Implement pinch-zoom scaling for main-frame scrollbars and pinch-zoom overlay scrollbars.

cc/pinch_zoom_scrollbars_manager.cc

+// Copyright 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "cc/pinch_zoom_scrollbars_manager.h"
+
+#include "cc/renderer.h"
+#include "skia/ext/platform_canvas.h"
+#include "ui/gfx/rect.h"
+
+using WebKit::WebRect;
+using WebKit::WebScrollbar;
+using WebKit::WebScrollbarThemeGeometry;
+
+namespace cc {
+
+scoped_ptr<PinchZoomScrollbarsManager> PinchZoomScrollbarsManager::create()
+{
+    return make_scoped_ptr(new PinchZoomScrollbarsManager());
+}
+
+PinchZoomScrollbarsManager::PinchZoomScrollbarsManager()
+    : m_scrollbarVertical(this, WebKit::WebScrollbar::Vertical)
+    , m_scrollbarHorizontal(this, WebKit::WebScrollbar::Horizontal)
+    , m_pinchZoomScrollbarVertical(0)
+    , m_pinchZoomScrollbarHorizontal(0)
+    , m_viewportScale(1)
+    , m_deviceScaleFactor(1)
+    , m_enabled(false)
+{
+}
+
+PinchZoomScrollbarsManager::~PinchZoomScrollbarsManager()
+{
+}
+
+void PinchZoomScrollbarsManager::setScrollbarVertical(ScrollbarLayerImpl* scrollbar)
+{
+    if (m_pinchZoomScrollbarVertical == scrollbar)
+        return;
+    m_pinchZoomScrollbarVertical = scrollbar;
+    if (m_pinchZoomScrollbarVertical) {
+        m_pinchZoomScrollbarVertical->setScrollbarGeometry(PZScrollbarGeometry::create(make_scoped_ptr(new ScrollbarThemeGeometry(this)).PassAs<WebScrollbarThemeGeometry>(), this));
+        m_pinchZoomScrollbarVertical->setScrollbarData(&m_scrollbarVertical);
+    }
+}
+
+void PinchZoomScrollbarsManager::setScrollbarHorizontal(ScrollbarLayerImpl* scrollbar)
+{
+    if (m_pinchZoomScrollbarHorizontal == scrollbar)
+        return;
+
+    m_pinchZoomScrollbarHorizontal = scrollbar;
+    if (m_pinchZoomScrollbarHorizontal) {
+        m_pinchZoomScrollbarHorizontal->setScrollbarGeometry(PZScrollbarGeometry::create(make_scoped_ptr(new ScrollbarThemeGeometry(this)).PassAs<WebScrollbarThemeGeometry>(), this));
+        m_pinchZoomScrollbarHorizontal->setScrollbarData(&m_scrollbarHorizontal);
+    }
+}
+
+scoped_ptr<ScrollbarGeometryFixedThumb>
+PinchZoomScrollbarsManager::PZScrollbarGeometry::create(scoped_ptr<WebKit::WebScrollbarThemeGeometry> theme, PinchZoomScrollbarsManager* owner)
+{
+    return make_scoped_ptr(new PZScrollbarGeometry(theme.Pass(), owner)).PassAs<ScrollbarGeometryFixedThumb>();
+}
+
+PinchZoomScrollbarsManager::PZScrollbarGeometry::PZScrollbarGeometry(scoped_ptr<WebKit::WebScrollbarThemeGeometry> theme, PinchZoomScrollbarsManager* owner)
+    : ScrollbarGeometryFixedThumb(theme.Pass())
+    , m_owner(owner)
+{
+}
+
+PinchZoomScrollbarsManager::PZScrollbarGeometry::~PZScrollbarGeometry()
+{
+}
+
+WebKit::WebScrollbarThemeGeometry* PinchZoomScrollbarsManager::PZScrollbarGeometry::clone() const
+{
+    PZScrollbarGeometry* geometry =
+        new PZScrollbarGeometry(make_scoped_ptr(ScrollbarGeometryFixedThumb::clone()), m_owner);
+
+    return geometry;
+}
+
+int PinchZoomScrollbarsManager::PZScrollbarGeometry::thumbLength(WebKit::WebScrollbar* scrollbar)
+{
+    return m_owner->thumbLength(scrollbar);
+}
+
+int PinchZoomScrollbarsManager::PZScrollbarGeometry::thumbPosition(WebKit::WebScrollbar* scrollbar)
+{
+    return m_owner->position(scrollbar);
+}
+
+void PinchZoomScrollbarsManager::PZScrollbarGeometry::splitTrack(WebKit::WebScrollbar* scrollbar, const WebKit::WebRect& track, WebKit::WebRect& startTrack, WebKit::WebRect& thumb, WebKit::WebRect& endTrack)
+{
+    thumb = m_owner->thumbRect(scrollbar);
+    // PinchZoomScrollbarsManager encodes the thumb positions in the thumbRect,
+    // but callers to this function will expect a zero-offset rect.
