Add m-esr52 at 52.6.0

1 files changed, 1030 insertions, 0 deletions

diff --git a/layout/base/nsCSSRendering.h b/layout/base/nsCSSRendering.h
new file mode 100644
index 000000000..791e9656e
--- /dev/null
+++ b/layout/base/nsCSSRendering.h
@@ -0,0 +1,1030 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+/* utility functions for drawing borders and backgrounds */
+
+#ifndef nsCSSRendering_h___
+#define nsCSSRendering_h___
+
+#include "gfxBlur.h"
+#include "gfxContext.h"
+#include "imgIContainer.h"
+#include "mozilla/gfx/PathHelpers.h"
+#include "mozilla/gfx/Rect.h"
+#include "mozilla/TypedEnumBits.h"
+#include "nsLayoutUtils.h"
+#include "nsStyleStruct.h"
+#include "nsIFrame.h"
+
+class gfxDrawable;
+class nsStyleContext;
+class nsPresContext;
+class nsRenderingContext;
+
+namespace mozilla {
+
+namespace gfx {
+struct Color;
+class DrawTarget;
+} // namespace gfx
+
+namespace layers {
+class ImageContainer;
+} // namespace layers
+
+// A CSSSizeOrRatio represents a (possibly partially specified) size for use
+// in computing image sizes. Either or both of the width and height might be
+// given. A ratio of width to height may also be given. If we at least two
+// of these then we can compute a concrete size, that is a width and height.
+struct CSSSizeOrRatio
+{
+  CSSSizeOrRatio()
+    : mRatio(0, 0)
+    , mHasWidth(false)
+    , mHasHeight(false) {}
+
+  bool CanComputeConcreteSize() const
+  {
+    return mHasWidth + mHasHeight + HasRatio() >= 2;
+  }
+  bool IsConcrete() const { return mHasWidth && mHasHeight; }
+  bool HasRatio() const { return mRatio.width > 0 && mRatio.height > 0; }
+  bool IsEmpty() const
+  {
+    return (mHasWidth && mWidth <= 0) ||
+           (mHasHeight && mHeight <= 0) ||
+           mRatio.width <= 0 || mRatio.height <= 0; 
+  }
+
+  // CanComputeConcreteSize must return true when ComputeConcreteSize is
+  // called.
+  nsSize ComputeConcreteSize() const;
+
+  void SetWidth(nscoord aWidth)
+  {
+    mWidth = aWidth;
+    mHasWidth = true;
+    if (mHasHeight) {
+      mRatio = nsSize(mWidth, mHeight);
+    }
+  }
+  void SetHeight(nscoord aHeight)
+  {
+    mHeight = aHeight;
+    mHasHeight = true;
+    if (mHasWidth) {
+      mRatio = nsSize(mWidth, mHeight);
+    }
+  }
+  void SetSize(const nsSize& aSize)
+  {
+    mWidth = aSize.width;
+    mHeight = aSize.height;
+    mHasWidth = true;
+    mHasHeight = true;
+    mRatio = aSize;    
+  }
+  void SetRatio(const nsSize& aRatio)
+  {
+    MOZ_ASSERT(!mHasWidth || !mHasHeight,
+               "Probably shouldn't be setting a ratio if we have a concrete size");
+    mRatio = aRatio;
+  }
+
+  nsSize mRatio;
+  nscoord mWidth;
+  nscoord mHeight;
+  bool mHasWidth;
+  bool mHasHeight;
+};
+
+enum class PaintBorderFlags : uint8_t
+{
+  SYNC_DECODE_IMAGES = 1 << 0
+};
+MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(PaintBorderFlags)
+
+} // namespace mozilla
+
+/**
+ * This is a small wrapper class to encapsulate image drawing that can draw an
+ * nsStyleImage image, which may internally be a real image, a sub image, or a
+ * CSS gradient.
+ *
+ * @note Always call the member functions in the order of PrepareImage(),
+ * SetSize(), and Draw*().
+ */
+class nsImageRenderer {
+public:
+  typedef mozilla::image::DrawResult DrawResult;
+  typedef mozilla::layers::LayerManager LayerManager;
+  typedef mozilla::layers::ImageContainer ImageContainer;
+
+  enum {
+    FLAG_SYNC_DECODE_IMAGES = 0x01,
+    FLAG_PAINTING_TO_WINDOW = 0x02
+  };
+  enum FitType
+  {
+    CONTAIN,
+    COVER
+  };
+
+  nsImageRenderer(nsIFrame* aForFrame, const nsStyleImage* aImage, uint32_t aFlags);
+  ~nsImageRenderer();
+  /**
+   * Populates member variables to get ready for rendering.
+   * @return true iff the image is ready, and there is at least a pixel to
+   * draw.
+   */
+  bool PrepareImage();
+
+  /**
+   * The three Compute*Size functions correspond to the sizing algorthms and
+   * definitions from the CSS Image Values and Replaced Content spec. See
+   * http://dev.w3.org/csswg/css-images-3/#sizing .
+   */
+   
+  /**
+   * Compute the intrinsic size of the image as defined in the CSS Image Values
+   * spec. The intrinsic size is the unscaled size which the image would ideally
+   * like to be in app units.
+   */
+  mozilla::CSSSizeOrRatio ComputeIntrinsicSize();
+
+  /**
+   * Computes the placement for a background image, or for the image data
+   * inside of a replaced element.
+   *
+   * @param aPos The CSS <position> value that specifies the image's position.
