How to dynamically scroll NSScrollView based on dragged control - macos

Question

I have an NSScrollView that contains a Drawing. Drawing is a subclass of NSView and is a drop target. I have another class called dragBox which is an NSBox and a drag source. I want to be able to dynamically change the size of the Drawing to accommodate dragging the dragBox outside the size of the NSScrollView. Currently I define a "hot area" in the NSScrollView's content view that automatically scrolls. The problem is that when I drop the dragBox, it doesn't drop it in the virtual space that was just created. It drops it relative to the size of the viewport. Here's the code.
#implementation Drawing
-(NSDragOperation)draggingUpdated:(id <NSDraggingInfo>)sender // validate
{
NSLog(#"Updated");
_drawHintPoint = [sender draggedImageLocation];
if ([sender draggingLocation].x > [[self superview] bounds].size.width - 30)
{
NSRect scrollRect = NSMakeRect(0,0, [self bounds].size.width + 30, [self bounds].size.height) ;
[self setFrame:scrollRect];
_drawHintPoint = NSMakePoint([self bounds].size.width + 30, [sender draggingLocation].y);
[self scrollPoint:_drawHintPoint];
}
return NSDragOperationEvery;
}
-(BOOL) prepareForDragOperation:(id<NSDraggingInfo>)sender
{
NSLog(#"Prepared");
return YES;
}
- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender {
NSLog(#"Move Box");
NSPoint pt = _drawHintPoint;
pt.x = pt.x - 32;
pt.y = pt.y - 32;
[[_ico box] setFrameOrigin:pt];
return YES;
}
- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender {
NSLog(#"Drag Entered");
_drawHintPoint = NSMakePoint(0, 0);
return NSDragOperationEvery;
}
How do I drop the dragBox so that it drops it in the virtual space provided?
Bruce

Answer 1

Solved!
In draggingUpdated, this did the trick:
_drawHintPoint = [[self superview] convertPoint:[sender draggingLocation] fromView:nil];
You need to convert the dragging location to coordinates in the scroll view. [self superview] in the above line refers to the NSClipRect.