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
51
52inline int offsetForOrientation(ScrollOffset offset, ScrollbarOrientation orientation)
53{
54 switch (orientation) {
55 case HorizontalScrollbar: return offset.x();
56 case VerticalScrollbar: return offset.y();
57 }
58 ASSERT_NOT_REACHED();
59 return 0;
60}
61
62
63class ScrollableArea : public CanMakeWeakPtr<ScrollableArea> {
64public:
65 WEBCORE_EXPORT bool scroll(ScrollDirection, ScrollGranularity, float multiplier = 1);
66 WEBCORE_EXPORT void scrollToOffsetWithoutAnimation(const FloatPoint&, ScrollClamping = ScrollClamping::Clamped);
67 void scrollToOffsetWithoutAnimation(ScrollbarOrientation, float offset);
68
69 // Should be called when the scroll position changes externally, for example if the scroll layer position
70 // is updated on the scrolling thread and we need to notify the main thread.
71 WEBCORE_EXPORT void notifyScrollPositionChanged(const ScrollPosition&);
72
73 // Allows subclasses to handle scroll position updates themselves. If this member function
74 // returns true, the scrollable area won't actually update the scroll position and instead
75 // expect it to happen sometime in the future.
76 virtual bool requestScrollPositionUpdate(const ScrollPosition&) { return false; }
77
78 WEBCORE_EXPORT bool handleWheelEvent(const PlatformWheelEvent&);
79
80#if ENABLE(CSS_SCROLL_SNAP)
81 WEBCORE_EXPORT const Vector<LayoutUnit>* horizontalSnapOffsets() const;
82 WEBCORE_EXPORT const Vector<LayoutUnit>* verticalSnapOffsets() const;
83 WEBCORE_EXPORT const Vector<ScrollOffsetRange<LayoutUnit>>* horizontalSnapOffsetRanges() const;
84 WEBCORE_EXPORT const Vector<ScrollOffsetRange<LayoutUnit>>* verticalSnapOffsetRanges() const;
85 virtual void updateSnapOffsets() { };
86 void setHorizontalSnapOffsets(const Vector<LayoutUnit>&);
87 void setVerticalSnapOffsets(const Vector<LayoutUnit>&);
88 void setHorizontalSnapOffsetRanges(const Vector<ScrollOffsetRange<LayoutUnit>>&);
89 void setVerticalSnapOffsetRanges(const Vector<ScrollOffsetRange<LayoutUnit>>&);
90 void clearHorizontalSnapOffsets();
91 void clearVerticalSnapOffsets();
92 unsigned currentHorizontalSnapPointIndex() const { return m_currentHorizontalSnapPointIndex; }
93 void setCurrentHorizontalSnapPointIndex(unsigned index) { m_currentHorizontalSnapPointIndex = index; }
94 unsigned currentVerticalSnapPointIndex() const { return m_currentVerticalSnapPointIndex; }
95 void setCurrentVerticalSnapPointIndex(unsigned index) { m_currentVerticalSnapPointIndex = index; }
96 IntPoint nearestActiveSnapPoint(const IntPoint&);
97#endif
98
99 void updateScrollSnapState();
100
101#if ENABLE(TOUCH_EVENTS)
102 virtual bool handleTouchEvent(const PlatformTouchEvent&);
103#endif
104
105#if PLATFORM(IOS_FAMILY)
106 virtual void didStartScroll() { }
107 virtual void didEndScroll() { }
108 virtual void didUpdateScroll() { }
109#endif
110
111 // Functions for controlling if you can scroll past the end of the document.