+   * @param aOriginBounds The box to which the tiling position should be
+   *          relative. For background images, this should correspond to
+   *          'background-origin' for the frame, except when painting on the
+   *          canvas, in which case the origin bounds should be the bounds
+   *          of the root element's frame. For a replaced element, this should
+   *          be the element's content-box.
+   * @param aTopLeft [out] The top-left corner where an image tile should be
+   *          drawn.
+   * @param aAnchorPoint [out] A point which should be pixel-aligned by
+   *          nsLayoutUtils::DrawImage. This is the same as aTopLeft, unless
+   *          CSS specifies a percentage (including 'right' or 'bottom'), in
+   *          which case it's that percentage within of aOriginBounds. So
+   *          'right' would set aAnchorPoint.x to aOriginBounds.XMost().
+   *
+   * Points are returned relative to aOriginBounds.
+   */
+  static void ComputeObjectAnchorPoint(const mozilla::Position& aPos,
+                                       const nsSize& aOriginBounds,
+                                       const nsSize& aImageSize,
+                                       nsPoint* aTopLeft,
+                                       nsPoint* aAnchorPoint);
+
+  /**
+   * Compute the size of the rendered image using either the 'cover' or
+   * 'contain' constraints (aFitType).
+   * aIntrinsicRatio may be an invalid ratio, that is one or both of its
+   * dimensions can be less than or equal to zero.
+   */
+  static nsSize ComputeConstrainedSize(const nsSize& aConstrainingSize,
+                                       const nsSize& aIntrinsicRatio,
+                                       FitType aFitType);
+  /**
+   * Compute the size of the rendered image (the concrete size) where no cover/
+   * contain constraints are given. The 'default algorithm' from the CSS Image
+   * Values spec.
+   */
+  static nsSize ComputeConcreteSize(const mozilla::CSSSizeOrRatio& aSpecifiedSize,
+                                    const mozilla::CSSSizeOrRatio& aIntrinsicSize,
+                                    const nsSize& aDefaultSize);
+
+  /**
+   * Set this image's preferred size. This will be its intrinsic size where
+   * specified and the default size where it is not. Used as the unscaled size
+   * when rendering the image.
+   */
+  void SetPreferredSize(const mozilla::CSSSizeOrRatio& aIntrinsicSize,
+                        const nsSize& aDefaultSize);
+
+  /**
+   * Draws the image to the target rendering context using background-specific
+   * arguments.
+   * @see nsLayoutUtils::DrawImage() for parameters.
+   */
+  DrawResult DrawBackground(nsPresContext*       aPresContext,
+                            nsRenderingContext&  aRenderingContext,
+                            const nsRect&        aDest,
+                            const nsRect&        aFill,
+                            const nsPoint&       aAnchor,
+                            const nsRect&        aDirty,
+                            const nsSize&        aRepeatSize);
+
+  /**
+   * Draw the image to a single component of a border-image style rendering.
+   * aFill The destination rect to be drawn into
+   * aSrc is the part of the image to be rendered into a tile (aUnitSize in
+   * aFill), if aSrc and the dest tile are different sizes, the image will be
+   * scaled to map aSrc onto the dest tile.
+   * aHFill and aVFill are the repeat patterns for the component -
+   * NS_STYLE_BORDER_IMAGE_REPEAT_*
+   * aUnitSize The scaled size of a single source rect (in destination coords)
+   * aIndex identifies the component: 0 1 2
+   *                                  3 4 5
+   *                                  6 7 8
+   * aSVGViewportSize The image size evaluated by default sizing algorithm.
+   * Pass Nothing() if we can read a valid viewport size or aspect-ratio from
+   * the drawing image directly, otherwise, pass Some() with viewport size
+   * evaluated from default sizing algorithm.
+   * aHasIntrinsicRatio is used to record if the source image has fixed
+   * intrinsic ratio.
+   */
+  DrawResult
+  DrawBorderImageComponent(nsPresContext*       aPresContext,
+                           nsRenderingContext&  aRenderingContext,
+                           const nsRect&        aDirtyRect,
+                           const nsRect&        aFill,
+                           const mozilla::CSSIntRect& aSrc,
+                           uint8_t              aHFill,
+                           uint8_t              aVFill,
+                           const nsSize&        aUnitSize,
+                           uint8_t              aIndex,
+                           const mozilla::Maybe<nsSize>& aSVGViewportSize,
+                           const bool           aHasIntrinsicRatio);
+
+  bool IsRasterImage();
+  bool IsAnimatedImage();
+
+  /// Retrieves the image associated with this nsImageRenderer, if there is one.
+  already_AddRefed<imgIContainer> GetImage();
+
+  bool IsReady() const { return mPrepareResult == DrawResult::SUCCESS; }
+  DrawResult PrepareResult() const { return mPrepareResult; }
+  void SetExtendMode(mozilla::gfx::ExtendMode aMode) { mExtendMode = aMode; }
+  void SetMaskOp(uint8_t aMaskOp) { mMaskOp = aMaskOp; }
+  void PurgeCacheForViewportChange(const mozilla::Maybe<nsSize>& aSVGViewportSize,
+                                   const bool aHasRatio);
+
+private:
+  /**
+   * Draws the image to the target rendering context.
+   * aSrc is a rect on the source image which will be mapped to aDest; it's
+   * currently only used for gradients.
+   *
+   * @see nsLayoutUtils::DrawImage() for other parameters.
