gecko-dev/layout/base/nsCSSRendering.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
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*
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/* utility functions for drawing borders and backgrounds */
#ifndef nsCSSRendering_h___
#define nsCSSRendering_h___
#include "nsIRenderingContext.h"
#include "nsStyleConsts.h"
#include "gfxBlur.h"
#include "gfxContext.h"
#include "gfxImageSurface.h"
struct nsPoint;
class nsStyleContext;
class nsPresContext;
struct nsCSSRendering {
/**
* Initialize any static variables used by nsCSSRendering.
*/
static nsresult Init();
/**
* Clean up any static variables used by nsCSSRendering.
*/
static void Shutdown();
static void PaintBoxShadow(nsPresContext* aPresContext,
nsIRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsPoint& aForFramePt);
/**
* Render the border for an element using css rendering rules
* for borders. aSkipSides is a bitmask of the sides to skip
* when rendering. If 0 then no sides are skipped.
*
* Both aDirtyRect and aBorderArea are in the local coordinate space
* of aForFrame
*/
static void PaintBorder(nsPresContext* aPresContext,
nsIRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
const nsStyleBorder& aBorderStyle,
nsStyleContext* aStyleContext,
PRIntn aSkipSides = 0);
/**
* Render the outline for an element using css rendering rules
* for borders. aSkipSides is a bitmask of the sides to skip
* when rendering. If 0 then no sides are skipped.
*
* Both aDirtyRect and aBorderArea are in the local coordinate space
* of aForFrame
*/
static void PaintOutline(nsPresContext* aPresContext,
nsIRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
const nsStyleBorder& aBorderStyle,
const nsStyleOutline& aOutlineStyle,
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,
nsIRenderingContext& aRenderingContext,
const nsRect& aFocusRect,
nscolor aColor);
/**
* Fill in an nsStyleBackground to be used to paint the background for
* an element. The nsStyleBackground should first be initialized
* using the pres context. This applies the rules for propagating
* backgrounds between BODY, the root element, and the canvas.
* @return PR_TRUE if there is some meaningful background.
*/
static PRBool FindBackground(nsPresContext* aPresContext,
nsIFrame* aForFrame,
const nsStyleBackground** aBackground,
PRBool* aIsCanvas);
/**
* Find a non-transparent background, for various table-related and
* HR-related backwards-compatibility hacks. Be very hesitant if
* you're considering calling this function -- it's usually not what
* you want.
*/
static const nsStyleBackground*
FindNonTransparentBackground(nsStyleContext* aContext,
PRBool aStartAtParent = PR_FALSE);
/**
* Render the background for an element using css rendering rules
* for backgrounds.
*
* Both aDirtyRect and aBorderArea are in the local coordinate space
* of aForFrame
*/
static void PaintBackground(nsPresContext* aPresContext,
nsIRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
PRBool aUsePrintSettings,
nsRect* aBGClipRect = nsnull);
/**
* 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.
*/
static void PaintBackgroundWithSC(nsPresContext* aPresContext,
nsIRenderingContext& aRenderingContext,
nsIFrame* aForFrame,
const nsRect& aDirtyRect,
const nsRect& aBorderArea,
const nsStyleBackground& aColor,
const nsStyleBorder& aBorder,
PRBool aUsePrintSettings = PR_FALSE,
nsRect* aBGClipRect = nsnull);
/**
* Called by the presShell when painting is finished, so we can clear our
* inline background data cache.
*/
static void DidPaint();
// Draw a border segment in the table collapsing border model without
// beveling corners
static void DrawTableBorderSegment(nsIRenderingContext& aContext,
PRUint8 aBorderStyle,
nscolor aBorderColor,
const nsStyleBackground* aBGColor,
const nsRect& aBorderRect,
PRInt32 aAppUnitsPerCSSPixel,
PRUint8 aStartBevelSide = 0,
nscoord aStartBevelOffset = 0,
PRUint8 aEndBevelSide = 0,
nscoord aEndBevelOffset = 0);
/**
* transform a color to a color that will show up on a printer if needed
* aMapColor - color to evaluate
* aIsPrinter - Is this a printing device
* return - the transformed color
*/
static nscolor TransformColor(nscolor aMapColor,PRBool aNoBackGround);
/**
* 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 aGfxContext
* @param aColor the color of the decoration line
* @param aPt the top/left edge of the text
* @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_UNDERLINE or
* NS_STYLE_TEXT_DECORATION_OVERLINE or
* NS_STYLE_TEXT_DECORATION_LINE_THROUGH.
* @param aStyle the style of the decoration line. The value
* can be NS_STYLE_BORDER_STYLE_SOLID or
* NS_STYLE_BORDER_STYLE_DOTTED or
* NS_STYLE_BORDER_STYLE_DASHED or
* NS_STYLE_BORDER_STYLE_DOUBLE.
*/
static void PaintDecorationLine(gfxContext* aGfxContext,
const nscolor aColor,
const gfxPoint& aPt,
const gfxSize& aLineSize,
const gfxFloat aAscent,
const gfxFloat aOffset,
const PRUint8 aDecoration,
const PRUint8 aStyle);
/**
* 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_UNDERLINE or
* NS_STYLE_TEXT_DECORATION_OVERLINE or
* NS_STYLE_TEXT_DECORATION_LINE_THROUGH.
* @param aStyle the style of the decoration line. The value
* can be NS_STYLE_BORDER_STYLE_SOLID or
* NS_STYLE_BORDER_STYLE_DOTTED or
* NS_STYLE_BORDER_STYLE_DASHED or
* NS_STYLE_BORDER_STYLE_DOUBLE.
* 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 PRUint8 aDecoration,
const PRUint8 aStyle);
};
/*
* 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:
/**
* 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().
*
* @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 gfxRect& aRect, nscoord aBlurRadius,
PRInt32 aAppUnitsPerDevPixel, gfxContext* aDestinationCtx);
/**
* 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();
protected:
gfxAlphaBoxBlur blur;
nsRefPtr<gfxContext> mContext;
gfxContext* mDestinationCtx;
};
#endif /* nsCSSRendering_h___ */