+    thumb.x = 0;
+    thumb.y = 0;
+}
+
+bool PinchZoomScrollbarsManager::Scrollbar::isOverlay() const
+{
+    return true;
+}
+
+int PinchZoomScrollbarsManager::Scrollbar::value() const
+{
+    return m_owner->position(this);
+}
+
+WebKit::WebPoint PinchZoomScrollbarsManager::Scrollbar::location() const
+{
+    WebRect rect = m_owner->trackRect(this);
+    return WebKit::WebPoint(rect.x, rect.y);
+}
+
+WebKit::WebSize PinchZoomScrollbarsManager::Scrollbar::size() const
+{
+    WebRect rect = m_owner->trackRect(this);
+    return WebKit::WebSize(rect.width, rect.height);
+}
+
+bool PinchZoomScrollbarsManager::Scrollbar::enabled() const
+{
+    return true;
+}
+
+int PinchZoomScrollbarsManager::Scrollbar::maximum() const
+{
+    return m_owner->maximum(this);
+}
+
+int PinchZoomScrollbarsManager::Scrollbar::totalSize() const
+{
+    return m_owner->trackLength(this);
+}
+
+bool PinchZoomScrollbarsManager::Scrollbar::isScrollViewScrollbar() const
+{
+    return false;
+}
+
+bool PinchZoomScrollbarsManager::Scrollbar::isScrollableAreaActive() const
+{
+    return true;
+}
+
+void PinchZoomScrollbarsManager::Scrollbar::getTickmarks(WebKit::WebVector<WebKit::WebRect>& tickmarks) const
+{
+    // Our overlay pinch-zoom scroll bars do not have tick marks.
+}
+
+WebScrollbar::ScrollbarControlSize PinchZoomScrollbarsManager::Scrollbar::controlSize() const
+{
+    return WebScrollbar::RegularScrollbar;
+}
+
+WebScrollbar::ScrollbarPart PinchZoomScrollbarsManager::Scrollbar::pressedPart() const
+{
+    return WebScrollbar::NoPart;
+}
+
+WebScrollbar::ScrollbarPart PinchZoomScrollbarsManager::Scrollbar::hoveredPart() const
+{
+    return WebScrollbar::NoPart;
+}
+
+WebScrollbar::ScrollbarOverlayStyle PinchZoomScrollbarsManager::Scrollbar::scrollbarOverlayStyle() const
+{
+    return WebScrollbar::ScrollbarOverlayStyleDefault;
+}
+
+WebScrollbar::Orientation PinchZoomScrollbarsManager::Scrollbar::orientation() const
+{
+    return m_orientation;
+}
+
+bool PinchZoomScrollbarsManager::Scrollbar::isCustomScrollbar() const
+{
+    return true;
+}
+
+WebScrollbarThemeGeometry* PinchZoomScrollbarsManager::ScrollbarThemeGeometry::clone() const
+{
+    return new ScrollbarThemeGeometry(m_owner);
+}
+
+int PinchZoomScrollbarsManager::ScrollbarThemeGeometry::thumbPosition(WebScrollbar* scrollbar)
+{
+    return m_owner->position(scrollbar);
+}
+
+int PinchZoomScrollbarsManager::ScrollbarThemeGeometry::thumbLength(WebScrollbar* scrollbar)
+{
+    return m_owner->thumbLength(scrollbar);
+}
+
+int PinchZoomScrollbarsManager::ScrollbarThemeGeometry::trackPosition(WebScrollbar*)
+{
+    return 0;
+}
+
+int PinchZoomScrollbarsManager::ScrollbarThemeGeometry::trackLength(WebScrollbar*)
+{
+    return 0;
+}
+
+bool PinchZoomScrollbarsManager::ScrollbarThemeGeometry::hasButtons(WebScrollbar*)
+{
+    return false;
+}
+
+bool PinchZoomScrollbarsManager::ScrollbarThemeGeometry::hasThumb(WebScrollbar*)
+{
+    return true;