112 bool constrainsScrollingToContentEdge() const { return m_constrainsScrollingToContentEdge; }
113 void setConstrainsScrollingToContentEdge(bool constrainsScrollingToContentEdge) { m_constrainsScrollingToContentEdge = constrainsScrollingToContentEdge; }
114
115 void setVerticalScrollElasticity(ScrollElasticity scrollElasticity) { m_verticalScrollElasticity = scrollElasticity; }
116 ScrollElasticity verticalScrollElasticity() const { return static_cast<ScrollElasticity>(m_verticalScrollElasticity); }
117
118 void setHorizontalScrollElasticity(ScrollElasticity scrollElasticity) { m_horizontalScrollElasticity = scrollElasticity; }
119 ScrollElasticity horizontalScrollElasticity() const { return static_cast<ScrollElasticity>(m_horizontalScrollElasticity); }
120
121 virtual ScrollbarMode horizontalScrollbarMode() const { return ScrollbarAuto; }
122 virtual ScrollbarMode verticalScrollbarMode() const { return ScrollbarAuto; }
123
124 virtual bool horizontalScrollbarHiddenByStyle() const { return false; }
125 virtual bool verticalScrollbarHiddenByStyle() const { return false; }
126
127 bool inLiveResize() const { return m_inLiveResize; }
128 WEBCORE_EXPORT virtual void willStartLiveResize();
129 WEBCORE_EXPORT virtual void willEndLiveResize();
130
131 WEBCORE_EXPORT void contentAreaWillPaint() const;
132 WEBCORE_EXPORT void mouseEnteredContentArea() const;
133 WEBCORE_EXPORT void mouseExitedContentArea() const;
134 WEBCORE_EXPORT void mouseMovedInContentArea() const;
135 WEBCORE_EXPORT void mouseEnteredScrollbar(Scrollbar*) const;
136 void mouseExitedScrollbar(Scrollbar*) const;
137 void mouseIsDownInScrollbar(Scrollbar*, bool) const;
138 void contentAreaDidShow() const;
139 void contentAreaDidHide() const;
140
141 void lockOverlayScrollbarStateToHidden(bool shouldLockState) const;
142 WEBCORE_EXPORT bool scrollbarsCanBeActive() const;
143
144 WEBCORE_EXPORT virtual void didAddScrollbar(Scrollbar*, ScrollbarOrientation);
145 WEBCORE_EXPORT virtual void willRemoveScrollbar(Scrollbar*, ScrollbarOrientation);
146
147 WEBCORE_EXPORT virtual void contentsResized();
148
149 // Force the contents to recompute their size (i.e. do layout).
150 virtual void updateContentsSize() { }
151
152 enum class AvailableSizeChangeReason {
153 ScrollbarsChanged,
154 AreaSizeChanged
155 };
156 WEBCORE_EXPORT virtual void availableContentSizeChanged(AvailableSizeChangeReason);
157
158 bool hasOverlayScrollbars() const;
159 WEBCORE_EXPORT virtual void setScrollbarOverlayStyle(ScrollbarOverlayStyle);
160 ScrollbarOverlayStyle scrollbarOverlayStyle() const { return static_cast<ScrollbarOverlayStyle>(m_scrollbarOverlayStyle); }
161 bool useDarkAppearanceForScrollbars() const;
162
163 virtual ScrollingNodeID scrollingNodeID() const { return 0; }
164
165 // This getter will create a ScrollAnimator if it doesn't already exist.
166 WEBCORE_EXPORT ScrollAnimator& scrollAnimator() const;
167
168 // This getter will return null if the ScrollAnimator hasn't been created yet.
169 ScrollAnimator* existingScrollAnimator() const { return m_scrollAnimator.get(); }
170
171 virtual bool isActive() const = 0;
172 WEBCORE_EXPORT virtual void invalidateScrollbar(Scrollbar&, const IntRect&);
173 virtual bool isScrollCornerVisible() const = 0;
174 virtual IntRect scrollCornerRect() const = 0;
175 WEBCORE_EXPORT virtual void invalidateScrollCorner(const IntRect&);
176
177 virtual bool forceUpdateScrollbarsOnMainThreadForPerformanceTesting() const = 0;
178
179 // Convert points and rects between the scrollbar and its containing view.
180 // The client needs to implement these in order to be aware of layout effects
181 // like CSS transforms.
