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Scenario: I want to be able to adjust the scale of an EPS-vector image.

From what I understand for Scaling an image (Raster/Vector): All the graphics routines are done within a subclass of the image’s NSView. In my case, a subclass of NSImageView. Here’s my plan of action within the image’s view (from what I’ve read):

The scaling is controlled by the NSSlider control via the action routine:

} // end adjScale().

#import <Cocoa/Cocoa.h>

@interface epsImageView : NSImageView { float scale; }

@implementation epsImageView //….

} @end

The drawRect routine is fired per NSSlider adjustment (continuous). But I don’t see any scaling effect. What am I missing here?



Have you tried just setting the size of the displayed image? If that worked, you could totally do away with the NSImageView subclass.

Shouldn’t the restorGraphicsState message come after the call to [super drawRect:rect] ?

I got a reply from Shawn Erickson concerning this. “I see two issues, one is outlined above… basically your scaling transform is not in place when you attempt to draw your image. I suggest trying the following. “

“The other issue I see is that you appear to be using NSImageView which is a control simply as a way to display an image. This is likely over kill and possibly problematic for the scaling you are attempting to do. I suggest instead subclassing NSView instead and dropping that custom view into your window/containing view. So something like (ignores any possible use of scroll view, etc.)…”

@interface epsImageView : NSView … … @end … …

“Note all code examples are written in mail from memory and not tested, bug likely exist.


I haven’t got the second set of code to work yet. So I’ll continue to play with it. I’m sure there are many was to do this. And I’m at the bottom of the learning curve here. I’ll toy with all suggestions to get a better understanding of this.

I also want to use the scroll view (NSScrollView).

If you want to use a scroll view, then you’ll not want to scale the image, but rather resize your entire view and draw the image to fit. The scroll view will show scrollers in such a way as to display a piece of your entire view, so your view’s size must be equal to the total size of whatever you’re displaying.