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gecko/layout/base/nsCSSRendering.h

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/* -*- 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 "nsLayoutUtils.h"
#include "nsStyleStruct.h"
#include "nsIFrame.h"
class nsStyleContext;
class nsPresContext;
class nsRenderingContext;
namespace mozilla {
namespace layers {
class ImageContainer;
}
// 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;
};
}
/**
* 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::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();
/**
* 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.
*/
void DrawBackground(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
const nsRect& aDest,
const nsRect& aFill,
const nsPoint& aAnchor,
const nsRect& aDirty);
/**
* 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
*/
void
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);
bool IsRasterImage();
bool IsAnimatedImage();
already_AddRefed<ImageContainer> GetContainer(LayerManager* aManager);
bool IsReady() { return mIsReady; }
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.
*/
void Draw(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
const nsRect& aDirtyRect,
const nsRect& aDest,
const nsRect& aFill,
const nsPoint& aAnchor,
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;
nsRefPtr<nsStyleGradient> mGradientData;
nsIFrame* mPaintServerFrame;
nsLayoutUtils::SurfaceFromElementResult mImageElementSurface;
bool mIsReady;
nsSize mSize; // unscaled size of the image, in app units
uint32_t mFlags;
};
/**
* A struct representing all the information needed to paint a background
* image to some target, taking into account all CSS background-* properties.
* See PrepareBackgroundLayer.
*/
struct nsBackgroundLayerState {
/**
* @param aFlags some combination of nsCSSRendering::PAINTBG_* flags
*/
nsBackgroundLayerState(nsIFrame* aForFrame, const nsStyleImage* aImage, uint32_t aFlags)
: mImageRenderer(aForFrame, aImage, aFlags), mCompositingOp(gfxContext::OPERATOR_OVER) {}
/**
* 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
* PrepareBackgroundLayer.
*/
nsRect mDestArea;
/**
* The actual rectangle that should be filled with (complete or partial)
* image tiles. Same coordinate system as aBorderArea/aBGClipRect passed into
* PrepareBackgroundLayer.
*/
nsRect mFillArea;
/**
* The anchor point that should be snapped to a pixel corner. Same
* coordinate system as aBorderArea/aBGClipRect passed into
* PrepareBackgroundLayer.
*/
nsPoint mAnchor;
/**
* The compositing operation that the image should use
*/
gfxContext::GraphicsOperator mCompositingOp;
};
struct nsCSSRendering {
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,
const nsRect& aDirtyRect);
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,
gfxCornerSizes *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 void PaintBorder(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
nsStyleContext* aStyleContext,
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 void PaintBorderWithStyleBorder(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
const nsStyleBorder& aBorderStyle,
nsStyleContext* aStyleContext,
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,
nsRenderingContext& aRenderingContext,
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 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)
{
NS_ABORT_IF_FALSE(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
ComputeBackgroundPositioningArea(nsPresContext* aPresContext,
nsIFrame* aForFrame,
const nsRect& aBorderArea,
const nsStyleBackground::Layer& aLayer,
nsIFrame** aAttachedToFrame);
static nsBackgroundLayerState
PrepareBackgroundLayer(nsPresContext* aPresContext,
nsIFrame* aForFrame,
uint32_t aFlags,
const nsRect& aBorderArea,
const nsRect& aBGClipRect,
const nsStyleBackground::Layer& aLayer);
struct BackgroundClipState {
nsRect mBGClipArea; // Affected by mClippedRadii
nsRect mAdditionalBGClipArea; // Not affected by mClippedRadii
nsRect mDirtyRect;
gfxRect mDirtyRectGfx;
nscoord mRadii[8];
gfxCornerSizes 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
GetBackgroundClip(const nsStyleBackground::Layer& aLayer,
nsIFrame* aForFrame, const nsStyleBorder& aBorder, const nsRect& aBorderArea,
const nsRect& aCallerDirtyRect, bool aWillPaintBorder,
nscoord aAppUnitsPerPixel,
/* out */ BackgroundClipState* aClipState);
/**
* Render the background for an element using css rendering rules
* for backgrounds.
*/
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
};
static void PaintBackground(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
uint32_t aFlags,
nsRect* aBGClipRect = nullptr,
int32_t aLayer = -1);
/**
* 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.
*/
static void PaintBackgroundWithSC(nsPresContext* aPresContext,
nsRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
nsStyleContext *aStyleContext,
const nsStyleBorder& aBorder,
uint32_t aFlags,
nsRect* aBGClipRect = nullptr,
int32_t aLayer = -1);
/**
* 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 nsStyleBackground::Layer& aLayer,
uint32_t aFlags);
/**
* Checks if image in layer aLayer of aBackground is currently decoded.
*/
static bool IsBackgroundImageDecodedForStyleContextAndLayer(
const nsStyleBackground *aBackground, uint32_t aLayer);
/**
* Checks if all images that are part of the background for aFrame are
* currently decoded.
*/
static bool AreAllBackgroundImagesDecodedForFrame(nsIFrame* aFrame);
/**
* 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(nsRenderingContext& aContext,
uint8_t aBorderStyle,
nscolor aBorderColor,
const nsStyleBackground* aBGColor,
const nsRect& aBorderRect,
int32_t aAppUnitsPerCSSPixel,
uint8_t aStartBevelSide = 0,
nscoord aStartBevelOffset = 0,
uint8_t aEndBevelSide = 0,
nscoord aEndBevelOffset = 0);
/**
* Function for painting the decoration lines for the text.
* NOTE: aPt, aLineSize, aAscent and aOffset are non-rounded device pixels,
* not app units.
