Legacy ImageMagick Discussions Archive

https://i.imgur.com/FRqephU.jpg

Any tips on achieving this output?

I do not know RMagick, but perhaps you can convert from the following command lines. I had to crop out your input image. It would be best in the future if you provide two separate images. Also always provide your IM version and platform. See viewtopic.php?f=1&t=9620

Code: Select all

size=`convert FRqephU.png -format "%wx%h" info:`
ww=`echo $size | cut -dx -f1`
hh=`echo $size | cut -dx -f2`
p1=0,0
p2="$((ww-1)),0"
p3="0,$((hh-1))"
echo "p1=$p1; p2=$p2; p3=$p3;"
convert FRqephU.png \
\( -clone 0 -colorspace gray \) \
\( -clone 0 -fill black -colorize 100 \
-fill white -draw "polygon $p1 $p2 $p3" \) \
-alpha off -compose over -composite result.png

Thanks so much. That's pretty close to what I need; it's just coming out a bit dark. How would I go about making the result lighter?

https://imgur.com/a/n4LgP - here's an album (original, expected, actual).

I really appreciate the help. Are you Fred?

Yes, Fred here.

What version of Imagemagick and what platform are you using? Please always provide that information since syntax and IM may work differently. see viewtopic.php?f=1&t=9620

Your problem may be due to older versions of IM using linear grayscale rather than sRGB or when RGB and sRGB were reversed.

Since I do not know what version of IM you are using try one of the following:

Code: Select all

size=`convert FRqephU.png -format "%wx%h" info:`
ww=`echo $size | cut -dx -f1`
hh=`echo $size | cut -dx -f2`
p1=0,0
p2="$((ww-1)),0"
p3="0,$((hh-1))"
echo "p1=$p1; p2=$p2; p3=$p3;"
convert FRqephU.png \
\( -clone 0 -set colorspace RGB -colorspace gray \) \
\( -clone 0 -fill black -colorize 100 \
-fill white -draw "polygon $p1 $p2 $p3" \) \
-alpha off -compose over -composite result.png

Code: Select all

size=`convert FRqephU.png -format "%wx%h" info:`
ww=`echo $size | cut -dx -f1`
hh=`echo $size | cut -dx -f2`
p1=0,0
p2="$((ww-1)),0"
p3="0,$((hh-1))"
echo "p1=$p1; p2=$p2; p3=$p3;"
convert FRqephU.png \
\( -clone 0 -set colorspace sRGB -colorspace gray \) \
\( -clone 0 -fill black -colorize 100 \
-fill white -draw "polygon $p1 $p2 $p3" \) \
-alpha off -compose over -composite result.png

Code: Select all

size=`convert FRqephU.png -format "%wx%h" info:`
ww=`echo $size | cut -dx -f1`
hh=`echo $size | cut -dx -f2`
p1=0,0
p2="$((ww-1)),0"
p3="0,$((hh-1))"
echo "p1=$p1; p2=$p2; p3=$p3;"
convert FRqephU.png \
\( -clone 0 -grayscale Rec709Luminance \) \
\( -clone 0 -fill black -colorize 100 \
-fill white -draw "polygon $p1 $p2 $p3" \) \
-alpha off -compose over -composite result.png

Code: Select all

size=`convert FRqephU.png -format "%wx%h" info:`
ww=`echo $size | cut -dx -f1`
hh=`echo $size | cut -dx -f2`
p1=0,0
p2="$((ww-1)),0"
p3="0,$((hh-1))"
echo "p1=$p1; p2=$p2; p3=$p3;"
convert FRqephU.png \
\( -clone 0 -grayscale Rec601Luminance \) \
\( -clone 0 -fill black -colorize 100 \
-fill white -draw "polygon $p1 $p2 $p3" \) \
-alpha off -compose over -composite result.png

see viewtopic.php?f=4&t=21269 and http://www.imagemagick.org/script/comma ... #grayscale and http://www.imagemagick.org/script/comma ... #intensity

If none of the above work, then it could be a profile issue. But I won't look into that until I hear back from you.

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