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bug or feature of -draw IM 6.5.4.-7 Q16

Posted: 2009-08-04T09:30:27-07:00
by fmw42
Mac OSX Tiger IM 6.5.4.-7 Q16 (HDRI)

just wondering if this is a bug or just the way things need to work.

When I do:

convert -size 256x256 xc:black -fill white \
-draw "line 121,128 135,128" motion15.png

and then check the verbose info:

I see that there is a fully opaque alpha channel left on. Is there some reason for leaving an opaque alpha channel on and not have it automatically disabled?

This relates to the FFT blurring and deblurring and the need to use -alpha off before -compose minus in my scripts. Alternately, I will turn of the alpha channel on the image above before using it.

Re: bug or feature of -draw IM 6.5.4.-7 Q16

Posted: 2009-08-04T10:04:08-07:00
by magick
  • just wondering if this is a bug or just the way things need to work.
Drawing is performed in RGBA space and its up to the user to disable the alpha-channel with -alpha off if that is their preference.

Re: bug or feature of -draw IM 6.5.4.-7 Q16

Posted: 2009-08-04T10:57:34-07:00
by fmw42
OK. I guess because of the possibility of using -matte in the commands that you need to leave the alpha channel on. Makes sense.