subchannel-get
Synopsis
(subchannel-get colormap)
Parameters
- colormap
Description
Side Effects
Return Value
The steganographic subchannel of the colormap is returned as a bitmap.
Example
Here is a test image (horses.jpg, JPG, 2400x1600):
> (define image (colormap-readjpg "horses.jpg"))
image
> (define subchannel (subchannel-get image))
subchannel
> subchannel
#<bitmap orow:-1 ocol:-1 xres:-1 yres:-1 w:2400 h:1600>
> (bitmap-writepng subchannel "horses-subchannel1.png")
ok
>
The subchannel as written to the PNG file horses-subchannel1.png displays as follows:
