1/*
2 * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
3 *
4 * Portions are Copyright (C) 1998 Netscape Communications Corporation.
5 *
6 * Other contributors:
7 *   Robert O'Callahan <roc+@cs.cmu.edu>
8 *   David Baron <dbaron@fas.harvard.edu>
9 *   Christian Biesinger <cbiesinger@web.de>
10 *   Randall Jesup <rjesup@wgate.com>
11 *   Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
12 *   Josh Soref <timeless@mac.com>
13 *   Boris Zbarsky <bzbarsky@mit.edu>
14 *
15 * This library is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU Lesser General Public
17 * License as published by the Free Software Foundation; either
18 * version 2.1 of the License, or (at your option) any later version.
19 *
20 * This library is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
23 * Lesser General Public License for more details.
24 *
25 * You should have received a copy of the GNU Lesser General Public
26 * License along with this library; if not, write to the Free Software
27 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
28 *
29 * Alternatively, the contents of this file may be used under the terms
30 * of either the Mozilla Public License Version 1.1, found at
31 * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
32 * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
33 * (the "GPL"), in which case the provisions of the MPL or the GPL are
34 * applicable instead of those above.  If you wish to allow use of your
35 * version of this file only under the terms of one of those two
36 * licenses (the MPL or the GPL) and not to allow others to use your
37 * version of this file under the LGPL, indicate your decision by
38 * deletingthe provisions above and replace them with the notice and
39 * other provisions required by the MPL or the GPL, as the case may be.
40 * If you do not delete the provisions above, a recipient may use your
41 * version of this file under any of the LGPL, the MPL or the GPL.
42 */
43
44#ifndef RenderLayerScrollableArea_h
45#define RenderLayerScrollableArea_h
46
47#include "platform/scroll/ScrollableArea.h"
48
49namespace blink {
50
51enum ResizerHitTestType {
52    ResizerForPointer,
53    ResizerForTouch
54};
55
56class PlatformEvent;
57class RenderBox;
58class RenderLayer;
59class RenderScrollbarPart;
60
61class RenderLayerScrollableArea FINAL : public ScrollableArea {
62    friend class Internals;
63
64public:
65    // FIXME: We should pass in the RenderBox but this opens a window
66    // for crashers during RenderLayer setup (see crbug.com/368062).
67    RenderLayerScrollableArea(RenderLayer&);
68    virtual ~RenderLayerScrollableArea();
69
70    bool hasHorizontalScrollbar() const { return horizontalScrollbar(); }
71    bool hasVerticalScrollbar() const { return verticalScrollbar(); }
72
73    virtual Scrollbar* horizontalScrollbar() const OVERRIDE { return m_hBar.get(); }
74    virtual Scrollbar* verticalScrollbar() const OVERRIDE { return m_vBar.get(); }
75
76    virtual HostWindow* hostWindow() const OVERRIDE;
77
78    virtual GraphicsLayer* layerForScrolling() const OVERRIDE;
79    virtual GraphicsLayer* layerForHorizontalScrollbar() const OVERRIDE;
80    virtual GraphicsLayer* layerForVerticalScrollbar() const OVERRIDE;
81    virtual GraphicsLayer* layerForScrollCorner() const OVERRIDE;
82    virtual bool usesCompositedScrolling() const OVERRIDE;
83    virtual void invalidateScrollbarRect(Scrollbar*, const IntRect&) OVERRIDE;
84    virtual void invalidateScrollCornerRect(const IntRect&) OVERRIDE;
85    virtual bool isActive() const OVERRIDE;
86    virtual bool isScrollCornerVisible() const OVERRIDE;
87    virtual IntRect scrollCornerRect() const OVERRIDE;
88    virtual IntRect convertFromScrollbarToContainingView(const Scrollbar*, const IntRect&) const OVERRIDE;
89    virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar*, const IntRect&) const OVERRIDE;
