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Skia
2DGraphicsLibrary
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Skia
2DGraphicsLibrary
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SkMaskFilter is the base class for object that perform transformations on an alpha-channel mask before drawing it. More...
#include <SkMaskFilter.h>
Classes | |
| struct | BlurRec |
| class | NinePatch |
Public Member Functions | |
| virtual SkMask::Format | getFormat () const =0 |
| Returns the format of the resulting mask that this subclass will return when its filterMask() method is called. | |
| virtual bool | filterMask (SkMask *dst, const SkMask &src, const SkMatrix &, SkIPoint *margin) const |
| Create a new mask by filter the src mask. More... | |
| virtual bool | asFragmentProcessor (GrFragmentProcessor **, GrTexture *, const SkMatrix &ctm) const |
| Returns true if the filter can be expressed a single-pass GrProcessor without requiring an explicit input mask. More... | |
| virtual bool | canFilterMaskGPU (const SkRRect &devRRect, const SkIRect &clipBounds, const SkMatrix &ctm, SkRect *maskRect) const |
| If asFragmentProcessor() fails the filter may be implemented on the GPU by a subclass overriding filterMaskGPU (declared below). More... | |
| virtual bool | directFilterMaskGPU (GrTextureProvider *texProvider, GrDrawContext *drawContext, GrPaint *grp, const GrClip &, const SkMatrix &viewMatrix, const SkStrokeRec &strokeRec, const SkPath &path) const |
| Try to directly render the mask filter into the target. More... | |
| virtual bool | directFilterRRectMaskGPU (GrContext *, GrDrawContext *drawContext, GrPaint *grp, const GrClip &, const SkMatrix &viewMatrix, const SkStrokeRec &strokeRec, const SkRRect &rrect, const SkRRect &devRRect) const |
| Try to directly render a rounded rect mask filter into the target. More... | |
| virtual bool | filterMaskGPU (GrTexture *src, const SkMatrix &ctm, const SkIRect &maskRect, GrTexture **result) const |
| This function is used to implement filters that require an explicit src mask. More... | |
| virtual void | computeFastBounds (const SkRect &src, SkRect *dest) const |
| The fast bounds function is used to enable the paint to be culled early in the drawing pipeline. More... | |
| virtual bool | asABlur (BlurRec *) const |
| If this filter can be represented by a BlurRec, return true and (if not null) fill in the provided BlurRec parameter. More... | |
 Public Member Functions inherited from SkFlattenable | |
| virtual Factory | getFactory () const =0 |
| Implement this to return a factory function pointer that can be called to recreate your class given a buffer (previously written to by your override of flatten(). | |
| virtual const char * | getTypeName () const |
| Returns the name of the object's class. More... | |
| virtual void | flatten (SkWriteBuffer &) const |
| Override this if your subclass needs to record data that it will need to recreate itself from its CreateProc (returned by getFactory()). | |
| Public Member Functions inherited from SkRefCntBase | |
| SkRefCntBase () | |
| Default construct, initializing the reference count to 1. | |
| virtual | ~SkRefCntBase () |
| Destruct, asserting that the reference count is 1. | |
| int32_t | getRefCnt () const |
| Return the reference count. More... | |
| void | validate () const |
| bool | unique () const |
| May return true if the caller is the only owner. More... | |
| void | ref () const |
| Increment the reference count. More... | |
| void | unref () const |
| Decrement the reference count. More... | |
Protected Types | |
| enum | FilterReturn { kFalse_FilterReturn, kTrue_FilterReturn, kUnimplemented_FilterReturn } |
Protected Member Functions | |
| virtual FilterReturn | filterRectsToNine (const SkRect[], int count, const SkMatrix &, const SkIRect &clipBounds, NinePatch *) const |
| Override if your subclass can filter a rect, and return the answer as a ninepatch mask to be stretched over the returned outerRect. More... | |
| virtual FilterReturn | filterRRectToNine (const SkRRect &, const SkMatrix &, const SkIRect &clipBounds, NinePatch *) const |
| Similar to filterRectsToNine, except it performs the work on a round rect. | |
| Protected Member Functions inherited from SkRefCntBase | |
| void | internal_dispose_restore_refcnt_to_1 () const |
| Allow subclasses to call this if they've overridden internal_dispose so they can reset fRefCnt before the destructor is called or if they choose not to call the destructor (e.g. More... | |
Private Types | |
| typedef SkFlattenable | INHERITED |
Private Member Functions | |
| bool | filterPath (const SkPath &devPath, const SkMatrix &ctm, const SkRasterClip &, SkBlitter *, SkStrokeRec::InitStyle) const |
| Helper method that, given a path in device space, will rasterize it into a kA8_Format mask and then call filterMask(). More... | |
| bool | filterRRect (const SkRRect &devRRect, const SkMatrix &ctm, const SkRasterClip &, SkBlitter *) const |
| Helper method that, given a roundRect in device space, will rasterize it into a kA8_Format mask and then call filterMask(). More... | |
Friends | |
| class | SkDraw |
Additional Inherited Members | |
| Public Types inherited from SkFlattenable | |
| enum | Type { kSkColorFilter_Type, kSkDrawable_Type, kSkDrawLooper_Type, kSkImageFilter_Type, kSkMaskFilter_Type, kSkPathEffect_Type, kSkPixelRef_Type, kSkRasterizer_Type, kSkShader_Type, kSkUnused_Type, kSkXfermode_Type, kSkNormalSource_Type } |
| typedef sk_sp< SkFlattenable >(* | Factory )(SkReadBuffer &) |
| Static Public Member Functions inherited from SkFlattenable | |
| static Factory | NameToFactory (const char name[]) |
| static const char * | FactoryToName (Factory) |
| static bool | NameToType (const char name[], Type *type) |
| static void | Register (const char name[], Factory, Type) |
SkMaskFilter is the base class for object that perform transformations on an alpha-channel mask before drawing it.
