1 // Copyright (c) 2012 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 "ui/views/controls/scroll_view.h"
6
7 #include <algorithm>
8
9 #include "base/bind.h"
10 #include "base/feature_list.h"
11 #include "base/logging.h"
12 #include "base/macros.h"
13 #include "base/numerics/ranges.h"
14 #include "build/build_config.h"
15 #include "ui/base/ui_base_features.h"
16 #include "ui/compositor/overscroll/scroll_input_handler.h"
17 #include "ui/events/event.h"
18 #include "ui/gfx/canvas.h"
19 #include "ui/native_theme/native_theme.h"
20 #include "ui/views/background.h"
21 #include "ui/views/border.h"
22 #include "ui/views/controls/focus_ring.h"
23 #include "ui/views/style/platform_style.h"
24 #include "ui/views/widget/widget.h"
25
26 namespace views {
27
28 namespace {
29
30 class ScrollCornerView : public View {
31 public:
32 ScrollCornerView() = default;
33
OnPaint(gfx::Canvas * canvas)34 void OnPaint(gfx::Canvas* canvas) override {
35 ui::NativeTheme::ExtraParams ignored;
36 GetNativeTheme()->Paint(
37 canvas->sk_canvas(), ui::NativeTheme::kScrollbarCorner,
38 ui::NativeTheme::kNormal, GetLocalBounds(), ignored);
39 }
40
41 private:
42 DISALLOW_COPY_AND_ASSIGN(ScrollCornerView);
43 };
44
45 // Returns true if any descendants of |view| have a layer (not including
46 // |view|).
DoesDescendantHaveLayer(View * view)47 bool DoesDescendantHaveLayer(View* view) {
48 return std::any_of(view->children().cbegin(), view->children().cend(),
49 [](View* child) {
50 return child->layer() || DoesDescendantHaveLayer(child);
51 });
52 }
53
54 // Returns the position for the view so that it isn't scrolled off the visible
55 // region.
CheckScrollBounds(int viewport_size,int content_size,int current_pos)56 int CheckScrollBounds(int viewport_size, int content_size, int current_pos) {
57 return base::ClampToRange(current_pos, 0,
58 std::max(content_size - viewport_size, 0));
59 }
60
61 // Make sure the content is not scrolled out of bounds
ConstrainScrollToBounds(View * viewport,View * view,bool scroll_with_layers_enabled)62 void ConstrainScrollToBounds(View* viewport,
63 View* view,
64 bool scroll_with_layers_enabled) {
65 if (!view)
66 return;
67
68 // Note that even when ScrollView::ScrollsWithLayers() is true, the header row
69 // scrolls by repainting.
70 const bool scrolls_with_layers =
71 scroll_with_layers_enabled && viewport->layer() != nullptr;
72 if (scrolls_with_layers) {
73 DCHECK(view->layer());
74 DCHECK_EQ(0, view->x());
75 DCHECK_EQ(0, view->y());
76 }
77 gfx::ScrollOffset offset = scrolls_with_layers
78 ? view->layer()->CurrentScrollOffset()
79 : gfx::ScrollOffset(-view->x(), -view->y());
80
81 int x = CheckScrollBounds(viewport->width(), view->width(), offset.x());
82 int y = CheckScrollBounds(viewport->height(), view->height(), offset.y());
83
84 if (scrolls_with_layers) {
85 view->layer()->SetScrollOffset(gfx::ScrollOffset(x, y));
86 } else {
87 // This is no op if bounds are the same
88 view->SetBounds(-x, -y, view->width(), view->height());
89 }
90 }
91
92 // Used by ScrollToPosition() to make sure the new position fits within the
93 // allowed scroll range.
AdjustPosition(int current_position,int new_position,int content_size,int viewport_size)94 int AdjustPosition(int current_position,
95 int new_position,
96 int content_size,
97 int viewport_size) {
98 if (-current_position == new_position)
99 return new_position;
100 if (new_position < 0)
101 return 0;
102 const int max_position = std::max(0, content_size - viewport_size);
103 return (new_position > max_position) ? max_position : new_position;
104 }
105
106 } // namespace
107
108 // Viewport contains the contents View of the ScrollView.
109 class ScrollView::Viewport : public View {
110 public:
Viewport(ScrollView * scroll_view)111 explicit Viewport(ScrollView* scroll_view) : scroll_view_(scroll_view) {}
112 ~Viewport() override = default;
113
ScrollRectToVisible(const gfx::Rect & rect)114 void ScrollRectToVisible(const gfx::Rect& rect) override {
115 if (children().empty() || !parent())
116 return;
117
118 View* contents = children().front();
119 gfx::Rect scroll_rect(rect);
120
121 if (scroll_view_->ScrollsWithLayers()) {
122 // With layer scrolling, there's no need to "undo" the offset done in the
123 // child's View::ScrollRectToVisible() before it calls this.
124 DCHECK_EQ(0, contents->x());
125 DCHECK_EQ(0, contents->y());
126 } else {
127 scroll_rect.Offset(-contents->x(), -contents->y());
128 }
129
130 scroll_view_->ScrollContentsRegionToBeVisible(scroll_rect);
131 }
132
133 // TODO(https://crbug.com/947053): this override should not be necessary, but
134 // there are some assumptions that this calls Layout().
