Heatmap opacity - Githubissues

lucasb-eyer / libheatmap

High performance C heatmap generation library. Supposed to be wrapped by higher-level languages.

MIT License

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Closed Grabber closed 11 years ago

Grabber commented 11 years ago

Dear Lucas,

How we could improve your outstanding work to allow us to set the heatmap opacity?

Hugs, Luiz VItor.

lucasb-eyer commented 11 years ago

Dear Luiz,

This can be done in three different ways:

use a colorscheme in which every color is translucent,
change the alpha channel of the resulting heatmap in a post-processing step, or
modify heatmap_render_saturated_to to change the alpha value (e.g. colorline[3] /= 2;) after the call to memcpy.

Cheers.