summaryrefslogtreecommitdiffstats
path: root/gfx/thebes/gfxBlur.h
diff options
context:
space:
mode:
Diffstat (limited to 'gfx/thebes/gfxBlur.h')
-rw-r--r--gfx/thebes/gfxBlur.h194
1 files changed, 194 insertions, 0 deletions
diff --git a/gfx/thebes/gfxBlur.h b/gfx/thebes/gfxBlur.h
new file mode 100644
index 000000000..9cc5f3716
--- /dev/null
+++ b/gfx/thebes/gfxBlur.h
@@ -0,0 +1,194 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GFX_BLUR_H
+#define GFX_BLUR_H
+
+#include "gfxTypes.h"
+#include "nsSize.h"
+#include "gfxPoint.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtr.h"
+
+class gfxContext;
+struct gfxRect;
+
+namespace mozilla {
+ namespace gfx {
+ class AlphaBoxBlur;
+ struct Color;
+ struct RectCornerRadii;
+ class SourceSurface;
+ class DrawTarget;
+ } // namespace gfx
+} // namespace mozilla
+
+/**
+ * Implementation of a triple box blur approximation of a Gaussian blur.
+ *
+ * A Gaussian blur is good for blurring because, when done independently
+ * in the horizontal and vertical directions, it matches the result that
+ * would be obtained using a different (rotated) set of axes. A triple
+ * box blur is a very close approximation of a Gaussian.
+ *
+ * Creates an 8-bit alpha channel context for callers to draw in,
+ * spreads the contents of that context, blurs the contents, and applies
+ * it as an alpha mask on a different existing context.
+ *
+ * A spread N makes each output pixel the maximum value of all source
+ * pixels within a square of side length 2N+1 centered on the output pixel.
+ *
+ * A temporary surface is created in the Init function. The caller then draws
+ * any desired content onto the context acquired through GetContext, and lastly
+ * calls Paint to apply the blurred content as an alpha mask.
+ */
+class gfxAlphaBoxBlur
+{
+ typedef mozilla::gfx::Color Color;
+ typedef mozilla::gfx::DrawTarget DrawTarget;
+ typedef mozilla::gfx::RectCornerRadii RectCornerRadii;
+
+public:
+ gfxAlphaBoxBlur();
+
+ ~gfxAlphaBoxBlur();
+
+ /**
+ * Constructs a box blur and initializes the temporary surface.
+ * @param aRect The coordinates of the surface to create in device units.
+ *
+ * @param aBlurRadius The blur radius in pixels. This is the radius of
+ * the entire (triple) kernel function. Each individual box blur has
+ * radius approximately 1/3 this value, or diameter approximately 2/3
+ * this value. This parameter should nearly always be computed using
+ * CalculateBlurRadius, below.
+ *
+ * @param aDirtyRect A pointer to a dirty rect, measured in device units,
+ * if available. This will be used for optimizing the blur operation. It
+ * is safe to pass nullptr here.
+ *
+ * @param aSkipRect A pointer to a rect, measured in device units, that
+ * represents an area where blurring is unnecessary and shouldn't be done
+ * for speed reasons. It is safe to pass nullptr here.
+ */
+ gfxContext* Init(const gfxRect& aRect,
+ const mozilla::gfx::IntSize& aSpreadRadius,
+ const mozilla::gfx::IntSize& aBlurRadius,
+ const gfxRect* aDirtyRect,
+ const gfxRect* aSkipRect);
+
+ /**
+ * Returns the context that should be drawn to supply the alpha mask to be
+ * blurred. If the returned surface is null, then there was an error in
+ * its creation.
+ */
+ gfxContext* GetContext()
+ {
+ return mContext;
+ }
+
+ already_AddRefed<mozilla::gfx::SourceSurface>
+ DoBlur(DrawTarget* aDT, mozilla::gfx::IntPoint* aTopLeft);
+
+ /**
+ * Does the actual blurring/spreading and mask applying. Users of this
+ * object must have drawn whatever they want to be blurred onto the internal
+ * gfxContext returned by GetContext before calling this.
