diff options
Diffstat (limited to 'example.c')
| -rw-r--r-- | example.c | 15 |
1 files changed, 13 insertions, 2 deletions
@@ -154,6 +154,10 @@ write_JPEG_file (char * filename, int quality) row_stride = image_width * 3; /* JSAMPLEs per row in image_buffer */ while (cinfo.next_scanline < cinfo.image_height) { + /* jpeg_write_scanlines expects an array of pointers to scanlines. + * Here the array is only one element long, but you could pass + * more than one scanline at a time if that's more convenient. + */ row_pointer[0] = & image_buffer[cinfo.next_scanline * row_stride]; (void) jpeg_write_scanlines(&cinfo, row_pointer, 1); } @@ -188,7 +192,7 @@ write_JPEG_file (char * filename, int quality) * (If you don't know what that's for, you don't need it.) * * If the compressor requires full-image buffers (for entropy-coding - * optimization or a noninterleaved JPEG file), it will create temporary + * optimization or a multi-scan JPEG file), it will create temporary * files for anything that doesn't fit within the maximum-memory setting. * (Note that temp files are NOT needed if you use the default parameters.) * On some systems you may need to set up a signal handler to ensure that @@ -342,7 +346,10 @@ read_JPEG_file (char * filename) /* Step 5: Start decompressor */ - jpeg_start_decompress(&cinfo); + (void) jpeg_start_decompress(&cinfo); + /* We can ignore the return value since suspension is not possible + * with the stdio data source. + */ /* We may need to do some setup of our own at this point before reading * the data. After jpeg_start_decompress() we have the correct scaled @@ -363,6 +370,10 @@ read_JPEG_file (char * filename) * loop counter, so that we don't have to keep track ourselves. */ while (cinfo.output_scanline < cinfo.output_height) { + /* jpeg_read_scanlines expects an array of pointers to scanlines. + * Here the array is only one element long, but you could ask for + * more than one scanline at a time if that's more convenient. + */ (void) jpeg_read_scanlines(&cinfo, buffer, 1); /* Assume put_scanline_someplace wants a pointer and sample count. */ put_scanline_someplace(buffer[0], row_stride); |