+   */
+  DrawResult Draw(nsPresContext*       aPresContext,
+                  nsRenderingContext&  aRenderingContext,
+                  const nsRect&        aDirtyRect,
+                  const nsRect&        aDest,
+                  const nsRect&        aFill,
+                  const nsPoint&       aAnchor,
+                  const nsSize&        aRepeatSize,
+                  const mozilla::CSSIntRect& aSrc);
+
+  /**
+   * Helper method for creating a gfxDrawable from mPaintServerFrame or
+   * mImageElementSurface.
+   * Requires mType is eStyleImageType_Element.
+   * Returns null if we cannot create the drawable.
+   */
+  already_AddRefed<gfxDrawable> DrawableForElement(const nsRect& aImageRect,
+                                                   nsRenderingContext&  aRenderingContext);
+
+  nsIFrame*                 mForFrame;
+  const nsStyleImage*       mImage;
+  nsStyleImageType          mType;
+  nsCOMPtr<imgIContainer>   mImageContainer;
+  RefPtr<nsStyleGradient> mGradientData;
+  nsIFrame*                 mPaintServerFrame;
+  nsLayoutUtils::SurfaceFromElementResult mImageElementSurface;
+  DrawResult                mPrepareResult;
+  nsSize                    mSize; // unscaled size of the image, in app units
+  uint32_t                  mFlags;
+  mozilla::gfx::ExtendMode  mExtendMode;
+  uint8_t                   mMaskOp;
+};
+
+/**
+ * A struct representing all the information needed to paint a background
+ * image to some target, taking into account all CSS background-* properties.
+ * See PrepareImageLayer.
+ */
+struct nsBackgroundLayerState {
+  typedef mozilla::gfx::CompositionOp CompositionOp;
+
+  /**
+   * @param aFlags some combination of nsCSSRendering::PAINTBG_* flags
+   */
+  nsBackgroundLayerState(nsIFrame* aForFrame, const nsStyleImage* aImage,
+                         uint32_t aFlags)
+    : mImageRenderer(aForFrame, aImage, aFlags)
+  {}
+
+  /**
+   * The nsImageRenderer that will be used to draw the background.
+   */
+  nsImageRenderer mImageRenderer;
+  /**
+   * A rectangle that one copy of the image tile is mapped onto. Same
+   * coordinate system as aBorderArea/aBGClipRect passed into
+   * PrepareImageLayer.
+   */
+  nsRect mDestArea;
+  /**
+   * The actual rectangle that should be filled with (complete or partial)
+   * image tiles. Same coordinate system as aBorderArea/aBGClipRect passed into
+   * PrepareImageLayer.
+   */
+  nsRect mFillArea;
+  /**
+   * The anchor point that should be snapped to a pixel corner. Same
+   * coordinate system as aBorderArea/aBGClipRect passed into
+   * PrepareImageLayer.
+   */
+  nsPoint mAnchor;
+  /**
+   * The background-repeat property space keyword computes the
+   * repeat size which is image size plus spacing.
+   */
+  nsSize mRepeatSize;
+};
+
+struct nsCSSRendering {
+  typedef mozilla::gfx::CompositionOp CompositionOp;
+  typedef mozilla::gfx::DrawTarget DrawTarget;
+  typedef mozilla::gfx::Float Float;
+  typedef mozilla::gfx::Point Point;
+  typedef mozilla::gfx::Rect Rect;
+  typedef mozilla::gfx::Size Size;
+  typedef mozilla::gfx::RectCornerRadii RectCornerRadii;
+  typedef mozilla::image::DrawResult DrawResult;
+  typedef nsIFrame::Sides Sides;
+
+  /**
+   * Initialize any static variables used by nsCSSRendering.
+   */
+  static void Init();
+  
+  /**
+   * Clean up any static variables used by nsCSSRendering.
+   */
+  static void Shutdown();
+  
+  static void PaintBoxShadowInner(nsPresContext* aPresContext,
+                                  nsRenderingContext& aRenderingContext,
+                                  nsIFrame* aForFrame,
+                                  const nsRect& aFrameArea);
+
+  static void PaintBoxShadowOuter(nsPresContext* aPresContext,
+                                  nsRenderingContext& aRenderingContext,
+                                  nsIFrame* aForFrame,
+                                  const nsRect& aFrameArea,
+                                  const nsRect& aDirtyRect,
+                                  float aOpacity = 1.0);
+
+  static void ComputePixelRadii(const nscoord *aAppUnitsRadii,
+                                nscoord aAppUnitsPerPixel,
+                                RectCornerRadii *oBorderRadii);
+
+  /**
+   * Render the border for an element using css rendering rules
+   * for borders. aSkipSides says which sides to skip
+   * when rendering, the default is to skip none.
+   */
+  static DrawResult PaintBorder(nsPresContext* aPresContext,
+                                nsRenderingContext& aRenderingContext,
+                                nsIFrame* aForFrame,
+                                const nsRect& aDirtyRect,
+                                const nsRect& aBorderArea,
+                                nsStyleContext* aStyleContext,
+                                mozilla::PaintBorderFlags aFlags,
+                                Sides aSkipSides = Sides());
+
+  /**
+   * Like PaintBorder, but taking an nsStyleBorder argument instead of
+   * getting it from aStyleContext. aSkipSides says which sides to skip
+   * when rendering, the default is to skip none.
+   */
+  static DrawResult PaintBorderWithStyleBorder(nsPresContext* aPresContext,
+                                               nsRenderingContext& aRenderingContext,
+                                               nsIFrame* aForFrame,
+                                               const nsRect& aDirtyRect,
+                                               const nsRect& aBorderArea,
+                                               const nsStyleBorder& aBorderStyle,
+                                               nsStyleContext* aStyleContext,
+                                               mozilla::PaintBorderFlags aFlags,
+                                               Sides aSkipSides = Sides());
+
+
+  /**
+   * Render the outline for an element using css rendering rules
+   * for borders.