A subclass of SkMaskFilter may be installed into a SkPaint. Once there, each time a primitive is drawn, it is first scan converted into a SkMask::kA8_Format mask, and handed to the filter, calling its filterMask() method. If this returns true, then the new mask is used to render into the device.
Blur and emboss are implemented as subclasses of SkMaskFilter.
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Returns true if the filter can be expressed a single-pass GrProcessor without requiring an explicit input mask.
Per-pixel, the effect receives the incoming mask's coverage as the input color and outputs the filtered covereage value. This means that each pixel's filtered coverage must only depend on the unfiltered mask value for that pixel and not on surrounding values.
If effect is non-NULL, a new GrProcessor instance is stored in it. The caller assumes ownership of the effect and must unref it.
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If asFragmentProcessor() fails the filter may be implemented on the GPU by a subclass overriding filterMaskGPU (declared below).
That code path requires constructing a src mask as input. Since that is a potentially expensive operation, the subclass must also override this function to indicate whether filterTextureMaskGPU would succeeed if the mask were to be created.
'maskRect' returns the device space portion of the mask that the filter needs. The mask passed into 'filterMaskGPU' should have the same extent as 'maskRect' but be translated to the upper-left corner of the mask (i.e., (maskRect.fLeft, maskRect.fTop) appears at (0, 0) in the mask).
Logically, how this works is: canFilterMaskGPU is called if (it returns true) the returned mask rect is used for quick rejecting either directFilterMaskGPU or directFilterRRectMaskGPU is then called if (neither of them handle the blur) the mask rect is used to generate the mask filterMaskGPU is called to filter the mask
TODO: this should work as: if (canFilterMaskGPU(devShape, ...)) // rect, rrect, drrect, path filterMaskGPU(devShape, ...) this would hide the RRect special case and the mask generation
The fast bounds function is used to enable the paint to be culled early in the drawing pipeline.
This function accepts the current bounds of the paint as its src param and the filter adjust those bounds using its current mask and returns the result using the dest param. Callers are allowed to provide the same struct for both src and dest so each implementation must accomodate that behavior.
The default impl calls filterMask with the src mask having no image, but subclasses may override this if they can compute the rect faster.
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Try to directly render the mask filter into the target.
Returns true if drawing was successful.
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Try to directly render a rounded rect mask filter into the target.
Returns true if drawing was successful.
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Create a new mask by filter the src mask.
If src.fImage == null, then do not allocate or create the dst image but do fill out the other fields in dstMask. If you do allocate a dst image, use SkMask::AllocImage() If this returns false, dst mask is ignored.
| dst | the result of the filter. If src.fImage == null, dst should not allocate its image |
| src | the original image to be filtered. |
| matrix | the CTM |
| margin | if not null, return the buffer dx/dy need when calculating the effect. Used when drawing a clipped object to know how much larger to allocate the src before applying the filter. If returning false, ignore this parameter. |
Reimplemented in SkTableMaskFilter, and SkEmbossMaskFilter.
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This function is used to implement filters that require an explicit src mask.
It should only be called if canFilterMaskGPU returned true and the maskRect param should be the output from that call. Implementations are free to get the GrContext from the src texture in order to create additional textures and perform multiple passes.
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Helper method that, given a path in device space, will rasterize it into a kA8_Format mask and then call filterMask().
If this returns true, the specified blitter will be called to render that mask. Returns false if filterMask() returned false. This method is not exported to java.
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Override if your subclass can filter a rect, and return the answer as a ninepatch mask to be stretched over the returned outerRect.
On success return kTrue_FilterReturn. On failure (e.g. out of memory) return kFalse_FilterReturn. If the normal filterMask() entry-point should be called (the default) return kUnimplemented_FilterReturn.
By convention, the caller will take the center rol/col from the returned mask as the slice it can replicate horizontally and vertically as we stretch the mask to fit inside outerRect. It is an error for outerRect to be smaller than the mask's bounds. This would imply that the width and height of the mask should be odd. This is not required, just that the caller will call mask.fBounds.centerX() and centerY() to find the strips that will be replicated.
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Helper method that, given a roundRect in device space, will rasterize it into a kA8_Format mask and then call filterMask().
If this returns true, the specified blitter will be called to render that mask. Returns false if filterMask() returned false.
