View previous topic :: View next topic |
Author |
Message |
johannes
Joined: 21 Jan 2011 Posts: 65 Location: Leimen, Germany
|
Posted: Wed Oct 10, 2012 2:10 pm Post subject: RGB and alpha channel value |
|
|
Hi all,
bmp files can not only hold the (3) RGB values of a pixel, but also a fourth number, the 'alpha' value (see http://en.wikipedia.org/wiki/Alpha_compositing).
Question: is there a way to extract this number pixel by pixel with FTN95/clearwin ?
johannes |
|
Back to top |
|
|
PaulLaidler Site Admin
Joined: 21 Feb 2005 Posts: 7924 Location: Salford, UK
|
Posted: Wed Oct 10, 2012 8:19 pm Post subject: |
|
|
I guess that it would depend on the context but as far as I know, ClearWin+ only uses 24 bit bitmaps. For a "drawing surface", GET_POINT@ gets the bit value at a given point but I would expect this to be only 24 bit. |
|
Back to top |
|
|
johannes
Joined: 21 Jan 2011 Posts: 65 Location: Leimen, Germany
|
Posted: Thu Oct 11, 2012 9:25 am Post subject: |
|
|
Hi Paul,
I checked my bmp file and indeed found that it is a 32 bit one. Thanks for the hint.
When I try to process it with my current FTN95 code (which works fine for <24 bit bmp), the result is just black. So I think you are right in saying that ClearWin can process only up to 24 bit.
Q to forum: Has anyone else experience with 32 bit bmps? A test file could be provided.
johannes |
|
Back to top |
|
|
|