1/*
2 * Copyright (C) 2004, 2006, 2008 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 COMPUTER, 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 COMPUTER, 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#include "config.h"
27#include "Scrollbar.h"
28
29#include "AXObjectCache.h"
30#include "AccessibilityScrollbar.h"
31#include "EventHandler.h"
32#include "Frame.h"
33#include "FrameView.h"
34#include "GraphicsContext.h"
35#include "PlatformMouseEvent.h"
36#include "ScrollableArea.h"
37#include "ScrollbarTheme.h"
38
39#include <algorithm>
40
41using namespace std;
42
43#if (PLATFORM(CHROMIUM) && (OS(LINUX) || OS(FREEBSD))) || PLATFORM(GTK)
44// The position of the scrollbar thumb affects the appearance of the steppers, so
45// when the thumb moves, we have to invalidate them for painting.
46#define THUMB_POSITION_AFFECTS_BUTTONS
47#endif
48
49namespace WebCore {
50
51#if !PLATFORM(EFL)
52PassRefPtr<Scrollbar> Scrollbar::createNativeScrollbar(ScrollableArea* scrollableArea, ScrollbarOrientation orientation, ScrollbarControlSize size)
53{
54    return adoptRef(new Scrollbar(scrollableArea, orientation, size));
55}
56#endif
57
58int Scrollbar::maxOverlapBetweenPages()
59{
60    static int maxOverlapBetweenPages = ScrollbarTheme::nativeTheme()->maxOverlapBetweenPages();
61    return maxOverlapBetweenPages;
62}
63
64Scrollbar::Scrollbar(ScrollableArea* scrollableArea, ScrollbarOrientation orientation, ScrollbarControlSize controlSize,
65                     ScrollbarTheme* theme)
66    : m_scrollableArea(scrollableArea)
67    , m_orientation(orientation)
68    , m_controlSize(controlSize)
69    , m_theme(theme)
70    , m_visibleSize(0)
71    , m_totalSize(0)
72    , m_currentPos(0)
73    , m_dragOrigin(0)
74    , m_lineStep(0)
75    , m_pageStep(0)
76    , m_pixelStep(1)
77    , m_hoveredPart(NoPart)
78    , m_pressedPart(NoPart)
79    , m_pressedPos(0)
80    , m_enabled(true)
81    , m_scrollTimer(this, &Scrollbar::autoscrollTimerFired)
82    , m_overlapsResizer(false)
83    , m_suppressInvalidation(false)
84{
85    if (!m_theme)
86        m_theme = ScrollbarTheme::nativeTheme();
87
88    m_theme->registerScrollbar(this);
89
90    // FIXME: This is ugly and would not be necessary if we fix cross-platform code to actually query for
91    // scrollbar thickness and use it when sizing scrollbars (rather than leaving one dimension of the scrollbar
92    // alone when sizing).
93    int thickness = m_theme->scrollbarThickness(controlSize);
94    Widget::setFrameRect(IntRect(0, 0, thickness, thickness));
95}
96
97Scrollbar::~Scrollbar()
98{
99    if (AXObjectCache::accessibilityEnabled() && axObjectCache())
100        axObjectCache()->remove(this);
101
102    stopTimerIfNeeded();
103
104    m_theme->unregisterScrollbar(this);
105}
106
107void Scrollbar::offsetDidChange()
108{
109    ASSERT(m_scrollableArea);
110
111    float position = static_cast<float>(m_scrollableArea->scrollPosition(this));
112    if (position == m_currentPos)
113        return;
114
115    int oldThumbPosition = theme()->thumbPosition(this);
116    m_currentPos = position;
117    updateThumbPosition();
118    if (m_pressedPart == ThumbPart)
119        setPressedPos(m_pressedPos + theme()->thumbPosition(this) - oldThumbPosition);
120}
121
122void Scrollbar::setProportion(int visibleSize, int totalSize)
123{
124    if (visibleSize == m_visibleSize && totalSize == m_totalSize)
125        return;
126
127    m_visibleSize = visibleSize;
128    m_totalSize = totalSize;
129
130    updateThumbProportion();
131}
132
133void Scrollbar::setSteps(int lineStep, int pageStep, int pixelsPerStep)
134{
135    m_lineStep = lineStep;
136    m_pageStep = pageStep;
137    m_pixelStep = 1.0f / pixelsPerStep;
138}
139
140void Scrollbar::updateThumb()
141{
142#ifdef THUMB_POSITION_AFFECTS_BUTTONS
