On 22 May 2004, Sven Neumann wrote: > So this API would allow you to queue a redraw even after the buffer is > only halfway written. Of course you would also have to run the main > loop for the redraw to actually happen. Anyway, I consider this rather > bad style. IMO, if the preview takes considerable time, then it > shouldn't be shown halfway done but instead the progress API should be > used to draw a progress indicator in place of the preview. What do > others think? There are a lot of image applications that perodically update the preview. In fact, this is essentially what the gimp color balance tools do -- load a large image and adjust the sliders intermittantly and you can watch the previews go by. There are good arguments for incremental update, and good arguments for a progressbar. Superimposing a busy cursor over the preview or replacing it with a progress indicator makes judging between slight differences in the settings harder. But I think the real issue here is that slow previews should be computed in small chunks in an idle handler so as to not impede interactivity. Rockwalrus