ChildPreferredSizeChanged(View * child)135 void ChildPreferredSizeChanged(View* child) override {
136 if (parent())
137 parent()->Layout();
138 }
139
ViewHierarchyChanged(const ViewHierarchyChangedDetails & details)140 void ViewHierarchyChanged(
141 const ViewHierarchyChangedDetails& details) override {
142 if (details.is_add && IsContentsViewport() && Contains(details.parent))
143 scroll_view_->UpdateViewportLayerForClipping();
144 }
145
OnChildLayerChanged(View * child)146 void OnChildLayerChanged(View* child) override {
147 if (IsContentsViewport())
148 scroll_view_->UpdateViewportLayerForClipping();
149 }
150
151 private:
IsContentsViewport() const152 bool IsContentsViewport() const {
153 return parent() && scroll_view_->contents_viewport_ == this;
154 }
155
156 ScrollView* scroll_view_;
157
158 DISALLOW_COPY_AND_ASSIGN(Viewport);
159 };
160
ScrollView()161 ScrollView::ScrollView()
162 : horiz_sb_(PlatformStyle::CreateScrollBar(true)),
163 vert_sb_(PlatformStyle::CreateScrollBar(false)),
164 corner_view_(std::make_unique<ScrollCornerView>()),
165 scroll_with_layers_enabled_(base::FeatureList::IsEnabled(
166 ::features::kUiCompositorScrollWithLayers)) {
167 set_notify_enter_exit_on_child(true);
168
169 // Since |contents_viewport_| is accessed during the AddChildView call, make
170 // sure the field is initialized.
171 auto contents_viewport = std::make_unique<Viewport>(this);
172 contents_viewport_ = contents_viewport.get();
173 AddChildView(std::move(contents_viewport));
174 header_viewport_ = AddChildView(std::make_unique<Viewport>(this));
175
176 // Don't add the scrollbars as children until we discover we need them
177 // (ShowOrHideScrollBar).
178 horiz_sb_->SetVisible(false);
179 horiz_sb_->set_controller(this);
180 vert_sb_->SetVisible(false);
181 vert_sb_->set_controller(this);
182 corner_view_->SetVisible(false);
183
184 // Just make sure the more_content indicators aren't visible for now. They'll
185 // be added as child controls and appropriately made visible depending on
186 // |show_edges_with_hidden_content_|.
187 more_content_left_->SetVisible(false);
188 more_content_top_->SetVisible(false);
189 more_content_right_->SetVisible(false);
190 more_content_bottom_->SetVisible(false);
191
192 if (scroll_with_layers_enabled_)
193 EnableViewportLayer();
194
195 // If we're scrolling with layers, paint the overflow indicators to the layer.
196 if (ScrollsWithLayers()) {
197 more_content_left_->SetPaintToLayer();
198 more_content_top_->SetPaintToLayer();
199 more_content_right_->SetPaintToLayer();
200 more_content_bottom_->SetPaintToLayer();
201 }
202 UpdateBackground();
203
204 focus_ring_ = FocusRing::Install(this);
205 focus_ring_->SetHasFocusPredicate([](View* view) -> bool {
206 auto* v = static_cast<ScrollView*>(view);
207 return v->draw_focus_indicator_;
208 });
209 }
210
211 ScrollView::~ScrollView() = default;
212
213 // static
CreateScrollViewWithBorder()214 std::unique_ptr<ScrollView> ScrollView::CreateScrollViewWithBorder() {
215 auto scroll_view = std::make_unique<ScrollView>();
216 scroll_view->AddBorder();
217 return scroll_view;
218 }
219
220 // static
GetScrollViewForContents(View * contents)221 ScrollView* ScrollView::GetScrollViewForContents(View* contents) {
222 View* grandparent =
223 contents->parent() ? contents->parent()->parent() : nullptr;
224 if (!grandparent || grandparent->GetClassName() != ScrollView::kViewClassName)
225 return nullptr;
226
227 auto* scroll_view = static_cast<ScrollView*>(grandparent);
228 DCHECK_EQ(contents, scroll_view->contents());
229 return scroll_view;
230 }
231
SetContentsImpl(std::unique_ptr<View> a_view)232 void ScrollView::SetContentsImpl(std::unique_ptr<View> a_view) {
233 // Protect against clients passing a contents view that has its own Layer.
234 DCHECK(!a_view->layer());
235 if (ScrollsWithLayers()) {
236 bool fills_opaquely = true;
237 if (!a_view->background()) {
238 // Contents views may not be aware they need to fill their entire bounds -
239 // play it safe here to avoid graphical glitches
240 // (https://crbug.com/826472). If there's no solid background, mark the
241 // view as not filling its bounds opaquely.
