chiu@efi.com (Chan Chiu) (11/02/90)
Hi net : My application is color image editing and display software. Typically, we have minimum of 24-bit pixmap with fairly size (>1 Meg). And, we have a few active pixmaps (~ 5-10). And, all these images, we may also want the application to do the editting (change color) and scrolling. All these requirements seem to slow down the performance. Questions: 1, Should I have pixmap of window's viewport size ? When scrooling, just change to content of pixmap ? 2, Or, Should I just create pixmap of its natural size and have the scroll window to do the scrolling ? Of course, the pixmap size can be very large (tiff image). 3, What are some other tricks can be used to both conserve memory requirents and improve the performance ? Thanks. /CC
cflatter@ZIA.AOC.NRAO.EDU (Chris Flatters) (11/03/90)
> My application is color image editing and display software. Typically, > we have minimum of 24-bit pixmap with fairly size (>1 Meg). And, we have > a few active pixmaps (~ 5-10). And, all these images, we may also > want the application to do the editting (change color) and scrolling. > > All these requirements seem to slow down the performance. Questions: > > 1, Should I have pixmap of window's viewport size ? When scrooling, > just change to content of pixmap ? > 2, Or, Should I just create pixmap of its natural size and have > the scroll window to do the scrolling ? Of course, the pixmap > size can be very large (tiff image). > 3, What are some other tricks can be used to both conserve memory > requirents and improve the performance ? If you have plenty of memory on your server option 2 should give better performance than option 1. This is because the client must retransmit the viewable portion of the image to the server every time you change the scroll parameters in option 1 while the whole image is kept in server memory space in option 2. However you may not see a significant difference in performance unless you have a graphics accelerator and, even then, you may run into paging problems. You might also consider using the shared memory extension if it is available to you. Chris Flatters