Merge "for ReadXXXX() image-readers, use the value of pic->use_argb"

examples/cwebp.c

@@ -967,7 +967,11 @@ int main(int argc, const char *argv[]) {
     goto Error;
   }
 
-  // Read the input
+  // Read the input. We need to decide if we prefer ARGB or YUVA
+  // samples, depending on the expected compression mode (this saves
+  // some conversion steps).
+  picture.use_argb = (config.lossless || config.preprocessing > 0 ||
+                      crop || (resize_w | resize_h) > 0);
   if (verbose) {
     StopwatchReset(&stop_watch);
   }

examples/jpegdec.c

@@ -272,7 +272,6 @@ int ReadJPEG(FILE* in_file, WebPPicture* const pic, Metadata* const metadata) {
   // WebP conversion.
   pic->width = width;
   pic->height = height;
-  pic->use_argb = 1;      // store raw RGB samples
   ok = WebPPictureImportRGB(pic, rgb, stride);
   if (!ok) goto Error;
 

examples/jpegdec.h

@@ -23,7 +23,7 @@ struct Metadata;
 struct WebPPicture;
 
 // Reads a JPEG from 'in_file', returning the decoded output in 'pic'.
-// The output is RGB.
+// The output is RGB or YUV depending on pic->use_argb value.
 // Returns true on success.
 int ReadJPEG(FILE* in_file, struct WebPPicture* const pic,
              struct Metadata* const metadata);

examples/pngdec.c

@@ -270,7 +270,6 @@ int ReadPNG(FILE* in_file, WebPPicture* const pic, int keep_alpha,
 
   pic->width = (int)width;
   pic->height = (int)height;
-  pic->use_argb = 1;
   ok = has_alpha ? WebPPictureImportRGBA(pic, rgb, (int)stride)
                  : WebPPictureImportRGB(pic, rgb, (int)stride);
 

examples/pngdec.h

@@ -22,8 +22,9 @@ struct Metadata;
 struct WebPPicture;
 
 // Reads a PNG from 'in_file', returning the decoded output in 'pic'.
+// Output is RGBA or YUVA, depending on pic->use_argb value.
 // If 'keep_alpha' is true and the PNG has an alpha channel, the output is RGBA
-// otherwise it will be RGB.
+// or YUVA. Otherwise, alpha channel is dropped and output is RGB or YUV.
 // Returns true on success.
 int ReadPNG(FILE* in_file, struct WebPPicture* const pic, int keep_alpha,
             struct Metadata* const metadata);

examples/tiffdec.c

@@ -100,7 +100,6 @@ int ReadTIFF(const char* const filename,
 #ifdef WORDS_BIGENDIAN
       TIFFSwabArrayOfLong(raster, width * height);
 #endif
-      pic->use_argb = 1;
       ok = keep_alpha
          ? WebPPictureImportRGBA(pic, (const uint8_t*)raster, stride)
          : WebPPictureImportRGBX(pic, (const uint8_t*)raster, stride);

examples/tiffdec.h

@@ -20,8 +20,9 @@ struct Metadata;
 struct WebPPicture;
 
 // Reads a TIFF from 'filename', returning the decoded output in 'pic'.
+// Output is RGBA or YUVA, depending on pic->use_argb value.
 // If 'keep_alpha' is true and the TIFF has an alpha channel, the output is RGBA
-// otherwise it will be RGB.
+// or YUVA. Otherwise, alpha channel is dropped and output is RGB or YUV.
 // Returns true on success.
 int ReadTIFF(const char* const filename,
              struct WebPPicture* const pic, int keep_alpha,

examples/webpdec.c

@@ -41,6 +41,8 @@ int ReadWebP(const char* const in_file, WebPPicture* const pic,
 
   if (ExUtilLoadWebP(in_file, &data, &data_size, bitstream)) {
     const int has_alpha = keep_alpha && bitstream->has_alpha;
+    // TODO(skal): use MODE_YUV(A), depending on the expected
+    // input pic->use_argb. This would save some conversion steps.
     output_buffer->colorspace = has_alpha ? MODE_RGBA : MODE_RGB;
 
     status = ExUtilDecodeWebP(data, data_size, 0, &config);
@@ -49,7 +51,6 @@ int ReadWebP(const char* const in_file, WebPPicture* const pic,
       const int stride = output_buffer->u.RGBA.stride;
       pic->width = output_buffer->width;
       pic->height = output_buffer->height;
-      pic->use_argb = 1;
       ok = has_alpha ? WebPPictureImportRGBA(pic, rgba, stride)
                      : WebPPictureImportRGB(pic, rgba, stride);
     }

examples/webpdec.h

@@ -20,8 +20,9 @@ struct Metadata;
 struct WebPPicture;
 
 // Reads a WebP from 'in_file', returning the decoded output in 'pic'.
-// If 'keep_alpha' is true and the WebP has an alpha channel, the output is
+// Output is RGBA or YUVA, depending on pic->use_argb value.
-// RGBA otherwise it will be RGB.
+// If 'keep_alpha' is true and the TIFF has an alpha channel, the output is RGBA
+// or YUVA. Otherwise, alpha channel is dropped and output is RGB or YUV.
 // Returns true on success.
 int ReadWebP(const char* const in_file, struct WebPPicture* const pic,
              int keep_alpha, struct Metadata* const metadata);

examples/wicdec.c

@@ -320,7 +320,7 @@ int ReadPictureWithWIC(const char* const filename,
     int ok;
     pic->width = width;
     pic->height = height;
-    pic->use_argb = 1;
+    pic->use_argb = 1;    // For WIC, we always force to argb
     ok = importer->import(pic, rgb, stride);
     if (!ok) hr = E_FAIL;
   }

examples/wicdec.h

@@ -21,7 +21,7 @@ struct WebPPicture;
 
 // Reads an image from 'filename', returning the decoded output in 'pic'.
 // If 'keep_alpha' is true and the image has an alpha channel, the output is
-// RGBA otherwise it will be RGB.
+// RGBA otherwise it will be RGB. pic->use_argb is always forced to true.
 // Returns true on success.
 int ReadPictureWithWIC(const char* const filename,
                        struct WebPPicture* const pic, int keep_alpha,