182 virtual IntRect convertFromScrollbarToContainingView(const Scrollbar& scrollbar, const IntRect& scrollbarRect) const
183 {
184 return scrollbar.Widget::convertToContainingView(scrollbarRect);
185 }
186 virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar& scrollbar, const IntRect& parentRect) const
187 {
188 return scrollbar.Widget::convertFromContainingView(parentRect);
189 }
190 virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar& scrollbar, const IntPoint& scrollbarPoint) const
191 {
192 return scrollbar.Widget::convertToContainingView(scrollbarPoint);
193 }
194 virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar& scrollbar, const IntPoint& parentPoint) const
195 {
196 return scrollbar.Widget::convertFromContainingView(parentPoint);
197 }
198
199 int horizontalScrollbarIntrusion() const;
200 int verticalScrollbarIntrusion() const;
201 WEBCORE_EXPORT IntSize scrollbarIntrusion() const;
202
203 virtual Scrollbar* horizontalScrollbar() const { return nullptr; }
204 virtual Scrollbar* verticalScrollbar() const { return nullptr; }
205
206 const IntPoint& scrollOrigin() const { return m_scrollOrigin; }
207 bool scrollOriginChanged() const { return m_scrollOriginChanged; }
208
209 virtual ScrollPosition scrollPosition() const = 0;
210 virtual ScrollPosition minimumScrollPosition() const;
211 virtual ScrollPosition maximumScrollPosition() const;
212
213 ScrollPosition constrainScrollPosition(const ScrollPosition& position) const
214 {
215 return position.constrainedBetween(minimumScrollPosition(), maximumScrollPosition());
216 }
217
218 WEBCORE_EXPORT ScrollOffset scrollOffset() const;
219
220 ScrollOffset maximumScrollOffset() const;
221
222 WEBCORE_EXPORT ScrollPosition scrollPositionFromOffset(ScrollOffset) const;
223 WEBCORE_EXPORT ScrollOffset scrollOffsetFromPosition(ScrollPosition) const;
224
225 template<typename PositionType, typename SizeType>
226 static PositionType scrollPositionFromOffset(PositionType offset, SizeType scrollOrigin)
227 {
228 return offset - scrollOrigin;
229 }
230
231 template<typename PositionType, typename SizeType>
232 static PositionType scrollOffsetFromPosition(PositionType position, SizeType scrollOrigin)
233 {
234 return position + scrollOrigin;
235 }
236
237 WEBCORE_EXPORT virtual bool scrolledToTop() const;
238 WEBCORE_EXPORT virtual bool scrolledToBottom() const;
239 WEBCORE_EXPORT virtual bool scrolledToLeft() const;
240 WEBCORE_EXPORT virtual bool scrolledToRight() const;
241
242 ScrollType currentScrollType() const { return static_cast<ScrollType>(m_currentScrollType); }
243 void setCurrentScrollType(ScrollType scrollType) { m_currentScrollType = static_cast<unsigned>(scrollType); }
244
245 bool scrollShouldClearLatchedState() const { return m_scrollShouldClearLatchedState; }
246 void setScrollShouldClearLatchedState(bool shouldClear) { m_scrollShouldClearLatchedState = shouldClear; }
247
248 enum VisibleContentRectIncludesScrollbars { ExcludeScrollbars, IncludeScrollbars };
249 enum VisibleContentRectBehavior {
250 ContentsVisibleRect,
251#if PLATFORM(IOS_FAMILY)
252 LegacyIOSDocumentViewRect,
253 LegacyIOSDocumentVisibleRect = LegacyIOSDocumentViewRect
254#else
255 LegacyIOSDocumentVisibleRect = ContentsVisibleRect
256#endif
257 };
258
259 WEBCORE_EXPORT IntRect visibleContentRect(VisibleContentRectBehavior = ContentsVisibleRect) const;
260 WEBCORE_EXPORT IntRect visibleContentRectIncludingScrollbars(VisibleContentRectBehavior = ContentsVisibleRect) const;
261
262 int visibleWidth() const { return visibleSize().width(); }
263 int visibleHeight() const { return visibleSize().height(); }
264 virtual IntSize visibleSize() const = 0;
265
266 virtual IntSize contentsSize() const = 0;
267 virtual IntSize overhangAmount() const { return IntSize(); }
268 virtual IntPoint lastKnownMousePosition() const { return IntPoint(); }
269 virtual bool isHandlingWheelEvent() const { return false; }
270
271 virtual int headerHeight() const { return 0; }
272 virtual int footerHeight() const { return 0; }
273
274 // The totalContentsSize() is equivalent to the contentsSize() plus the header and footer heights.
