get data from gdImagePtr

this may seems offtopic for php developers but not for gd-devs I am doing some vector rendering using libgd. I filled the gdImagePtr with drawpoint/drawline/drawpolygon functions. now if I save the gdImagePtr to some file i will get png/jpeg image. upto here its fine now comes the real problem...... I am using Qt as a front end for displaying image from gd. currently it works like this gdImagePtr --> pngfile --> QPixmap --> Qt I dont want to create a png file everytime the gdImagePtr is update (each zoom/pan will update gdImagePtr) so converting to file and reading again is a overhead in my case I want to show gdImagePtr on QPixmap with all conversion process running on memory. Is that possible in gd? How to pull chunk of data from gdImagePtr? Any will be much appreciated... Thanks in Advance -- Regards, Rashad