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
9 #include "base/numerics/ranges.h"
10 #include "cc/trees/effect_node.h"
11 #include "cc/trees/layer_tree_impl.h"
12 #include "cc/trees/scroll_node.h"
13 #include "ui/gfx/geometry/rect_conversions.h"
14
15 namespace cc {
16
ScrollbarLayerImplBase(LayerTreeImpl * tree_impl,int id,ScrollbarOrientation orientation,bool is_left_side_vertical_scrollbar,bool is_overlay)17 ScrollbarLayerImplBase::ScrollbarLayerImplBase(
18 LayerTreeImpl* tree_impl,
19 int id,
20 ScrollbarOrientation orientation,
21 bool is_left_side_vertical_scrollbar,
22 bool is_overlay)
23 : LayerImpl(tree_impl, id),
24 is_overlay_scrollbar_(is_overlay),
25 thumb_thickness_scale_factor_(1.f),
26 current_pos_(0.f),
27 clip_layer_length_(0.f),
28 scroll_layer_length_(0.f),
29 orientation_(orientation),
30 is_left_side_vertical_scrollbar_(is_left_side_vertical_scrollbar),
31 vertical_adjust_(0.f) {
32 set_is_scrollbar(true);
33 }
34
~ScrollbarLayerImplBase()35 ScrollbarLayerImplBase::~ScrollbarLayerImplBase() {
36 layer_tree_impl()->UnregisterScrollbar(this);
37 }
38
PushPropertiesTo(LayerImpl * layer)39 void ScrollbarLayerImplBase::PushPropertiesTo(LayerImpl* layer) {
40 LayerImpl::PushPropertiesTo(layer);
41 DCHECK(layer->ToScrollbarLayer());
42 layer->ToScrollbarLayer()->set_is_overlay_scrollbar(is_overlay_scrollbar_);
43 layer->ToScrollbarLayer()->SetScrollElementId(scroll_element_id());
44 }
45
ToScrollbarLayer()46 ScrollbarLayerImplBase* ScrollbarLayerImplBase::ToScrollbarLayer() {
47 return this;
48 }
49
SetScrollElementId(ElementId scroll_element_id)50 void ScrollbarLayerImplBase::SetScrollElementId(ElementId scroll_element_id) {
51 if (scroll_element_id_ == scroll_element_id)
52 return;
53
54 layer_tree_impl()->UnregisterScrollbar(this);
55 scroll_element_id_ = scroll_element_id;
56 layer_tree_impl()->RegisterScrollbar(this);
57 }
58
SetCurrentPos(float current_pos)59 bool ScrollbarLayerImplBase::SetCurrentPos(float current_pos) {
60 if (current_pos_ == current_pos)
61 return false;
62 current_pos_ = current_pos;
63 NoteLayerPropertyChanged();
64 return true;
65 }
66
current_pos() const67 float ScrollbarLayerImplBase::current_pos() const {
68 DCHECK(!layer_tree_impl()->ScrollbarGeometriesNeedUpdate());
69 return current_pos_;
70 }
71
clip_layer_length() const72 float ScrollbarLayerImplBase::clip_layer_length() const {
73 DCHECK(!layer_tree_impl()->ScrollbarGeometriesNeedUpdate());
74 return clip_layer_length_;
75 }
76
scroll_layer_length() const77 float ScrollbarLayerImplBase::scroll_layer_length() const {
78 DCHECK(!layer_tree_impl()->ScrollbarGeometriesNeedUpdate());
79 return scroll_layer_length_;
80 }
81
vertical_adjust() const82 float ScrollbarLayerImplBase::vertical_adjust() const {
83 DCHECK(!layer_tree_impl()->ScrollbarGeometriesNeedUpdate());
84 return vertical_adjust_;
85 }
86
CanScrollOrientation() const87 bool ScrollbarLayerImplBase::CanScrollOrientation() const {
88 PropertyTrees* property_trees = layer_tree_impl()->property_trees();
89 const auto* scroll_node =
90 property_trees->scroll_tree.FindNodeFromElementId(scroll_element_id_);
91 DCHECK(scroll_node);
92 // TODO(bokan): Looks like we sometimes get here without a ScrollNode. It
93 // should be safe to just return false here (we don't use scroll_element_id_
94 // anywhere else) so we can merge the fix. Once merged, will investigate the
95 // underlying cause. https://crbug.com/924068.
96 if (!scroll_node)
97 return false;
98
99 if (orientation() == ScrollbarOrientation::HORIZONTAL) {
100 if (!scroll_node->user_scrollable_horizontal)
101 return false;
102 } else {
103 if (!scroll_node->user_scrollable_vertical)
104 return false;
105 }
106
107 // Ensure the clip_layer_length and scroll_layer_length values are up-to-date.
108 // TODO(pdr): Instead of using the clip and scroll layer lengths which require
109 // an update, refactor to use the scroll tree (ScrollTree::MaxScrollOffset
110 // as in LayerTreeHostImpl::TryScroll).
