Lexmark Optra C710 Technical Reference - Page 76

2-65 PCL Group 3 and Group 4 Raster Compression Since Group 4 images do not use line endings, the width of the image must be specified using the Raster Width command (ESC*r#S). The compressed image data is sent to the printer using the Transfer Raster Data command (ESC*b#W). The maximum number of bytes that can be sent using the Transfer Raster Data command is 32K bytes. Images larger than 32K bytes must be broken up and sent using multiple commands. It does not matter where the image is broken, or how many Transfer Raster Data commands are used. Once the image is started (with a Transfer Raster Data command), no other commands are allowed until the entire image has been sent. The following example prints a Group 4 image file that is 256 bits wide and 9,645 bytes long: ESC*b1002M ESC*r256S ESC*r1A ESC*b9645W ...[Group 4 image data]... ESC*rB |Set Raster Compression to Group 4 |Define width of image in input bits |Start Raster Graphics at current position |9,645 bytes of a Group 4 image |End Raster Graphics All lines of data must be the same length. If they are not, zeroes (0) must be added to attain the same length. Note: If the uncompressed image extends beyond the logical page dimensions or beyond the raster width specified in the Raster Width command (ESC*r#S), the image is clipped at print time. Additional Compression Modes When the compression mode is 1008 (Lexmark Adaptive), TIFF word and doubleword can be printed using compression scan modes 254 and 255 respectively. This compression method sends a raster image as a block of raster data.