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Re: Several suggestions for image support
From: |
Kim F. Storm |
Subject: |
Re: Several suggestions for image support |
Date: |
21 Apr 2004 03:08:26 +0200 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.3.50 |
David Kastrup <address@hidden> writes:
> PNG images support transparency. Emacs can't make use of it. You can
> only have Emacs declare a particular color as transparent. This is
> dissatisfactory. It should tell the PNG decoding routines Emacs'
> background color for the purpose of transparency.
>
> I would find it important if an image specifier could restrict the
> displayed portion of an image.
I have just implemented image slicing via a new slice property:
display ((slice X Y WIDTH HEIGHT) (image ...))
I have installed changes for W32 and MAC ports also, but as usual I
have no way to test if they actually do something sensible.
>
> The reason is that large images always appear as a single big
> character to Emacs. If I could split such an image into a bunch of
> smaller images, I could walk through it with the cursor. But it
> should only be necessary to instantiate the complete image itself once
> for this purpose. Of course, one should find a way that does not
> cause all of the subimages to be entered separately into the image
> cache.
Try this with http://www.w3.org/Graphics/PNG/alphatest.png :
(setq im (create-image "alphatest.png" nil nil))
(insert "\n")
(insert-sliced-image im nil nil 5 4)
(insert "\n")
Note on XPM images:
There are severe problems with sliced XPM images, at least on X.
The clip mask for each slice is taken from top/leftmost part of the
image, rather than the actual slice of the image. I have tried a
zillion things to setup the clip mask (and rewrite other parts of the
code) to make this work, but to no avail.
So I hereby ask for help from more skilled X people. How do you setup
the clip mask of an image with an image mask so that XCopyArea will
use the corresponding part of the image mask when copying a slice from
the image ?
Here is some code to illustrate the bug:
(setq im2 (create-image "etc/gnus.png" nil nil))
(insert "\n")
(insert-sliced-image im2 nil nil 5 4)
(insert "\n")
--
Kim F. Storm <address@hidden> http://www.cua.dk
Re: Several suggestions for image support, Werner LEMBERG, 2004/04/17
Re: Several suggestions for image support,
Kim F. Storm <=
Re: Several suggestions for image support, Kim F. Storm, 2004/04/22
Re: Several suggestions for image support, David Kastrup, 2004/04/22
Re: Several suggestions for image support, Kim F. Storm, 2004/04/23