+   */
+  static void PaintOutline(nsPresContext* aPresContext,
+                          nsRenderingContext& aRenderingContext,
+                          nsIFrame* aForFrame,
+                          const nsRect& aDirtyRect,
+                          const nsRect& aBorderArea,
+                          nsStyleContext* aStyleContext);
+
+  /**
+   * Render keyboard focus on an element.
+   * |aFocusRect| is the outer rectangle of the focused element.
+   * Uses a fixed style equivalent to "1px dotted |aColor|".
+   * Not used for controls, because the native theme may differ.
+   */
+  static void PaintFocus(nsPresContext* aPresContext,
+                         DrawTarget* aDrawTarget,
+                         const nsRect& aFocusRect,
+                         nscolor aColor);
+
+  /**
+   * Render a gradient for an element.
+   * aDest is the rect for a single tile of the gradient on the destination.
+   * aFill is the rect on the destination to be covered by repeated tiling of
+   * the gradient.
+   * aSrc is the part of the gradient to be rendered into a tile (aDest), if
+   * aSrc and aDest are different sizes, the image will be scaled to map aSrc
+   * onto aDest.
+   * aIntrinsicSize is the size of the source gradient.
+   */
+  static void PaintGradient(nsPresContext* aPresContext,
+                            nsRenderingContext& aRenderingContext,
+                            nsStyleGradient* aGradient,
+                            const nsRect& aDirtyRect,
+                            const nsRect& aDest,
+                            const nsRect& aFill,
+                            const nsSize& aRepeatSize,
+                            const mozilla::CSSIntRect& aSrc,
+                            const nsSize& aIntrinsiceSize);
+
+  /**
+   * Find the frame whose background style should be used to draw the
+   * canvas background. aForFrame must be the frame for the root element
+   * whose background style should be used. This function will return
+   * aForFrame unless the <body> background should be propagated, in
+   * which case we return the frame associated with the <body>'s background.
+   */
+  static nsIFrame* FindBackgroundStyleFrame(nsIFrame* aForFrame);
+
+  /**
+   * @return true if |aFrame| is a canvas frame, in the CSS sense.
+   */
+  static bool IsCanvasFrame(nsIFrame* aFrame);
+
+  /**
+   * Fill in an aBackgroundSC to be used to paint the background
+   * for an element.  This applies the rules for propagating
+   * backgrounds between BODY, the root element, and the canvas.
+   * @return true if there is some meaningful background.
+   */
+  static bool FindBackground(nsIFrame* aForFrame,
+                             nsStyleContext** aBackgroundSC);
+
+  /**
+   * As FindBackground, but the passed-in frame is known to be a root frame
+   * (returned from nsCSSFrameConstructor::GetRootElementStyleFrame())
+   * and there is always some meaningful background returned.
+   */
+  static nsStyleContext* FindRootFrameBackground(nsIFrame* aForFrame);
+
+  /**
+   * Returns background style information for the canvas.
+   *
+   * @param aForFrame
+   *   the frame used to represent the canvas, in the CSS sense (i.e.
+   *   nsCSSRendering::IsCanvasFrame(aForFrame) must be true)
+   * @param aRootElementFrame
+   *   the frame representing the root element of the document
+   * @param aBackground
+   *   contains background style information for the canvas on return
+   */
+  static nsStyleContext*
+  FindCanvasBackground(nsIFrame* aForFrame, nsIFrame* aRootElementFrame)
+  {
+    MOZ_ASSERT(IsCanvasFrame(aForFrame), "not a canvas frame");
+    if (aRootElementFrame)
+      return FindRootFrameBackground(aRootElementFrame);
+
+    // This should always give transparent, so we'll fill it in with the
+    // default color if needed.  This seems to happen a bit while a page is
+    // being loaded.
+    return aForFrame->StyleContext();
+  }
+
+  /**
+   * Find a frame which draws a non-transparent background,
+   * for various table-related and HR-related backwards-compatibility hacks.
+   * This function will also stop if it finds themed frame which might draw
+   * background.
+   *
+   * Be very hesitant if you're considering calling this function -- it's
+   * usually not what you want.
+   */
+  static nsIFrame*
+  FindNonTransparentBackgroundFrame(nsIFrame* aFrame,
+                                    bool aStartAtParent = false);
+
+  /**
+   * Determine the background color to draw taking into account print settings.
+   */
+  static nscolor
+  DetermineBackgroundColor(nsPresContext* aPresContext,
+                           nsStyleContext* aStyleContext,
+                           nsIFrame* aFrame,
+                           bool& aDrawBackgroundImage,
+                           bool& aDrawBackgroundColor);
+
+  static nsRect
+  ComputeImageLayerPositioningArea(nsPresContext* aPresContext,
+                                   nsIFrame* aForFrame,
+                                   const nsRect& aBorderArea,
+                                   const nsStyleImageLayers::Layer& aLayer,
+                                   nsIFrame** aAttachedToFrame,
+                                   bool* aOutTransformedFixed);
+
+  static nsBackgroundLayerState
+  PrepareImageLayer(nsPresContext* aPresContext,
+                    nsIFrame* aForFrame,
+                    uint32_t aFlags,
+                    const nsRect& aBorderArea,
+                    const nsRect& aBGClipRect,
+                    const nsStyleImageLayers::Layer& aLayer,
+                    bool* aOutIsTransformedFixed = nullptr);
+
+  struct ImageLayerClipState {
+    nsRect mBGClipArea;  // Affected by mClippedRadii
+    nsRect mAdditionalBGClipArea;  // Not affected by mClippedRadii
+    nsRect mDirtyRect;
+    gfxRect mDirtyRectGfx;
+
+    nscoord mRadii[8];
+    RectCornerRadii mClippedRadii;
+    bool mHasRoundedCorners;
+    bool mHasAdditionalBGClipArea;
+
+    // Whether we are being asked to draw with a caller provided background
+    // clipping area. If this is true we also disable rounded corners.
