1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/core/SkBlitter.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,172 @@
1.4 +
1.5 +/*
1.6 + * Copyright 2006 The Android Open Source Project
1.7 + *
1.8 + * Use of this source code is governed by a BSD-style license that can be
1.9 + * found in the LICENSE file.
1.10 + */
1.11 +
1.12 +
1.13 +#ifndef SkBlitter_DEFINED
1.14 +#define SkBlitter_DEFINED
1.15 +
1.16 +#include "SkBitmap.h"
1.17 +#include "SkBitmapProcShader.h"
1.18 +#include "SkMask.h"
1.19 +#include "SkMatrix.h"
1.20 +#include "SkPaint.h"
1.21 +#include "SkRefCnt.h"
1.22 +#include "SkRegion.h"
1.23 +#include "SkShader.h"
1.24 +#include "SkSmallAllocator.h"
1.25 +
1.26 +/** SkBlitter and its subclasses are responsible for actually writing pixels
1.27 + into memory. Besides efficiency, they handle clipping and antialiasing.
1.28 +*/
1.29 +class SkBlitter {
1.30 +public:
1.31 + virtual ~SkBlitter();
1.32 +
1.33 + /// Blit a horizontal run of one or more pixels.
1.34 + virtual void blitH(int x, int y, int width);
1.35 + /// Blit a horizontal run of antialiased pixels; runs[] is a *sparse*
1.36 + /// zero-terminated run-length encoding of spans of constant alpha values.
1.37 + virtual void blitAntiH(int x, int y, const SkAlpha antialias[],
1.38 + const int16_t runs[]);
1.39 + /// Blit a vertical run of pixels with a constant alpha value.
1.40 + virtual void blitV(int x, int y, int height, SkAlpha alpha);
1.41 + /// Blit a solid rectangle one or more pixels wide.
1.42 + virtual void blitRect(int x, int y, int width, int height);
1.43 + /** Blit a rectangle with one alpha-blended column on the left,
1.44 + width (zero or more) opaque pixels, and one alpha-blended column
1.45 + on the right.
1.46 + The result will always be at least two pixels wide.
1.47 + */
1.48 + virtual void blitAntiRect(int x, int y, int width, int height,
1.49 + SkAlpha leftAlpha, SkAlpha rightAlpha);
1.50 + /// Blit a pattern of pixels defined by a rectangle-clipped mask;
1.51 + /// typically used for text.
1.52 + virtual void blitMask(const SkMask&, const SkIRect& clip);
1.53 +
1.54 + /** If the blitter just sets a single value for each pixel, return the
1.55 + bitmap it draws into, and assign value. If not, return NULL and ignore
1.56 + the value parameter.
1.57 + */
1.58 + virtual const SkBitmap* justAnOpaqueColor(uint32_t* value);
1.59 +
1.60 + /**
1.61 + * Special method just to identify the null blitter, which is returned
1.62 + * from Choose() if the request cannot be fulfilled. Default impl
1.63 + * returns false.
1.64 + */
1.65 + virtual bool isNullBlitter() const;
1.66 +
1.67 + ///@name non-virtual helpers
1.68 + void blitMaskRegion(const SkMask& mask, const SkRegion& clip);
1.69 + void blitRectRegion(const SkIRect& rect, const SkRegion& clip);
1.70 + void blitRegion(const SkRegion& clip);
1.71 + ///@}
1.72 +
1.73 + /** @name Factories
1.74 + Return the correct blitter to use given the specified context.
1.75 + */
1.76 + static SkBlitter* Choose(const SkBitmap& device,
1.77 + const SkMatrix& matrix,
1.78 + const SkPaint& paint,
1.79 + SkTBlitterAllocator*,
1.80 + bool drawCoverage = false);
1.81 +
1.82 + static SkBlitter* ChooseSprite(const SkBitmap& device,
1.83 + const SkPaint&,
1.84 + const SkBitmap& src,
1.85 + int left, int top,
1.86 + SkTBlitterAllocator*);
1.87 + ///@}
1.88 +
1.89 +private:
1.90 +};
1.91 +
1.92 +/** This blitter silently never draws anything.
