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Alex95

Linear Gradient - unexpected noise

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Hi,

 

Tool Linear Gradient: no repeat, color mode, antialiasing enabled, normal blending.

primary color - white - alpha is zero

secondary - white alpha - 100%

 

Original image:

post-135365-0-76614800-1400774240_thumb.

 

Gradient from left to white. In the middle of image.

( I used Ctrl key in order to create horizontal gradient).

post-135365-0-85064200-1400774350_thumb.

 

Looks fine, however, right part is not solid white.There are a lot of non white dots, especially in the right bottom.  Pixels can be RGB(255,255,254) or even RGB(252,252,253).

I can imagine that 254 may be caused by rounding errors, but 252 is very strange.

 

Not sure how this tool works in 3.5, but I think it was fine. I quite often use Magic Wand with zero tolerance in order to select white areas and never had problems.

Now this tool does not work after gradient in my case.

 

In gimp this tool works as expected.

 

 

Thanks,

Alex

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This may be a case where the R,G,and B values of a pixel are "undefined" when alpha is 0.

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If that's what I think it is, then it's actually a feature, not a bug. Disabling anti-aliasing should get rid of the noise.

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No, I still think gradient does not work properly. But suggestion may help to do what I need.

See another image. This was screenshot of Paint.Net itself.

post-135365-0-89936500-1400792426_thumb.

 

I've tried horizontal linear gradient. From RGBA(255,255,255,0) to RGBA(255,255,255,255). Start , End are shown on screenshot.

1. Left part is not affected by gradient - this is fine, alpha is zero.

2. Middle part - I see some noise on screenshot, not sure is this right or not - probably you are trying to achieve better quality and avoid vertical lines. If yes, I'm fine with that. Looks good.

3. Right part - should be fully white, without noise. This is what I expect.

Open this image in Paint.Net, zoom and check area where the status bar was. Colors there are in range from 253 to 255. In rest parts colors jumping from 254 to 255.

 

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