On 27/02/2008, at 11:05 AM, Jamie Phelps wrote:
Hey, guys. I'm having what I assume is a simple problem.
[NSBezierPath fillRect:[self bounds]]; fills my NSView subclass fine
the first time drawRect: is called, but breaks the frame on redraw.
Here is some more code for context if needed. I tried adding the
initial background fill to an awakeFromNib: method with no success.
If anyone can offer thoughts on where I'm going wrong I'd appreciate
it.
There are several major problems with your code. You need to go back
and read the Cocoa Drawing Guide and make sure you understand it. You
should probably also have a look at the Sketch example project.
You cannot call -setNeedsDisplay: in your -drawRect: method. -drawRect
is called automatically at the end of the event loop if the view is
marked as needing display and setting -setNeedsDisplay: in the
drawRect makes no sense at all.
In your -mouseUp: method, you are directly calling -drawRect: without
locking focus on anything - this is not permitted and will cause
massive problems. You should never call -drawRect: directly, just call
-setNeedsDisplay:YES and -drawRect: will be called automatically.
I also don't see why you're calling -setNeedsDisplay on mouse down,
since there is no change in what is to be drawn.
You also don't initialize your ovalBounds NSRect or test to see
whether it is valid, which would be good practice.
I have made a few changes to your code, including using -mouseDragged:
to handle the oval drawing instead of -mouseUp: and I think it
achieves what you are probably looking for.
@implementation DrawingView
- (id)initWithFrame:(NSRect)rect{
self = [super initWithFrame:rect];
[NSBezierPath setDefaultLineWidth:5.0];
//initialize the ovalBounds
ovalBounds=NSZeroRect;
return self;
}
- (void)drawRect:(NSRect)rect{
[[NSColor blueColor] set];
[NSBezierPath fillRect:[self bounds]];
//test to ensure that the oval is valid
if(!NSEqualRects(NSZeroRect, ovalBounds))
{
path = [NSBezierPath bezierPathWithOvalInRect:ovalBounds];
[[NSColor yellowColor] set];
[path stroke];
[[NSColor greenColor] set];
[path fill];
}
}
//in mouseDown we just set the origin point
- (void)mouseDown:(NSEvent *)event{
NSPoint p = [event locationInWindow];
downPoint = [self convertPoint:p
fromView:nil];
}
-(void) mouseDragged:(NSEvent*) event
{
NSPoint p = [event locationInWindow];
currentPoint = [self convertPoint:p
fromView:nil];
float minX = MIN(downPoint.x, currentPoint.x);
float maxX = MAX(downPoint.x, currentPoint.x);
float minY = MIN(downPoint.y, currentPoint.y);
float maxY = MAX(downPoint.y, currentPoint.y);
ovalBounds = NSMakeRect(minX, minY, maxX-minX, maxY-minY);
[self setNeedsDisplay:YES];
}
@end
--
Rob Keniger
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