-3

It is normal to create a white color whose alpha is 255.

enter image description here

Is it possible to create a white color whose alpha is 0 ?If so,how to do?

showkey
  • 482
  • 42
  • 140
  • 295
  • This is more of a usage question than a programming question - this explains the downvotes. And it's likely also answered on other parts opf the StackExchange network already, likely SuperUser or the Graphic Design SE. – Michael Schumacher Dec 05 '16 at 13:47

1 Answers1

0

There are color selectors that have an additional alpha value but AFAIK they are only used to set color values to render channels and "quickmask" when these are made visible.

To paint "manually" with a given opacity you set the opacity on the tool (opacity slider in the Tool options dialog). Programmatically things are a bit more complex and only the bucket-fill API seems to directly support an opacity, but you can always paint on another layer and set the opacity of that layer (gimp-layer-set-opacity).

xenoid
  • 8,396
  • 3
  • 23
  • 49
  • If more than one layer is involved, you will likely not get anything but transparent black, though - GIMP does not make any promises about the colors for transparent pixels, in general.. – Michael Schumacher Dec 05 '16 at 13:34