275 WEBCORE_EXPORT IntSize totalContentsSize() const;
276 WEBCORE_EXPORT virtual IntSize reachableTotalContentsSize() const;
277
278 virtual bool useDarkAppearance() const { return false; }
279
280 virtual bool shouldSuspendScrollAnimations() const { return true; }
281 WEBCORE_EXPORT virtual void scrollbarStyleChanged(ScrollbarStyle /*newStyle*/, bool /*forceUpdate*/);
282 virtual void setVisibleScrollerThumbRect(const IntRect&) { }
283
284 // Note that this only returns scrollable areas that can actually be scrolled.
285 virtual ScrollableArea* enclosingScrollableArea() const = 0;
286
287 virtual bool isScrollableOrRubberbandable() = 0;
288 virtual bool hasScrollableOrRubberbandableAncestor() = 0;
289
290 // Returns the bounding box of this scrollable area, in the coordinate system of the enclosing scroll view.
291 virtual IntRect scrollableAreaBoundingBox(bool* = nullptr) const = 0;
292
293 virtual bool isRubberBandInProgress() const { return false; }
294 virtual bool isScrollSnapInProgress() const { return false; }
295
296 virtual bool scrollAnimatorEnabled() const { return false; }
297
298 // NOTE: Only called from Internals for testing.
299 WEBCORE_EXPORT void setScrollOffsetFromInternals(const ScrollOffset&);
300
301 WEBCORE_EXPORT static LayoutPoint constrainScrollPositionForOverhang(const LayoutRect& visibleContentRect, const LayoutSize& totalContentsSize, const LayoutPoint& scrollPosition, const LayoutPoint& scrollOrigin, int headerHeight, int footetHeight);
302 LayoutPoint constrainScrollPositionForOverhang(const LayoutPoint& scrollPosition);
303
304 // Computes the double value for the scrollbar's current position and the current overhang amount.
305 // This function is static so that it can be called from the main thread or the scrolling thread.
306 WEBCORE_EXPORT static void computeScrollbarValueAndOverhang(float currentPosition, float totalSize, float visibleSize, float& doubleValue, float& overhangAmount);
307
308 // Let subclasses provide a way of asking for and servicing scroll
309 // animations.
310 virtual bool scheduleAnimation() { return false; }
311 void serviceScrollAnimations();
312
313 bool isHorizontalScrollerPinnedToMinimumPosition() const { return !horizontalScrollbar() || scrollOffset().x() <= 0; }
314 bool isHorizontalScrollerPinnedToMaximumPosition() const { return !horizontalScrollbar() || scrollOffset().x() >= maximumScrollOffset().x(); }
315 bool isVerticalScrollerPinnedToMinimumPosition() const { return !verticalScrollbar() || scrollOffset().y() <= 0; }
316 bool isVerticalScrollerPinnedToMaximumPosition() const { return !verticalScrollbar() || scrollOffset().y() >= maximumScrollOffset().y(); }
317
318 bool isPinnedInBothDirections(const IntSize&) const;
319 bool isPinnedHorizontallyInDirection(int horizontalScrollDelta) const;
320 bool isPinnedVerticallyInDirection(int verticalScrollDelta) const;
321
322 // True if scrolling happens by moving compositing layers.
323 virtual bool usesCompositedScrolling() const { return false; }
324 // True if the contents can be scrolled asynchronously (i.e. by a ScrollingCoordinator).
