1/*
2 * Copyright (C) 2004, 2006, 2007, 2008 Apple Inc. All rights reserved.
3 * Copyright (C) 2009 Holger Hans Peter Freyther
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#ifndef ScrollView_h
28#define ScrollView_h
29
30#include "platform/PlatformExport.h"
31#include "platform/Widget.h"
32#include "platform/geometry/IntRect.h"
33#include "platform/scroll/ScrollTypes.h"
34#include "platform/scroll/ScrollableArea.h"
35#include "platform/scroll/Scrollbar.h"
36
37#include "wtf/HashSet.h"
38#include "wtf/TemporaryChange.h"
39
40namespace blink {
41
42class Scrollbar;
43
44class PLATFORM_EXPORT ScrollView : public Widget, public ScrollableArea {
45public:
46    virtual ~ScrollView();
47
48    // ScrollableArea functions.
49    virtual int scrollSize(ScrollbarOrientation) const OVERRIDE;
50    virtual void setScrollOffset(const IntPoint&) OVERRIDE;
51    virtual bool isScrollCornerVisible() const OVERRIDE;
52    virtual void scrollbarStyleChanged() OVERRIDE;
53    virtual bool userInputScrollable(ScrollbarOrientation) const OVERRIDE;
54    virtual bool shouldPlaceVerticalScrollbarOnLeft() const OVERRIDE;
55
56    virtual void notifyPageThatContentAreaWillPaint() const;
57
58    // The window that hosts the ScrollView. The ScrollView will communicate scrolls and repaints to the
59    // host window in the window's coordinate space.
60    virtual HostWindow* hostWindow() const = 0;
61
62    // Returns a clip rect in host window coordinates. Used to clip the blit on a scroll.
63    virtual IntRect windowClipRect(IncludeScrollbarsInRect = ExcludeScrollbars) const = 0;
64
65    // Functions for child manipulation and inspection.
66    const HashSet<RefPtr<Widget> >* children() const { return &m_children; }
67    virtual void addChild(PassRefPtr<Widget>);
68    virtual void removeChild(Widget*);
69
70    // If the scroll view does not use a native widget, then it will have cross-platform Scrollbars. These functions
71    // can be used to obtain those scrollbars.
72    virtual Scrollbar* horizontalScrollbar() const OVERRIDE { return m_horizontalScrollbar.get(); }
73    virtual Scrollbar* verticalScrollbar() const OVERRIDE { return m_verticalScrollbar.get(); }
74    bool isScrollViewScrollbar(const Widget* child) const { return horizontalScrollbar() == child || verticalScrollbar() == child; }
75
76    void positionScrollbarLayers();
77
78    // Functions for setting and retrieving the scrolling mode in each axis (horizontal/vertical). The mode has values of
79    // AlwaysOff, AlwaysOn, and Auto. AlwaysOff means never show a scrollbar, AlwaysOn means always show a scrollbar.
80    // Auto means show a scrollbar only when one is needed.
81    // Note that for platforms with native widgets, these modes are considered advisory. In other words the underlying native
82    // widget may choose not to honor the requested modes.
83    void setScrollbarModes(ScrollbarMode horizontalMode, ScrollbarMode verticalMode, bool horizontalLock = false, bool verticalLock = false);
84    void setHorizontalScrollbarMode(ScrollbarMode mode, bool lock = false) { setScrollbarModes(mode, verticalScrollbarMode(), lock, verticalScrollbarLock()); }
85    void setVerticalScrollbarMode(ScrollbarMode mode, bool lock = false) { setScrollbarModes(horizontalScrollbarMode(), mode, horizontalScrollbarLock(), lock); };
86    void scrollbarModes(ScrollbarMode& horizontalMode, ScrollbarMode& verticalMode) const;
87    ScrollbarMode horizontalScrollbarMode() const { ScrollbarMode horizontal, vertical; scrollbarModes(horizontal, vertical); return horizontal; }
88    ScrollbarMode verticalScrollbarMode() const { ScrollbarMode horizontal, vertical; scrollbarModes(horizontal, vertical); return vertical; }
89
90    void setHorizontalScrollbarLock(bool lock = true) { m_horizontalScrollbarLock = lock; }
91    bool horizontalScrollbarLock() const { return m_horizontalScrollbarLock; }
92    void setVerticalScrollbarLock(bool lock = true) { m_verticalScrollbarLock = lock; }
93    bool verticalScrollbarLock() const { return m_verticalScrollbarLock; }
94
95    void setScrollingModesLock(bool lock = true) { m_horizontalScrollbarLock = m_verticalScrollbarLock = lock; }
96
97    virtual void setCanHaveScrollbars(bool);
98    bool canHaveScrollbars() const { return horizontalScrollbarMode() != ScrollbarAlwaysOff || verticalScrollbarMode() != ScrollbarAlwaysOff; }
99
100    // By default, paint events are clipped to the visible area.  If set to
101    // false, paint events are no longer clipped.