+}
+
+WebRect PinchZoomScrollbarsManager::ScrollbarThemeGeometry::trackRect(WebScrollbar* scrollbar)
+{
+    return m_owner->trackRect(scrollbar);
+}
+
+WebRect PinchZoomScrollbarsManager::thumbRect(const WebScrollbar* scrollbar) const
+{
+    WebRect rect;
+    if (scrollbar->orientation() == WebScrollbar::Vertical) {
+        rect = gfx::Rect(m_layoutViewportSize.width() - trackWidth(), position(scrollbar), trackWidth(), thumbLength(scrollbar));
+    } else {
+        rect = gfx::Rect(position(scrollbar), m_layoutViewportSize.height() - trackWidth(), thumbLength(scrollbar), trackWidth());
+    }
+    return rect;
+}
+
+WebRect PinchZoomScrollbarsManager::trackRect(const WebScrollbar* scrollbar) const
+{
+    if (scrollbar->orientation() == WebScrollbar::Vertical)
+        return WebRect(m_layoutViewportSize.width() - trackWidth(), 0, trackWidth(), m_layoutViewportSize.height());
+    else
+        return WebRect(0, m_layoutViewportSize.height() - trackWidth(), m_layoutViewportSize.width(), trackWidth());
+}
+
+int PinchZoomScrollbarsManager::thumbLength(const WebScrollbar* scrollbar) const
+{
+    if (scrollbar->orientation() == WebScrollbar::Vertical) {
+        float thumbFraction = static_cast<float>(m_layoutViewportSize.height())
+                                / m_layoutDocumentSize.height() * m_deviceScaleFactor;
+        return thumbFraction * trackLength(scrollbar);
+    } else {
+        float thumbFraction = static_cast<float>(m_layoutViewportSize.width())
+                                   / m_layoutDocumentSize.width() * m_deviceScaleFactor;
+        return thumbFraction * trackLength(scrollbar);
+    }
+}
+
+int PinchZoomScrollbarsManager::trackLength(const WebScrollbar* scrollbar) const
+{
+    if (scrollbar->orientation() == WebScrollbar::Vertical)
+        return m_layoutViewportSize.height() - trackWidth();
+    else
+        return m_layoutViewportSize.width() - trackWidth();
+}
+
+int PinchZoomScrollbarsManager::position(const WebScrollbar* scrollbar) const
+{
+    if (scrollbar->orientation() == WebScrollbar::Vertical) {
+        float maxOffset = m_rootMaxScrollOffset.y() + (m_viewportScale - 1) / m_viewportScale * m_layoutViewportSize.height();
+        if (maxOffset < 1)
+            return 0;
+
+        float offset = m_rootScrollOffset.y() + m_layoutViewportPosition.y();
+        int scrollPosition = offset / maxOffset * maximum(scrollbar);
+        return scrollPosition;
+    } else {
+        float maxOffset = m_rootMaxScrollOffset.x() + (m_viewportScale - 1) / m_viewportScale * m_layoutViewportSize.width();
+        if (maxOffset < 1)
+            return 0;
+
+        float offset = m_rootScrollOffset.x() + m_layoutViewportPosition.x();
+        int scrollPosition = offset / maxOffset * maximum(scrollbar);
+        return scrollPosition;
+    }
+}
+
+int PinchZoomScrollbarsManager::maximum(const WebScrollbar* scrollbar) const
+{
