Return png images as G or GA instead of RGBA?

[perlman]

Some endpoints, e.g. /png-image, return data as RGBA (specifically, "PNG image data, 1024 x 1024, 8-bit/color RGBA, non-interlaced").

I am considering adding flags to force grayscale and/or disable transparency for PNG output. (The PNG format supports both G and GA at both 8- and 16-bit depths.)

Is this a reasonable approach?

[perlman]

This is from playing around with support for 16-bit PNG output:
https://github.com/neurodata/render/blob/png16/render-ws/src/main/java/org/janelia/render/service/util/BufferedImageStreamingOutput.java

[trautmane]

Hi Eric,
Apologies for my delayed response.
This looks reasonable to me - kudos for digging into the https://github.com/leonbloy/pngj library details.
Did it work for you?
-- Eric T.

[perlman]

The 16-bit grayscale PNG output is working well.

I have not touched 8-bit output yet. I don't want to break RGBA support for those that use it...