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Operating System Specific Discussions => Amiga OS => Amiga OS -- Development => Topic started by: jonssonj on February 21, 2006, 05:31:07 PM

Title: change background color in c-programming
Post by: jonssonj on February 21, 2006, 05:31:07 PM

Hello!

I have opened a custom screen and my own window in c-code. Now I would like to change the background color of the window.

How do I change the background color from the default to white?

BR
JJ

Title: Re: change background color in c-programming
Post by: Piru on February 21, 2006, 08:51:25 PM

@jonssonj

If your window is borderless you can just:

Code: [Select]

SetRast(win->RPort, 2);

However, if your window has borders then you need to account for them:

Code: [Select]


{
  LONG l, t, w, h;

  l = win->BorderLeft;
  t = win->BorderTop;
  w = win->Width - win->BorderLeft - win->BorderRight;
  h = win->Height - win->BorderTop - win->BorderBottom;

  if (w > 0 && h > 0)
  {
    /* White background */
    SetAPen(win->RPort, 2);
    RectFill(win->RPort, l, t, l + w - 1, t + h - 1);

    ...
  }
}


Another possibility is using WA_BackFill and custom backfill hook.

Here's slightly more complex example showing how it is possible to handle custom colour rendering on any public screen: simplewindow.c (http://www.iki.fi/sintonen/src/misc/simplewindow.c)

Title: Re: change background color in c-programming
Post by: jonssonj on February 22, 2006, 10:31:36 AM

Thanks a lot Piru!

I will come back with more questions. I have started a little project just to learn me the Amiga GUI stuff.

BR
JJ