[Drawkit] Selection behavior with groups

[Brad Larson]

I added an instance variable to the DKSelectAndEditTool,  
mAllowMultiObjectKnobDrag, as a boolean which is set via  
setDragsAllObjectsInSelectionWhenDraggingKnob: .  By default, it is  
NO, but if it is YES, mouseDownAtPoint:targetObject:layer:event:event  
delegate: will now take that into account and move the selection  
rather than edit the control point.

I then call

DKSelectAndEditTool *selectTool = [[DKSelectAndEditTool alloc] init];
[selectTool setDragsAllObjectsInSelectionWhenDraggingKnob:YES];
[DKDrawingTool registerDrawingTool:selectTool  
withName:kDKStandardSelectionToolName];
[selectTool setKeyboardEquivalent:@" " modifierFlags:0];

at the start of my application to override the default selection  
behavior.  I also had to modify DKToolController, because setDrawing:  
was not grabbing the selection tool by its name, it was just creating  
a new one.  This caused different selection behavior on first load of  
a document.

I apologize if the naming isn't the best, but this approach would seem  
to add the option of selecting in this fashion for others who wish to  
have it while preserving the current method as the default.

On Aug 4, 2008, at 7:36 PM, Graham Cox wrote:

> Currently this is the intended behaviour, not because it makes life  
> difficult (though I accept it does in your case where your objects  
> are very small) but because for the typical case it is more usable.  
> If the user has several objects selected but then deliberately  
> clicks in a knob, the expected behaviour is to operate that knob as  
> normal (and refocusing the selection onto that one object  
> beforehand), not move the selected objects. It means that what a  
> knob represents in terms of behaviour is consistent.
>
> The problem you're having is of course, that the knobs start to  
> overwhelm the objects at very small scales, so it's hard to click  
> something that isn't a knob.
>
> I can suggest a few ways out of this. The behaviour is implemented  
> by the DKSelectAndEditTool, as part of its mouseDown... method. So  
> you could modify that to detect a multiple selection and to treat  
> any knob hits as body hits instead. Maybe also factor in the zoom  
> scale and/or object size so that at larger scales the usual  
> behaviour is kept the same. Another option would be to change the  
> DKKnob scaling ratio and knob size so that the knobs are smaller at  
> the scales you are working at so they are less likely to get in the  
> way. You could also implement your own selection/move tool that  
> ignored knob hits altogether (so you'd have separate tools for  
> moving objects and editing them). You could also try grouping the  
> objects and moving the group - that ignores all knobs for objects  
> within the group (this is more of a workaround than a real solution).
>
> If you let me know your preferred approach I can help you out with  
> specifics.
>
> cheers, Graham
>
>
>
> On 5 Aug 2008, at 9:27 am, Brad Larson wrote:
>
>> One thing I encountered today was a difficulty in moving a large  
>> group selection, which might require a change in the way that knobs  
>> are selected.  When you select an object with a large number of  
>> features, you normally can move that group selection by clicking  
>> and dragging on any of the features within the selection.  The  
>> problems come in when you have a group selection and click and drag  
>> on a knob from one of the selected objects.  It's been my  
>> experience in other draw programs that this would also cause a  
>> dragging of the whole selection, but in DrawKit that currently  
>> causes the selection to be lost and for you to edit the object by  
>> dragging that control point.
>>
>> This really causes a problem with groups containing many fine  
>> features, as often the knobs will be the only thing in the  
>> selection that you can click on to move it.  For example, in the  
>> Beta of SonoDraw, try loading the sample PCBExample.pattern,  
>> enlarging the canvas, selecting all objects, copying and pasting  
>> another group of objects, then moving the selection.  It is very  
>> difficult to do unless you zoom way in and select a non-knob part  
>> of one of the lines.
>>
>> This seems like something that is fundamental in the functioning of  
>> the DKKnob, so I didn't know where to start with modifications or  
>> even if they were  desired.  Do you prefer this method of  
>> selection / editing?
>
> _______________________________________________
> Drawkit mailing list
> Drawkit at lists.apptree.net
> http://lists.apptree.net/listinfo.cgi/drawkit-apptree.net

______________________
Brad Larson
SonoPlot, Inc.
3030 Laura Lane, Suite 120
Middleton, WI 53562


-------------- next part --------------
A non-text attachment was scrubbed...
Name: DKSelectAndEditTool.h
Type: application/octet-stream
Size: 4798 bytes
Desc: not available
URL: <http://lists.apptree.net/pipermail/drawkit-apptree.net/attachments/20080806/c6a4c854/attachment-0003.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: DKSelectAndEditTool.m
Type: application/octet-stream
Size: 38743 bytes
Desc: not available
URL: <http://lists.apptree.net/pipermail/drawkit-apptree.net/attachments/20080806/c6a4c854/attachment-0004.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: DKToolController.m
Type: application/octet-stream
Size: 29264 bytes
Desc: not available
URL: <http://lists.apptree.net/pipermail/drawkit-apptree.net/attachments/20080806/c6a4c854/attachment-0005.obj>