+    bool mCustomClip;
+  };
+
+  static void
+  GetImageLayerClip(const nsStyleImageLayers::Layer& aLayer,
+                    nsIFrame* aForFrame, const nsStyleBorder& aBorder,
+                    const nsRect& aBorderArea, const nsRect& aCallerDirtyRect,
+                    bool aWillPaintBorder, nscoord aAppUnitsPerPixel,
+                    /* out */ ImageLayerClipState* aClipState);
+
+  /**
+   * Render the background for an element using css rendering rules
+   * for backgrounds or mask.
+   */
+  enum {
+    /**
+     * When this flag is passed, the element's nsDisplayBorder will be
+     * painted immediately on top of this background.
+     */
+    PAINTBG_WILL_PAINT_BORDER = 0x01,
+    /**
+     * When this flag is passed, images are synchronously decoded.
+     */
+    PAINTBG_SYNC_DECODE_IMAGES = 0x02,
+    /**
+     * When this flag is passed, painting will go to the screen so we can
+     * take advantage of the fact that it will be clipped to the viewport.
+     */
+    PAINTBG_TO_WINDOW = 0x04,
+    /**
+     * When this flag is passed, painting will read properties of mask-image
+     * style, instead of background-image.
+     */
+    PAINTBG_MASK_IMAGE = 0x08
+  };
+
+  struct PaintBGParams {
+    nsPresContext& presCtx;
+    nsRenderingContext& renderingCtx;
+    nsRect dirtyRect;
+    nsRect borderArea;
+    nsIFrame* frame;
+    uint32_t paintFlags;
+    nsRect* bgClipRect = nullptr;
+    int32_t layer;                  // -1 means painting all layers; other
+                                    // value means painting one specific
+                                    // layer only.
+    CompositionOp compositionOp;
+
+    static PaintBGParams ForAllLayers(nsPresContext& aPresCtx,
+                                      nsRenderingContext& aRenderingCtx,
+                                      const nsRect& aDirtyRect,
+                                      const nsRect& aBorderArea,
+                                      nsIFrame *aFrame,
+                                      uint32_t aPaintFlags);
+    static PaintBGParams ForSingleLayer(nsPresContext& aPresCtx,
+                                        nsRenderingContext& aRenderingCtx,
+                                        const nsRect& aDirtyRect,
+                                        const nsRect& aBorderArea,
+                                        nsIFrame *aFrame,
+                                        uint32_t aPaintFlags,
+                                        int32_t aLayer,
+                                        CompositionOp aCompositionOp  = CompositionOp::OP_OVER);
+
+  private:
+    PaintBGParams(nsPresContext& aPresCtx,
+                  nsRenderingContext& aRenderingCtx,
+                  const nsRect& aDirtyRect,
+                  const nsRect& aBorderArea,
+                  nsIFrame* aFrame,
+                  uint32_t aPaintFlags,
+                  int32_t aLayer,
+                  CompositionOp aCompositionOp)
+     : presCtx(aPresCtx),
+       renderingCtx(aRenderingCtx),
+       dirtyRect(aDirtyRect),
+       borderArea(aBorderArea),
+       frame(aFrame),
+       paintFlags(aPaintFlags),
+       layer(aLayer),
+       compositionOp(aCompositionOp) {}
+  };
+
+  static DrawResult PaintBackground(const PaintBGParams& aParams);
+
+
+  /**
+   * Same as |PaintBackground|, except using the provided style structs.
+   * This short-circuits the code that ensures that the root element's
+   * background is drawn on the canvas.
+   * The aLayer parameter allows you to paint a single layer of the background.
+   * The default value for aLayer, -1, means that all layers will be painted.
+   * The background color will only be painted if the back-most layer is also
+   * being painted.
+   * aCompositionOp is only respected if a single layer is specified (aLayer != -1).
+   * If all layers are painted, the image layer's blend mode (or the mask
+   * layer's composition mode) will be used.
+   */
+  static DrawResult PaintBackgroundWithSC(const PaintBGParams& aParams,
+                                          nsStyleContext *mBackgroundSC,
+                                          const nsStyleBorder& aBorder);
+
+  /**
+   * Returns the rectangle covered by the given background layer image, taking
+   * into account background positioning, sizing, and repetition, but not
+   * clipping.
+   */
+  static nsRect GetBackgroundLayerRect(nsPresContext* aPresContext,
+                                       nsIFrame* aForFrame,
+                                       const nsRect& aBorderArea,
+                                       const nsRect& aClipRect,
+                                       const nsStyleImageLayers::Layer& aLayer,
+                                       uint32_t aFlags);
+
+  /**
+   * Called when we start creating a display list. The frame tree will not
+   * change until a matching EndFrameTreeLocked is called.
+   */
+  static void BeginFrameTreesLocked();
+  /**
+   * Called when we've finished using a display list. When all
+   * BeginFrameTreeLocked calls have been balanced by an EndFrameTreeLocked,
+   * the frame tree may start changing again.
