Hi Rajesh,

Thank for the link. The gpimage.prg is definitely more than what I need. I have scanned through the coding of the Capture and SaveAsJPEG methods. It seems to me that the Capture method is using BitBlt to capture the image of the Desktop, which I believe is considered as a bitmap, to a newly created bitmap. Then GdipCreateBitmapFromHBITMAP is used to create another bitmap from the handle of the newly created bitmap. SaveAsJPEG just simply encode the last bitmap into JPEG format. I hope you can clarify some points regarding this process:

1. Can we just encode the Desktop into JPEG directly?
2. What is the difference between the source bitmap and destination bitmap used by the BitBlt function?
3. Why do we need to create another bitmap using GdipCreateBitmapFromHBITMAP?
4. Does HBITMAP always stand for handle of a bitmap?

As you can tell, I'm not familiar with GDI or GDI+ at all.


Thank you for your help.