242 if (GetBackgroundColor()) {
243 a_view->SetBackground(
244 CreateSolidBackground(GetBackgroundColor().value()));
245 } else {
246 fills_opaquely = false;
247 }
248 }
249 a_view->SetPaintToLayer();
250 a_view->layer()->SetDidScrollCallback(base::BindRepeating(
251 &ScrollView::OnLayerScrolled, base::Unretained(this)));
252 a_view->layer()->SetScrollable(contents_viewport_->bounds().size());
253 a_view->layer()->SetFillsBoundsOpaquely(fills_opaquely);
254 }
255 SetHeaderOrContents(contents_viewport_, std::move(a_view), &contents_);
256 }
257
SetContents(std::nullptr_t)258 void ScrollView::SetContents(std::nullptr_t) {
259 SetContentsImpl(nullptr);
260 }
261
SetHeaderImpl(std::unique_ptr<View> a_header)262 void ScrollView::SetHeaderImpl(std::unique_ptr<View> a_header) {
263 SetHeaderOrContents(header_viewport_, std::move(a_header), &header_);
264 }
265
SetHeader(std::nullptr_t)266 void ScrollView::SetHeader(std::nullptr_t) {
267 SetHeaderImpl(nullptr);
268 }
269
SetBackgroundColor(const base::Optional<SkColor> & color)270 void ScrollView::SetBackgroundColor(const base::Optional<SkColor>& color) {
271 if (background_color_ == color && !background_color_id_)
272 return;
273 background_color_ = color;
274 background_color_id_ = base::nullopt;
275 UpdateBackground();
276 OnPropertyChanged(&background_color_, kPropertyEffectsPaint);
277 }
278
SetBackgroundThemeColorId(const base::Optional<ui::NativeTheme::ColorId> & color_id)279 void ScrollView::SetBackgroundThemeColorId(
280 const base::Optional<ui::NativeTheme::ColorId>& color_id) {
281 if (background_color_id_ == color_id && !background_color_)
282 return;
283 background_color_id_ = color_id;
284 background_color_ = base::nullopt;
285 UpdateBackground();
286 OnPropertyChanged(&background_color_id_, kPropertyEffectsPaint);
287 }
288
GetVisibleRect() const289 gfx::Rect ScrollView::GetVisibleRect() const {
290 if (!contents_)
291 return gfx::Rect();
292 gfx::ScrollOffset offset = CurrentOffset();
293 return gfx::Rect(offset.x(), offset.y(), contents_viewport_->width(),
294 contents_viewport_->height());
295 }
296
SetHideHorizontalScrollBar(bool visible)297 void ScrollView::SetHideHorizontalScrollBar(bool visible) {
298 if (hide_horizontal_scrollbar_ == visible)
299 return;
300 hide_horizontal_scrollbar_ = visible;
301 OnPropertyChanged(&hide_horizontal_scrollbar_, kPropertyEffectsPaint);
302 }
303
SetDrawOverflowIndicator(bool draw_overflow_indicator)304 void ScrollView::SetDrawOverflowIndicator(bool draw_overflow_indicator) {
305 if (draw_overflow_indicator_ == draw_overflow_indicator)
306 return;
307 draw_overflow_indicator_ = draw_overflow_indicator;
308 OnPropertyChanged(&draw_overflow_indicator_, kPropertyEffectsPaint);
309 }
310
ClipHeightTo(int min_height,int max_height)311 void ScrollView::ClipHeightTo(int min_height, int max_height) {
312 min_height_ = min_height;
313 max_height_ = max_height;
314 }
315
GetScrollBarLayoutWidth() const316 int ScrollView::GetScrollBarLayoutWidth() const {
317 return vert_sb_ && !vert_sb_->OverlapsContent() ? vert_sb_->GetThickness()
318 : 0;
319 }
320
GetScrollBarLayoutHeight() const321 int ScrollView::GetScrollBarLayoutHeight() const {
322 return horiz_sb_ && !horiz_sb_->OverlapsContent() ? horiz_sb_->GetThickness()
323 : 0;
324 }
325
SetHorizontalScrollBar(std::unique_ptr<ScrollBar> horiz_sb)326 ScrollBar* ScrollView::SetHorizontalScrollBar(
327 std::unique_ptr<ScrollBar> horiz_sb) {
328 DCHECK(horiz_sb);
329 horiz_sb->SetVisible(horiz_sb_->GetVisible());
330 horiz_sb->set_controller(this);
331 horiz_sb_ = std::move(horiz_sb);
332 return horiz_sb_.get();
333 }
334
SetVerticalScrollBar(std::unique_ptr<ScrollBar> vert_sb)335 ScrollBar* ScrollView::SetVerticalScrollBar(
336 std::unique_ptr<ScrollBar> vert_sb) {
337 DCHECK(vert_sb);
338 vert_sb->SetVisible(vert_sb_->GetVisible());
339 vert_sb->set_controller(this);
340 vert_sb_ = std::move(vert_sb);
341 return vert_sb_.get();
342 }
343
SetHasFocusIndicator(bool has_focus_indicator)344 void ScrollView::SetHasFocusIndicator(bool has_focus_indicator) {
345 if (has_focus_indicator == draw_focus_indicator_)
346 return;
347 draw_focus_indicator_ = has_focus_indicator;
348
349 focus_ring_->SchedulePaint();
350 SchedulePaint();
351 OnPropertyChanged(&draw_focus_indicator_, kPropertyEffectsPaint);
352 }
353
CalculatePreferredSize() const354 gfx::Size ScrollView::CalculatePreferredSize() const {
355 if (!is_bounded())
356 return View::CalculatePreferredSize();
357
358 gfx::Size size = contents_->GetPreferredSize();
359 size.SetToMax(gfx::Size(size.width(), min_height_));
360 size.SetToMin(gfx::Size(size.width(), max_height_));
361 gfx::Insets insets = GetInsets();
362 size.Enlarge(insets.width(), insets.height());
363 return size;
364 }
365
GetHeightForWidth(int width) const366 int ScrollView::GetHeightForWidth(int width) const {
367 if (!is_bounded())
368 return View::GetHeightForWidth(width);
369
370 gfx::Insets insets = GetInsets();
371 width = std::max(0, width - insets.width());
372 int height = contents_->GetHeightForWidth(width) + insets.height();
373 return base::ClampToRange(height, min_height_, max_height_);
374 }
375
Layout()376 void ScrollView::Layout() {
377 // When horizontal scrollbar is disabled, it should not matter
378 // if its OverlapsContent matches vertical bar's.
379 if (!hide_horizontal_scrollbar_) {
380 #if defined(OS_MACOSX)
381 // On Mac, scrollbars may update their style one at a time, so they may
382 // temporarily be of different types. Refuse to lay out at this point.
383 if (horiz_sb_->OverlapsContent() != vert_sb_->OverlapsContent())
384 return;
385 #endif
386 DCHECK_EQ(horiz_sb_->OverlapsContent(), vert_sb_->OverlapsContent());
387 }
388
389 if (focus_ring_)
390 focus_ring_->Layout();
391
392 gfx::Rect available_rect = GetContentsBounds();
393 if (is_bounded()) {
394 int content_width = available_rect.width();
395 int content_height = contents_->GetHeightForWidth(content_width);
396 if (content_height > height()) {
397 content_width = std::max(content_width - GetScrollBarLayoutWidth(), 0);
398 content_height = contents_->GetHeightForWidth(content_width);
399 }
400 contents_->SetSize(gfx::Size(content_width, content_height));
401 }
402
403 // Place an overflow indicator on each of the four edges of the content
404 // bounds.
