1/*
2 * Copyright (C) 2008-2016 Apple Inc. All Rights Reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include "ScrollSnapOffsetsInfo.h"
29#include "ScrollTypes.h"
30#include "Scrollbar.h"
31#include <wtf/Forward.h>
32#include <wtf/WeakPtr.h>
33
34namespace WebCore {
35
36class FloatPoint;
37class GraphicsContext;
38class LayoutPoint;
39class LayoutSize;
40class PlatformTouchEvent;
41class PlatformWheelEvent;
42class ScrollAnimator;
43class GraphicsLayer;
44class TiledBacking;
45
46// scrollPosition is in content coordinates (0,0 is at scrollOrigin), so may have negative components.
47typedef IntPoint ScrollPosition;
48// scrollOffset() is the value used by scrollbars (min is 0,0), and should never have negative components.
49typedef IntPoint ScrollOffset;
50
51class ScrollableArea : public CanMakeWeakPtr<ScrollableArea> {
52public:
53 WEBCORE_EXPORT bool scroll(ScrollDirection, ScrollGranularity, float multiplier = 1);
54 WEBCORE_EXPORT void scrollToOffsetWithoutAnimation(const FloatPoint&, ScrollClamping = ScrollClamping::Clamped);
55 void scrollToOffsetWithoutAnimation(ScrollbarOrientation, float offset);
56
57 // Should be called when the scroll position changes externally, for example if the scroll layer position
58 // is updated on the scrolling thread and we need to notify the main thread.
59 WEBCORE_EXPORT void notifyScrollPositionChanged(const ScrollPosition&);
60
61 // Allows subclasses to handle scroll position updates themselves. If this member function
62 // returns true, the scrollable area won't actually update the scroll position and instead
63 // expect it to happen sometime in the future.
64 virtual bool requestScrollPositionUpdate(const ScrollPosition&) { return false; }
65
66 WEBCORE_EXPORT bool handleWheelEvent(const PlatformWheelEvent&);
67
68#if ENABLE(CSS_SCROLL_SNAP)
69 WEBCORE_EXPORT const Vector<LayoutUnit>* horizontalSnapOffsets() const;
70 WEBCORE_EXPORT const Vector<LayoutUnit>* verticalSnapOffsets() const;
71 WEBCORE_EXPORT const Vector<ScrollOffsetRange<LayoutUnit>>* horizontalSnapOffsetRanges() const;
72 WEBCORE_EXPORT const Vector<ScrollOffsetRange<LayoutUnit>>* verticalSnapOffsetRanges() const;
73 virtual void updateSnapOffsets() { };
74 void setHorizontalSnapOffsets(const Vector<LayoutUnit>&);
75 void setVerticalSnapOffsets(const Vector<LayoutUnit>&);
76 void setHorizontalSnapOffsetRanges(const Vector<ScrollOffsetRange<LayoutUnit>>&);
77 void setVerticalSnapOffsetRanges(const Vector<ScrollOffsetRange<LayoutUnit>>&);
78 void clearHorizontalSnapOffsets();
79 void clearVerticalSnapOffsets();
80 unsigned currentHorizontalSnapPointIndex() const { return m_currentHorizontalSnapPointIndex; }
81 void setCurrentHorizontalSnapPointIndex(unsigned index) { m_currentHorizontalSnapPointIndex = index; }
82 unsigned currentVerticalSnapPointIndex() const { return m_currentVerticalSnapPointIndex; }
83 void setCurrentVerticalSnapPointIndex(unsigned index) { m_currentVerticalSnapPointIndex = index; }
84 IntPoint nearestActiveSnapPoint(const IntPoint&);
85#endif
86
87 void updateScrollSnapState();
88
89#if ENABLE(TOUCH_EVENTS)
90 virtual bool handleTouchEvent(const PlatformTouchEvent&);
91#endif
92
93#if PLATFORM(IOS_FAMILY)
94 virtual void didStartScroll() { }
95 virtual void didEndScroll() { }
96 virtual void didUpdateScroll() { }
97#endif
98
99 // Functions for controlling if you can scroll past the end of the document.