* input:
* @param aFrame the frame which needs the decoration line
* @param aGfxContext
* @param aDirtyRect no need to paint outside this rect
* @param aColor the color of the decoration line
* @param aPt the top/left edge of the text
* @param aXInFrame the distance between aPt.x and left edge of
* aFrame. If the decoration line is for shadow,
* set the distance between the left edge of
* the aFrame and the position of the text as
* positioned without offset of the shadow.
* @param aLineSize the width and the height of the decoration
* line
* @param aAscent the ascent of the text
* @param aOffset the offset of the decoration line from
* the baseline of the text (if the value is
* positive, the line is lifted up)
* @param aDecoration 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.
* @param aStyle the style of the decoration line such as
* NS_STYLE_TEXT_DECORATION_STYLE_*.
* @param aDescentLimit If aDescentLimit 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.
*/
static void PaintDecorationLine(nsIFrame* aFrame,
gfxContext* aGfxContext,
const gfxRect& aDirtyRect,
const nscolor aColor,
const gfxPoint& aPt,
const gfxFloat aXInFrame,
const gfxSize& aLineSize,
const gfxFloat aAscent,
const gfxFloat aOffset,
const uint8_t aDecoration,
const uint8_t aStyle,
const gfxFloat aDescentLimit = -1.0);
/**
* Adds a path corresponding to the outline of the decoration line to
* the specified context. Arguments have the same meaning as for
* PaintDecorationLine. Currently this only works for solid
* decorations; for other decoration styles, an empty path is added
* to the context.
*/
static void DecorationLineToPath(nsIFrame* aFrame,
gfxContext* aGfxContext,
const gfxRect& aDirtyRect,
const nscolor aColor,
const gfxPoint& aPt,
const gfxFloat aXInFrame,
const gfxSize& aLineSize,
const gfxFloat aAscent,
const gfxFloat aOffset,
const uint8_t aDecoration,
const uint8_t aStyle,
const gfxFloat aDescentLimit = -1.0);
/**
* 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
* @param aLineSize the width and the height of the decoration
* line
* @param aAscent the ascent of the text
* @param aOffset the offset of the decoration line from
* the baseline of the text (if the value is
* positive, the line is lifted up)
* @param aDecoration 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.
* @param aStyle the style of the decoration line such as
* NS_STYLE_TEXT_DECORATION_STYLE_*.
* @param aDescentLimit If aDescentLimit 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.
* output:
* @return the decoration line rect for the input,
* the each values are app units.
*/
static nsRect GetTextDecorationRect(nsPresContext* aPresContext,
const gfxSize& aLineSize,
const gfxFloat aAscent,
const gfxFloat aOffset,
const uint8_t aDecoration,
const uint8_t aStyle,
const gfxFloat aDescentLimit = -1.0);
static gfxContext::GraphicsOperator GetGFXBlendMode(uint8_t mBlendMode) {
switch (mBlendMode) {
case NS_STYLE_BLEND_NORMAL: return gfxContext::OPERATOR_OVER;
case NS_STYLE_BLEND_MULTIPLY: return gfxContext::OPERATOR_MULTIPLY;
case NS_STYLE_BLEND_SCREEN: return gfxContext::OPERATOR_SCREEN;
case NS_STYLE_BLEND_OVERLAY: return gfxContext::OPERATOR_OVERLAY;
case NS_STYLE_BLEND_DARKEN: return gfxContext::OPERATOR_DARKEN;
case NS_STYLE_BLEND_LIGHTEN: return gfxContext::OPERATOR_LIGHTEN;
case NS_STYLE_BLEND_COLOR_DODGE: return gfxContext::OPERATOR_COLOR_DODGE;
case NS_STYLE_BLEND_COLOR_BURN: return gfxContext::OPERATOR_COLOR_BURN;
case NS_STYLE_BLEND_HARD_LIGHT: return gfxContext::OPERATOR_HARD_LIGHT;
case NS_STYLE_BLEND_SOFT_LIGHT: return gfxContext::OPERATOR_SOFT_LIGHT;
case NS_STYLE_BLEND_DIFFERENCE: return gfxContext::OPERATOR_DIFFERENCE;
case NS_STYLE_BLEND_EXCLUSION: return gfxContext::OPERATOR_EXCLUSION;
case NS_STYLE_BLEND_HUE: return gfxContext::OPERATOR_HUE;
case NS_STYLE_BLEND_SATURATION: return gfxContext::OPERATOR_SATURATION;
case NS_STYLE_BLEND_COLOR: return gfxContext::OPERATOR_COLOR;
case NS_STYLE_BLEND_LUMINOSITY: return gfxContext::OPERATOR_LUMINOSITY;
default: MOZ_ASSERT(false); return gfxContext::OPERATOR_OVER;
}
return gfxContext::OPERATOR_OVER;
}
protected:
static gfxRect GetTextDecorationRectInternal(const gfxPoint& aPt,
const gfxSize& aLineSize,
const gfxFloat aAscent,
const gfxFloat aOffset,
const uint8_t aDecoration,
const uint8_t aStyle,
const gfxFloat aDscentLimit);
/**
* 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 aXInFrame the distance between left edge of aFrame and
* aClippedRect.pos.x.
* @param aCycleLength the width of one cycle of the line style.
*/
static gfxRect ExpandPaintingRectForDecorationLine(
nsIFrame* aFrame,
const uint8_t aStyle,
const gfxRect &aClippedRect,
const gfxFloat aXInFrame,
const gfxFloat aCycleLength);
};
/*
* 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 {
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,
gfxCornerSizes* aCornerRadii,
nscoord aBlurRadius,
const gfxRGBA& aShadowColor,
const nsRect& aDirtyRect,
const gfxRect& aSkipRect);
protected:
gfxAlphaBoxBlur mAlphaBoxBlur;
nsRefPtr<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___ */
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