405 PositionOverflowIndicators();
406
407 // Most views will want to auto-fit the available space. Most of them want to
408 // use all available width (without overflowing) and only overflow in
409 // height. Examples are HistoryView, MostVisitedView, DownloadTabView, etc.
410 // Other views want to fit in both ways. An example is PrintView. To make both
411 // happy, assume a vertical scrollbar but no horizontal scrollbar. To override
412 // this default behavior, the inner view has to calculate the available space,
413 // used ComputeScrollBarsVisibility() to use the same calculation that is done
414 // here and sets its bound to fit within.
415 gfx::Rect viewport_bounds = available_rect;
416 const int contents_x = viewport_bounds.x();
417 const int contents_y = viewport_bounds.y();
418 if (viewport_bounds.IsEmpty()) {
419 // There's nothing to layout.
420 return;
421 }
422
423 const int header_height =
424 std::min(viewport_bounds.height(),
425 header_ ? header_->GetPreferredSize().height() : 0);
426 viewport_bounds.set_height(
427 std::max(0, viewport_bounds.height() - header_height));
428 viewport_bounds.set_y(viewport_bounds.y() + header_height);
429 // viewport_size is the total client space available.
430 gfx::Size viewport_size = viewport_bounds.size();
431
432 // Assume both a vertical and horizontal scrollbar exist before calling
433 // contents_->Layout(). This is because some contents_ will set their own size
434 // to the contents_viewport_'s bounds. Failing to pre-allocate space for
435 // the scrollbars will [non-intuitively] cause scrollbars to appear in
436 // ComputeScrollBarsVisibility. This solution is also not perfect - if
437 // scrollbars turn out *not* to be necessary, the contents will have slightly
438 // less horizontal/vertical space than it otherwise would have had access to.
439 // Unfortunately, there's no way to determine this without introducing a
440 // circular dependency.
441 const int horiz_sb_layout_height = GetScrollBarLayoutHeight();
442 const int vert_sb_layout_width = GetScrollBarLayoutWidth();
443 viewport_bounds.set_width(viewport_bounds.width() - vert_sb_layout_width);
444 viewport_bounds.set_height(viewport_bounds.height() - horiz_sb_layout_height);
445
446 // Update the bounds right now so the inner views can fit in it.
447 contents_viewport_->SetBoundsRect(viewport_bounds);
448
449 // Give |contents_| a chance to update its bounds if it depends on the
450 // viewport.
451 if (contents_)
452 contents_->Layout();
453
454 bool should_layout_contents = false;
455 bool horiz_sb_required = false;
456 bool vert_sb_required = false;
457 if (contents_) {
458 gfx::Size content_size = contents_->size();
459 ComputeScrollBarsVisibility(viewport_size, content_size, &horiz_sb_required,
460 &vert_sb_required);
461 }
462 // Overlay scrollbars don't need a corner view.
463 bool corner_view_required =
464 horiz_sb_required && vert_sb_required && !vert_sb_->OverlapsContent();
465 // Take action.
466 SetControlVisibility(horiz_sb_.get(), horiz_sb_required);
467 SetControlVisibility(vert_sb_.get(), vert_sb_required);
468 SetControlVisibility(corner_view_.get(), corner_view_required);
469
470 // Default.
471 if (!horiz_sb_required) {
472 viewport_bounds.set_height(viewport_bounds.height() +
473 horiz_sb_layout_height);
474 should_layout_contents = true;
475 }
476 // Default.
477 if (!vert_sb_required) {
478 viewport_bounds.set_width(viewport_bounds.width() + vert_sb_layout_width);
479 should_layout_contents = true;
480 }
481
482 if (horiz_sb_required) {
483 gfx::Rect horiz_sb_bounds(contents_x, viewport_bounds.bottom(),
484 viewport_bounds.right() - contents_x,
485 horiz_sb_layout_height);
486 if (horiz_sb_->OverlapsContent()) {
487 horiz_sb_bounds.Inset(
488 gfx::Insets(-horiz_sb_->GetThickness(), 0, 0,
489 vert_sb_required ? vert_sb_->GetThickness() : 0));
490 }
491
492 horiz_sb_->SetBoundsRect(horiz_sb_bounds);
493 }
494 if (vert_sb_required) {
495 gfx::Rect vert_sb_bounds(viewport_bounds.right(), contents_y,
496 vert_sb_layout_width,
497 viewport_bounds.bottom() - contents_y);
498 if (vert_sb_->OverlapsContent()) {
499 // In the overlay scrollbar case, the scrollbar only covers the viewport
500 // (and not the header).
501 vert_sb_bounds.Inset(
502 gfx::Insets(header_height, -vert_sb_->GetThickness(),
503 horiz_sb_required ? horiz_sb_->GetThickness() : 0, 0));
504 }
505
506 vert_sb_->SetBoundsRect(vert_sb_bounds);
507 }
508 if (corner_view_required) {
509 // Show the resize corner.
510 corner_view_->SetBounds(vert_sb_->bounds().x(), horiz_sb_->bounds().y(),
511 vert_sb_layout_width, horiz_sb_layout_height);
512 }
513
514 // Update to the real client size with the visible scrollbars.
515 contents_viewport_->SetBoundsRect(viewport_bounds);
516 if (should_layout_contents && contents_)
517 contents_->Layout();
518
519 // Even when |contents_| needs to scroll, it can still be narrower or wider
520 // the viewport. So ensure the scrolling layer can fill the viewport, so that
521 // events will correctly hit it, and overscroll looks correct.