+ *
+ * @param aDestinationCtx The graphics context on which to apply the
+ * blurred mask.
+ */
+ void Paint(gfxContext* aDestinationCtx);
+
+ /**
+ * Calculates a blur radius that, when used with box blur, approximates
+ * a Gaussian blur with the given standard deviation. The result of
+ * this function should be used as the aBlurRadius parameter to Init,
+ * above.
+ */
+ static mozilla::gfx::IntSize CalculateBlurRadius(const gfxPoint& aStandardDeviation);
+
+ /**
+ * Blurs a coloured rectangle onto aDestinationCtx. This is equivalent
+ * to calling Init(), drawing a rectangle onto the returned surface
+ * and then calling Paint, but may let us optimize better in the
+ * backend.
+ *
+ * @param aDestinationCtx The destination to blur to.
+ * @param aRect The rectangle to blur in device pixels.
+ * @param aCornerRadii Corner radii for aRect, if it is a rounded
+ * rectangle.
+ * @param aBlurRadius The standard deviation of the blur.
+ * @param aShadowColor The color to draw the blurred shadow.
+ * @param aDirtyRect An area in device pixels that is dirty and needs
+ * to be redrawn.
+ * @param aSkipRect An area in device pixels to avoid blurring over,
+ * to prevent unnecessary work.
+ */
+ static void BlurRectangle(gfxContext *aDestinationCtx,
+ const gfxRect& aRect,
+ RectCornerRadii* aCornerRadii,
+ const gfxPoint& aBlurStdDev,
+ const Color& aShadowColor,
+ const gfxRect& aDirtyRect,
+ const gfxRect& aSkipRect);
+
+ static void ShutdownBlurCache();
+
+ /***
+ * Blurs an inset box shadow according to a given path.
+ * This is equivalent to calling Init(), drawing the inset path,
+ * and calling paint. Do not call Init() if using this method.
+ *
+ * @param aDestinationCtx The destination to blur to.
+ * @param aDestinationRect The destination rect in device pixels
+ * @param aShadowClipRect The destiniation inner rect of the
+ * inset path in device pixels.
+ * @param aBlurRadius The standard deviation of the blur.
+ * @param aSpreadRadius The spread radius in device pixels.
+ * @param aShadowColor The color of the blur.
+ * @param aHasBorderRadius If this element also has a border radius
+ * @param aInnerClipRadii Corner radii for the inside rect if it is a rounded rect.
+ * @param aSKipRect An area in device pixels we don't have to paint in.
+ */
+ void BlurInsetBox(gfxContext* aDestinationCtx,
+ const mozilla::gfx::Rect aDestinationRect,
+ const mozilla::gfx::Rect aShadowClipRect,
+ const mozilla::gfx::IntSize aBlurRadius,
+ const mozilla::gfx::IntSize aSpreadRadius,
+ const mozilla::gfx::Color& aShadowColor,
+ const bool aHasBorderRadius,
+ const RectCornerRadii& aInnerClipRadii,
+ const mozilla::gfx::Rect aSkipRect,
+ const mozilla::gfx::Point aShadowOffset);
+
+protected:
+ already_AddRefed<mozilla::gfx::SourceSurface>
+ GetInsetBlur(const mozilla::gfx::Rect aOuterRect,
+ const mozilla::gfx::Rect aWhitespaceRect,
+ const bool aIsDestRect,
+ const mozilla::gfx::Color& aShadowColor,
+ const mozilla::gfx::IntSize& aBlurRadius,
+ const bool aHasBorderRadius,
+ const RectCornerRadii& aInnerClipRadii,
+ DrawTarget* aDestDrawTarget);
+
+ /**
+ * The context of the temporary alpha surface.
+ */
+ RefPtr<gfxContext> mContext;
+
+ /**
+ * The temporary alpha surface.
+ */
+ mozilla::UniquePtr<unsigned char[]> mData;
+
+ /**
+ * The object that actually does the blurring for us.
+ */
+ mozilla::UniquePtr<mozilla::gfx::AlphaBoxBlur> mBlur;
+};
+
+#endif /* GFX_BLUR_H */