102    bool clipsPaintInvalidations() const { return m_clipsRepaints; }
103    void setClipsRepaints(bool);
104
105    // Overridden by FrameView to create custom CSS scrollbars if applicable.
106    virtual PassRefPtr<Scrollbar> createScrollbar(ScrollbarOrientation);
107
108    // The visible content rect has a location that is the scrolled offset of the document. The width and height are the viewport width
109    // and height. By default the scrollbars themselves are excluded from this rectangle, but an optional boolean argument allows them to be
110    // included.
111    virtual IntRect visibleContentRect(IncludeScrollbarsInRect = ExcludeScrollbars) const OVERRIDE;
112    IntSize visibleSize() const { return visibleContentRect().size(); }
113
114    // visibleContentRect().size() is computed from unscaledVisibleContentSize() divided by the value of visibleContentScaleFactor.
115    // For the main frame, visibleContentScaleFactor is equal to the page's pageScaleFactor; it's 1 otherwise.
116    IntSize unscaledVisibleContentSize(IncludeScrollbarsInRect = ExcludeScrollbars) const;
117    virtual float visibleContentScaleFactor() const { return 1; }
118
119    // Offset used to convert incoming input events while emulating device metics.
120    virtual IntSize inputEventsOffsetForEmulation() const { return IntSize(); }
121
122    // Scale used to convert incoming input events. Usually the same as visibleContentScaleFactor(), unless specifically changed.
123    virtual float inputEventsScaleFactor() const { return visibleContentScaleFactor(); }
124
125    // Functions for getting/setting the size of the document contained inside the ScrollView (as an IntSize or as individual width and height
126    // values).
127    virtual IntSize contentsSize() const OVERRIDE; // Always at least as big as the visibleWidth()/visibleHeight().
128    int contentsWidth() const { return contentsSize().width(); }
129    int contentsHeight() const { return contentsSize().height(); }
130    virtual void setContentsSize(const IntSize&);
131
132    // Functions for querying the current scrolled position (both as a point, a size, or as individual X and Y values).
133    virtual IntPoint scrollPosition() const OVERRIDE { return visibleContentRect().location(); }
134    IntSize scrollOffset() const { return toIntSize(visibleContentRect().location()); } // Gets the scrolled position as an IntSize. Convenient for adding to other sizes.
135    IntSize pendingScrollDelta() const { return m_pendingScrollDelta; }
136    virtual IntPoint maximumScrollPosition() const OVERRIDE; // The maximum position we can be scrolled to.
137    virtual IntPoint minimumScrollPosition() const OVERRIDE; // The minimum position we can be scrolled to.
138    // Adjust the passed in scroll position to keep it between the minimum and maximum positions.
139    IntPoint adjustScrollPositionWithinRange(const IntPoint&) const;
140    int scrollX() const { return scrollPosition().x(); }
141    int scrollY() const { return scrollPosition().y(); }
142
143    virtual IntSize overhangAmount() const OVERRIDE;
144
145    void cacheCurrentScrollPosition() { m_cachedScrollPosition = scrollPosition(); }
146    IntPoint cachedScrollPosition() const { return m_cachedScrollPosition; }
147
148    // Functions for scrolling the view.
149    virtual void setScrollPosition(const IntPoint&, ScrollBehavior = ScrollBehaviorInstant);
150    void scrollBy(const IntSize& s, ScrollBehavior behavior = ScrollBehaviorInstant)
151    {
152        return setScrollPosition(scrollPosition() + s, behavior);
153    }
154
155    bool scroll(ScrollDirection, ScrollGranularity);
156
157    // Scroll the actual contents of the view (either blitting or invalidating as needed).
158    void scrollContents(const IntSize& scrollDelta);
159
160    // This gives us a means of blocking painting on our scrollbars until the first layout has occurred.