522 if (contents_ && ScrollsWithLayers()) {
523 gfx::Size container_size = contents_ ? contents_->size() : gfx::Size();
524 container_size.SetToMax(viewport_bounds.size());
525 contents_->SetBoundsRect(gfx::Rect(container_size));
526 contents_->layer()->SetScrollable(viewport_bounds.size());
527
528 // Flip the viewport with layer transforms under RTL. Note the net effect is
529 // to flip twice, so the text is not mirrored. This is necessary because
530 // compositor scrolling is not RTL-aware. So although a toolkit-views layout
531 // will flip, increasing a horizontal gfx::ScrollOffset will move content to
532 // the left, regardless of RTL. A gfx::ScrollOffset must be positive, so to
533 // move (unscrolled) content to the right, we need to flip the viewport
534 // layer. That would flip all the content as well, so flip (and translate)
535 // the content layer. Compensating in this way allows the scrolling/offset
536 // logic to remain the same when scrolling via layers or bounds offsets.
537 if (base::i18n::IsRTL()) {
538 gfx::Transform flip;
539 flip.Translate(viewport_bounds.width(), 0);
540 flip.Scale(-1, 1);
541 contents_viewport_->layer()->SetTransform(flip);
542
543 // Add `contents_->width() - viewport_width` to the translation step. This
544 // is to prevent the top-left of the (flipped) contents aligning to the
545 // top-left of the viewport. Instead, the top-right should align in RTL.
546 gfx::Transform shift;
547 shift.Translate(2 * contents_->width() - viewport_bounds.width(), 0);
548 shift.Scale(-1, 1);
549 contents_->layer()->SetTransform(shift);
550 }
551 }
552
553 header_viewport_->SetBounds(contents_x, contents_y, viewport_bounds.width(),
554 header_height);
555 if (header_)
556 header_->Layout();
557
558 ConstrainScrollToBounds(header_viewport_, header_,
559 scroll_with_layers_enabled_);
560 ConstrainScrollToBounds(contents_viewport_, contents_,
561 scroll_with_layers_enabled_);
562 SchedulePaint();
563 UpdateScrollBarPositions();
564 if (contents_)
565 UpdateOverflowIndicatorVisibility(CurrentOffset());
566 }
567
OnKeyPressed(const ui::KeyEvent & event)568 bool ScrollView::OnKeyPressed(const ui::KeyEvent& event) {
569 bool processed = false;
570
571 // Give vertical scrollbar priority
572 if (vert_sb_->GetVisible())
573 processed = vert_sb_->OnKeyPressed(event);
574
575 if (!processed && horiz_sb_->GetVisible())
576 processed = horiz_sb_->OnKeyPressed(event);
577
578 return processed;
579 }
580
OnMouseWheel(const ui::MouseWheelEvent & e)581 bool ScrollView::OnMouseWheel(const ui::MouseWheelEvent& e) {
582 bool processed = false;
583
584 // TODO(https://crbug.com/615948): Use composited scrolling.
585 if (vert_sb_->GetVisible())
586 processed = vert_sb_->OnMouseWheel(e);
587
588 if (horiz_sb_->GetVisible())
589 processed = horiz_sb_->OnMouseWheel(e) || processed;
590
591 return processed;
592 }
593
OnScrollEvent(ui::ScrollEvent * event)594 void ScrollView::OnScrollEvent(ui::ScrollEvent* event) {
595 if (!contents_)
596 return;
597
598 ui::ScrollInputHandler* compositor_scroller =
599 GetWidget()->GetCompositor()->scroll_input_handler();
600 if (compositor_scroller) {
601 DCHECK(scroll_with_layers_enabled_);
602 if (compositor_scroller->OnScrollEvent(*event, contents_->layer())) {
603 event->SetHandled();
604 event->StopPropagation();
605 }
606 }
607
608 // A direction might not be known when the event stream starts, notify both
609 // scrollbars that they may be about scroll, or that they may need to cancel
610 // UI feedback once the scrolling direction is known.
611 if (horiz_sb_)
612 horiz_sb_->ObserveScrollEvent(*event);
613 if (vert_sb_)
614 vert_sb_->ObserveScrollEvent(*event);
615 }
616
OnGestureEvent(ui::GestureEvent * event)617 void ScrollView::OnGestureEvent(ui::GestureEvent* event) {
618 // If the event happened on one of the scrollbars, then those events are
619 // sent directly to the scrollbars. Otherwise, only scroll events are sent to
620 // the scrollbars.
621 bool scroll_event = event->type() == ui::ET_GESTURE_SCROLL_UPDATE ||
622 event->type() == ui::ET_GESTURE_SCROLL_BEGIN ||
623 event->type() == ui::ET_GESTURE_SCROLL_END ||
624 event->type() == ui::ET_SCROLL_FLING_START;
625
626 // TODO(https://crbug.com/615948): Use composited scrolling.
