Hi. > Does anyone know how to scroll a huge picture resource fast. The pictures > are 32000 pixels high or more. The widths are less than a 1000 pixels. I > need to scroll the picture up and down, left and right based on the use of > scroll bars. I havent been able to come up with an algorithm that will > quickly scroll the pictures. Currently I check the delta of the scroll bar > value and redraw the picture in the window. > > I tried drawing the picture into a gworld and drawing the scroll picture > into the window using the gworld. The drawing was just as slow if not > slower. The memory requirements went through the roof when I started using > gworlds. (1) Make gworld on VRAM. I will be possible with NewNewGWorld (?) Toolbox. (2) Check the depth of gworld and monitor (Graphics Device) (3) If you use CopyBits(), try Fdecompress QuickTime Toolbox, too. This procesure draws picture sometimes faster than CopyBits and sometimes slower. You will find demo code on icefloe at Apple's developer web site.