90    virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar*, const IntPoint&) const OVERRIDE;
91    virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar*, const IntPoint&) const OVERRIDE;
92    virtual int scrollSize(ScrollbarOrientation) const OVERRIDE;
93    virtual void setScrollOffset(const IntPoint&) OVERRIDE;
94    virtual IntPoint scrollPosition() const OVERRIDE;
95    virtual IntPoint minimumScrollPosition() const OVERRIDE;
96    virtual IntPoint maximumScrollPosition() const OVERRIDE;
97    virtual IntRect visibleContentRect(IncludeScrollbarsInRect) const OVERRIDE;
98    virtual int visibleHeight() const OVERRIDE;
99    virtual int visibleWidth() const OVERRIDE;
100    virtual IntSize contentsSize() const OVERRIDE;
101    virtual IntSize overhangAmount() const OVERRIDE;
102    virtual IntPoint lastKnownMousePosition() const OVERRIDE;
103    virtual bool shouldSuspendScrollAnimations() const OVERRIDE;
104    virtual bool scrollbarsCanBeActive() const OVERRIDE;
105    virtual IntRect scrollableAreaBoundingBox() const OVERRIDE;
106    virtual bool userInputScrollable(ScrollbarOrientation) const OVERRIDE;
107    virtual bool shouldPlaceVerticalScrollbarOnLeft() const OVERRIDE;
108    virtual int pageStep(ScrollbarOrientation) const OVERRIDE;
109
110    int scrollXOffset() const { return m_scrollOffset.width() + scrollOrigin().x(); }
111    int scrollYOffset() const { return m_scrollOffset.height() + scrollOrigin().y(); }
112
113    IntSize scrollOffset() const { return m_scrollOffset; }
114
115    // FIXME: We shouldn't allow access to m_overflowRect outside this class.
116    LayoutRect overflowRect() const { return m_overflowRect; }
117
118    void scrollToOffset(const IntSize& scrollOffset, ScrollOffsetClamping = ScrollOffsetUnclamped);
119    void scrollToXOffset(int x, ScrollOffsetClamping clamp = ScrollOffsetUnclamped) { scrollToOffset(IntSize(x, scrollYOffset()), clamp); }
120    void scrollToYOffset(int y, ScrollOffsetClamping clamp = ScrollOffsetUnclamped) { scrollToOffset(IntSize(scrollXOffset(), y), clamp); }
121
122    void updateAfterLayout();
123    void updateAfterStyleChange(const RenderStyle*);
124    void updateAfterOverflowRecalc();
125
126    virtual bool updateAfterCompositingChange() OVERRIDE;
127
128    bool hasScrollbar() const { return m_hBar || m_vBar; }
129
130    // FIXME: This should be removed.
131    bool hasScrollCorner() const { return m_scrollCorner; }
132
133    void resize(const PlatformEvent&, const LayoutSize&);
134    IntSize offsetFromResizeCorner(const IntPoint& absolutePoint) const;
135
136    bool inResizeMode() const { return m_inResizeMode; }
137    void setInResizeMode(bool inResizeMode) { m_inResizeMode = inResizeMode; }
138
139    IntRect touchResizerCornerRect(const IntRect& bounds) const
140    {
141        return resizerCornerRect(bounds, ResizerForTouch);
142    }
143
144    LayoutUnit scrollWidth() const;
145    LayoutUnit scrollHeight() const;
146    int pixelSnappedScrollWidth() const;
147    int pixelSnappedScrollHeight() const;
148
149    int verticalScrollbarWidth(OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize) const;
150    int horizontalScrollbarHeight(OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize) const;
151
152    IntSize adjustedScrollOffset() const { return IntSize(scrollXOffset(), scrollYOffset()); }
153
154    void paintResizer(GraphicsContext*, const IntPoint& paintOffset, const IntRect& damageRect);
155    void paintOverflowControls(GraphicsContext*, const IntPoint& paintOffset, const IntRect& damageRect, bool paintingOverlayControls);
156    void paintScrollCorner(GraphicsContext*, const IntPoint&, const IntRect& damageRect);
157
158    void positionOverflowControls(const IntSize& offsetFromRoot);
159
160    // isPointInResizeControl() is used for testing if a pointer/touch position is in the resize control
161    // area.