1.93 +*/
1.94 +class SkNullBlitter : public SkBlitter {
1.95 +public:
1.96 + virtual void blitH(int x, int y, int width) SK_OVERRIDE;
1.97 + virtual void blitAntiH(int x, int y, const SkAlpha[],
1.98 + const int16_t runs[]) SK_OVERRIDE;
1.99 + virtual void blitV(int x, int y, int height, SkAlpha alpha) SK_OVERRIDE;
1.100 + virtual void blitRect(int x, int y, int width, int height) SK_OVERRIDE;
1.101 + virtual void blitMask(const SkMask&, const SkIRect& clip) SK_OVERRIDE;
1.102 + virtual const SkBitmap* justAnOpaqueColor(uint32_t* value) SK_OVERRIDE;
1.103 + virtual bool isNullBlitter() const SK_OVERRIDE;
1.104 +};
1.105 +
1.106 +/** Wraps another (real) blitter, and ensures that the real blitter is only
1.107 + called with coordinates that have been clipped by the specified clipRect.
1.108 + This means the caller need not perform the clipping ahead of time.
1.109 +*/
1.110 +class SkRectClipBlitter : public SkBlitter {
1.111 +public:
1.112 + void init(SkBlitter* blitter, const SkIRect& clipRect) {
1.113 + SkASSERT(!clipRect.isEmpty());
1.114 + fBlitter = blitter;
1.115 + fClipRect = clipRect;
1.116 + }
1.117 +
1.118 + virtual void blitH(int x, int y, int width) SK_OVERRIDE;
1.119 + virtual void blitAntiH(int x, int y, const SkAlpha[],
1.120 + const int16_t runs[]) SK_OVERRIDE;
1.121 + virtual void blitV(int x, int y, int height, SkAlpha alpha) SK_OVERRIDE;
1.122 + virtual void blitRect(int x, int y, int width, int height) SK_OVERRIDE;
1.123 + virtual void blitAntiRect(int x, int y, int width, int height,
1.124 + SkAlpha leftAlpha, SkAlpha rightAlpha) SK_OVERRIDE;
1.125 + virtual void blitMask(const SkMask&, const SkIRect& clip) SK_OVERRIDE;
1.126 + virtual const SkBitmap* justAnOpaqueColor(uint32_t* value) SK_OVERRIDE;
1.127 +
1.128 +private:
1.129 + SkBlitter* fBlitter;
1.130 + SkIRect fClipRect;
1.131 +};
1.132 +
1.133 +/** Wraps another (real) blitter, and ensures that the real blitter is only
1.134 + called with coordinates that have been clipped by the specified clipRgn.
1.135 + This means the caller need not perform the clipping ahead of time.
1.136 +*/
1.137 +class SkRgnClipBlitter : public SkBlitter {
1.138 +public:
1.139 + void init(SkBlitter* blitter, const SkRegion* clipRgn) {
1.140 + SkASSERT(clipRgn && !clipRgn->isEmpty());
1.141 + fBlitter = blitter;
1.142 + fRgn = clipRgn;
1.143 + }
1.144 +
1.145 + virtual void blitH(int x, int y, int width) SK_OVERRIDE;
1.146 + virtual void blitAntiH(int x, int y, const SkAlpha[],
1.147 + const int16_t runs[]) SK_OVERRIDE;
1.148 + virtual void blitV(int x, int y, int height, SkAlpha alpha) SK_OVERRIDE;
1.149 + virtual void blitRect(int x, int y, int width, int height) SK_OVERRIDE;
1.150 + virtual void blitAntiRect(int x, int y, int width, int height,
1.151 + SkAlpha leftAlpha, SkAlpha rightAlpha) SK_OVERRIDE;
1.152 + virtual void blitMask(const SkMask&, const SkIRect& clip) SK_OVERRIDE;
1.153 + virtual const SkBitmap* justAnOpaqueColor(uint32_t* value) SK_OVERRIDE;
1.154 +
1.155 +private:
1.156 + SkBlitter* fBlitter;
1.157 + const SkRegion* fRgn;
1.158 +};
1.159 +
1.160 +/** Factory to set up the appropriate most-efficient wrapper blitter
1.161 + to apply a clip. Returns a pointer to a member, so lifetime must
1.162 + be managed carefully.
1.163 +*/
1.164 +class SkBlitterClipper {
1.165 +public:
1.166 + SkBlitter* apply(SkBlitter* blitter, const SkRegion* clip,
1.167 + const SkIRect* bounds = NULL);
1.168 +
1.169 +private:
1.170 + SkNullBlitter fNullBlitter;
1.171 + SkRectClipBlitter fRectBlitter;
1.172 + SkRgnClipBlitter fRgnBlitter;
1.173 +};
1.174 +
1.175 +#endif