161    void setScrollbarsSuppressed(bool suppressed, bool repaintOnUnsuppress = false);
162    bool scrollbarsSuppressed() const { return m_scrollbarsSuppressed; }
163
164    IntPoint rootViewToContents(const IntPoint&) const;
165    IntPoint contentsToRootView(const IntPoint&) const;
166    IntRect rootViewToContents(const IntRect&) const;
167    IntRect contentsToRootView(const IntRect&) const;
168
169    // Event coordinates are assumed to be in the coordinate space of a window that contains
170    // the entire widget hierarchy. It is up to the platform to decide what the precise definition
171    // of containing window is. (For example on Mac it is the containing NSWindow.)
172    IntPoint windowToContents(const IntPoint&) const;
173    FloatPoint windowToContents(const FloatPoint&) const;
174    IntPoint contentsToWindow(const IntPoint&) const;
175    IntRect windowToContents(const IntRect&) const;
176    IntRect contentsToWindow(const IntRect&) const;
177
178    // Functions for converting to screen coordinates.
179    IntRect contentsToScreen(const IntRect&) const;
180
181    // These functions are used to enable scrollbars to avoid window resizer controls that overlap the scroll view. This happens on Mac
182    // for example.
183    virtual IntRect windowResizerRect() const { return IntRect(); }
184    bool containsScrollbarsAvoidingResizer() const;
185    void adjustScrollbarsAvoidingResizerCount(int overlapDelta);
186    void windowResizerRectChanged();
187
188    virtual void setParent(Widget*) OVERRIDE; // Overridden to update the overlapping scrollbar count.
189
190    // Called when our frame rect changes (or the rect/scroll position of an ancestor changes).
191    virtual void frameRectsChanged() OVERRIDE;
192
193    // Widget override to update our scrollbars and notify our contents of the resize.
194    virtual void setFrameRect(const IntRect&) OVERRIDE;
195
196    // For platforms that need to hit test scrollbars from within the engine's event handlers (like Win32).
197    Scrollbar* scrollbarAtWindowPoint(const IntPoint& windowPoint);
198    Scrollbar* scrollbarAtViewPoint(const IntPoint& viewPoint);
199
200    virtual IntPoint convertChildToSelf(const Widget* child, const IntPoint& point) const OVERRIDE
201    {
202        IntPoint newPoint = point;
203        if (!isScrollViewScrollbar(child))
204            newPoint = point - scrollOffset();
205        newPoint.moveBy(child->location());
206        return newPoint;
207    }
208
209    virtual IntPoint convertSelfToChild(const Widget* child, const IntPoint& point) const OVERRIDE
210    {
211        IntPoint newPoint = point;
212        if (!isScrollViewScrollbar(child))
213            newPoint = point + scrollOffset();
214        newPoint.moveBy(-child->location());
215        return newPoint;
216    }
217
218    // Widget override. Handles painting of the contents of the view as well as the scrollbars.
219    virtual void paint(GraphicsContext*, const IntRect&) OVERRIDE;
220    void paintScrollbars(GraphicsContext*, const IntRect&);
221
222    // Widget overrides to ensure that our children's visibility status is kept up to date when we get shown and hidden.
223    virtual void show() OVERRIDE;
224    virtual void hide() OVERRIDE;
225    virtual void setParentVisible(bool) OVERRIDE;
226
227    // Pan scrolling.
228    static const int noPanScrollRadius = 15;
229    void addPanScrollIcon(const IntPoint&);
230    void removePanScrollIcon();
231    void paintPanScrollIcon(GraphicsContext*);
232
233    virtual bool isPointInScrollbarCorner(const IntPoint&);
234    virtual bool scrollbarCornerPresent() const;
235    virtual IntRect scrollCornerRect() const OVERRIDE;
236    virtual void paintScrollCorner(GraphicsContext*, const IntRect& cornerRect);
237    virtual void paintScrollbar(GraphicsContext*, Scrollbar*, const IntRect&);
238
239    virtual IntRect convertFromScrollbarToContainingView(const Scrollbar*, const IntRect&) const OVERRIDE;
240    virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar*, const IntRect&) const OVERRIDE;
241    virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar*, const IntPoint&) const OVERRIDE;
242    virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar*, const IntPoint&) const OVERRIDE;
243
244    void calculateAndPaintOverhangAreas(GraphicsContext*, const IntRect& dirtyRect);
245    void calculateAndPaintOverhangBackground(GraphicsContext*, const IntRect& dirtyRect);
246
247    virtual bool isScrollView() const OVERRIDE FINAL { return true; }
248
249protected:
250    ScrollView();
251
252    // NOTE: This should only be called by the overriden setScrollOffset from ScrollableArea.
