Can transparency be made variable in COLR font

mitradranirban
mitradranirban
edited February 2025 in Font Technology
Say I have 3 layers in a color pallette CPAL table. Can their alpha values be modifiable accross desingnspace ?
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Comments

  • Thomas Phinney
    Thomas Phinney
    Yes, in COLR/CPAL v1, but not in v0.

    The alpha value is just another channel, one of the 4 in each ColorRecord in CPAL. The v1 version of COLR and CPAL allows you to vary the colors across the designspace, which includes the alpha (transparency) value as well as R, G and B.
  • Peter Constable
    Peter Constable
    Clarifying a bit from what Tom said: in COLR v1, the RGBA values of a CPAL entry are not variable, but the wherever a CPAL entry is referenced there is a separate alpha value that can be variable. Also, when using a gradient, the placement of the gradient and the position of colour stops along the colour line of the gradient can be variable, which provide some ways to make the colour of certain pixels variable.
  • Yves Michel
    Yves Michel
    A question on the matter of COLR v1 fonts: Is it worth to create this kind of font ?
    I like their ability to include gradients but it seems not many software support them. Affinity doesn't. MS Word does.

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