+   */
+  static void EndFrameTreesLocked();
+
+  // Draw a border segment in the table collapsing border model without
+  // beveling corners
+  static void DrawTableBorderSegment(DrawTarget&          aDrawTarget,
+                                     uint8_t              aBorderStyle,
+                                     nscolor              aBorderColor,
+                                     const nsStyleBackground* aBGColor,
+                                     const nsRect&        aBorderRect,
+                                     int32_t              aAppUnitsPerDevPixel,
+                                     int32_t              aAppUnitsPerCSSPixel,
+                                     uint8_t              aStartBevelSide = 0,
+                                     nscoord              aStartBevelOffset = 0,
+                                     uint8_t              aEndBevelSide = 0,
+                                     nscoord              aEndBevelOffset = 0);
+
+  // NOTE: pt, dirtyRect, lineSize, ascent, offset in the following
+  //       structs are non-rounded device pixels, not app units.
+  struct DecorationRectParams
+  {
+    // The width [length] and the height [thickness] of the decoration
+    // line. This is a "logical" size in textRun orientation, so that
+    // for a vertical textrun, width will actually be a physical height;
+    // and conversely, height will be a physical width.
+    Size lineSize;
+    // The ascent of the text.
+    Float ascent = 0.0f;
+    // The offset of the decoration line from the baseline of the text
+    // (if the value is positive, the line is lifted up).
+    Float offset = 0.0f;
+    // If descentLimit is zero or larger and the underline overflows
+    // from the descent space, the underline should be lifted up as far
+    // as possible.  Note that this does not mean the underline never
+    // overflows from this limitation, because if the underline is
+    // positioned to the baseline or upper, it causes unreadability.
+    // Note that if this is zero or larger, the underline rect may be
+    // shrunken if it's possible.  Therefore, this value is used for
+    // strikeout line and overline too.
+    Float descentLimit = -1.0f;
+    // Which line will be painted. The value can be
+    // NS_STYLE_TEXT_DECORATION_LINE_UNDERLINE or
+    // NS_STYLE_TEXT_DECORATION_LINE_OVERLINE or
+    // NS_STYLE_TEXT_DECORATION_LINE_LINE_THROUGH.
+    uint8_t decoration = NS_STYLE_TEXT_DECORATION_LINE_UNDERLINE;
+    // The style of the decoration line such as
+    // NS_STYLE_TEXT_DECORATION_STYLE_*.
+    uint8_t style = NS_STYLE_TEXT_DECORATION_STYLE_NONE;
+    bool vertical = false;
+  };
+  struct PaintDecorationLineParams : DecorationRectParams
+  {
+    // No need to paint outside this rect.
+    Rect dirtyRect;
+    // The top/left edge of the text.
+    Point pt;
+    // The color of the decoration line.
+    nscolor color = NS_RGBA(0, 0, 0, 0);
+    // The distance between the left edge of the given frame and the
+    // position of the text as positioned without offset of the shadow.
+    Float icoordInFrame = 0.0f;
+  };
+
+  /**
+   * Function for painting the decoration lines for the text.
+   *
+   *   input:
+   *     @param aFrame            the frame which needs the decoration line
+   *     @param aGfxContext
+   */
+  static void PaintDecorationLine(nsIFrame* aFrame, DrawTarget& aDrawTarget,
+                                  const PaintDecorationLineParams& aParams);
+
+  /**
+   * Returns a Rect corresponding to the outline of the decoration line for the
+   * given text metrics.  Arguments have the same meaning as for
+   * PaintDecorationLine.  Currently this only works for solid
+   * decorations; for other decoration styles the returned Rect will be empty.
+   */
+  static Rect DecorationLineToPath(const PaintDecorationLineParams& aParams);
+
+  /**
+   * Function for getting the decoration line rect for the text.
+   * NOTE: aLineSize, aAscent and aOffset are non-rounded device pixels,
+   *       not app units.
+   *   input:
+   *     @param aPresContext
+   *   output:
+   *     @return                  the decoration line rect for the input,
+   *                              the each values are app units.