143    invalidate();
144#else
145    theme()->invalidateParts(this, ForwardTrackPart | BackTrackPart | ThumbPart);
146#endif
147}
148
149void Scrollbar::updateThumbPosition()
150{
151    updateThumb();
152}
153
154void Scrollbar::updateThumbProportion()
155{
156    updateThumb();
157}
158
159void Scrollbar::paint(GraphicsContext* context, const IntRect& damageRect)
160{
161    if (context->updatingControlTints() && theme()->supportsControlTints()) {
162        invalidate();
163        return;
164    }
165
166    if (context->paintingDisabled() || !frameRect().intersects(damageRect))
167        return;
168
169    if (!theme()->paint(this, context, damageRect))
170        Widget::paint(context, damageRect);
171}
172
173void Scrollbar::autoscrollTimerFired(Timer<Scrollbar>*)
174{
175    autoscrollPressedPart(theme()->autoscrollTimerDelay());
176}
177
178static bool thumbUnderMouse(Scrollbar* scrollbar)
179{
180    int thumbPos = scrollbar->theme()->trackPosition(scrollbar) + scrollbar->theme()->thumbPosition(scrollbar);
181    int thumbLength = scrollbar->theme()->thumbLength(scrollbar);
182    return scrollbar->pressedPos() >= thumbPos && scrollbar->pressedPos() < thumbPos + thumbLength;
183}
184
185void Scrollbar::autoscrollPressedPart(double delay)
186{
187    // Don't do anything for the thumb or if nothing was pressed.
188    if (m_pressedPart == ThumbPart || m_pressedPart == NoPart)
189        return;
190
191    // Handle the track.
192    if ((m_pressedPart == BackTrackPart || m_pressedPart == ForwardTrackPart) && thumbUnderMouse(this)) {
193        theme()->invalidatePart(this, m_pressedPart);
194        setHoveredPart(ThumbPart);
195        return;
196    }
197
198    // Handle the arrows and track.
199    if (m_scrollableArea && m_scrollableArea->scroll(pressedPartScrollDirection(), pressedPartScrollGranularity()))
200        startTimerIfNeeded(delay);
201}
202
203void Scrollbar::startTimerIfNeeded(double delay)
204{
205    // Don't do anything for the thumb.
206    if (m_pressedPart == ThumbPart)
207        return;
208
209    // Handle the track.  We halt track scrolling once the thumb is level
210    // with us.
211    if ((m_pressedPart == BackTrackPart || m_pressedPart == ForwardTrackPart) && thumbUnderMouse(this)) {
212        theme()->invalidatePart(this, m_pressedPart);
213        setHoveredPart(ThumbPart);
214        return;
215    }
216
217    // We can't scroll if we've hit the beginning or end.
218    ScrollDirection dir = pressedPartScrollDirection();
219    if (dir == ScrollUp || dir == ScrollLeft) {
220        if (m_currentPos == 0)
221            return;
222    } else {
223        if (m_currentPos == maximum())
224            return;
225    }
226
227    m_scrollTimer.startOneShot(delay);
228}
229
230void Scrollbar::stopTimerIfNeeded()
231{
232    if (m_scrollTimer.isActive())
233        m_scrollTimer.stop();
234}
235
236ScrollDirection Scrollbar::pressedPartScrollDirection()
237{
238    if (m_orientation == HorizontalScrollbar) {
239        if (m_pressedPart == BackButtonStartPart || m_pressedPart == BackButtonEndPart || m_pressedPart == BackTrackPart)
240            return ScrollLeft;
241        return ScrollRight;
242    } else {
243        if (m_pressedPart == BackButtonStartPart || m_pressedPart == BackButtonEndPart || m_pressedPart == BackTrackPart)
244            return ScrollUp;
245        return ScrollDown;
246    }
247}
248
249ScrollGranularity Scrollbar::pressedPartScrollGranularity()
250{
251    if (m_pressedPart == BackButtonStartPart || m_pressedPart == BackButtonEndPart ||  m_pressedPart == ForwardButtonStartPart || m_pressedPart == ForwardButtonEndPart)
252        return ScrollByLine;
253    return ScrollByPage;
254}
255
256void Scrollbar::moveThumb(int pos)
257{
258    // Drag the thumb.
