CocoaDev

If I move an General/NSView programatically (say I have a ball I made by doing an oval in the bounds of the General/NSView subclass, and I move it like this)

    General/NSRect frame = [ball frame];
    frame.origin.x++;
    [ball setFrameOrigin: frame.origin];
    [ball setNeedsDisplay:YES];

This works, but it leaves behind a little trail of the color of the oval drawn. Why? How can I fix this?

Thanks

–General/CharlieMiller

You need to set the area you’ve vacated as needing display too. – Bo

Thanks. This worked.

General/window contentView]setNeedsDisplay:YES];

–[[CharlieMiller

That’s a little like squashing a fly with a piano. It’s probably better to just save the old frame and call General/self superView] setNeedsDisplayInRect:[[NSUnionRect(oldFrame, frame)]; – Bo

Ah, allright. How about this one then, I’m trying to tell where the farthest right part of the window is, by getting the width of the window, but if I ask for the width of [window frame] (window, by the way, is just a reference to the window), it says the width is 0. Odd. Thanks.

–General/CharlieMiller

Dunno. Are you perhaps trying to read it into an int instead of a float?

Yep. (Smacks self in the forehead). Things work now.

I make that mistake at least weekly and usually much more. I really wish there was a compiler warning for this considering that it doesn’t even convert between floats and ints in a mathematically correct fashion unless you coerce it. – Bo

Good lord, that’s horrible. But yeah, I’ve run into that myself… one of my personal prides is that before Jaguar was released, I found a bug in GLUT which led to timers being all screwed due to a conversion between double and int gone awry. – General/RobRix