What does this warning message mean

Permanently deleted user

• March 26, 2020 11:47

I had created a gradient mask and was going to erase part of the mask with a brush. As I started I got a warning message:

Do you want to rasterize the mask?

...This means that you will not be able to edit the parametric mask any longer.

I understand that rasterizing converts the image to pixels but I am not really certain what the ramifications of that are. I've also not heard the term "parametric mask" before and am wondering what it means.

Thanks.

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  Eric Valk

  • March 26, 2020 12:33
  • Edited

  Rasterizing converts the Mask to a table of values for each pixel. There is no impact to the image pixels or to other layers.

  It means you can't go back and change the settings of the gradient mask.

  Parametric Mask means that the strength of the mask at each pixel is determined by a formula. The formula has parameters that determine its result.

  Simplified example:  For a horizontal gradient, suppose that X is the horizontal position of a pixel. The mask strength, M, for each pixel is  M=aX+b, where a and b are the parameters. b is the mask strength at the first pixel. a is how much the mask strength rises for each horizontal pixel. More formally one would write this as M(X), meaning that M changes with X.

  After rasterisation the formula is replaced by a list {M1, M2, M3, M4, ....}

  The actual implementation is more complex because each pixel has an X and a Y postion, the gradient can be both horizontal and vertical, the start position isn't an edge of the image, the end position isn't an edge of the image, the curve might be something more complicated than a straight line, and the user wants to set ending value not the rise per pixel. But its all just algebra.

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  Permanently deleted user

  • March 26, 2020 12:43

  Thanks for the really clear explanation, I did not realize it was layer specific. 

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