_color_scrollbar_color,
+                 false);
+    quad_sink->Append(quad.PassAs<DrawQuad>(), append_quads_data);
+    return;
+  }
+
+  gfx::Rect track_quad_rect = content_bounds_rect;
+
+  ResourceProvider::ResourceId thumb_resource_id =
+    layer_tree_impl()->ResourceIdForUIResource(thumb_ui_resource_id_);
+  ResourceProvider::ResourceId track_resource_id =
+    layer_tree_impl()->ResourceIdForUIResource(track_ui_resource_id_);
+
+  if (thumb_resource_id) {
+    scoped_ptr<TileDrawQuad> thumb_quad = TileDrawQuad::Create();
+    thumb_quad->SetNew(shared_quad_state,
+                       thumb_quad_rect,
+                       thumb_quad_rect,
+                       thumb_resource_id,
+                       gfx::RectF(0, 0, 1, 1),
+                       gfx::Size(1, 1),
+                       false);
+    quad_sink->Append(thumb_quad.PassAs<DrawQuad>(), append_quads_data);
+  }
+
+  if (!track_quad_rect.IsEmpty() && track_resource_id) {
+    scoped_ptr<TileDrawQuad> track_quad = TileDrawQuad::Create();
+    track_quad->SetNew(shared_quad_state,
+                       track_quad_rect,
+                       track_quad_rect,
+                       track_resource_id,
+                       gfx::RectF(0, 0, 1, 1),
+                       gfx::Size(1, 1),
+                       false);
+    quad_sink->Append(track_quad.PassAs<DrawQuad>(), append_quads_data);
+  }
+}
+
+ScrollbarOrientation ScrollbarLayerImpl::Orientation() const {
+  return orientation_;
+}
+
+float ScrollbarLayerImpl::CurrentPos() const {
+  return current_pos_;
+}
+
+int ScrollbarLayerImpl::Maximum() const {
+  return maximum_;
+}
+
+gfx::Rect ScrollbarLayerImpl::ScrollbarLayerRectToContentRect(
+    gfx::RectF layer_rect) const {
+  // Don't intersect with the bounds as in layerRectToContentRect() because
+  // layer_rect here might be in coordinates of the containing layer.
+  gfx::RectF content_rect = gfx::ScaleRect(layer_rect,
+                                           contents_scale_x(),
+                                           contents_scale_y());
+  return gfx::ToEnclosingRect(content_rect);
+}
+
+gfx::Rect ScrollbarLayerImpl::ComputeThumbQuadRect() const {
+  // Thumb extent is the length of the thumb in the scrolling direction, thumb
+  // thickness is in the perpendicular direction. Here's an example of a
+  // horizontal scrollbar - inputs are above the scrollbar, computed values
+  // below:
+  //
+  //    |<------------------- track_length_ ------------------->|
+  //
+  // |--| <-- start_offset
+  //
+  // +--+----------------------------+------------------+-------+--+
+  // |<||                            |##################|       ||>|
+  // +--+----------------------------+------------------+-------+--+
+  //
+  //                                 |<- thumb_length ->|
+  //
+  // |<------- thumb_offset -------->|
+  //
+  // For painted, scrollbars, the length is fixed. For solid color scrollbars we
+  // have to compute it. The ratio of the thumb's length to the track's length
+  // is the same as that of the visible viewport to the total viewport, unless
+  // that would make the thumb's length less than its thickness.
+  //
+  // vertical_adjust_ is used when the layer geometry from the main thread is
+  // not in sync with what the user sees. For instance on Android scrolling the
+  // top bar controls out of view reveals more of the page content. We want the
+  // root layer scrollbars to reflect what the user sees even if we haven't
+  // received new layer geometry from the main thread.  If the user has scrolled
+  // down by 50px and the initial viewport size was 950px the geometry would
+  // look something like this:
+  //
+  // vertical_adjust_ = 50, scroll position 0, visible ratios 99%
+  // Layer geometry:             Desired thumb positions:
+  // +--------------------+-+   +----------------------+   <-- 0px
+  // |                    |v|   |                     #|
+  // |                    |e|   |                     #|
+  // |                    |r|   |                     #|
+  // |                    |t|   |                     #|
+  // |                    |i|   |                     #|
+  // |                    |c|   |                     #|
+  // |                    |a|   |                     #|
+  // |                    |l|   |                     #|
+  // |                    | |   |                     #|
+  // |                    |l|   |                     #|
+  // |                    |a|   |                     #|
+  // |                    |y|   |                     #|
+  // |                    |e|   |                     #|
+  // |                    |r|   |                     #|
+  // +--------------------+-+   |                     #|
+  // | horizontal  layer  | |   |                     #|
+  // +--------------------+-+   |                     #|  <-- 950px
+  // |                      |   |                     #|
+  // |                      |   |##################### |
+  // +----------------------+   +----------------------+  <-- 1000px
+  //
+  // The layer geometry is set up for a 950px tall viewport, but the user can
+  // actually see down to 1000px. Thus we have to move the quad for the
+  // horizontal scrollbar down by the vertical_adjust_ factor and lay the
+  // vertical thumb out on a track lengthed by the vertical_adjust_ factor. This
+  // means the quads may extend outside the layer's bounds.
+
+  int thumb_length = thumb_length_;
+  float track_length = track_length_;
+  if (orientation_ == VERTICAL)
+    track_length += vertical_adjust_;
+
+  if (layer_tree_impl()->settings().solid_color_scrollbars) {
+    thumb_length = std::max(
+        static_cast<int>(visible_to_total_length_ratio_ * track_length),
+        thumb_thickness_);
+  }
+
+  // With the length known, we can compute the thumb's position.
+  float ratio = current_pos_ / maximum_;
+  float max_offset = track_length - thumb_length;
+  int thumb_offset = static_cast<int>(ratio * max_offset) + track_start_;
+
+  gfx::RectF thumb_rect;
+  if (orientation_ == HORIZONTAL) {
+    thumb_rect = gfx::RectF(thumb_offset, vertical_adjust_,
+                            thumb_length, thumb_thickness_);
+  } else {
+    thumb_rect = gfx::RectF(0.f, thumb_offset,
+                            thumb_thickness_, thumb_length);
+  }
+
+  return ScrollbarLayerRectToContentRect(thumb_rect);
+}
+
+void ScrollbarLayerImpl::DidLoseOutputSurface() {
+}
+
+const char* ScrollbarLayerImpl::LayerTypeAsString() const {
+  return "cc::ScrollbarLayerImpl";
+}
+
+void ScrollbarLayerImpl::set_track_ui_resource_id(UIResourceId uid) {
+  track_ui_resource_id_ = uid;
+}
+
+void ScrollbarLayerImpl::set_thumb_ui_resource_id(UIResourceId uid) {
+  thumb_ui_resource_id_ = uid;
+}
+
+}  // namespace cc
+
+#endif