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Make rescaler methods generic

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to be used in rescaling of lossless bitstreams.
(cherry picked from commit 2e12a3045498b6faf13b93bc25391e8226119f0a)
This commit is contained in:
Urvang Joshi
2012-03-21 06:48:50 +00:00
committed by James Zern
parent 3eacee8158
commit efc2016a31
3 changed files with 45 additions and 34 deletions
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11
src/dec/webpi.h
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@ -27,6 +27,7 @@ typedef int (*OutputFunc)(const VP8Io* const io, WebPDecParams* const p);
// Structure use for on-the-fly rescaling
typedef struct {
int x_expand; // true if we're expanding in the x direction
int num_channels; // bytes to jump between pixels
int fy_scale, fx_scale; // fixed-point scaling factor
int64_t fxy_scale; // ''
// we need hpel-precise add/sub increments, for the downsampled U/V planes.
@ -168,12 +169,14 @@ int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
// Initialize a rescaler given scratch area 'work' and dimensions of src & dst.
void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height,
uint8_t* dst, int dst_width, int dst_height,
int dst_stride, int x_add, int x_sub, int y_add,
int y_sub, int32_t* work);
uint8_t* const dst, int dst_width, int dst_height,
int dst_stride, int num_channels, int x_add, int x_sub,
int y_add, int y_sub, int32_t* const work);
// Import a row of data and save its contribution in the rescaler.
void WebPRescalerImportRow(const uint8_t* const src, WebPRescaler* const wrk);
// 'channel' denotes the channel number to be imported.
void WebPRescalerImportRow(const uint8_t* const src, int channel,
WebPRescaler* const wrk);
// Export a row from rescaler.
void WebPRescalerExportRow(WebPRescaler* const wrk);