private void emit_adobe_app14()
{
/*
* Length of APP14 block (2 bytes)
* Block ID (5 bytes - ASCII "Adobe")
* Version Number (2 bytes - currently 100)
* Flags0 (2 bytes - currently 0)
* Flags1 (2 bytes - currently 0)
* Color transform (1 byte)
*
* Although Adobe TN 5116 mentions Version = 101, all the Adobe files
* now in circulation seem to use Version = 100, so that's what we write.
*
* We write the color transform byte as 1 if the JPEG color space is
* YCbCr, 2 if it's YCCK, 0 otherwise. Adobe's definition has to do with
* whether the encoder performed a transformation, which is pretty useless.
*/
emit_marker(JPEG_MARKER.APP14);
emit_2bytes(2 + 5 + 2 + 2 + 2 + 1); /* length */
emit_byte(0x41); /* Identifier: ASCII "Adobe" */
emit_byte(0x64);
emit_byte(0x6F);
emit_byte(0x62);
emit_byte(0x65);
emit_2bytes(100); /* Version */
emit_2bytes(0); /* Flags0 */
emit_2bytes(0); /* Flags1 */
switch (m_cinfo.m_jpeg_color_space)
{
case J_COLOR_SPACE.JCS_YCbCr:
emit_byte(1); /* Color transform = 1 */
break;
case J_COLOR_SPACE.JCS_YCCK:
emit_byte(2); /* Color transform = 2 */
break;
default:
emit_byte(0); /* Color transform = 0 */
break;
}
}