100 bool constrainsScrollingToContentEdge() const { return m_constrainsScrollingToContentEdge; }
101 void setConstrainsScrollingToContentEdge(bool constrainsScrollingToContentEdge) { m_constrainsScrollingToContentEdge = constrainsScrollingToContentEdge; }
102
103 void setVerticalScrollElasticity(ScrollElasticity scrollElasticity) { m_verticalScrollElasticity = scrollElasticity; }
104 ScrollElasticity verticalScrollElasticity() const { return static_cast<ScrollElasticity>(m_verticalScrollElasticity); }
105
106 void setHorizontalScrollElasticity(ScrollElasticity scrollElasticity) { m_horizontalScrollElasticity = scrollElasticity; }
107 ScrollElasticity horizontalScrollElasticity() const { return static_cast<ScrollElasticity>(m_horizontalScrollElasticity); }
108
109 virtual ScrollbarMode horizontalScrollbarMode() const { return ScrollbarAuto; }
110 virtual ScrollbarMode verticalScrollbarMode() const { return ScrollbarAuto; }
111
112 virtual bool horizontalScrollbarHiddenByStyle() const { return false; }
113 virtual bool verticalScrollbarHiddenByStyle() const { return false; }
114
115 bool inLiveResize() const { return m_inLiveResize; }
116 WEBCORE_EXPORT virtual void willStartLiveResize();
117 WEBCORE_EXPORT virtual void willEndLiveResize();
118
119 WEBCORE_EXPORT void contentAreaWillPaint() const;
120 WEBCORE_EXPORT void mouseEnteredContentArea() const;
121 WEBCORE_EXPORT void mouseExitedContentArea() const;
122 WEBCORE_EXPORT void mouseMovedInContentArea() const;
123 WEBCORE_EXPORT void mouseEnteredScrollbar(Scrollbar*) const;
124 void mouseExitedScrollbar(Scrollbar*) const;
125 void mouseIsDownInScrollbar(Scrollbar*, bool) const;
126 void contentAreaDidShow() const;
127 void contentAreaDidHide() const;
128
129 void lockOverlayScrollbarStateToHidden(bool shouldLockState) const;
130 WEBCORE_EXPORT bool scrollbarsCanBeActive() const;
131
132 WEBCORE_EXPORT virtual void didAddScrollbar(Scrollbar*, ScrollbarOrientation);
133 WEBCORE_EXPORT virtual void willRemoveScrollbar(Scrollbar*, ScrollbarOrientation);
134
135 WEBCORE_EXPORT virtual void contentsResized();
136
137 // Force the contents to recompute their size (i.e. do layout).
138 virtual void updateContentsSize() { }
139
140 enum class AvailableSizeChangeReason {
141 ScrollbarsChanged,
142 AreaSizeChanged
143 };
144 WEBCORE_EXPORT virtual void availableContentSizeChanged(AvailableSizeChangeReason);
145
146 bool hasOverlayScrollbars() const;
147 WEBCORE_EXPORT virtual void setScrollbarOverlayStyle(ScrollbarOverlayStyle);
148 ScrollbarOverlayStyle scrollbarOverlayStyle() const { return static_cast<ScrollbarOverlayStyle>(m_scrollbarOverlayStyle); }
149 bool useDarkAppearanceForScrollbars() const;
150
151 virtual ScrollingNodeID scrollingNodeID() const { return 0; }
152
153 // This getter will create a ScrollAnimator if it doesn't already exist.
154 WEBCORE_EXPORT ScrollAnimator& scrollAnimator() const;
155
156 // This getter will return null if the ScrollAnimator hasn't been created yet.
157 ScrollAnimator* existingScrollAnimator() const { return m_scrollAnimator.get(); }
158
159 virtual bool isActive() const = 0;
160 virtual int scrollSize(ScrollbarOrientation) const = 0;
161 virtual int scrollOffset(ScrollbarOrientation) const = 0;
162 WEBCORE_EXPORT virtual void invalidateScrollbar(Scrollbar&, const IntRect&);
163 virtual bool isScrollCornerVisible() const = 0;
164 virtual IntRect scrollCornerRect() const = 0;
165 WEBCORE_EXPORT virtual void invalidateScrollCorner(const IntRect&);
166
167 virtual bool forceUpdateScrollbarsOnMainThreadForPerformanceTesting() const = 0;
168
169 // Convert points and rects between the scrollbar and its containing view.
