High banding in the gradients generated by gg about gg HOT 6 OPEN

@fogleman Could you help us with this? Is there anything we must do to ensure less banding in the gradients generated.

This is a great library for generating gradients since its very simple and intuitive. It's unfortunate that we get such high banding.

from gg.

Can you post code and an image showing the effect? I don't see an issue in the gradient examples.

from gg.

grad := gg.NewLinearGradient(0, 0, 1920, 0)
	grad.AddColorStop(0, color.RGBA{0, 0, 0, 200})
	grad.AddColorStop(1, color.RGBA{0, 0, 0, 128})

	dc.SetFillStyle(grad)
	dc.MoveTo(0, 0)
	dc.LineTo(1920, 0)
	dc.LineTo(1920, 1080)
	dc.LineTo(0, 1080)
	dc.ClosePath()
	dc.Fill()
	gradientOverlay := dc.Image()
	imaging.Save(gradientOverlay, "out.png")

from gg.

Well the only way to improve that would be to go to a 16-bit image.

Currently gg only does 8-bit. It wouldn't be too hard to do 16-bit but might be API-breaking.

from gg.

Oh alright! Is it possible to create a v2 package? I am also happy to help through PRs if you can give me an overview of the places that require changing.

from gg.

It would start by changing RGBA -> NRGBA64 and Alpha -> Alpha16 throughout the code.

But it might not actually be so easy. The freetype/raster package which gg is built upon only seems to support RGBA and Alpha.

https://github.com/golang/freetype/blob/master/raster/paint.go

from gg.