Re: drawRect: called twice for NSView subclass.
Re: drawRect: called twice for NSView subclass.
- Subject: Re: drawRect: called twice for NSView subclass.
- From: David Duncan <email@hidden>
- Date: Sun, 20 Apr 2008 11:13:04 -0700
On Apr 19, 2008, at 5:15 PM, William Hunt wrote:
Essentially I have a window with a custom view atop a button. What
happens at each refresh, however, is that the custom view's
drawRect: is called twice. First it is called with the whole
window's NSRect, then it is called with the "proper" NSRect. The
result is that if I draw a circle at (0,0), it gets drawn twice at
different locations:
What is going on here? Is this buggy behavior or correct behavior?
My code is basically a new Cocoa application with a single NSView
subclass. There is absolutely nothing funny (that I know of) going
on here. That leads me to believe that the behavior is "correct,"
and that I'm just missing something.
For the record, I only want the one call to drawRect:, the one with
the "proper" NSRect.
FYI, the "proper" rect is not guaranteed to be the bounds rect of your
view either. If Cocoa only needs you to refresh a subsection of your
view, then you will get a -drawRect: with just that subsection. In
general, you should only use the rect passed to you in -drawRect: as a
guideline for what needs to be updated (i.e. for rejection tests)
rather than to define the coordinate system to draw into.
--
David Duncan
Apple DTS Animation and Printing
email@hidden
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