259    int thumbPos = theme()->thumbPosition(this);
260    int thumbLen = theme()->thumbLength(this);
261    int trackLen = theme()->trackLength(this);
262    int maxPos = trackLen - thumbLen;
263    int delta = pos - m_pressedPos;
264    if (delta > 0)
265        delta = min(maxPos - thumbPos, delta);
266    else if (delta < 0)
267        delta = max(-thumbPos, delta);
268
269    if (delta) {
270        float newPosition = static_cast<float>(thumbPos + delta) * maximum() / (trackLen - thumbLen);
271        if (m_scrollableArea)
272            m_scrollableArea->scrollToOffsetWithoutAnimation(m_orientation, newPosition);
273    }
274}
275
276void Scrollbar::setHoveredPart(ScrollbarPart part)
277{
278    if (part == m_hoveredPart)
279        return;
280
281    if ((m_hoveredPart == NoPart || part == NoPart) && theme()->invalidateOnMouseEnterExit())
282        invalidate();  // Just invalidate the whole scrollbar, since the buttons at either end change anyway.
283    else if (m_pressedPart == NoPart) {  // When there's a pressed part, we don't draw a hovered state, so there's no reason to invalidate.
284        theme()->invalidatePart(this, part);
285        theme()->invalidatePart(this, m_hoveredPart);
286    }
287    m_hoveredPart = part;
288}
289
290void Scrollbar::setPressedPart(ScrollbarPart part)
291{
292    if (m_pressedPart != NoPart)
293        theme()->invalidatePart(this, m_pressedPart);
294    m_pressedPart = part;
295    if (m_pressedPart != NoPart)
296        theme()->invalidatePart(this, m_pressedPart);
297    else if (m_hoveredPart != NoPart)  // When we no longer have a pressed part, we can start drawing a hovered state on the hovered part.
298        theme()->invalidatePart(this, m_hoveredPart);
299}
300
301bool Scrollbar::mouseMoved(const PlatformMouseEvent& evt)
302{
303    if (m_pressedPart == ThumbPart) {
304        if (theme()->shouldSnapBackToDragOrigin(this, evt)) {
305            if (m_scrollableArea)
306                m_scrollableArea->scrollToOffsetWithoutAnimation(m_orientation, m_dragOrigin);
307        } else {
308            moveThumb(m_orientation == HorizontalScrollbar ?
309                      convertFromContainingWindow(evt.pos()).x() :
310                      convertFromContainingWindow(evt.pos()).y());
311        }
312        return true;
313    }
314
315    if (m_pressedPart != NoPart)
316        m_pressedPos = (orientation() == HorizontalScrollbar ? convertFromContainingWindow(evt.pos()).x() : convertFromContainingWindow(evt.pos()).y());
317
318    ScrollbarPart part = theme()->hitTest(this, evt);
319    if (part != m_hoveredPart) {
320        if (m_pressedPart != NoPart) {
321            if (part == m_pressedPart) {
322                // The mouse is moving back over the pressed part.  We
323                // need to start up the timer action again.
324                startTimerIfNeeded(theme()->autoscrollTimerDelay());
325                theme()->invalidatePart(this, m_pressedPart);
326            } else if (m_hoveredPart == m_pressedPart) {
327                // The mouse is leaving the pressed part.  Kill our timer
328                // if needed.
329                stopTimerIfNeeded();
330                theme()->invalidatePart(this, m_pressedPart);
331            }
332        }
333
334        setHoveredPart(part);
335    }
336
337    return true;
338}
339
340bool Scrollbar::mouseExited()
341{
342    setHoveredPart(NoPart);
343    return true;
344}
345
346bool Scrollbar::mouseUp()
347{
348    setPressedPart(NoPart);
349    m_pressedPos = 0;
350    stopTimerIfNeeded();
351
352    if (parent() && parent()->isFrameView())
353        static_cast<FrameView*>(parent())->frame()->eventHandler()->setMousePressed(false);
354
355    return true;
356}
357
358bool Scrollbar::mouseDown(const PlatformMouseEvent& evt)
359{
360    // Early exit for right click
361    if (evt.button() == RightButton)
362        return true; // FIXME: Handled as context menu by Qt right now.  Should just avoid even calling this method on a right click though.
363
364    setPressedPart(theme()->hitTest(this, evt));
365    int pressedPos = (orientation() == HorizontalScrollbar ? convertFromContainingWindow(evt.pos()).x() : convertFromContainingWindow(evt.pos()).y());
366
367    if ((m_pressedPart == BackTrackPart || m_pressedPart == ForwardTrackPart) && theme()->shouldCenterOnThumb(this, evt)) {
368        setHoveredPart(ThumbPart);
369        setPressedPart(ThumbPart);
370        m_dragOrigin = m_currentPos;
371        int thumbLen = theme()->thumbLength(this);
372        int desiredPos = pressedPos;
373        // Set the pressed position to the middle of the thumb so that when we do the move, the delta
374        // will be from the current pixel position of the thumb to the new desired position for the thumb.