170 // The client needs to implement these in order to be aware of layout effects
171 // like CSS transforms.
172 virtual IntRect convertFromScrollbarToContainingView(const Scrollbar& scrollbar, const IntRect& scrollbarRect) const
173 {
174 return scrollbar.Widget::convertToContainingView(scrollbarRect);
175 }
176 virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar& scrollbar, const IntRect& parentRect) const
177 {
178 return scrollbar.Widget::convertFromContainingView(parentRect);
179 }
180 virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar& scrollbar, const IntPoint& scrollbarPoint) const
181 {
182 return scrollbar.Widget::convertToContainingView(scrollbarPoint);
183 }
184 virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar& scrollbar, const IntPoint& parentPoint) const
185 {
186 return scrollbar.Widget::convertFromContainingView(parentPoint);
187 }
188
189 int horizontalScrollbarIntrusion() const;
190 int verticalScrollbarIntrusion() const;
191 WEBCORE_EXPORT IntSize scrollbarIntrusion() const;
192
193 virtual Scrollbar* horizontalScrollbar() const { return nullptr; }
194 virtual Scrollbar* verticalScrollbar() const { return nullptr; }
195
196 const IntPoint& scrollOrigin() const { return m_scrollOrigin; }
197 bool scrollOriginChanged() const { return m_scrollOriginChanged; }
198
199 virtual ScrollPosition scrollPosition() const;
200 virtual ScrollPosition minimumScrollPosition() const;
201 virtual ScrollPosition maximumScrollPosition() const;
202
203 ScrollPosition constrainScrollPosition(const ScrollPosition& position) const
204 {
205 return position.constrainedBetween(minimumScrollPosition(), maximumScrollPosition());
206 }
207
208 ScrollOffset maximumScrollOffset() const;
209
210 WEBCORE_EXPORT ScrollPosition scrollPositionFromOffset(ScrollOffset) const;
211 WEBCORE_EXPORT ScrollOffset scrollOffsetFromPosition(ScrollPosition) const;
212
213 template<typename PositionType, typename SizeType>
214 static PositionType scrollPositionFromOffset(PositionType offset, SizeType scrollOrigin)
215 {
216 return offset - scrollOrigin;
217 }
218
219 template<typename PositionType, typename SizeType>
220 static PositionType scrollOffsetFromPosition(PositionType position, SizeType scrollOrigin)
221 {
222 return position + scrollOrigin;
223 }
224
225 WEBCORE_EXPORT virtual bool scrolledToTop() const;
226 WEBCORE_EXPORT virtual bool scrolledToBottom() const;
227 WEBCORE_EXPORT virtual bool scrolledToLeft() const;
228 WEBCORE_EXPORT virtual bool scrolledToRight() const;
229
230 ScrollType currentScrollType() const { return static_cast<ScrollType>(m_currentScrollType); }
231 void setCurrentScrollType(ScrollType scrollType) { m_currentScrollType = static_cast<unsigned>(scrollType); }
232
233 bool scrollShouldClearLatchedState() const { return m_scrollShouldClearLatchedState; }
234 void setScrollShouldClearLatchedState(bool shouldClear) { m_scrollShouldClearLatchedState = shouldClear; }
235
236 enum VisibleContentRectIncludesScrollbars { ExcludeScrollbars, IncludeScrollbars };
237 enum VisibleContentRectBehavior {
238 ContentsVisibleRect,
239#if PLATFORM(IOS_FAMILY)
240 LegacyIOSDocumentViewRect,
241 LegacyIOSDocumentVisibleRect = LegacyIOSDocumentViewRect
242#else
243 LegacyIOSDocumentVisibleRect = ContentsVisibleRect
244#endif
245 };
246
247 WEBCORE_EXPORT IntRect visibleContentRect(VisibleContentRectBehavior = ContentsVisibleRect) const;
248 WEBCORE_EXPORT IntRect visibleContentRectIncludingScrollbars(VisibleContentRectBehavior = ContentsVisibleRect) const;
249
250 int visibleWidth() const { return visibleSize().width(); }
251 int visibleHeight() const { return visibleSize().height(); }
252 virtual IntSize visibleSize() const = 0;
253
254 virtual IntSize contentsSize() const = 0;
255 virtual IntSize overhangAmount() const { return IntSize(); }
256 virtual IntPoint lastKnownMousePosition() const { return IntPoint(); }
257 virtual bool isHandlingWheelEvent() const { return false; }
258
259 virtual int headerHeight() const { return 0; }
260 virtual int footerHeight() const { return 0; }
261
262 // The totalContentsSize() is equivalent to the contentsSize() plus the header and footer heights.
