Some time ago we had a discussion about the rendering of palette
images, dithering, etc. Today I looked for the jira issue for this, but
I did not find one. Is there none, or did I search badly?
I would like to add the special case I was thinking of lately, while
creating coverages specially for displaying them in Google Earth, which
wants gifs. Special case would be this
1. input coverageStore is a palette image (png8, gif, sld palette with
<256 items)
2. wms request is for only that layer
3. wms imagetype is palette (gif or png8)
In this case, the entire rendering chain could maintain the palette of
the input image, which would allow for a simple dithering optimization
by users. Currently if I want to display e.g. grayscale (radar) images
as gif, I get all kinds of fancy pastel colors because geoserver's
palette is fixed. I could easily convert these images to palette
locally, and add these as CoverageStore to geoserver. Because in GE I'd
do only 1-layer requests, theoretically geoserver could just keep the
original palette and thus have much better output images.
I have no idea if this is feasibly code-wise...