raw manipulation of #image data possible?

mskuma · Post by **mskuma** » Mon Oct 30, 2006 10:52 am

If I write something like this

  StartDrawing(ImageOutput(#ImgText)) 
    Box(0,0,40,25,#Black) 
    DrawText(10,10,"Hello",#White) 
  StopDrawing()

Can I later access & manipulate the raw image data (RGBA) in anyway? Thanks.

Trond · Post by **Trond** » Mon Oct 30, 2006 11:47 am

You can use Windows API:

Code: Select all

Bmp.BITMAP
GetObject_(ImageID(#Image), SizeOf(BITMAP), @Bmp)
MemoryBuffer = Bmp\bmBits

mskuma · Post by **mskuma** » Mon Oct 30, 2006 12:03 pm

I tried that but got a null pointer. Isn't that valid only after loading a bitmap from a file?

srod · Post by **srod** » Mon Oct 30, 2006 12:14 pm

Could try GetDiBits_() and SetDiBits_().

venom · Post by **venom** » Mon Oct 30, 2006 12:22 pm

DrawingBuffer()? Not sure if it works with images though.

mskuma · Post by **mskuma** » Mon Oct 30, 2006 12:48 pm

Thanks folks for your reply - looks like GetDiBits_() and SetDiBits_() is the ticket. Thanks srod.

srod · Post by **srod** » Mon Oct 30, 2006 1:11 pm

I'm not sure about the alpha channel though?

Using GetDIBits_() with #DIB_RGB_COLORS, seems to only account for the usual 3 channels. Not sure if it will return the alpha channel as such as I have little experience with such things. In fact I don't know how Windows handles alpha-channels, if indeed it does at all?

netmaestro · Post by **netmaestro** » Mon Oct 30, 2006 1:16 pm

Have a look at Trond's BlitImageTranslucent routine, found here:

http://www.purebasic.fr/english/viewtop ... 92&start=5