bitblt and memory DC

[jsbach]

Hi all,

I posted this thread to the API forum but didn't get any response so I thought it might be a good idea to repost it here.
Currently I'm working on a program that makes an extensive use of bitblt Api function to copy images from one picture box to another.

My questions are:
1. Will the copying be significantly faster if I'll use memory DC for storing the source picture? (by using CreatCompaibleDC and LoadImage Api functions), and
2. I would like to hide the picture files from the user, so is there a way to load the pictures to the memory DC from a picture box rather then in a file?
Any help or a piece of code will be greatly appreciated.

[toughcoder]

hi bach,
well the loadImage+Create.... will significantly boost performance but it must be used with care. U must consider ur client specifications also. If any1 using a 32 MB ram sys gets using loadimage, chances r the function will return a -ve value(a failed function) and the image doesnt load. This wil effect the app. So its better to use a pixBox.
for ur second query, u can blit a pix from a pixBox to a DC. That will help not loading a pix from file.

[jsbach]

Hi toughcoder,
After I posted this thread I made some tests to see how faster is bitbliting from a memory DC
vs picture box. surprisingly, all tests showed that there are not any advantage to memory DC over
picture box when speed is in concern. Apparently in both method the data is being read directly
from memory. If you want I'll post the code I used for testing.
As for the other one, I guess it can be worked out this way.
Thanks allot!