(v13) Rendering band by band

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

In a single-processor Harlequin RIP, the renderer tackles each band in turn, rasterizing the appropriate elements of the display list into the final output band ready for compression and/or delivery to the page-buffer or output device.

If the RIP runs out of memory to store its display list, it can perform a partial paint . This involves invoking the renderer to rasterize all the bands of the display list so far, writing away the Raster via the page-buffer device (for example, to disk). The display list is then truncated so that new elements can once again be added as page interpretation continues. After a partial-paint subsequent rendering of any further elements of the display list involves reading back the partly rasterized band from the page-buffer device before merging in the newly rendered raster.

Any compositing necessary for transparent areas is performed before rasterization. (The additional complications of partial paint with transparency a are not described here.)

In a multi-processor Harlequin RIP, several bands can be rendered simultaneously by separate threads. The Harlequin RIP always writes bands in order, from the top of the raster to the bottom.