RFR: 8333919: dragViewOffsetX/dragViewOffsetY are ignored for the dragView image [v2]

[Lukasz Kostyra]

On Mon, 12 Aug 2024 09:54:19 GMT, Jose Pereda <jpereda at openjdk.org> wrote:

>> Lukasz Kostyra has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   GlassViewDelegate: Correctly set origin and offset in dragImage
>>   
>>   - Centering to dragImage was removed - origin is now top-left of dragImage
>>   - Offset direction was swapped
>
> modules/javafx.graphics/src/main/native-glass/mac/GlassViewDelegate.m line 1068:
> 
>> 1066: 
>> 1067:                 dragPoint.x -= offset.x;
>> 1068:                 dragPoint.y -= offset.y;
> 
> This works fine now, _if_ the offset values are smaller than the imageHalf X,Y values, which doesn't make sense anymore:
> 
> - If you drag from {0,0} (top-left), it works from that position
> - But if you drag from {imageW, imageH} (bottom-right), the offset is clamped to the image centre, which it is not expected.
> 
> So now we need to change the above lines to clamp the offset between 0,0 and imageW,H (though Windows doesn't clamp the offset at all).

Out of curiosity I removed offset clamping (macOS snaps the drag image regardless) and technically it still works, but when you cancel the drag the image snaps back to the offset position. With high enough (or negative) values drag image can animate back even outside the application bounds, which makes little sense and looks weird. I'll clamp it between 0,0 and imageW,H as you mentioned.

I also didn't find a way to disable above drag image "snapping". However, if it makes sense to clamp it on macOS, maybe it would also make sense to introduce similar limits to offsets on other platforms (probably as a separate issue)?

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PR Review Comment: https://git.openjdk.org/jfx/pull/1532#discussion_r1713643394