1 files changed, 118 insertions, 0 deletions
diff --git a/WebCore/platform/graphics/ContextShadow.h b/WebCore/platform/graphics/ContextShadow.h
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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.
+ */
+
+#ifndef ContextShadow_h
+#define ContextShadow_h
+
+#include "Color.h"
+#include "FloatRect.h"
+#include "IntRect.h"
+#include "RefCounted.h"
+
+#if PLATFORM(CAIRO)
+typedef struct _cairo cairo_t;
+typedef struct _cairo_surface cairo_surface_t;
+typedef cairo_surface_t* PlatformImage;
+typedef cairo_t* PlatformContext;
+#elif PLATFORM(QT)
+#include <QImage>
+class QPainter;
+typedef QImage PlatformImage;
+typedef QPainter* PlatformContext;
+#endif
+
+namespace WebCore {
+
+// This is to track and keep the shadow state. We use this rather than
+// using GraphicsContextState to allow possible optimizations (right now
+// only to determine the shadow type, but in future it might covers things
+// like cached scratch image, persistent shader, etc).
+
+// This class should be copyable since GraphicsContextQt keeps a stack of
+// the shadow state for savePlatformState and restorePlatformState.
+
+class ContextShadow {
+public:
+    enum {
+        NoShadow,
+        SolidShadow,
+        BlurShadow
+    } m_type;
+
+    Color m_color;
+    int m_blurRadius;
+    FloatSize m_offset;
+
+    ContextShadow();
+    ContextShadow(const Color&, float radius, const FloatSize& offset);
+
+    void clear();
+
+    // The pair beginShadowLayer and endShadowLayer creates a temporary image
+    // where the caller can draw onto, using the returned context. This context
+    // must be used only to draw between the call to beginShadowLayer and
+    // endShadowLayer.
+    //
+    // Note: multiple/nested shadow layers are NOT allowed.
+    //
+    // The current clip region will be used to optimize the size of the
+    // temporary image. Thus, the original context should not change any
+    // clipping until endShadowLayer. If the shadow will be completely outside
+    // the clipping region, beginShadowLayer will return 0.
+    //
+    // The returned context will have the transformation matrix and clipping
+    // properly initialized to start doing the painting (no need to account for
+    // the shadow offset), however it will not have the same render hints, pen,
+    // brush, etc as the passed context. This is intentional, usually shadows
+    // have different properties than the shapes which cast them.
+    //
+    // Once endShadowLayer is called, the temporary image will be drawn with the
+    // original context. If blur radius is specified, the shadow will be
+    // filtered first.
+
+    PlatformContext beginShadowLayer(PlatformContext, const FloatRect& layerArea);
+    void endShadowLayer(PlatformContext);
+    static void purgeScratchBuffer();
+
+#if PLATFORM(QT)
+    QPointF offset() { return QPointF(m_offset.width(), m_offset.height()); }
+#endif
+
+
+private:
+    IntRect m_layerRect;
+    PlatformImage m_layerImage;
+    PlatformContext m_layerContext;
+
+    void blurLayerImage(unsigned char*, const IntSize& imageSize, int stride);
+    void calculateLayerBoundingRect(const FloatRect& layerArea, const IntRect& clipRect);
+};
+
+} // namespace WebCore
+
+#endif // ContextShadow_h