Jay Smith wrote:
> Using Gimp 2.6.6 on Ubuntu 8.04 (Hardy) Linux.
> We are testing using Gimp to replace Photoshop on Windoze. However, we
> are hitting one problem/feature we have not been able to resolve.
> We scan images of postage stamps (using xsane from inside gimp). There
> are multiple postage stamps are on a black background. Some of them are
> a little crooked and need to be rotated.
> We CAN rotate them as desired, but are ending up with unwanted white
> triangles at the corners.
> We have set the background color to black (and tried changing foreground
> too). Then reselecting and rotating. No difference.
> In the preferences on file creation, for background, there are setting
> choices for white, transparent, foreground color, or background color --
> but NOT black (unlike Photoshop). Not sure if this is the problem.
> When the image is created, coming in from xsane, there is only one layer.
> - Scanned using xsane from inside gimp: multiple postage stamps on a
> black background.
> - Set background color to black.
> - Draw selection around ONE stamp and use rotate tool by dragging the
> grid around.
> Direction = corrective; grid on -- works as desired (but gets
> white triangles)
> Transform (in the rotate tool palette)
> - tried Layer (works but gets white triangles)
> - tried Selection (just rotates the selection box and not any
> part of the picture -- that is very odd!!! -- does this not
> work or do I not understand what it is supposed to do??)
> Clipping -- is set to Adjust, but also tried the other settings
> all of which still end up with white areas.
> I understand that I could draw selections around the various unwanted
> white parts and fill with black, but that is a big pain -- we scan
> thousands of such images and would thus have to do 4x thousands of fills.
> Is Gimp unable to auto-fill those background areas? Or do I not have
> something setup correctly?
> Is the problem related to the way in which we acquire the image in the
> first place?
> What am I missing????
> This is automatic in Photoshop (as long as the background is set to
> black), so I assume that Gimp would do it even better.
There's probably a better solution to this, but if you add an alpha
channel to the image before rotating the selection, then instead of
white triangles you'll get transparent sections and you can add a black
layer below to fill them in.
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