michael@0: 
michael@0: /*
michael@0:  * Copyright 2011 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: #ifndef SkScaledBitmapSampler_DEFINED
michael@0: #define SkScaledBitmapSampler_DEFINED
michael@0: 
michael@0: #include "SkTypes.h"
michael@0: #include "SkColor.h"
michael@0: #include "SkImageDecoder.h"
michael@0: 
michael@0: class SkBitmap;
michael@0: 
michael@0: class SkScaledBitmapSampler {
michael@0: public:
michael@0:     SkScaledBitmapSampler(int origWidth, int origHeight, int cellSize);
michael@0: 
michael@0:     int scaledWidth() const { return fScaledWidth; }
michael@0:     int scaledHeight() const { return fScaledHeight; }
michael@0: 
michael@0:     int srcY0() const { return fY0; }
michael@0:     int srcDX() const { return fDX; }
michael@0:     int srcDY() const { return fDY; }
michael@0: 
michael@0:     enum SrcConfig {
michael@0:         kGray,  // 1 byte per pixel
michael@0:         kIndex, // 1 byte per pixel
michael@0:         kRGB,   // 3 bytes per pixel
michael@0:         kRGBX,  // 4 byes per pixel (ignore 4th)
michael@0:         kRGBA,  // 4 bytes per pixel
michael@0:         kRGB_565 // 2 bytes per pixel
michael@0:     };
michael@0: 
michael@0:     // Given a dst bitmap (with pixels already allocated) and a src-config,
michael@0:     // prepares iterator to process the src colors and write them into dst.
michael@0:     // Returns false if the request cannot be fulfulled.
michael@0:     bool begin(SkBitmap* dst, SrcConfig sc, const SkImageDecoder& decoder,
michael@0:                const SkPMColor* = NULL);
michael@0:     // call with row of src pixels, for y = 0...scaledHeight-1.
michael@0:     // returns true if the row had non-opaque alpha in it
michael@0:     bool next(const uint8_t* SK_RESTRICT src);
michael@0: 
michael@0:     // Like next(), but specifies the y value of the source row, so the
michael@0:     // rows can come in any order. If the row is not part of the output
michael@0:     // sample, it will be skipped. Only sampleInterlaced OR next should
michael@0:     // be called for one SkScaledBitmapSampler.
michael@0:     bool sampleInterlaced(const uint8_t* SK_RESTRICT src, int srcY);
michael@0: 
michael@0:     typedef bool (*RowProc)(void* SK_RESTRICT dstRow,
michael@0:                             const uint8_t* SK_RESTRICT src,
michael@0:                             int width, int deltaSrc, int y,
michael@0:                             const SkPMColor[]);
michael@0: 
michael@0: private:
michael@0:     int fScaledWidth;
michael@0:     int fScaledHeight;
michael@0: 
michael@0:     int fX0;    // first X coord to sample
michael@0:     int fY0;    // first Y coord (scanline) to sample
michael@0:     int fDX;    // step between X samples
michael@0:     int fDY;    // step between Y samples
michael@0: 
michael@0: #ifdef SK_DEBUG
michael@0:     // Keep track of whether the caller is using next or sampleInterlaced.
michael@0:     // Only one can be used per sampler.
michael@0:     enum SampleMode {
michael@0:         kUninitialized_SampleMode,
michael@0:         kConsecutive_SampleMode,
michael@0:         kInterlaced_SampleMode,
michael@0:     };
michael@0: 
michael@0:     SampleMode fSampleMode;
michael@0: #endif
michael@0: 
michael@0:     // setup state
michael@0:     char*   fDstRow; // points into bitmap's pixels
michael@0:     size_t  fDstRowBytes;
michael@0:     int     fCurrY; // used for dithering
michael@0:     int     fSrcPixelSize;  // 1, 3, 4
michael@0:     RowProc fRowProc;
michael@0: 
michael@0:     // optional reference to the src colors if the src is a palette model
michael@0:     const SkPMColor* fCTable;
michael@0: 
michael@0: #ifdef SK_DEBUG
michael@0:     // Helper class allowing a test to have access to fRowProc.
michael@0:     friend class RowProcTester;
michael@0: #endif
michael@0: };
michael@0: 
michael@0: #endif