// Dumps a picture as a PGM file using the IMC4 layout.
static int DumpPicture(const WebPPicture* const picture, const char* PGM_name) {
int y;
const int uv_width = (picture->width + 1) / 2;
const int uv_height = (picture->height + 1) / 2;
const int stride = (picture->width + 1) & ~1;
const int alpha_height =
WebPPictureHasTransparency(picture) ? picture->height : 0;
const int height = picture->height + uv_height + alpha_height;
FILE* const f = fopen(PGM_name, "wb");
if (f == NULL) return 0;
fprintf(f, "P5\n%d %d\n255\n", stride, height);
for (y = 0; y < picture->height; ++y) {
if (fwrite(picture->y + y * picture->y_stride, picture->width, 1, f) != 1)
return 0;
if (picture->width & 1) fputc(0, f); // pad
}
for (y = 0; y < uv_height; ++y) {
if (fwrite(picture->u + y * picture->uv_stride, uv_width, 1, f) != 1)
return 0;
if (fwrite(picture->v + y * picture->uv_stride, uv_width, 1, f) != 1)
return 0;
}
for (y = 0; y < alpha_height; ++y) {
if (fwrite(picture->a + y * picture->a_stride, picture->width, 1, f) != 1)
return 0;
if (picture->width & 1) fputc(0, f); // pad
}
fclose(f);
return 1;
}
void VP8EncInitAlpha(VP8Encoder* const enc) {
enc->has_alpha_ = WebPPictureHasTransparency(enc->pic_);
enc->alpha_data_ = NULL;
enc->alpha_data_size_ = 0;
if (enc->thread_level_ > 0) {
WebPWorker* const worker = &enc->alpha_worker_;
WebPWorkerInit(worker);
worker->data1 = enc;
worker->data2 = NULL;
worker->hook = (WebPWorkerHook)CompressAlphaJob;
}
}
void VP8EncInitAlpha(VP8Encoder* const enc) {
enc->has_alpha_ = WebPPictureHasTransparency(enc->pic_);
enc->alpha_data_ = NULL;
enc->alpha_data_size_ = 0;
}