+   */
+  static nsRect GetTextDecorationRect(nsPresContext* aPresContext,
+                                      const DecorationRectParams& aParams);
+
+  static CompositionOp GetGFXBlendMode(uint8_t mBlendMode) {
+    switch (mBlendMode) {
+      case NS_STYLE_BLEND_NORMAL:      return CompositionOp::OP_OVER;
+      case NS_STYLE_BLEND_MULTIPLY:    return CompositionOp::OP_MULTIPLY;
+      case NS_STYLE_BLEND_SCREEN:      return CompositionOp::OP_SCREEN;
+      case NS_STYLE_BLEND_OVERLAY:     return CompositionOp::OP_OVERLAY;
+      case NS_STYLE_BLEND_DARKEN:      return CompositionOp::OP_DARKEN;
+      case NS_STYLE_BLEND_LIGHTEN:     return CompositionOp::OP_LIGHTEN;
+      case NS_STYLE_BLEND_COLOR_DODGE: return CompositionOp::OP_COLOR_DODGE;
+      case NS_STYLE_BLEND_COLOR_BURN:  return CompositionOp::OP_COLOR_BURN;
+      case NS_STYLE_BLEND_HARD_LIGHT:  return CompositionOp::OP_HARD_LIGHT;
+      case NS_STYLE_BLEND_SOFT_LIGHT:  return CompositionOp::OP_SOFT_LIGHT;
+      case NS_STYLE_BLEND_DIFFERENCE:  return CompositionOp::OP_DIFFERENCE;
+      case NS_STYLE_BLEND_EXCLUSION:   return CompositionOp::OP_EXCLUSION;
+      case NS_STYLE_BLEND_HUE:         return CompositionOp::OP_HUE;
+      case NS_STYLE_BLEND_SATURATION:  return CompositionOp::OP_SATURATION;
+      case NS_STYLE_BLEND_COLOR:       return CompositionOp::OP_COLOR;
+      case NS_STYLE_BLEND_LUMINOSITY:  return CompositionOp::OP_LUMINOSITY;
+      default:      MOZ_ASSERT(false); return CompositionOp::OP_OVER;
+    }
+  }
+
+  static CompositionOp GetGFXCompositeMode(uint8_t aCompositeMode) {
+    switch (aCompositeMode) {
+      case NS_STYLE_MASK_COMPOSITE_ADD:       return CompositionOp::OP_OVER;
+      case NS_STYLE_MASK_COMPOSITE_SUBTRACT:  return CompositionOp::OP_OUT;
+      case NS_STYLE_MASK_COMPOSITE_INTERSECT: return CompositionOp::OP_IN;
+      case NS_STYLE_MASK_COMPOSITE_EXCLUDE:   return CompositionOp::OP_XOR;
+      default: MOZ_ASSERT(false);             return CompositionOp::OP_OVER;
+    }
+  }
+protected:
+  static gfxRect GetTextDecorationRectInternal(
+      const Point& aPt, const DecorationRectParams& aParams);
+
+  /**
+   * Returns inflated rect for painting a decoration line.
+   * Complex style decoration lines should be painted from leftmost of nearest
+   * ancestor block box because that makes better look of connection of lines
+   * for different nodes.  ExpandPaintingRectForDecorationLine() returns
+   * a rect for actual painting rect for the clipped rect.
+   *
+   * input:
+   *     @param aFrame            the frame which needs the decoration line.
+   *     @param aStyle            the style of the complex decoration line
+   *                              NS_STYLE_TEXT_DECORATION_STYLE_DOTTED or
+   *                              NS_STYLE_TEXT_DECORATION_STYLE_DASHED or
+   *                              NS_STYLE_TEXT_DECORATION_STYLE_WAVY.
+   *     @param aClippedRect      the clipped rect for the decoration line.
+   *                              in other words, visible area of the line.
+   *     @param aICoordInFrame  the distance between inline-start edge of aFrame
+   *                              and aClippedRect.pos.
+   *     @param aCycleLength      the width of one cycle of the line style.
+   */
+  static Rect ExpandPaintingRectForDecorationLine(
+                   nsIFrame* aFrame,
+                   const uint8_t aStyle,
+                   const Rect &aClippedRect,
+                   const Float aICoordInFrame,
+                   const Float aCycleLength,
+                   bool aVertical);
+};
+
+/*
+ * nsContextBoxBlur
+ * Creates an 8-bit alpha channel context for callers to draw in, blurs the
+ * contents of that context and applies it as a 1-color mask on a
+ * different existing context. Uses gfxAlphaBoxBlur as its back end.
+ *
+ * You must call Init() first to create a suitable temporary surface to draw
+ * on.  You must then draw any desired content onto the given context, then
+ * call DoPaint() to apply the blurred content as a single-color mask. You
+ * can only call Init() once, so objects cannot be reused.
+ *
+ * This is very useful for creating drop shadows or silhouettes.
+ */
+class nsContextBoxBlur {
+  typedef mozilla::gfx::Color Color;
+  typedef mozilla::gfx::DrawTarget DrawTarget;
+  typedef mozilla::gfx::RectCornerRadii RectCornerRadii;
+
+public:
+  enum {
+    FORCE_MASK = 0x01
+  };
+  /**
+   * Prepares a gfxContext to draw on. Do not call this twice; if you want
+   * to get the gfxContext again use GetContext().
+   *
+   * @param aRect                The coordinates of the surface to create.
+   *                             All coordinates must be in app units.
+   *                             This must not include the blur radius, pass
+   *                             it as the second parameter and everything
+   *                             is taken care of.
+   *
+   * @param aBlurRadius          The blur radius in app units.
+   *
+   * @param aAppUnitsPerDevPixel The number of app units in a device pixel,
+   *                             for conversion.  Most of the time you'll
+   *                             pass this from the current PresContext if
+   *                             available.
+   *
+   * @param aDestinationCtx      The graphics context to apply the blurred
+   *                             mask to when you call DoPaint(). Make sure
+   *                             it is not destroyed before you call
+   *                             DoPaint(). To set the color of the
+   *                             resulting blurred graphic mask, you must
+   *                             set the color on this context before
+   *                             calling Init().
+   *
+   * @param aDirtyRect           The absolute dirty rect in app units. Used to
+   *                             optimize the temporary surface size and speed up blur.
+   *
+   * @param aSkipRect            An area in device pixels (NOT app units!) to avoid
+   *                             blurring over, to prevent unnecessary work.
+   *                             
+   * @param aFlags               FORCE_MASK to ensure that the content drawn to the
+   *                             returned gfxContext is used as a mask, and not
+   *                             drawn directly to aDestinationCtx.
+   *
+   * @return            A blank 8-bit alpha-channel-only graphics context to
+   *                    draw on, or null on error. Must not be freed. The
+   *                    context has a device offset applied to it given by
+   *                    aRect. This means you can use coordinates as if it
+   *                    were at the desired position at aRect and you don't
+   *                    need to worry about translating any coordinates to
+   *                    draw on this temporary surface.
