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/scrollbar_layer_impl_base.h" 6 7 #include <algorithm> 8 #include "cc/trees/layer_tree_impl.h" 9 #include "ui/gfx/rect_conversions.h" 10 11 namespace cc { 12 13 ScrollbarLayerImplBase::ScrollbarLayerImplBase( 14 LayerTreeImpl* tree_impl, 15 int id, 16 ScrollbarOrientation orientation, 17 bool is_left_side_vertical_scrollbar, 18 bool is_overlay) 19 : LayerImpl(tree_impl, id), 20 scroll_layer_(NULL), 21 clip_layer_(NULL), 22 is_overlay_scrollbar_(is_overlay), 23 thumb_thickness_scale_factor_(1.f), 24 current_pos_(0.f), 25 maximum_(0), 26 orientation_(orientation), 27 is_left_side_vertical_scrollbar_(is_left_side_vertical_scrollbar), 28 vertical_adjust_(0.f), 29 visible_to_total_length_ratio_(1.f) {} 30 31 ScrollbarLayerImplBase::~ScrollbarLayerImplBase() {} 32 33 void ScrollbarLayerImplBase::PushPropertiesTo(LayerImpl* layer) { 34 float active_opacity = layer->opacity(); 35 LayerImpl::PushPropertiesTo(layer); 36 layer->SetOpacity(active_opacity); 37 DCHECK(layer->ToScrollbarLayer()); 38 layer->ToScrollbarLayer()->set_is_overlay_scrollbar(is_overlay_scrollbar_); 39 PushScrollClipPropertiesTo(layer); 40 } 41 42 void ScrollbarLayerImplBase::PushScrollClipPropertiesTo(LayerImpl* layer) { 43 DCHECK(layer->ToScrollbarLayer()); 44 layer->ToScrollbarLayer()->SetScrollLayerAndClipLayerByIds(ScrollLayerId(), 45 ClipLayerId()); 46 } 47 48 ScrollbarLayerImplBase* ScrollbarLayerImplBase::ToScrollbarLayer() { 49 return this; 50 } 51 52 namespace { 53 54 typedef void (LayerImpl::*ScrollbarRegistrationOperation)( 55 ScrollbarLayerImplBase*); 56 57 void RegisterScrollbarWithLayers(ScrollbarLayerImplBase* scrollbar, 58 LayerImpl* container_layer, 59 LayerImpl* scroll_layer, 60 ScrollbarRegistrationOperation operation) { 61 if (!container_layer || !scroll_layer) 62 return; 63 64 DCHECK(scrollbar); 65 66 // Scrollbars must be notifed of changes to their scroll and container layers 67 // and all scrollable layers in between. 68 for (LayerImpl* current_layer = scroll_layer; 69 current_layer && current_layer != container_layer->parent(); 70 current_layer = current_layer->parent()) { 71 // TODO(wjmaclean) We shouldn't need to exempt the scroll_layer from the 72 // scrollable() test below. https://crbug.com/367858. 73 if (current_layer->scrollable() || current_layer == container_layer || 74 current_layer == scroll_layer) 75 (current_layer->*operation)(scrollbar); 76 } 77 } 78 } // namespace 79 80 void ScrollbarLayerImplBase::SetScrollLayerAndClipLayerByIds( 81 int scroll_layer_id, 82 int clip_layer_id) { 83 LayerImpl* scroll_layer = layer_tree_impl()->LayerById(scroll_layer_id); 84 LayerImpl* clip_layer = layer_tree_impl()->LayerById(clip_layer_id); 85 if (scroll_layer_ == scroll_layer && clip_layer_ == clip_layer) 86 return; 87 88 RegisterScrollbarWithLayers( 89 this, clip_layer_, scroll_layer_, &LayerImpl::RemoveScrollbar); 90 scroll_layer_ = scroll_layer; 91 clip_layer_ = clip_layer; 92 RegisterScrollbarWithLayers( 93 this, clip_layer_, scroll_layer_, &LayerImpl::AddScrollbar); 94 95 ScrollbarParametersDidChange(); 96 } 97 98 gfx::Rect ScrollbarLayerImplBase::ScrollbarLayerRectToContentRect( 99 const gfx::RectF& layer_rect) const { 100 // Don't intersect with the bounds as in LayerRectToContentRect() because 101 // layer_rect here might be in coordinates of the containing layer. 102 gfx::RectF content_rect = gfx::ScaleRect(layer_rect, 103 contents_scale_x(), 104 contents_scale_y()); 105 return gfx::ToEnclosingRect(content_rect); 106 } 107 108 bool ScrollbarLayerImplBase::SetCurrentPos(float current_pos) { 109 if (current_pos_ == current_pos) 110 return false; 111 current_pos_ = current_pos; 112 NoteLayerPropertyChanged(); 113 return true; 114 } 115 116 bool ScrollbarLayerImplBase::SetMaximum(int maximum) { 117 if (maximum_ == maximum) 118 return false; 119 maximum_ = maximum; 120 NoteLayerPropertyChanged(); 121 return true; 122 } 123 124 bool ScrollbarLayerImplBase::SetVerticalAdjust(float vertical_adjust) { 125 if (vertical_adjust_ == vertical_adjust) 126 return false; 127 vertical_adjust_ = vertical_adjust; 128 NoteLayerPropertyChanged(); 129 return true; 130 } 131 132 bool ScrollbarLayerImplBase::SetVisibleToTotalLengthRatio(float ratio) { 133 if (!IsThumbResizable()) 134 return false; 135 136 if (visible_to_total_length_ratio_ == ratio) 137 return false; 138 visible_to_total_length_ratio_ = ratio; 139 NoteLayerPropertyChanged(); 140 return true; 141 } 142 143 bool ScrollbarLayerImplBase::SetThumbThicknessScaleFactor(float factor) { 144 if (thumb_thickness_scale_factor_ == factor) 145 return false; 146 thumb_thickness_scale_factor_ = factor; 147 NoteLayerPropertyChanged(); 148 return true; 149 } 150 151 gfx::Rect ScrollbarLayerImplBase::ComputeThumbQuadRect() const { 152 // Thumb extent is the length of the thumb in the scrolling direction, thumb 153 // thickness is in the perpendicular direction. Here's an example of a 154 // horizontal scrollbar - inputs are above the scrollbar, computed values 155 // below: 156 // 157 // |<------------------- track_length_ ------------------->| 158 // 159 // |--| <-- start_offset 160 // 161 // +--+----------------------------+------------------+-------+--+ 162 // |<|| |##################| ||>| 163 // +--+----------------------------+------------------+-------+--+ 164 // 165 // |<- thumb_length ->| 166 // 167 // |<------- thumb_offset -------->| 168 // 169 // For painted, scrollbars, the length is fixed. For solid color scrollbars we 170 // have to compute it. The ratio of the thumb's length to the track's length 171 // is the same as that of the visible viewport to the total viewport, unless 172 // that would make the thumb's length less than its thickness. 173 // 174 // vertical_adjust_ is used when the layer geometry from the main thread is 175 // not in sync with what the user sees. For instance on Android scrolling the 176 // top bar controls out of view reveals more of the page content. We want the 177 // root layer scrollbars to reflect what the user sees even if we haven't 178 // received new layer geometry from the main thread. If the user has scrolled 179 // down by 50px and the initial viewport size was 950px the geometry would 180 // look something like this: 181 // 182 // vertical_adjust_ = 50, scroll position 0, visible ratios 99% 183 // Layer geometry: Desired thumb positions: 184 // +--------------------+-+ +----------------------+ <-- 0px 185 // | |v| | #| 186 // | |e| | #| 187 // | |r| | #| 188 // | |t| | #| 189 // | |i| | #| 190 // | |c| | #| 191 // | |a| | #| 192 // | |l| | #| 193 // | | | | #| 194 // | |l| | #| 195 // | |a| | #| 196 // | |y| | #| 197 // | |e| | #| 198 // | |r| | #| 199 // +--------------------+-+ | #| 200 // | horizontal layer | | | #| 201 // +--------------------+-+ | #| <-- 950px 202 // | | | #| 203 // | | |##################### | 204 // +----------------------+ +----------------------+ <-- 1000px 205 // 206 // The layer geometry is set up for a 950px tall viewport, but the user can 207 // actually see down to 1000px. Thus we have to move the quad for the 208 // horizontal scrollbar down by the vertical_adjust_ factor and lay the 209 // vertical thumb out on a track lengthed by the vertical_adjust_ factor. This 210 // means the quads may extend outside the layer's bounds. 211 212 // With the length known, we can compute the thumb's position. 213 float track_length = TrackLength(); 214 int thumb_length = ThumbLength(); 215 int thumb_thickness = ThumbThickness(); 216 217 // With the length known, we can compute the thumb's position. 218 float clamped_current_pos = 219 std::min(std::max(current_pos_, 0.f), static_cast<float>(maximum_)); 220 221 int thumb_offset = TrackStart(); 222 if (maximum_ > 0) { 223 float ratio = clamped_current_pos / maximum_; 224 float max_offset = track_length - thumb_length; 225 thumb_offset += static_cast<int>(ratio * max_offset); 226 } 227 228 float thumb_thickness_adjustment = 229 thumb_thickness * (1.f - thumb_thickness_scale_factor_); 230 231 gfx::RectF thumb_rect; 232 if (orientation_ == HORIZONTAL) { 233 thumb_rect = gfx::RectF(thumb_offset, 234 vertical_adjust_ + thumb_thickness_adjustment, 235 thumb_length, 236 thumb_thickness - thumb_thickness_adjustment); 237 } else { 238 thumb_rect = gfx::RectF( 239 is_left_side_vertical_scrollbar_ 240 ? bounds().width() - thumb_thickness 241 : thumb_thickness_adjustment, 242 thumb_offset, 243 thumb_thickness - thumb_thickness_adjustment, 244 thumb_length); 245 } 246 247 return ScrollbarLayerRectToContentRect(thumb_rect); 248 } 249 250 void ScrollbarLayerImplBase::ScrollbarParametersDidChange() { 251 if (!clip_layer_ || !scroll_layer_) 252 return; 253 254 scroll_layer_->SetScrollbarPosition(this, clip_layer_); 255 } 256 257 } // namespace cc 258