possible bug IM 7.0.8.46 -alpha deactivate/activate

Post any defects you find in the released or beta versions of the ImageMagick software here. Include the ImageMagick version, OS, and any command-line required to reproduce the problem. Got a patch for a bug? Post it here.
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fmw42
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possible bug IM 7.0.8.46 -alpha deactivate/activate

Post by fmw42 » 2019-05-23T07:48:16-07:00

From the porting guide:
-alpha activate/deactivate
enables and disables the alpha channel, respectively, with persistence. This is like on/off in Imagemagick 6. In Imagemagick 7, -alpha off will remove the alpha channel permanently such that -alpha on will not re-enable it.
But that does not work in IM 7.

Input:
Image

IM 7.0.8.46

Code: Select all

magick text.png -alpha deactivate -blur 0x6 -shade 135x5 -alpha activate -normalize +level 30% shaded7.png
Image


IM 6.9.10.46

Code: Select all

convert text.png -alpha off -blur 0x6 -shade 135x5 -alpha on -normalize +level 30% shaded6.png
Image

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magick
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Re: possible bug IM 7.0.8.46 -alpha deactivate/activate

Post by magick » 2019-05-23T18:22:38-07:00

Grab the latest beta (building now). This command works for both IMv6 and IMv7:

Code: Select all

convert text.png -alpha deactivate -blur 0x6 -shade 135x5 -normalize +level 30% -alpha activate shaded7.png
There is a slight difference in shading. You can change the intensity to Rec609 and the results should match.

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fmw42
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Re: possible bug IM 7.0.8.46 -alpha deactivate/activate

Post by fmw42 » 2019-05-24T17:06:44-07:00

In IM 7.0.8.47 beta Q16 Mac OSX, this command produce no bevel from the -shade as it should in comparison to the IM 6 result above.

Code: Select all

magick text.png -alpha deactivate -blur 0x6 -shade 135x5 -normalize +level 30% -alpha activate shaded7a.png
Image

So there is still an issue.



Understood about the colorspace. IM 6 uses Rec601luma and IM 7 use Rec709luma. So you meant to say use -intensity Rec601luma to make IM 7 reproduce IM 6 results.

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magick
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Re: possible bug IM 7.0.8.46 -alpha deactivate/activate

Post by magick » 2019-05-25T13:23:18-07:00

Try now. We built a new Beta release.

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Re: possible bug IM 7.0.8.46 -alpha deactivate/activate

Post by fmw42 » 2019-05-25T14:34:53-07:00

Yes. It seems to work fine now in the 7.0.8.47 beta. Thanks

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