Re: All seems well but image doesn't show up.
Re: All seems well but image doesn't show up.
- Subject: Re: All seems well but image doesn't show up.
- From: Steve Bird <email@hidden>
- Date: Mon, 23 Jul 2007 07:13:23 -0400
On Jul 22, 2007, at 10:30 PM, David Arnold wrote:
Commenting out the code
/*
- (void)drawRect:(NSRect)rect {
// Drawing code here.
}
*/
cured the problem.
However, I am so new to this, I can't say that I "see" the
problem. I used the File Assistant to subclass an NSView class, so
the drawRect command was put there by the XCode machinery. A naive
guess would be that an empty drawRect method would cause an empty
NSView,
--- Not so naive. When you're commanded to draw the view (or part of
it), and you respond by doing nothing, then nothing is exactly what
shows up.
but I cannot say for certain why the lines
- (void)windowDidLoad
{
NSImage *image = [[self document] activeImage];
NSLog(@"%@",image);
[view setImage:image];
in the IAWindowController still don't provide an image.
--- They did provide the image.... to the view. But the view did
nothing with it. The default drawRect: method takes the image it has
and puts it on screen. But since you overrode the default with your
own method which does nothing, then nothing is what you get.
And finally, when we get ourselves into these situations, other
than pouring
--- that would be "poring".
over the code again, what good ideas come to mind to debug the
source of the problem?
--- The only solution here is to understand what is "supposed" to
happen. If you aren't aware that the drawRect: method is responsible
for ALL drawing into the view, then stepping thru the code will not
reveal anything until you pull your hair out to reveal your scalp.
If your code works the way it's supposed to, then you have to be
willing to question whether your suppositions are wrong.
"It's not what you don't know that hurts you, it's what you do know
that ain't so."
--Will Rogers
----------------------------------------------------------------
Steve Bird
Culverson Software - Elegant software that is a pleasure to use.
www.Culverson.com (toll free) 1-877-676-8175
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