Color interleaving methods

This page applies to Harlequin v13.1r0 and later; both Harlequin Core and Harlequin MultiRIP.

For monochrome output, each pixel simply follows the previous one in the raster. For color, however, there are various possible methods of interleaving pixels; which method is used depends on the characteristics of the output device. The Harlequin RIP supports interleaving of multi-bit color data and band interleaving for single-bit rasters. For other single-bit formats, color separations must be used.

• Pixel interleaved: all of the color components of a color pixel are adjacent in the raster. The Harlequin RIP currently only supports pixel interleaving for contone color data.
• Line interleaved: a whole scanline of one color component is followed by a line of the next color component, and so on. (The Harlequin RIP does not produce line interleaved rasters directly, but if they are required, lines of each color can be extracted from band interleaved format).
• Band interleaved: a band’s worth of one component is followed by a band of the second component and so on. (A band is a group of contiguous scan lines, of some fixed size.) This is supported for both contone and halftone data. The number of scanlines in a band may be different from page to page, and the last band on each page typically has a different number of lines from the others.
• Frame interleaved: a whole page’s worth of one color component is delivered before any of the second component. This is essentially the same as color separations, except that the whole page is treated as one unit.

This figure shows the different methods of interleaving for 3-component output, such as RGB output.

Pixel interleaved

Line interleaved

Frame interleaved

These interleavings all contain the same amount of data: 252 small squares representing 7 lines x 12 pixels x 3 components. Each small square represents one component of one pixel, with each shade of gray (including white) representing a different component. The different arrangement for pixel-interleaved data emphasizes the way in which the data corresponds to the lines in the final image.

The layout in memory can be slightly more complex than the diagrams, particularly at the end of a band-interleaved page, but this is a topic more relevant to raster backends (see Raster layouts) and plugins (see Delivery and format of the output data).