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Scrolling

Although scrolling is a rare occurrence in the Center's dialogues, and almost never part of screen design, it can nevertheless still be needed. PCVideo therefore continues to provide it.

PCVideo under Turbo Pascal supports the multiple-row, upward-only scrolling of rectangular parts of text windows as is supplied by the p-System's PCVideo. To perform under graphics mode it uses Borland graphics' GetImage and PutImage routines. Since these have to allocate the image on the heap before they move it, they are prepared to subdivide the move into successive parts that will fit in memory. So the more memory made available to the running program, the smoother any necessary scrolling is likely to be; but scrolling should nevertheless be safe even on low-memory systems.