627 if (vert_sb_->GetVisible()) {
628 if (vert_sb_->bounds().Contains(event->location()) || scroll_event)
629 vert_sb_->OnGestureEvent(event);
630 }
631 if (!event->handled() && horiz_sb_->GetVisible()) {
632 if (horiz_sb_->bounds().Contains(event->location()) || scroll_event)
633 horiz_sb_->OnGestureEvent(event);
634 }
635 }
636
OnThemeChanged()637 void ScrollView::OnThemeChanged() {
638 View::OnThemeChanged();
639 UpdateBorder();
640 if (background_color_id_)
641 UpdateBackground();
642 }
643
ScrollToPosition(ScrollBar * source,int position)644 void ScrollView::ScrollToPosition(ScrollBar* source, int position) {
645 if (!contents_)
646 return;
647
648 gfx::ScrollOffset offset = CurrentOffset();
649 if (source == horiz_sb_.get() && horiz_sb_->GetVisible()) {
650 position = AdjustPosition(offset.x(), position, contents_->width(),
651 contents_viewport_->width());
652 if (offset.x() == position)
653 return;
654 offset.set_x(position);
655 } else if (source == vert_sb_.get() && vert_sb_->GetVisible()) {
656 position = AdjustPosition(offset.y(), position, contents_->height(),
657 contents_viewport_->height());
658 if (offset.y() == position)
659 return;
660 offset.set_y(position);
661 }
662 ScrollToOffset(offset);
663
664 if (!ScrollsWithLayers())
665 contents_->SchedulePaintInRect(contents_->GetVisibleBounds());
666 }
667
GetScrollIncrement(ScrollBar * source,bool is_page,bool is_positive)668 int ScrollView::GetScrollIncrement(ScrollBar* source,
669 bool is_page,
670 bool is_positive) {
671 bool is_horizontal = source->IsHorizontal();
672 if (is_page) {
673 return is_horizontal ? contents_viewport_->width()
674 : contents_viewport_->height();
675 }
676 return is_horizontal ? contents_viewport_->width() / 5
677 : contents_viewport_->height() / 5;
678 }
679
DoesViewportOrScrollViewHaveLayer() const680 bool ScrollView::DoesViewportOrScrollViewHaveLayer() const {
681 return layer() || contents_viewport_->layer();
682 }
683
UpdateViewportLayerForClipping()684 void ScrollView::UpdateViewportLayerForClipping() {
685 if (scroll_with_layers_enabled_)
686 return;
687
688 const bool has_layer = DoesViewportOrScrollViewHaveLayer();
689 const bool needs_layer = DoesDescendantHaveLayer(contents_viewport_);
690 if (has_layer == needs_layer)
691 return;
692 if (needs_layer)
693 EnableViewportLayer();
694 else
695 contents_viewport_->DestroyLayer();
696 }
697
SetHeaderOrContents(View * parent,std::unique_ptr<View> new_view,View ** member)698 void ScrollView::SetHeaderOrContents(View* parent,
699 std::unique_ptr<View> new_view,
700 View** member) {
701 delete *member;
702 if (new_view.get())
703 *member = parent->AddChildView(std::move(new_view));
704 else
705 *member = nullptr;
706 // TODO(https://crbug.com/947053): this should call InvalidateLayout(), but
707 // there are some assumptions that it call Layout(). These assumptions should
708 // be updated.
709 Layout();
710 }
711
ScrollContentsRegionToBeVisible(const gfx::Rect & rect)712 void ScrollView::ScrollContentsRegionToBeVisible(const gfx::Rect& rect) {
713 if (!contents_ || (!horiz_sb_->GetVisible() && !vert_sb_->GetVisible()))
714 return;
715
716 // Figure out the maximums for this scroll view.
717 const int contents_max_x =
718 std::max(contents_viewport_->width(), contents_->width());
719 const int contents_max_y =
720 std::max(contents_viewport_->height(), contents_->height());
721
722 int x = base::ClampToRange(rect.x(), 0, contents_max_x);
723 int y = base::ClampToRange(rect.y(), 0, contents_max_y);
724
725 // Figure out how far and down the rectangle will go taking width
726 // and height into account. This will be "clipped" by the viewport.
727 const int max_x = std::min(
728 contents_max_x, x + std::min(rect.width(), contents_viewport_->width()));
729 const int max_y =
730 std::min(contents_max_y,
731 y + std::min(rect.height(), contents_viewport_->height()));
732
733 // See if the rect is already visible. Note the width is (max_x - x)
734 // and the height is (max_y - y) to take into account the clipping of
735 // either viewport or the content size.
736 const gfx::Rect vis_rect = GetVisibleRect();
737 if (vis_rect.Contains(gfx::Rect(x, y, max_x - x, max_y - y)))
738 return;
739
740 // Shift contents_'s X and Y so that the region is visible. If we
741 // need to shift up or left from where we currently are then we need
742 // to get it so that the content appears in the upper/left
743 // corner. This is done by setting the offset to -X or -Y. For down
744 // or right shifts we need to make sure it appears in the
745 // lower/right corner. This is calculated by taking max_x or max_y
746 // and scaling it back by the size of the viewport.
747 const int new_x =
748 (vis_rect.x() > x) ? x : std::max(0, max_x - contents_viewport_->width());
749 const int new_y = (vis_rect.y() > y)
750 ? y
751 : std::max(0, max_y - contents_viewport_->height());
752
753 ScrollToOffset(gfx::ScrollOffset(new_x, new_y));
754 }
755
ComputeScrollBarsVisibility(const gfx::Size & vp_size,const gfx::Size & content_size,bool * horiz_is_shown,bool * vert_is_shown) const756 void ScrollView::ComputeScrollBarsVisibility(const gfx::Size& vp_size,
757 const gfx::Size& content_size,
758 bool* horiz_is_shown,
759 bool* vert_is_shown) const {
760 if (hide_horizontal_scrollbar_) {
761 *horiz_is_shown = false;
762 *vert_is_shown = content_size.height() > vp_size.height();
763 return;
764 }
765
766 // Try to fit both ways first, then try vertical bar only, then horizontal
767 // bar only, then defaults to both shown.