325 virtual bool usesAsyncScrolling() const { return false; }
326
327 virtual GraphicsLayer* layerForHorizontalScrollbar() const { return nullptr; }
328 virtual GraphicsLayer* layerForVerticalScrollbar() const { return nullptr; }
329
330 bool hasLayerForHorizontalScrollbar() const;
331 bool hasLayerForVerticalScrollbar() const;
332
333 void verticalScrollbarLayerDidChange();
334 void horizontalScrollbarLayerDidChange();
335
336 virtual bool usesMockScrollAnimator() const { return false; }
337 virtual void logMockScrollAnimatorMessage(const String&) const { };
338
339 virtual bool shouldPlaceBlockDirectionScrollbarOnLeft() const = 0;
340
341protected:
342 WEBCORE_EXPORT ScrollableArea();
343 WEBCORE_EXPORT virtual ~ScrollableArea();
344
345 void setScrollOrigin(const IntPoint&);
346 void resetScrollOriginChanged() { m_scrollOriginChanged = false; }
347
348 WEBCORE_EXPORT virtual float adjustScrollStepForFixedContent(float step, ScrollbarOrientation, ScrollGranularity);
349 virtual void invalidateScrollbarRect(Scrollbar&, const IntRect&) = 0;
350 virtual void invalidateScrollCornerRect(const IntRect&) = 0;
351
352 friend class ScrollingCoordinator;
353 virtual GraphicsLayer* layerForScrollCorner() const { return nullptr; }
354#if ENABLE(RUBBER_BANDING)
355 virtual GraphicsLayer* layerForOverhangAreas() const { return nullptr; }
356#endif
357
358 bool hasLayerForScrollCorner() const;
359
360private:
361 WEBCORE_EXPORT virtual IntRect visibleContentRectInternal(VisibleContentRectIncludesScrollbars, VisibleContentRectBehavior) const;
362 void scrollPositionChanged(const ScrollPosition&);
363
364 // NOTE: Only called from the ScrollAnimator.
365 friend class ScrollAnimator;
366 void setScrollOffsetFromAnimation(const ScrollOffset&);
367
368 // This function should be overridden by subclasses to perform the actual
369 // scroll of the content.
370 virtual void setScrollOffset(const ScrollOffset&) = 0;
371 ScrollSnapOffsetsInfo<LayoutUnit>& ensureSnapOffsetsInfo();
372
373 mutable std::unique_ptr<ScrollAnimator> m_scrollAnimator;
374
375#if ENABLE(CSS_SCROLL_SNAP)
376 std::unique_ptr<ScrollSnapOffsetsInfo<LayoutUnit>> m_snapOffsetsInfo;
377 unsigned m_currentHorizontalSnapPointIndex { 0 };
378 unsigned m_currentVerticalSnapPointIndex { 0 };
379#endif
380
381 // There are 8 possible combinations of writing mode and direction. Scroll origin will be non-zero in the x or y axis
382 // if there is any reversed direction or writing-mode. The combinations are:
383 // writing-mode / direction scrollOrigin.x() set scrollOrigin.y() set
384 // horizontal-tb / ltr NO NO
385 // horizontal-tb / rtl YES NO
386 // horizontal-bt / ltr NO YES
387 // horizontal-bt / rtl YES YES
388 // vertical-lr / ltr NO NO
389 // vertical-lr / rtl NO YES
390 // vertical-rl / ltr YES NO
391 // vertical-rl / rtl YES YES
392 IntPoint m_scrollOrigin;
393
394 unsigned m_constrainsScrollingToContentEdge : 1;
395
396 unsigned m_inLiveResize : 1;
397
398 unsigned m_verticalScrollElasticity : 2; // ScrollElasticity
399 unsigned m_horizontalScrollElasticity : 2; // ScrollElasticity
400
401 unsigned m_scrollbarOverlayStyle : 2; // ScrollbarOverlayStyle
402
403 unsigned m_scrollOriginChanged : 1;
404 unsigned m_currentScrollType : 1; // ScrollType
405 unsigned m_scrollShouldClearLatchedState : 1;
406};
407
408} // namespace WebCore
409
410