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Pass stride parameter to WebPDequantizeLevels()

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and also pass 'VP8Io* io' extra param to VP8DecompressAlphaRows()

This is somehow in preparation for some memory optimizations in
the 'cropping' case. For now, only the easy crop_bottom case is
optimized.

Change-Id: Ib54531ba057bf62b98422dbb6c181dda626c72c2
This commit is contained in:
Pascal Massimino
2016-03-18 15:36:58 +01:00
parent e88c4ca013
commit 64eed38779
5 changed files with 23 additions and 14 deletions
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18
src/dec/alpha.c
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@ -120,16 +120,18 @@ static int ALPHDecode(VP8Decoder* const dec, int row, int num_rows) {
// Main entry point.
const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,
const VP8Io* const io,
int row, int num_rows) {
const int width = dec->pic_hdr_.width_;
const int height = dec->pic_hdr_.height_;
assert(dec != NULL && io != NULL);
if (row < 0 || num_rows <= 0 || row + num_rows > height) {
return NULL; // sanity check.
}
if (row == 0) {
// Initialize decoding.
if (dec->alph_dec_ == NULL) { // Initialize decoder.
assert(dec->alpha_plane_ != NULL);
dec->alph_dec_ = ALPHNew();
if (dec->alph_dec_ == NULL) return NULL;
@ -147,12 +149,17 @@ const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,
}
}
if (io->use_cropping) {
if (row + num_rows > io->crop_bottom) {
num_rows = io->crop_bottom - row;
}
}
if (!dec->is_alpha_decoded_) {
int ok = 0;
int ok = ALPHDecode(dec, row, num_rows);
assert(dec->alph_dec_ != NULL);
ok = ALPHDecode(dec, row, num_rows);
if (ok && dec->alpha_dithering_ > 0) {
ok = WebPDequantizeLevels(dec->alpha_plane_, width, height,
ok = WebPDequantizeLevels(dec->alpha_plane_, width, height, width,
dec->alpha_dithering_);
}
if (!ok || dec->is_alpha_decoded_) {
@ -161,7 +168,6 @@ const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,
}
if (!ok) return NULL; // Error.
}
// Return a pointer to the current decoded row.
return dec->alpha_plane_ + row * width;
}