768 if (content_size.width() <= vp_size.width() &&
769 content_size.height() <= vp_size.height()) {
770 *horiz_is_shown = false;
771 *vert_is_shown = false;
772 } else if (content_size.width() <=
773 vp_size.width() - GetScrollBarLayoutWidth()) {
774 *horiz_is_shown = false;
775 *vert_is_shown = true;
776 } else if (content_size.height() <=
777 vp_size.height() - GetScrollBarLayoutHeight()) {
778 *horiz_is_shown = true;
779 *vert_is_shown = false;
780 } else {
781 *horiz_is_shown = true;
782 *vert_is_shown = true;
783 }
784 }
785
786 // Make sure that a single scrollbar is created and visible as needed
SetControlVisibility(View * control,bool should_show)787 void ScrollView::SetControlVisibility(View* control, bool should_show) {
788 if (!control)
789 return;
790 if (should_show) {
791 if (!control->GetVisible()) {
792 AddChildView(control);
793 control->SetVisible(true);
794 }
795 } else {
796 RemoveChildView(control);
797 control->SetVisible(false);
798 }
799 }
800
UpdateScrollBarPositions()801 void ScrollView::UpdateScrollBarPositions() {
802 if (!contents_)
803 return;
804
805 const gfx::ScrollOffset offset = CurrentOffset();
806 if (horiz_sb_->GetVisible()) {
807 int vw = contents_viewport_->width();
808 int cw = contents_->width();
809 horiz_sb_->Update(vw, cw, offset.x());
810 }
811 if (vert_sb_->GetVisible()) {
812 int vh = contents_viewport_->height();
813 int ch = contents_->height();
814 vert_sb_->Update(vh, ch, offset.y());
815 }
816 }
817
CurrentOffset() const818 gfx::ScrollOffset ScrollView::CurrentOffset() const {
819 return ScrollsWithLayers()
820 ? contents_->layer()->CurrentScrollOffset()
821 : gfx::ScrollOffset(-contents_->x(), -contents_->y());
822 }
823
ScrollToOffset(const gfx::ScrollOffset & offset)824 void ScrollView::ScrollToOffset(const gfx::ScrollOffset& offset) {
825 if (ScrollsWithLayers()) {
826 contents_->layer()->SetScrollOffset(offset);
827
828 // TODO(tapted): Remove this call to OnLayerScrolled(). It's unnecessary,
829 // but will only be invoked (asynchronously) when a Compositor is present
830 // and commits a frame, which isn't true in some tests.
831 // See http://crbug.com/637521.
832 OnLayerScrolled(offset, contents_->layer()->element_id());
833 } else {
834 contents_->SetPosition(gfx::Point(-offset.x(), -offset.y()));
835 ScrollHeader();
836 }
837 UpdateOverflowIndicatorVisibility(offset);
838 UpdateScrollBarPositions();
839 }
840
ScrollsWithLayers() const841 bool ScrollView::ScrollsWithLayers() const {
842 if (!scroll_with_layers_enabled_)
843 return false;
844 // Just check for the presence of a layer since it's cheaper than querying the
845 // Feature flag each time.
846 return contents_viewport_->layer() != nullptr;
847 }
848
EnableViewportLayer()849 void ScrollView::EnableViewportLayer() {
850 if (DoesViewportOrScrollViewHaveLayer())
851 return;
852
853 contents_viewport_->SetPaintToLayer();
854 contents_viewport_->layer()->SetMasksToBounds(true);
855 more_content_left_->SetPaintToLayer();
856 more_content_top_->SetPaintToLayer();
857 more_content_right_->SetPaintToLayer();
858 more_content_bottom_->SetPaintToLayer();
859 UpdateBackground();
860 }
861
OnLayerScrolled(const gfx::ScrollOffset &,const cc::ElementId &)862 void ScrollView::OnLayerScrolled(const gfx::ScrollOffset&,
863 const cc::ElementId&) {
864 UpdateScrollBarPositions();
865 ScrollHeader();
866 }
867
ScrollHeader()868 void ScrollView::ScrollHeader() {
869 if (!header_)
870 return;
871
872 int x_offset = CurrentOffset().x();
873 if (header_->x() != -x_offset) {
874 header_->SetX(-x_offset);
875 header_->SchedulePaintInRect(header_->GetVisibleBounds());
876 }
877 }
878
AddBorder()879 void ScrollView::AddBorder() {
880 draw_border_ = true;
881 UpdateBorder();
882 }
883
UpdateBorder()884 void ScrollView::UpdateBorder() {
885 if (!draw_border_ || !GetWidget())
886 return;
887
888 SetBorder(CreateSolidBorder(
889 1, GetNativeTheme()->GetSystemColor(
890 draw_focus_indicator_
891 ? ui::NativeTheme::kColorId_FocusedBorderColor
892 : ui::NativeTheme::kColorId_UnfocusedBorderColor)));
893 }
894
UpdateBackground()895 void ScrollView::UpdateBackground() {
896 const base::Optional<SkColor> background_color = GetBackgroundColor();
897
898 auto create_background = [background_color]() {
899 return background_color ? CreateSolidBackground(background_color.value())
900 : nullptr;
901 };
902
903 SetBackground(create_background());
904 // In addition to setting the background of |this|, set the background on
905 // the viewport as well. This way if the viewport has a layer
906 // SetFillsBoundsOpaquely() is honored.