111 layer_tree_impl()->UpdateScrollbarGeometries();
112
113 // Ensure clip_layer_length is smaller than scroll_layer_length, not including
114 // small deltas due to floating point error.
115 return !MathUtil::IsFloatNearlyTheSame(clip_layer_length(),
116 scroll_layer_length()) &&
117 clip_layer_length() < scroll_layer_length();
118 }
119
SetVerticalAdjust(float vertical_adjust)120 void ScrollbarLayerImplBase::SetVerticalAdjust(float vertical_adjust) {
121 if (vertical_adjust_ == vertical_adjust)
122 return;
123 vertical_adjust_ = vertical_adjust;
124 NoteLayerPropertyChanged();
125 }
126
SetClipLayerLength(float clip_layer_length)127 void ScrollbarLayerImplBase::SetClipLayerLength(float clip_layer_length) {
128 if (clip_layer_length_ == clip_layer_length)
129 return;
130 clip_layer_length_ = clip_layer_length;
131 NoteLayerPropertyChanged();
132 }
133
SetScrollLayerLength(float scroll_layer_length)134 void ScrollbarLayerImplBase::SetScrollLayerLength(float scroll_layer_length) {
135 if (scroll_layer_length_ == scroll_layer_length)
136 return;
137 scroll_layer_length_ = scroll_layer_length;
138 NoteLayerPropertyChanged();
139 return;
140 }
141
SetThumbThicknessScaleFactor(float factor)142 void ScrollbarLayerImplBase::SetThumbThicknessScaleFactor(float factor) {
143 if (thumb_thickness_scale_factor_ == factor)
144 return;
145 thumb_thickness_scale_factor_ = factor;
146 NoteLayerPropertyChanged();
147 }
148
ComputeThumbQuadRectWithThumbThicknessScale(float thumb_thickness_scale_factor) const149 gfx::Rect ScrollbarLayerImplBase::ComputeThumbQuadRectWithThumbThicknessScale(
150 float thumb_thickness_scale_factor) const {
151 // Thumb extent is the length of the thumb in the scrolling direction, thumb
152 // thickness is in the perpendicular direction. Here's an example of a
153 // horizontal scrollbar - inputs are above the scrollbar, computed values
154 // below:
155 //
156 // |<------------------- track_length_ ------------------->|
157 //
158 // |--| <-- start_offset
159 //
160 // +--+----------------------------+------------------+-------+--+
161 // |<|| |##################| ||>|
162 // +--+----------------------------+------------------+-------+--+
163 //
164 // |<- thumb_length ->|
165 //
166 // |<------- thumb_offset -------->|
167 //
168 // For painted, scrollbars, the length is fixed. For solid color scrollbars we
169 // have to compute it. The ratio of the thumb's length to the track's length
170 // is the same as that of the visible viewport to the total viewport, unless
171 // that would make the thumb's length less than its thickness.
172 //
173 // vertical_adjust_ is used when the layer geometry from the main thread is
174 // not in sync with what the user sees. For instance on Android scrolling the
175 // top bar controls out of view reveals more of the page content. We want the
176 // root layer scrollbars to reflect what the user sees even if we haven't
177 // received new layer geometry from the main thread. If the user has scrolled
178 // down by 50px and the initial viewport size was 950px the geometry would
179 // look something like this:
180 //
181 // vertical_adjust_ = 50, scroll position 0, visible ratios 99%
182 // Layer geometry: Desired thumb positions:
183 // +--------------------+-+ +----------------------+ <-- 0px
184 // | |v| | #|
185 // | |e| | #|
186 // | |r| | #|
187 // | |t| | #|
188 // | |i| | #|
189 // | |c| | #|
190 // | |a| | #|
191 // | |l| | #|
192 // | | | | #|
193 // | |l| | #|
194 // | |a| | #|
195 // | |y| | #|
196 // | |e| | #|
197 // | |r| | #|
198 // +--------------------+-+ | #|
199 // | horizontal layer | | | #|
200 // +--------------------+-+ | #| <-- 950px
201 // | | | #|
202 // | | |##################### |
203 // +----------------------+ +----------------------+ <-- 1000px
204 //
205 // The layer geometry is set up for a 950px tall viewport, but the user can
206 // actually see down to 1000px. Thus we have to move the quad for the
207 // horizontal scrollbar down by the vertical_adjust_ factor and lay the
208 // vertical thumb out on a track lengthed by the vertical_adjust_ factor. This
209 // means the quads may extend outside the layer's bounds.
210
211 // With the length known, we can compute the thumb's position.
212 float track_length = TrackLength();
213 int thumb_length = ThumbLength();
214 int thumb_thickness = ThumbThickness();
215 float maximum = scroll_layer_length() - clip_layer_length();
216
217 // With the length known, we can compute the thumb's position.