+    return trackLength(scrollbar) - thumbLength(scrollbar);
+}
+
+WebRect PinchZoomScrollbarsManager::ScrollbarThemeGeometry::thumbRect(WebScrollbar* scrollbar)
+{
+    return m_owner->thumbRect(scrollbar);
+}
+
+int PinchZoomScrollbarsManager::ScrollbarThemeGeometry::minimumThumbLength(WebScrollbar*)
+{
+    return 0;
+}
+
+int PinchZoomScrollbarsManager::ScrollbarThemeGeometry::scrollbarThickness(WebScrollbar*)
+{
+    return 0;
+}
+
+WebRect PinchZoomScrollbarsManager::ScrollbarThemeGeometry::backButtonStartRect(WebScrollbar*)
+{
+    return WebRect();
+}
+
+WebRect PinchZoomScrollbarsManager::ScrollbarThemeGeometry::backButtonEndRect(WebScrollbar*)
+{
+    return WebRect();
+}
+
+WebRect PinchZoomScrollbarsManager::ScrollbarThemeGeometry::forwardButtonStartRect(WebScrollbar*)
+{
+    return WebRect();
+}
+
+WebRect PinchZoomScrollbarsManager::ScrollbarThemeGeometry::forwardButtonEndRect(WebScrollbar*)
+{
+    return WebRect();
+}
+
+WebRect PinchZoomScrollbarsManager::ScrollbarThemeGeometry::constrainTrackRectToTrackPieces(WebScrollbar*, const WebRect&)
+{
+    return WebRect();
+}
+
+void PinchZoomScrollbarsManager::ScrollbarThemeGeometry::splitTrack(WebScrollbar* scrollbar, const WebRect& track, WebRect& startTrack, WebRect& thumb, WebRect& endTrack)
+{
+    NOTREACHED() << "This call is supposed to be overridden by PZScrollbarGeometry.";
+}
+
+void allocateTextureResourceIfNeeded(scoped_ptr<ScopedResource>& texture, const gfx::Size& size, ResourceProvider* resourceProvider)
+{
+    if (!texture)
+        texture = ScopedResource::create(resourceProvider);
+
+    if (texture->size() != size)
+        texture->Free();
+
+    if (!texture->id())
+        texture->Allocate(Renderer::ImplPool, size, GL_RGBA, ResourceProvider::TextureUsageAny);
+}
+
+void PinchZoomScrollbarsManager::updateOneThumb(ScrollbarLayerImpl* scrollbarImpl,
+                    Scrollbar& scrollbar,
+                    scoped_ptr<ScopedResource>& thumbTexture,
+                    scoped_ptr<SkCanvas>& thumbCanvas,
+                    ResourceProvider* resourceProvider)
+{
+    gfx::Rect thumbRect = this->thumbRect(&scrollbar);
+    thumbRect = gfx::Rect(thumbRect.width() * m_deviceScaleFactor, thumbRect.height() * m_deviceScaleFactor);
+
+    allocateTextureResourceIfNeeded(thumbTexture, thumbRect.size(), resourceProvider);
+    scrollbarImpl->setThumbResourceId(thumbTexture->id());
+
+    SkISize canvasSize;
+    if (thumbCanvas)
+        canvasSize = thumbCanvas->getDeviceSize();
+    else
+        canvasSize.set(0, 0);
+
+    if (canvasSize.fWidth == thumbRect.width() && canvasSize.fHeight == thumbRect.height() && thumbCanvas)
+        return;
+
+    thumbCanvas = make_scoped_ptr(skia::CreateBitmapCanvas(thumbRect.width(), thumbRect.height(), false /* opaque */));
+
+    thumbCanvas->clear(SkColorSetARGB(0, 0, 0, 0));
+    SkPaint paint;
+    // WJM: the 255 below refers to blue, not red, but I haven't applied a swizzle.
