Re: How to set the scrollers in an NSScrollView?
Re: How to set the scrollers in an NSScrollView?
- Subject: Re: How to set the scrollers in an NSScrollView?
- From: Greg Titus <email@hidden>
- Date: Tue, 24 Jul 2001 11:06:20 -0700
On Tuesday, July 24, 2001, at 05:01 AM, HAEUPL Friedrich - RTAA wrote:
I want to display data graphically in a View. The amplitude of the data
is limited to a rang of 0..255.
A part of the data (about 600 points visible) is displayed. As the
amount of data points can be
quite huge, it should be possible to scroll to a certain position of
the data points and display data
starting from this point. So a scroller is necessary.
The position of the scroller should reflect the position in the
datafile and the length of the scroller
should reflect the relation of visible point to the complete amount of
points. (Maybe it is necessary
to have a minimum size of the scroller, so that it doesn't become too
small)
For performance reasons it is not possible to render all data in the
drawRect methode, but only those
that have to be displayed. How do I set the scrollers then?
Actually, you should be able to use a custom view inside a scrollview as
normal to do this. Just set the width/height of your custom view to be
appropriate for the complete amount of data and the scrollview itself
will handle the scrollbars reflecting the relation of visible to
complete. The important part is: when your -drawRect: method is called,
the rect passed in to the method will be only the VISIBLE part of your
view, so as long as you pay attention to that parameter and only draw
your points within that rectangle you will never have to render any
unneccesary data.
Hope this helps,
--Greg