218 float clamped_current_pos = base::ClampToRange(current_pos(), 0.0f, maximum);
219
220 int thumb_offset = TrackStart();
221 if (maximum > 0) {
222 float ratio = clamped_current_pos / maximum;
223 float _max_offset = track_length - thumb_length;
224 thumb_offset += static_cast<int>(ratio * _max_offset);
225 }
226
227 float thumb_thickness_adjustment =
228 thumb_thickness * (1.f - thumb_thickness_scale_factor);
229
230 gfx::RectF thumb_rect;
231 if (orientation_ == HORIZONTAL) {
232 thumb_rect = gfx::RectF(thumb_offset,
233 vertical_adjust_ + thumb_thickness_adjustment,
234 thumb_length,
235 thumb_thickness - thumb_thickness_adjustment);
236 } else {
237 thumb_rect = gfx::RectF(
238 is_left_side_vertical_scrollbar_
239 ? bounds().width() - thumb_thickness
240 : thumb_thickness_adjustment,
241 thumb_offset,
242 thumb_thickness - thumb_thickness_adjustment,
243 thumb_length);
244 }
245
246 return gfx::ToEnclosingRect(thumb_rect);
247 }
248
ComputeExpandedThumbQuadRect() const249 gfx::Rect ScrollbarLayerImplBase::ComputeExpandedThumbQuadRect() const {
250 DCHECK(is_overlay_scrollbar());
251 return ComputeThumbQuadRectWithThumbThicknessScale(1.f);
252 }
253
ComputeThumbQuadRect() const254 gfx::Rect ScrollbarLayerImplBase::ComputeThumbQuadRect() const {
255 return ComputeThumbQuadRectWithThumbThicknessScale(
256 thumb_thickness_scale_factor_);
257 }
258
SetOverlayScrollbarLayerOpacityAnimated(float opacity)259 void ScrollbarLayerImplBase::SetOverlayScrollbarLayerOpacityAnimated(
260 float opacity) {
261 DCHECK(is_overlay_scrollbar());
262 if (!layer_tree_impl())
263 return;
264
265 PropertyTrees* property_trees = layer_tree_impl()->property_trees();
266
267 EffectNode* node = property_trees->effect_tree.Node(effect_tree_index());
268 if (node->opacity == opacity)
269 return;
270
271 node->opacity = opacity;
272 node->effect_changed = true;
273 property_trees->changed = true;
274 property_trees->effect_tree.set_needs_update(true);
275 layer_tree_impl()->set_needs_update_draw_properties();
276 }
277
278 LayerTreeSettings::ScrollbarAnimator
GetScrollbarAnimator() const279 ScrollbarLayerImplBase::GetScrollbarAnimator() const {
280 return layer_tree_impl()->settings().scrollbar_animator;
281 }
282
HasFindInPageTickmarks() const283 bool ScrollbarLayerImplBase::HasFindInPageTickmarks() const {
284 return false;
285 }
286
OverlayScrollbarOpacity() const287 float ScrollbarLayerImplBase::OverlayScrollbarOpacity() const {
288 return Opacity();
289 }
290
SupportsDragSnapBack() const291 bool ScrollbarLayerImplBase::SupportsDragSnapBack() const {
292 return false;
293 }
294
BackButtonRect() const295 gfx::Rect ScrollbarLayerImplBase::BackButtonRect() const {
296 return gfx::Rect(0, 0);
297 }
298
ForwardButtonRect() const299 gfx::Rect ScrollbarLayerImplBase::ForwardButtonRect() const {
300 return gfx::Rect(0, 0);
301 }
302
BackTrackRect() const303 gfx::Rect ScrollbarLayerImplBase::BackTrackRect() const {
304 return gfx::Rect(0, 0);
305 }
306
ForwardTrackRect() const307 gfx::Rect ScrollbarLayerImplBase::ForwardTrackRect() const {
308 return gfx::Rect(0, 0);
309 }
310
311 // This manages identifying which part of a composited scrollbar got hit based
312 // on the position_in_widget.
IdentifyScrollbarPart(const gfx::PointF position_in_widget) const313 ScrollbarPart ScrollbarLayerImplBase::IdentifyScrollbarPart(
314 const gfx::PointF position_in_widget) const {
315 const gfx::Point pointer_location(position_in_widget.x(),
316 position_in_widget.y());
317 if (BackButtonRect().Contains(pointer_location))
318 return ScrollbarPart::BACK_BUTTON;
319
320 if (ForwardButtonRect().Contains(pointer_location))
321 return ScrollbarPart::FORWARD_BUTTON;
322
323 if (ComputeThumbQuadRect().Contains(pointer_location))
324 return ScrollbarPart::THUMB;
325
326 if (BackTrackRect().Contains(pointer_location))
327 return ScrollbarPart::BACK_TRACK;
328
329 if (ForwardTrackRect().Contains(pointer_location))
330 return ScrollbarPart::FORWARD_TRACK;
331
332 // TODO(arakeri): Once crbug.com/952314 is fixed, add a DCHECK to verify that
333 // the point that is passed in is within the TrackRect. Also, please note that
334 // hit testing other scrollbar parts is not yet implemented.
335 return ScrollbarPart::NO_PART;
336 }
337
338 } // namespace cc
339