+    paint.setColor(SkColorSetARGB(128, 255, 0, 0));
+    SkScalar border = m_deviceScaleFactor;
+    SkScalar cornerRadius = m_deviceScaleFactor * 5;
+
+    SkRect rect = SkRect::MakeXYWH(border, border,
+                                   thumbRect.width() - 2 * border,
+                                   thumbRect.height() - 2 * border);
+    thumbCanvas->drawRoundRect(rect, cornerRadius, cornerRadius, paint);
+
+    const SkBitmap* bitmap = &thumbCanvas->getDevice()->accessBitmap(false);
+    SkAutoLockPixels locker(*bitmap);
+    gfx::Rect layerRect(gfx::Point(), thumbRect.size());
+    DCHECK(bitmap->config() == SkBitmap::kARGB_8888_Config);
+    resourceProvider->setPixels(thumbTexture->id(), static_cast<const uint8_t*>(bitmap->getPixels()), layerRect, layerRect, gfx::Vector2d());
+}
+
+void PinchZoomScrollbarsManager::updateThumbTextures(ResourceProvider* resourceProvider)
+{
+    if (m_pinchZoomScrollbarVertical)
+        updateOneThumb(m_pinchZoomScrollbarVertical, m_scrollbarVertical, m_verticalThumbTexture,
+                       m_verticalThumbCanvas, resourceProvider);
+    if (m_pinchZoomScrollbarHorizontal)
+        updateOneThumb(m_pinchZoomScrollbarHorizontal, m_scrollbarHorizontal, m_horizontalThumbTexture,
+                       m_horizontalThumbCanvas, resourceProvider);
+}
+
+void PinchZoomScrollbarsManager::updateScrollbarImpl(ScrollbarLayerImpl* scrollbarLayerImpl,
+                                                  WebScrollbar* scrollbar)
+{
+    if (!scrollbarLayerImpl || !scrollbar)
+        return;
+
+    scrollbarLayerImpl->setCurrentPos(scrollbar->value());
+    scrollbarLayerImpl->setMaximum(scrollbar->maximum());
+    scrollbarLayerImpl->setTotalSize(scrollbar->totalSize());
+    WebRect rect = thumbRect(scrollbar);
+    scrollbarLayerImpl->setPosition(gfx::PointF(rect.x, rect.y));
+    scrollbarLayerImpl->setBounds(gfx::Size(rect.width, rect.height));
+    scrollbarLayerImpl->setContentBounds(gfx::Size(rect.width, rect.height));
+    scrollbarLayerImpl->setDrawsContent(m_enabled);
+}
+
+void PinchZoomScrollbarsManager::setContentBounds(const gfx::Size& size)
+{
+    m_layoutDocumentSize = size;
+    updateScrollbarImpl(m_pinchZoomScrollbarVertical, &m_scrollbarVertical);
+    updateScrollbarImpl(m_pinchZoomScrollbarHorizontal, &m_scrollbarHorizontal);
+}
+
+void PinchZoomScrollbarsManager::setPinchZoomViewportPosition(const gfx::Vector2dF& location, float scale)
+{
+    m_layoutViewportPosition = location;
+    m_viewportScale = scale;
+    updateScrollbarImpl(m_pinchZoomScrollbarVertical, &m_scrollbarVertical);
+    updateScrollbarImpl(m_pinchZoomScrollbarHorizontal, &m_scrollbarHorizontal);
+}
+
+void PinchZoomScrollbarsManager::setPinchZoomViewportBounds(const gfx::Size& size)
+{
+    m_layoutViewportSize = size;
+    updateScrollbarImpl(m_pinchZoomScrollbarVertical, &m_scrollbarVertical);
+    updateScrollbarImpl(m_pinchZoomScrollbarHorizontal, &m_scrollbarHorizontal);
+}
+
+void PinchZoomScrollbarsManager::setRootScrollLayerOffset(const gfx::Vector2d& offset, const gfx::Vector2d& maxOffset)
+{
+    m_rootScrollOffset = offset;
+    m_rootMaxScrollOffset = maxOffset;
+    updateScrollbarImpl(m_pinchZoomScrollbarVertical, &m_scrollbarVertical);
+    updateScrollbarImpl(m_pinchZoomScrollbarHorizontal, &m_scrollbarHorizontal);
+}
+
+}