reference: Add Color

[gaocegege]

Signed-off-by: Ce Gao [email protected]

[gaocegege]

I can't find the laDefense.jpg...

PImage img;
img = loadImage("laDefense.jpg");
background(img);

[jeremydouglass]

Was the issue with laDefense.jpg ever resolved?

https://github.com/processing/processing-docs/search?utf8=%E2%9C%93&q=laDefense.jpg&type=

If not, submit the question to processing-docs issues.

[jeremydouglass]

Did you ever find laDefense.jpg? If not, did you submit an issue to processing-docs?

[gaocegege]

I haven't. OK, I will file an issue.

[jeremydouglass]

Great, thanks!

If we don't have it, are we also skipping the end-to-end tests on examples that would use it? e.g. background:

• examples/reference/background/background3/background3.rpde
• https://processing-r.github.io/reference/background.html