Convert Image to Greyscale

[ab623]

I have looked everywhere for an answer to this, apparently its not a problem that has ever existed, or its so easy that noone has asked a question on it!

I have the following code which I would have though would scale the image to greyscale (based on a standard scaling formula), however it come out with a green tint. I have tried multiple approaches but not found anything that seems to easily greyscale the image.

func (s *screen) Draw(screen *ebiten.Image) {
	op := &ebiten.DrawImageOptions{}
	op.ColorScale.Scale(0.299, 0.587, 0.114, 1)

	screen.DrawImage(s.currentImage, op)
}

Any suggestions?

[hajimehoshi]

You can use ColorM.

https://pkg.go.dev/github.com/hajimehoshi/ebiten/v2/colorm#ColorM.ChangeHSV

op.ColorM.ChangeHSV(0, 0, 1)

See also examples/hsv

[ab623]

Thank you!

That has solved the issue. Although ColorM is being depreciated from ebiten.DrawImageOptions, so I am using the colorm packaged instead.

For anyone in future that has the same issue and would like the see the updated code, I have pasted it below.

func (s *screen) Draw(screen *ebiten.Image) {
	op := &colorm.DrawImageOptions{}

	var c colorm.ColorM
	c.ChangeHSV(0, 0, 1)

	colorm.DrawImage(screen, s.currentImage, c, op)
}