263 WEBCORE_EXPORT IntSize totalContentsSize() const;
264 WEBCORE_EXPORT virtual IntSize reachableTotalContentsSize() const;
265
266 virtual bool useDarkAppearance() const { return false; }
267
268 virtual bool shouldSuspendScrollAnimations() const { return true; }
269 WEBCORE_EXPORT virtual void scrollbarStyleChanged(ScrollbarStyle /*newStyle*/, bool /*forceUpdate*/);
270 virtual void setVisibleScrollerThumbRect(const IntRect&) { }
271
272 // Note that this only returns scrollable areas that can actually be scrolled.
273 virtual ScrollableArea* enclosingScrollableArea() const = 0;
274
275 virtual bool isScrollableOrRubberbandable() = 0;
276 virtual bool hasScrollableOrRubberbandableAncestor() = 0;
277
278 // Returns the bounding box of this scrollable area, in the coordinate system of the enclosing scroll view.
279 virtual IntRect scrollableAreaBoundingBox(bool* = nullptr) const = 0;
280
281 virtual bool isRubberBandInProgress() const { return false; }
282 virtual bool isScrollSnapInProgress() const { return false; }
283
284 virtual bool scrollAnimatorEnabled() const { return false; }
285
286 // NOTE: Only called from Internals for testing.
287 WEBCORE_EXPORT void setScrollOffsetFromInternals(const ScrollOffset&);
288
289 WEBCORE_EXPORT static LayoutPoint constrainScrollPositionForOverhang(const LayoutRect& visibleContentRect, const LayoutSize& totalContentsSize, const LayoutPoint& scrollPosition, const LayoutPoint& scrollOrigin, int headerHeight, int footetHeight);
290 LayoutPoint constrainScrollPositionForOverhang(const LayoutPoint& scrollPosition);
291
292 // Computes the double value for the scrollbar's current position and the current overhang amount.
293 // This function is static so that it can be called from the main thread or the scrolling thread.
294 WEBCORE_EXPORT static void computeScrollbarValueAndOverhang(float currentPosition, float totalSize, float visibleSize, float& doubleValue, float& overhangAmount);
295
296 // Let subclasses provide a way of asking for and servicing scroll
297 // animations.
298 virtual bool scheduleAnimation() { return false; }
299 void serviceScrollAnimations();
300
301#if PLATFORM(IOS_FAMILY)
302 bool isHorizontalScrollerPinnedToMinimumPosition() const { return !horizontalScrollbar() || scrollOffset(HorizontalScrollbar) <= 0; }
303 bool isHorizontalScrollerPinnedToMaximumPosition() const { return !horizontalScrollbar() || scrollOffset(HorizontalScrollbar) >= maximumScrollOffset().x(); }
304 bool isVerticalScrollerPinnedToMinimumPosition() const { return !verticalScrollbar() || scrollOffset(VerticalScrollbar) <= 0; }
305 bool isVerticalScrollerPinnedToMaximumPosition() const { return !verticalScrollbar() || scrollOffset(VerticalScrollbar) >= maximumScrollOffset().y(); }
306
307 bool isPinnedInBothDirections(const IntSize&) const;
308 bool isPinnedHorizontallyInDirection(int horizontalScrollDelta) const;
309 bool isPinnedVerticallyInDirection(int verticalScrollDelta) const;
310#endif
311
312 virtual TiledBacking* tiledBacking() const { return nullptr; }
313
314 // True if scrolling happens by moving compositing layers.
315 virtual bool usesCompositedScrolling() const { return false; }
316 // True if the contents can be scrolled asynchronously (i.e. by a ScrollingCoordinator).
