1 files changed, 170 insertions, 0 deletions
diff --git a/WebCore/platform/gtk/WidgetRenderingContextGtk2.cpp b/WebCore/platform/gtk/WidgetRenderingContextGtk2.cpp
new file mode 100644
index 0000000..b8712d2
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+++ b/WebCore/platform/gtk/WidgetRenderingContextGtk2.cpp
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+/*
+ * Copyright (C) 2010 Sencha, Inc.
+ * Copyright (C) 2010 Igalia S.L.
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifdef GTK_API_VERSION_2
+
+#include "config.h"
+#include "WidgetRenderingContext.h"
+
+#include "GraphicsContext.h"
+#include "RefPtrCairo.h"
+#include "RenderThemeGtk.h"
+#include "Timer.h"
+#include <gdk/gdk.h>
+#include <gtk/gtk.h>
+
+namespace WebCore {
+
+static GdkPixmap* gScratchBuffer = 0;
+static void purgeScratchBuffer()
+{
+    if (gScratchBuffer)
+        g_object_unref(gScratchBuffer);
+    gScratchBuffer = 0;
+}
+
+// FIXME: Perhaps we can share some of this code with the ContextShadowCairo.
+// Widget rendering needs a scratch image as the buffer for the intermediate
+// render. Instead of creating and destroying the buffer for every operation,
+// we create a buffer which will be automatically purged via a timer.
+class PurgeScratchBufferTimer : public TimerBase {
+private:
+    virtual void fired() { purgeScratchBuffer(); }
+};
+static PurgeScratchBufferTimer purgeScratchBufferTimer;
+static void scheduleScratchBufferPurge()
+{
+    if (purgeScratchBufferTimer.isActive())
+        purgeScratchBufferTimer.stop();
+    purgeScratchBufferTimer.startOneShot(2);
+}
+
+static IntSize getExtraSpaceForWidget(RenderThemeGtk* theme)
+{
+    // Checkboxes and scrollbar thumbs often draw outside their boundaries. Here we figure out
+    // the maximum amount of space we need for any type of widget and use that to increase the
+    // size of the scratch buffer, while preserving the final widget position.
+
+    // The checkbox extra space is calculated by looking at the widget style.
+    int indicatorSize, indicatorSpacing;
+    theme->getIndicatorMetrics(CheckboxPart, indicatorSize, indicatorSpacing);
+    IntSize extraSpace(indicatorSpacing, indicatorSpacing);
+
+    // Scrollbar thumbs need at least an extra pixel along their movement axis.
+    return extraSpace.expandedTo(IntSize(1, 1));
+}
+
+WidgetRenderingContext::WidgetRenderingContext(GraphicsContext* graphicsContext, const IntRect& targetRect)
+    : m_graphicsContext(graphicsContext)
+    , m_targetRect(targetRect)
+    , m_hadError(false)
+{
+    RenderThemeGtk* theme = static_cast<RenderThemeGtk*>(RenderTheme::defaultTheme().get());
+
+    // Fallback: We failed to create an RGBA colormap earlier, so we cannot properly paint 
+    // to a temporary surface and preserve transparency. To ensure decent widget rendering, just
+    // paint directly to the target drawable. This will not render CSS rotational transforms properly.
+    if (!theme->m_themePartsHaveRGBAColormap && graphicsContext->gdkDrawable()) {
+        m_paintRect = graphicsContext->getCTM().mapRect(targetRect);
+        m_target = graphicsContext->gdkDrawable();
+        return;
+    }
+
+    // Some widgets render outside their rectangles. We need to account for this.
+    m_extraSpace = getExtraSpaceForWidget(theme);
+
+    // Offset the target rectangle so that the extra space is within the boundaries of the scratch buffer.
+    m_paintRect = IntRect(IntPoint(m_extraSpace.width(), m_extraSpace.height()),
+                                   m_targetRect.size());
+
+    int width = m_targetRect.width() + (m_extraSpace.width() * 2);
+    int height = m_targetRect.height() + (m_extraSpace.height() * 2);
+    int scratchWidth = 0;
+    int scratchHeight = 0;
+    if (gScratchBuffer)
+        gdk_drawable_get_size(gScratchBuffer, &scratchWidth, &scratchHeight);
+
+    // We do not need to recreate the buffer if the current buffer is large enough.
+    if (!gScratchBuffer || scratchWidth < width || scratchHeight < height) {
+        purgeScratchBuffer();
+        // Round to the nearest 32 pixels so we do not grow the buffer for similar sized requests.
+        width = (1 + (width >> 5)) << 5;
+        height = (1 + (height >> 5)) << 5;
+
+        gScratchBuffer = gdk_pixmap_new(0, width, height, gdk_colormap_get_visual(theme->m_themeParts.colormap)->depth);
+        gdk_drawable_set_colormap(gScratchBuffer, theme->m_themeParts.colormap);
+    }
+    m_target = gScratchBuffer;
+
+    // Clear the scratch buffer.
+    RefPtr<cairo_t> scratchBufferContext = adoptRef(gdk_cairo_create(gScratchBuffer));
+    cairo_set_operator(scratchBufferContext.get(), CAIRO_OPERATOR_CLEAR);
+    cairo_paint(scratchBufferContext.get());
+}
+
+WidgetRenderingContext::~WidgetRenderingContext()
+{
+    // We do not need to blit back to the target in the fallback case. See above.
+    RenderThemeGtk* theme = static_cast<RenderThemeGtk*>(RenderTheme::defaultTheme().get());
+    if (!theme->m_themePartsHaveRGBAColormap && m_graphicsContext->gdkDrawable())
+        return;
+
+    // Don't paint the results back if there was an error.
+    if (m_hadError) {
+        scheduleScratchBufferPurge();
+        return;
+    }
+
+    // FIXME: It's unclear if it is necessary to preserve the current source here.
+    cairo_t* cairoContext = m_graphicsContext->platformContext();
+    RefPtr<cairo_pattern_t> previousSource(cairo_get_source(cairoContext));
+
+    // The blit rectangle is the original target rectangle adjusted for any extra space.
+    IntRect fullTargetRect(m_targetRect);
+    fullTargetRect.inflateX(m_extraSpace.width());
+    fullTargetRect.inflateY(m_extraSpace.height());
+
+    gdk_cairo_set_source_pixmap(cairoContext, gScratchBuffer, fullTargetRect.x(), fullTargetRect.y());
+    cairo_rectangle(cairoContext, fullTargetRect.x(), fullTargetRect.y(), fullTargetRect.width(), fullTargetRect.height());
+    cairo_fill(cairoContext);
+    cairo_set_source(cairoContext, previousSource.get());
+    scheduleScratchBufferPurge();
+}
+
+bool WidgetRenderingContext::paintMozillaWidget(GtkThemeWidgetType type, GtkWidgetState* state, int flags, GtkTextDirection textDirection)
+{
+    // Sometimes moz_gtk_widget_paint modifies the clipping rectangle, so we must use a copy.
+    GdkRectangle clipRect = m_paintRect;
+    m_hadError = moz_gtk_widget_paint(type, m_target, &clipRect, &m_paintRect,
+        state, flags, textDirection) != MOZ_GTK_SUCCESS;
+    return !m_hadError;
+}
+
+}
+
+#endif // GTK_API_VERSION_2