| Re: Rotating a Pixmap? [message #22879] |
Wed, 13 December 2000 10:31  |
efrans
Messages: 8
Registered: June 2000
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Junior Member |
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Ben Tupper <btupper@bigelow.org> replied:
>
>
> efrans@my-deja.com wrote:
>>
>> I have copied an image from a window into a pixmap. Now I'd like to
>> rotate the pixmap before I copy it into a different window. How is
this
>> done?
>>
>
> Hello,
>
> I think that you will need to take a snapshot of the pixmap (or the
> original window), storing it into an array, using TVRD(). Then you
can
> fiddle with the orientation of the image before redisplaying it else
> where.
Thanks Ben. Initially I was planning on using TVRD() instead of a
pixmap, but I got fed up because I couldn't get the *color* image to
display correctly after the rotation. After consulting the ever useful
David Fanning site, I found the section "What Can Be Done?" on the
"Strange TVRD Results":
http://www.dfanning.com/tips/strange_tvrd.html
My problem was that I followed the golden rule of setting DEVICE,
DECOMPOSED=0, but I forgot to set DEVICE, DECOMPOSED=1 before displaying
the rotated color image!
Here is an example:
PRO tvcolor
image = BYTARR(256,256)
image[*,*] = INDGEN(256,256)
WINDOW, 0, XSIZE=256, YSIZE=256
DEVICE, DECOMPOSED=0
LOADCT, 33
TV, image
image2 = TVRD(TRUE=1)
; rotate 90 degrees ccw
FOR i=0,2 DO image2[i,*,*] = ROTATE(REFORM(image2[i,*,*]),1)
WINDOW, 1, XSIZE=256, YSIZE=256
DEVICE, DECOMPOSED=1 ; <--- the key
TV, image2, TRUE=1
END
- Eric Frans
Sent via Deja.com
http://www.deja.com/
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