907 contents_viewport_->SetBackground(create_background());
908 if (contents_ && ScrollsWithLayers())
909 contents_->SetBackground(create_background());
910 if (contents_viewport_->layer()) {
911 contents_viewport_->layer()->SetFillsBoundsOpaquely(!!background_color);
912 }
913 SchedulePaint();
914 }
915
GetBackgroundColor() const916 base::Optional<SkColor> ScrollView::GetBackgroundColor() const {
917 return background_color_id_
918 ? GetNativeTheme()->GetSystemColor(background_color_id_.value())
919 : background_color_;
920 }
921
GetBackgroundThemeColorId() const922 base::Optional<ui::NativeTheme::ColorId> ScrollView::GetBackgroundThemeColorId()
923 const {
924 return background_color_id_;
925 }
926
PositionOverflowIndicators()927 void ScrollView::PositionOverflowIndicators() {
928 const gfx::Rect bounds = GetContentsBounds();
929 const int x = bounds.x();
930 const int y = bounds.y();
931 const int w = bounds.width();
932 const int h = bounds.height();
933 const int t = Separator::kThickness;
934 more_content_left_->SetBounds(x, y, t, h);
935 more_content_top_->SetBounds(x, y, w, t);
936 more_content_right_->SetBounds(bounds.right() - t, y, t, h);
937 more_content_bottom_->SetBounds(x, bounds.bottom() - t, w, t);
938 }
939
UpdateOverflowIndicatorVisibility(const gfx::ScrollOffset & offset)940 void ScrollView::UpdateOverflowIndicatorVisibility(
941 const gfx::ScrollOffset& offset) {
942 SetControlVisibility(more_content_top_.get(),
943 !draw_border_ && !header_ && vert_sb_->GetVisible() &&
944 offset.y() > vert_sb_->GetMinPosition() &&
945 draw_overflow_indicator_);
946 SetControlVisibility(
947 more_content_bottom_.get(),
948 !draw_border_ && vert_sb_->GetVisible() && !horiz_sb_->GetVisible() &&
949 offset.y() < vert_sb_->GetMaxPosition() && draw_overflow_indicator_);
950 SetControlVisibility(more_content_left_.get(),
951 !draw_border_ && horiz_sb_->GetVisible() &&
952 offset.x() > horiz_sb_->GetMinPosition() &&
953 draw_overflow_indicator_);
954 SetControlVisibility(
955 more_content_right_.get(),
956 !draw_border_ && horiz_sb_->GetVisible() && !vert_sb_->GetVisible() &&
957 offset.x() < horiz_sb_->GetMaxPosition() && draw_overflow_indicator_);
958 }
959
960 BEGIN_METADATA(ScrollView)
METADATA_PARENT_CLASS(View)961 METADATA_PARENT_CLASS(View)
962 ADD_READONLY_PROPERTY_METADATA(ScrollView, int, MinHeight)
963 ADD_READONLY_PROPERTY_METADATA(ScrollView, int, MaxHeight)
964 ADD_PROPERTY_METADATA(ScrollView, base::Optional<SkColor>, BackgroundColor)
965 ADD_PROPERTY_METADATA(ScrollView,
966 base::Optional<ui::NativeTheme::ColorId>,
967 BackgroundThemeColorId)
968 ADD_PROPERTY_METADATA(ScrollView, bool, DrawOverflowIndicator)
969 ADD_PROPERTY_METADATA(ScrollView, bool, HasFocusIndicator)
970 ADD_PROPERTY_METADATA(ScrollView, bool, HideHorizontalScrollBar)
971 END_METADATA()
972
973 // VariableRowHeightScrollHelper ----------------------------------------------
974
975 VariableRowHeightScrollHelper::VariableRowHeightScrollHelper(
976 Controller* controller)
977 : controller_(controller) {}
978
979 VariableRowHeightScrollHelper::~VariableRowHeightScrollHelper() = default;
980
GetPageScrollIncrement(ScrollView * scroll_view,bool is_horizontal,bool is_positive)981 int VariableRowHeightScrollHelper::GetPageScrollIncrement(
982 ScrollView* scroll_view,
983 bool is_horizontal,
984 bool is_positive) {
985 if (is_horizontal)
986 return 0;
987 // y coordinate is most likely negative.
988 int y = abs(scroll_view->contents()->y());
989 int vis_height = scroll_view->contents()->parent()->height();
990 if (is_positive) {
991 // Align the bottom most row to the top of the view.
992 int bottom =
993 std::min(scroll_view->contents()->height() - 1, y + vis_height);
994 RowInfo bottom_row_info = GetRowInfo(bottom);
995 // If 0, ScrollView will provide a default value.
996 return std::max(0, bottom_row_info.origin - y);
997 } else {
998 // Align the row on the previous page to to the top of the view.
999 int last_page_y = y - vis_height;
1000 RowInfo last_page_info = GetRowInfo(std::max(0, last_page_y));
1001 if (last_page_y != last_page_info.origin)
1002 return std::max(0, y - last_page_info.origin - last_page_info.height);
1003 return std::max(0, y - last_page_info.origin);
1004 }
1005 }
1006
GetLineScrollIncrement(ScrollView * scroll_view,bool is_horizontal,bool is_positive)1007 int VariableRowHeightScrollHelper::GetLineScrollIncrement(
1008 ScrollView* scroll_view,
1009 bool is_horizontal,
1010 bool is_positive) {
1011 if (is_horizontal)
1012 return 0;
1013 // y coordinate is most likely negative.
1014 int y = abs(scroll_view->contents()->y());
1015 RowInfo row = GetRowInfo(y);
1016 if (is_positive) {
1017 return row.height - (y - row.origin);
1018 } else if (y == row.origin) {
1019 row = GetRowInfo(std::max(0, row.origin - 1));
1020 return y - row.origin;
1021 } else {
1022 return y - row.origin;
1023 }
1024 }
1025
1026 VariableRowHeightScrollHelper::RowInfo
GetRowInfo(int y)1027 VariableRowHeightScrollHelper::GetRowInfo(int y) {
1028 return controller_->GetRowInfo(y);
1029 }
1030
1031 // FixedRowHeightScrollHelper -----------------------------------------------
1032
FixedRowHeightScrollHelper(int top_margin,int row_height)1033 FixedRowHeightScrollHelper::FixedRowHeightScrollHelper(int top_margin,
1034 int row_height)
1035 : VariableRowHeightScrollHelper(nullptr),
1036 top_margin_(top_margin),
1037 row_height_(row_height) {
1038 DCHECK_GT(row_height, 0);
1039 }
1040
GetRowInfo(int y)1041 VariableRowHeightScrollHelper::RowInfo FixedRowHeightScrollHelper::GetRowInfo(
1042 int y) {
1043 if (y < top_margin_)
1044 return RowInfo(0, top_margin_);
1045 return RowInfo((y - top_margin_) / row_height_ * row_height_ + top_margin_,
1046 row_height_);
1047 }
1048
1049 } // namespace views
1050