375        m_pressedPos = theme()->trackPosition(this) + theme()->thumbPosition(this) + thumbLen / 2;
376        moveThumb(desiredPos);
377        return true;
378    } else if (m_pressedPart == ThumbPart)
379        m_dragOrigin = m_currentPos;
380
381    m_pressedPos = pressedPos;
382
383    autoscrollPressedPart(theme()->initialAutoscrollTimerDelay());
384    return true;
385}
386
387void Scrollbar::setFrameRect(const IntRect& rect)
388{
389    // Get our window resizer rect and see if we overlap.  Adjust to avoid the overlap
390    // if necessary.
391    IntRect adjustedRect(rect);
392    bool overlapsResizer = false;
393    ScrollView* view = parent();
394    if (view && !rect.isEmpty() && !view->windowResizerRect().isEmpty()) {
395        IntRect resizerRect = view->convertFromContainingWindow(view->windowResizerRect());
396        if (rect.intersects(resizerRect)) {
397            if (orientation() == HorizontalScrollbar) {
398                int overlap = rect.maxX() - resizerRect.x();
399                if (overlap > 0 && resizerRect.maxX() >= rect.maxX()) {
400                    adjustedRect.setWidth(rect.width() - overlap);
401                    overlapsResizer = true;
402                }
403            } else {
404                int overlap = rect.maxY() - resizerRect.y();
405                if (overlap > 0 && resizerRect.maxY() >= rect.maxY()) {
406                    adjustedRect.setHeight(rect.height() - overlap);
407                    overlapsResizer = true;
408                }
409            }
410        }
411    }
412    if (overlapsResizer != m_overlapsResizer) {
413        m_overlapsResizer = overlapsResizer;
414        if (view)
415            view->adjustScrollbarsAvoidingResizerCount(m_overlapsResizer ? 1 : -1);
416    }
417
418    Widget::setFrameRect(adjustedRect);
419}
420
421void Scrollbar::setParent(ScrollView* parentView)
422{
423    if (!parentView && m_overlapsResizer && parent())
424        parent()->adjustScrollbarsAvoidingResizerCount(-1);
425    Widget::setParent(parentView);
426}
427
428void Scrollbar::setEnabled(bool e)
429{
430    if (m_enabled == e)
431        return;
432    m_enabled = e;
433    invalidate();
434}
435
436bool Scrollbar::isOverlayScrollbar() const
437{
438    return m_theme->usesOverlayScrollbars();
439}
440
441bool Scrollbar::isWindowActive() const
442{
443    return m_scrollableArea && m_scrollableArea->isActive();
444}
445
446AXObjectCache* Scrollbar::axObjectCache() const
447{
448    if (!parent() || !parent()->isFrameView())
449        return 0;
450
451    Document* document = static_cast<FrameView*>(parent())->frame()->document();
452    return document->axObjectCache();
453}
454
455void Scrollbar::invalidateRect(const IntRect& rect)
456{
457    if (suppressInvalidation())
458        return;
459
460    if (m_scrollableArea)
461        m_scrollableArea->invalidateScrollbar(this, rect);
462}
463
464IntRect Scrollbar::convertToContainingView(const IntRect& localRect) const
465{
466    if (m_scrollableArea)
467        return m_scrollableArea->convertFromScrollbarToContainingView(this, localRect);
468
469    return Widget::convertToContainingView(localRect);
470}
471
472IntRect Scrollbar::convertFromContainingView(const IntRect& parentRect) const
473{
474    if (m_scrollableArea)
475        return m_scrollableArea->convertFromContainingViewToScrollbar(this, parentRect);
476
477    return Widget::convertFromContainingView(parentRect);
478}
479
480IntPoint Scrollbar::convertToContainingView(const IntPoint& localPoint) const
481{
482    if (m_scrollableArea)
483        return m_scrollableArea->convertFromScrollbarToContainingView(this, localPoint);
484
485    return Widget::convertToContainingView(localPoint);
486}
487
488IntPoint Scrollbar::convertFromContainingView(const IntPoint& parentPoint) const
489{
490    if (m_scrollableArea)
491        return m_scrollableArea->convertFromContainingViewToScrollbar(this, parentPoint);
492
493    return Widget::convertFromContainingView(parentPoint);
494}
495
496} // namespace WebCore
497