<Swing Dev> Fw: review request for 6899434: Add affine transformsupport to JLayer

[Piet Blok]

Hi Artem,

To demonstrate the implemention via the AWTAccessor pattern, I created a 
version 2 implementation:

http://www.pbjar.org/OpenJDK/6899434/version-2/webrev/

This implementation is much cleaner than the original one.

Looking forward for yout comments,
Piet



> Hi Artem,
>
> The problem with making existing methods public is that it solves only 
> half of the problem at hand:
>
> 1) Locate the correct component (can be solved)
>
> 2) Recalculating the mouse point from rendered space to layout space is 
> not solved because the locating methods only return a component. 
> Recalculation is needed to correctly set a mouse point in the new events, 
> relative to the target component.
>
> In my proposed implementation the shift caused by transformations is 
> stored when looking up the target (for future use: creating new events 
> from the original event). This future is quite an immediate future because 
> creating a new event from an existing event will always be directly 
> preceded by looking up that target event.
>
> An alternative would be to again iterate through the hierarchy and do the 
> transformations. This must be done in LightweightDispatcher in the 
> methods:
>
> 1) retargetMouseEvent (an inverse transform is needed, so the new 
> Container method getConvertedPoint can be used)
>
> 2) eventDispatched. Unfortunately here an ordinary transform is needed, so 
> a second new Container method must be defined that does an ordinary 
> transform.
>
> But.... a completely different approach is also possible. I did this in an 
> earlier version, so I know that it works. With this approach no new public 
> or protected methods need to be introduced and no existing methods need to 
> go public or protected. All remains private or package private.
>
> That approach is as follows:
>
> 1) Define the AffineTransform as a private field in Component.
>
> 2) Use the AWTAccessor pattern to make the transform available in 
> Container and LightweightDispatcher and in swing classes.
>
> 3) In Container and LightweightDispatcher, get the transform and do 
> transformations when needed.
>
> In my opinion, the solution with the AWTAccessor pattern is the cleanest. 
> However, it requires Component and AWTAccessor to be touched.
>
> Please let me know what you think.
>
> Piet
>
>
>
>> Hi, Piet,
>>
>> I haven't looked through the entire webrev and inspected mostly an AWT 
>> part of the fix. A question is whether it's possible to get rid of the 
>> new "conversionShift" field in Container, to make transformations support 
>> really stateless?
>>
>> Another option to consider is to make some of the existing methods (e.g. 
>> getMouseEventTargetImpl()) public instead of introducing new ones.
>>
>> Thanks,
>>
>> Artem
>>
>> On 1/28/2010 8:21 PM, Piet Blok wrote:
>>> Hello all,
>>>
>>> review request for 6899434: Add affine transform support to JLayer
>>>
>>> The webrev: http://www.pbjar.org/OpenJDK/6899434/webrev/
>>>
>>> The patch covers all the requested functionality. It is concentrated in
>>> JLayer class, keeping in mind to affect the library as little as 
>>> possible.
>>>
>>> 1) A setter and getter for the transform in JLayer
>>>
>>> 2) The paint method in JLayer has been adapted to use the transform
>>>
>>> 3) RepaintManager has been adapted to propagate repaint requests from
>>> the view or any of its children to the top level JLayer and have the
>>> dirty region transformed.
>>>
>>> 4) java.awt.Container and java.awt.LightweightDispatcher (both in the
>>> same source) have been adapted to redispatch MouseEvents to the intended
>>> target component. The lookup for the component that provides a custon
>>> cursor has also been adapted.
>>>
>>> 5) To enable Container to do necessary reculculations, a protected
>>> method has been introduced that will be overridden by JLayer:
>>> protected Point getConvertedPoint(Point point).
>>> (If someone can suggest a better name for this method I'm glad to hear)
>>>
>>> 6) A package private method in SwingUtilities has been added that helps
>>> JPopupMenu and ToolTipManager to find the correct popup location.
>>> JPopupMenu and ToolTipManager have been changed to use this new method
>>> in their calculations.
>>>
>>> 7) Two jtreg tests have been added.
>>>
>>> Looking forward for comments.
>>>
>>> Thanks,
>>> Piet
>>>
>>>
>>>
>>
>
>
>