[Drawkit] Pan / Hand Tool?

[Allan Daly]

As always, thanks for your very helpful reply.

In my work  (building system design) I do lots of CAD and I find that  
a very useful UI element is to use the scroll wheel to zoom in and out  
and to use the scroll wheel button (third button) in the way you  
describe below -- to 'flip' to the pan tool temporarily, then revert  
to the originally selected tool. In this way all of your navigation in/ 
out/pan is all on a single button and it makes moving around 'inside'  
another command easy and intuitive. Perhaps give this a try when you  
get around to implementing that flip code. (This is the way AutoDesk  
AutoCAD works.)

-Allan


On Aug 31, 2009, at 7:07 PM, Graham Cox wrote:

> Hi Allan,
>
> Right now the pan tool is not part of DK, but it is an extremely  
> simple tool. It'll probably end up in DK, especially as I want to  
> implement a way to 'flip' to the pan tool when the spacebar is  
> pressed while using other tools, though that's harder to do than it  
> looks from the user's POV.
>
> Anyway, the current implementation is as follows:
>
> #import <GCDrawKit/DKDrawingTool.h>
>
>
> @interface DKOPanTool : DKDrawingTool
> {
> 	NSPoint		mAnchor;
> 	NSPoint		mViewOrigin;
> 	BOOL		mDragging;
> }
>
> @end
>
> // -------------------
>
>
> #import "DKOPanTool.h"
> #import <GCDrawKit/DKDrawingView.h>
> #import <GCDrawKit/DKLayer.h>
>
> @implementation DKOPanTool
>
>
> - (int)				mouseDownAtPoint:(NSPoint) p targetObject: 
> (DKDrawableObject*) obj layer:(DKLayer*) layer event:(NSEvent*)  
> event delegate:(id) aDel
> {
> 	#pragma unused(obj, p, aDel)
> 	
> 	mDragging = YES;
> 	mAnchor = [event locationInWindow];
> 	DKDrawingView* zv = (DKDrawingView*)[layer currentView];
> 	
> 	float scale = [zv scale];
> 	
> 	NSClipView* clippy = (NSClipView*)[zv superview];
> 	mViewOrigin = [clippy documentVisibleRect].origin;
> 	
> 	mViewOrigin.x *= scale;
> 	mViewOrigin.y *= scale;
> 	
> 	//NSLog(@"will begin pan at point: %@, clip view origin = %@",  
> NSStringFromPoint( p ), NSStringFromPoint( mViewOrigin ));
> 	
> 	[[NSCursor closedHandCursor] set];
> 	
> 	return 0;
> }
>
>
> - (void)			mouseDraggedToPoint:(NSPoint) p partCode:(int) pc layer: 
> (DKLayer*) layer event:(NSEvent*) event delegate:(id) aDel
> {
> 	#pragma unused(pc, p, aDel)
> 	
> 	DKDrawingView* zv = (DKDrawingView*)[layer currentView];
> 	NSPoint newOrigin = NSMakePoint( mViewOrigin.x - ([event  
> locationInWindow].x - mAnchor.x), mViewOrigin.y + ([event  
> locationInWindow].y - mAnchor.y));
> 	
> 	// take into account the zoom factor of the view
> 	
> 	float scale = [zv scale];
> 	
> 	newOrigin.x /= scale;
> 	newOrigin.y /= scale;
> 	
> 	[zv scrollPoint:newOrigin];
> }
>
>
> - (BOOL)			mouseUpAtPoint:(NSPoint) p partCode:(int) pc layer: 
> (DKLayer*) layer event:(NSEvent*) event delegate:(id) aDel;
> {
> 	#pragma unused( p, pc, layer, event, aDel )
> 	
> 	[[NSCursor openHandCursor] set];
> 	
> 	mDragging = NO;
> 	return NO;
> }
>
>
> - (NSCursor*)		cursor
> {
> 	if( mDragging )
> 		return [NSCursor closedHandCursor];
> 	else
> 		return [NSCursor openHandCursor];
> }
>
>
>
> @end
>
>
>
>
> On 01/09/2009, at 11:54 AM, Allan Daly wrote:
>
>> Hi Graham,
>>
>> I've got my copy of Ortelius up and running. What fun. Nice job and  
>> congrats.
>>
>> I see that you have a "hand" tool implemented in there that pans  
>> around the screen when you're zoomed in. This is something I have  
>> been thinking about doing in my app and I wonder if this is a  
>> standard tool now in DK (didn't see it when I looked around) or if  
>> not if I could please ask you to please send along a few notes on  
>> the best route to implement that.
>>
>> Thanks.
>>
>> -Allan
>
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