+   *
+   * If aBlurRadius is 0, the returned context is aDestinationCtx and
+   * DoPaint() does nothing, because no blurring is required. Therefore, you
+   * should prepare the destination context as if you were going to draw
+   * directly on it instead of any temporary surface created in this class.
+   */
+  gfxContext* Init(const nsRect& aRect, nscoord aSpreadRadius,
+                   nscoord aBlurRadius,
+                   int32_t aAppUnitsPerDevPixel, gfxContext* aDestinationCtx,
+                   const nsRect& aDirtyRect, const gfxRect* aSkipRect,
+                   uint32_t aFlags = 0);
+
+  /**
+   * Does the actual blurring and mask applying. Users of this object *must*
+   * have called Init() first, then have drawn whatever they want to be
+   * blurred onto the internal gfxContext before calling this.
+   */
+  void DoPaint();
+
+  /**
+   * Gets the internal gfxContext at any time. Must not be freed. Avoid
+   * calling this before calling Init() since the context would not be
+   * constructed at that point.
+   */
+  gfxContext* GetContext();
+
+
+  /**
+   * Get the margin associated with the given blur radius, i.e., the
+   * additional area that might be painted as a result of it.  (The
+   * margin for a spread radius is itself, on all sides.)
+   */
+  static nsMargin GetBlurRadiusMargin(nscoord aBlurRadius,
+                                      int32_t aAppUnitsPerDevPixel);
+
+  /**
+   * Blurs a coloured rectangle onto aDestinationCtx. This is equivalent
+   * to calling Init(), drawing a rectangle onto the returned surface
+   * and then calling DoPaint, but may let us optimize better in the
+   * backend.
+   *
+   * @param aDestinationCtx      The destination to blur to.
+   * @param aRect                The rectangle to blur in app units.
+   * @param aAppUnitsPerDevPixel The number of app units in a device pixel,
+   *                             for conversion.  Most of the time you'll
+   *                             pass this from the current PresContext if
+   *                             available.
+   * @param aCornerRadii         Corner radii for aRect, if it is a rounded
+   *                             rectangle.
+   * @param aBlurRadius          The blur radius in app units.
+   * @param aShadowColor         The color to draw the blurred shadow.
+   * @param aDirtyRect           The absolute dirty rect in app units. Used to
+   *                             optimize the temporary surface size and speed up blur.
+   * @param aSkipRect            An area in device pixels (NOT app units!) to avoid
+   *                             blurring over, to prevent unnecessary work.
+   */
+  static void BlurRectangle(gfxContext* aDestinationCtx,
+                            const nsRect& aRect,
+                            int32_t aAppUnitsPerDevPixel,
+                            RectCornerRadii* aCornerRadii,
+                            nscoord aBlurRadius,
+                            const Color& aShadowColor,
+                            const nsRect& aDirtyRect,
+                            const gfxRect& aSkipRect);
+
+  /**
+   * Draws a blurred inset box shadow shape onto the destination surface.
+   * Like BlurRectangle, this is equivalent to calling Init(),
+   * drawing a rectangle onto the returned surface
+   * and then calling DoPaint, but may let us optimize better in the
+   * backend.
+   *
+   * @param aDestinationCtx      The destination to blur to.
+   * @param aDestinationRect     The rectangle to blur in app units.
+   * @param aShadowClipRect      The inside clip rect that creates the path.
+   * @param aShadowColor         The color of the blur
+   * @param aBlurRadiusAppUnits  The blur radius in app units
+   * @param aSpreadRadiusAppUnits The spread radius in app units.
+   * @param aAppUnitsPerDevPixel The number of app units in a device pixel,
+   *                             for conversion.  Most of the time you'll
+   *                             pass this from the current PresContext if
+   *                             available.
+   * @param aHasBorderRadius     If this inset box blur has a border radius
+   * @param aInnerClipRectRadii  The clip rect radii used for the inside rect's path.
+   * @param aSkipRect            An area in device pixels (NOT app units!) to avoid
+   *                             blurring over, to prevent unnecessary work.
+   */
+  bool InsetBoxBlur(gfxContext* aDestinationCtx,
+                    mozilla::gfx::Rect aDestinationRect,
+                    mozilla::gfx::Rect aShadowClipRect,
+                    mozilla::gfx::Color& aShadowColor,
+                    nscoord aBlurRadiusAppUnits,
+                    nscoord aSpreadRadiusAppUnits,
+                    int32_t aAppUnitsPerDevPixel,
+                    bool aHasBorderRadius,
+                    RectCornerRadii& aInnerClipRectRadii,
+                    mozilla::gfx::Rect aSkipRect,
+                    mozilla::gfx::Point aShadowOffset);
+
+protected:
+  static void GetBlurAndSpreadRadius(DrawTarget* aDestDrawTarget,
+                                     int32_t aAppUnitsPerDevPixel,
+                                     nscoord aBlurRadius,
+                                     nscoord aSpreadRadius,
+                                     mozilla::gfx::IntSize& aOutBlurRadius,
+                                     mozilla::gfx::IntSize& aOutSpreadRadius,
+                                     bool aConstrainSpreadRadius = true);
+
+  gfxAlphaBoxBlur mAlphaBoxBlur;
+  RefPtr<gfxContext> mContext;
+  gfxContext* mDestinationCtx;
+
+  /* This is true if the blur already has it's content transformed
+   * by mDestinationCtx's transform */
+  bool mPreTransformed;
+};
+
+#endif /* nsCSSRendering_h___ */