162    bool isPointInResizeControl(const IntPoint& absolutePoint, ResizerHitTestType) const;
163    bool hitTestOverflowControls(HitTestResult&, const IntPoint& localPoint);
164
165    bool hitTestResizerInFragments(const LayerFragments&, const HitTestLocation&) const;
166
167    LayoutRect exposeRect(const LayoutRect&, const ScrollAlignment& alignX, const ScrollAlignment& alignY);
168
169    // Returns true our scrollable area is in the FrameView's collection of scrollable areas. This can
170    // only happen if we're both scrollable, and we do in fact overflow. This means that overflow: hidden
171    // layers never get added to the FrameView's collection.
172    bool scrollsOverflow() const { return m_scrollsOverflow; }
173
174    // Rectangle encompassing the scroll corner and resizer rect.
175    IntRect scrollCornerAndResizerRect() const;
176
177    void updateNeedsCompositedScrolling();
178    bool needsCompositedScrolling() const { return m_needsCompositedScrolling; }
179
180    // These are used during compositing updates to determine if the overflow
181    // controls need to be repositioned in the GraphicsLayer tree.
182    void setTopmostScrollChild(RenderLayer*);
183    RenderLayer* topmostScrollChild() const { ASSERT(!m_nextTopmostScrollChild); return m_topmostScrollChild; }
184
185private:
186    bool hasHorizontalOverflow() const;
187    bool hasVerticalOverflow() const;
188    bool hasScrollableHorizontalOverflow() const;
189    bool hasScrollableVerticalOverflow() const;
190
191    void computeScrollDimensions();
192
193    IntSize clampScrollOffset(const IntSize&) const;
194
195    void setScrollOffset(const IntSize& scrollOffset) { m_scrollOffset = scrollOffset; }
196
197    IntRect rectForHorizontalScrollbar(const IntRect& borderBoxRect) const;
198    IntRect rectForVerticalScrollbar(const IntRect& borderBoxRect) const;
199    LayoutUnit verticalScrollbarStart(int minX, int maxX) const;
200    LayoutUnit horizontalScrollbarStart(int minX) const;
201    IntSize scrollbarOffset(const Scrollbar*) const;
202
203    PassRefPtr<Scrollbar> createScrollbar(ScrollbarOrientation);
204    void destroyScrollbar(ScrollbarOrientation);
205
206    void setHasHorizontalScrollbar(bool hasScrollbar);
207    void setHasVerticalScrollbar(bool hasScrollbar);
208
209    void updateScrollCornerStyle();
210
211    // See comments on isPointInResizeControl.
212    IntRect resizerCornerRect(const IntRect&, ResizerHitTestType) const;
213    bool overflowControlsIntersectRect(const IntRect& localRect) const;
214    void updateResizerAreaSet();
215    void updateResizerStyle();
216    void drawPlatformResizerImage(GraphicsContext*, IntRect resizerCornerRect);
217
218    RenderBox& box() const;
219    RenderLayer* layer() const;
220
221    void updateScrollableAreaSet(bool hasOverflow);
222
223    void updateCompositingLayersAfterScroll();
224
225    RenderLayer& m_layer;
226
227    // Keeps track of whether the layer is currently resizing, so events can cause resizing to start and stop.
228    unsigned m_inResizeMode : 1;
229    unsigned m_scrollsOverflow : 1;
230
231    unsigned m_scrollDimensionsDirty : 1;
232    unsigned m_inOverflowRelayout : 1;
233
234    RenderLayer* m_nextTopmostScrollChild;
235    RenderLayer* m_topmostScrollChild;
236
237    // FIXME: once cc can handle composited scrolling with clip paths, we will
238    // no longer need this bit.
239    unsigned m_needsCompositedScrolling : 1;
240
241    // The width/height of our scrolled area.
242    LayoutRect m_overflowRect;
243
244    // This is the (scroll) offset from scrollOrigin().
245    IntSize m_scrollOffset;
246
247    IntPoint m_cachedOverlayScrollbarOffset;
248
249    // For areas with overflow, we have a pair of scrollbars.
250    RefPtr<Scrollbar> m_hBar;
251    RefPtr<Scrollbar> m_vBar;
252
253    // Renderers to hold our custom scroll corner.
254    RawPtrWillBePersistent<RenderScrollbarPart> m_scrollCorner;
255
256    // Renderers to hold our custom resizer.
257    RawPtrWillBePersistent<RenderScrollbarPart> m_resizer;
258};
259
260} // namespace blink
261
262#endif // RenderLayerScrollableArea_h
263