253    virtual void scrollTo(const IntSize& newOffset);
254
255    virtual void contentRectangleForPaintInvalidation(const IntRect&);
256    virtual void paintContents(GraphicsContext*, const IntRect& damageRect) = 0;
257
258    virtual void paintOverhangAreas(GraphicsContext*, const IntRect& horizontalOverhangArea, const IntRect& verticalOverhangArea, const IntRect& dirtyRect);
259
260    virtual void scrollbarExistenceDidChange() = 0;
261    // These functions are used to create/destroy scrollbars.
262    void setHasHorizontalScrollbar(bool);
263    void setHasVerticalScrollbar(bool);
264
265    virtual void updateScrollCorner();
266    virtual void invalidateScrollCornerRect(const IntRect&) OVERRIDE;
267
268    virtual void scrollContentsIfNeeded();
269    // Scroll the content by via the compositor.
270    virtual bool scrollContentsFastPath(const IntSize& scrollDelta) { return true; }
271    // Scroll the content by invalidating everything.
272    virtual void scrollContentsSlowPath(const IntRect& updateRect);
273
274    void setScrollOrigin(const IntPoint&, bool updatePositionAtAll, bool updatePositionSynchronously);
275
276    // Subclassed by FrameView to check the writing-mode of the document.
277    virtual bool isVerticalDocument() const { return true; }
278    virtual bool isFlippedDocument() const { return false; }
279
280    enum ComputeScrollbarExistenceOption {
281        FirstPass,
282        Incremental
283    };
284    void computeScrollbarExistence(bool& newHasHorizontalScrollbar, bool& newHasVerticalScrollbar, const IntSize& docSize, ComputeScrollbarExistenceOption = FirstPass) const;
285    void updateScrollbarGeometry();
286
287    // Called to update the scrollbars to accurately reflect the state of the view.
288    void updateScrollbars(const IntSize& desiredOffset);
289
290    IntSize excludeScrollbars(const IntSize&) const;
291
292    class InUpdateScrollbarsScope {
293    public:
294        explicit InUpdateScrollbarsScope(ScrollView* view)
295            : m_scope(view->m_inUpdateScrollbars, true)
296        { }
297    private:
298        TemporaryChange<bool> m_scope;
299    };
300
301    virtual bool scrollbarsDisabled() const { return false; }
302
303private:
304    bool adjustScrollbarExistence(ComputeScrollbarExistenceOption = FirstPass);
305    void adjustScrollbarOpacity();
306    // FIXME(bokan): setScrollOffset, setScrollPosition, scrollTo, scrollToOffsetWithoutAnimation,
307    // notifyScrollPositionChanged...there's too many ways to scroll this class. This needs
308    // some cleanup.
309    void setScrollOffsetFromUpdateScrollbars(const IntSize&);
310
311    RefPtr<Scrollbar> m_horizontalScrollbar;
312    RefPtr<Scrollbar> m_verticalScrollbar;
313    ScrollbarMode m_horizontalScrollbarMode;
314    ScrollbarMode m_verticalScrollbarMode;
315
316    bool m_horizontalScrollbarLock;
317    bool m_verticalScrollbarLock;
318
319    HashSet<RefPtr<Widget> > m_children;
320
321    IntSize m_pendingScrollDelta;
322    IntSize m_scrollOffset; // FIXME: Would rather store this as a position, but we will wait to make this change until more code is shared.
323    IntPoint m_cachedScrollPosition;
324    IntSize m_contentsSize;
325
326    int m_scrollbarsAvoidingResizer;
327    bool m_scrollbarsSuppressed;
328
329    bool m_inUpdateScrollbars;
330
331    IntPoint m_panScrollIconPoint;
332    bool m_drawPanScrollIcon;
333
334    bool m_clipsRepaints;
335
336    void init();
337    void destroy();
338
339    IntRect rectToCopyOnScroll() const;
340
341    void calculateOverhangAreasForPainting(IntRect& horizontalOverhangRect, IntRect& verticalOverhangRect);
342    void updateOverhangAreas();
343}; // class ScrollView
344
345DEFINE_TYPE_CASTS(ScrollView, Widget, widget, widget->isScrollView(), widget.isScrollView());
346
347} // namespace blink
348
349#endif // ScrollView_h
350