317 virtual bool usesAsyncScrolling() const { return false; }
318
319 virtual GraphicsLayer* layerForHorizontalScrollbar() const { return nullptr; }
320 virtual GraphicsLayer* layerForVerticalScrollbar() const { return nullptr; }
321
322 bool hasLayerForHorizontalScrollbar() const;
323 bool hasLayerForVerticalScrollbar() const;
324
325 void verticalScrollbarLayerDidChange();
326 void horizontalScrollbarLayerDidChange();
327
328 virtual bool usesMockScrollAnimator() const { return false; }
329 virtual void logMockScrollAnimatorMessage(const String&) const { };
330
331 virtual bool shouldPlaceBlockDirectionScrollbarOnLeft() const = 0;
332
333protected:
334 WEBCORE_EXPORT ScrollableArea();
335 WEBCORE_EXPORT virtual ~ScrollableArea();
336
337 void setScrollOrigin(const IntPoint&);
338 void resetScrollOriginChanged() { m_scrollOriginChanged = false; }
339
340 WEBCORE_EXPORT virtual float adjustScrollStepForFixedContent(float step, ScrollbarOrientation, ScrollGranularity);
341 virtual void invalidateScrollbarRect(Scrollbar&, const IntRect&) = 0;
342 virtual void invalidateScrollCornerRect(const IntRect&) = 0;
343
344 friend class ScrollingCoordinator;
345 virtual GraphicsLayer* layerForScrollCorner() const { return nullptr; }
346#if ENABLE(RUBBER_BANDING)
347 virtual GraphicsLayer* layerForOverhangAreas() const { return nullptr; }
348#endif
349
350 bool hasLayerForScrollCorner() const;
351
352private:
353 WEBCORE_EXPORT virtual IntRect visibleContentRectInternal(VisibleContentRectIncludesScrollbars, VisibleContentRectBehavior) const;
354 void scrollPositionChanged(const ScrollPosition&);
355
356 // NOTE: Only called from the ScrollAnimator.
357 friend class ScrollAnimator;
358 void setScrollOffsetFromAnimation(const ScrollOffset&);
359
360 // This function should be overridden by subclasses to perform the actual
361 // scroll of the content.
362 virtual void setScrollOffset(const ScrollOffset&) = 0;
363 ScrollSnapOffsetsInfo<LayoutUnit>& ensureSnapOffsetsInfo();
364
365 mutable std::unique_ptr<ScrollAnimator> m_scrollAnimator;
366
367#if ENABLE(CSS_SCROLL_SNAP)
368 std::unique_ptr<ScrollSnapOffsetsInfo<LayoutUnit>> m_snapOffsetsInfo;
369 unsigned m_currentHorizontalSnapPointIndex { 0 };
370 unsigned m_currentVerticalSnapPointIndex { 0 };
371#endif
372
373 // There are 8 possible combinations of writing mode and direction. Scroll origin will be non-zero in the x or y axis
374 // if there is any reversed direction or writing-mode. The combinations are:
375 // writing-mode / direction scrollOrigin.x() set scrollOrigin.y() set
376 // horizontal-tb / ltr NO NO
377 // horizontal-tb / rtl YES NO
378 // horizontal-bt / ltr NO YES
379 // horizontal-bt / rtl YES YES
380 // vertical-lr / ltr NO NO
381 // vertical-lr / rtl NO YES
382 // vertical-rl / ltr YES NO
383 // vertical-rl / rtl YES YES
384 IntPoint m_scrollOrigin;
385
386 unsigned m_constrainsScrollingToContentEdge : 1;
387
388 unsigned m_inLiveResize : 1;
389
390 unsigned m_verticalScrollElasticity : 2; // ScrollElasticity
391 unsigned m_horizontalScrollElasticity : 2; // ScrollElasticity
392
393 unsigned m_scrollbarOverlayStyle : 2; // ScrollbarOverlayStyle
394
395 unsigned m_scrollOriginChanged : 1;
396 unsigned m_currentScrollType : 1; // ScrollType
397 unsigned m_scrollShouldClearLatchedState : 1;
398};
399
400} // namespace WebCore
401
402