Hi Nigel, Thankyou so very very much mate. This really fixed up the colour issues i was having - really can't thank you enough for pointing this out, it was eluding me for a long time (and probably would have continued to), but as soon as you mentioned it, it makes perfect sense of course :)
I owe you a drink whenever you are in Sydney mate :) cheers, simran. On Thu, Jul 7, 2016 at 11:43 AM, Nigel Tao <nigel...@golang.org> wrote: > On Mon, Jul 4, 2016 at 2:50 PM, simran <simrangamb...@gmail.com> wrote: > > Interestingly though, when i do a colour swap (without any type casting > happening now) - the colour problem is still there. > > https://github.com/simran91/monkeysee/blob/master/mimage/mimage.go says: > > r, g, b, a := colour.RGBA() > column[y] = color.RGBA{uint8(r), uint8(g), uint8(b), uint8(a)} > > Don't do that. As https://blog.golang.org/go-image-package says, > "There are three important subtleties about the return values... > Second, the channels have a 16-bit effective range: 100% red is > represented by RGBA returning an r of 65535, not 255." > > Thus, when creating an color.RGBA value, you want the high 8 bits, not > the low 8 bits. That second line should be: > > column[y] = color.RGBA{uint8(r>>8), uint8(g>>8), uint8(b>>8), uint8(a>>8)} > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
