Stroke not processed and simply remains on screen

[dgsachs@…]

Several times in my testing I encountered a problem where I'd draw something and the stroke simply remained on the screen until I tapped/drew something else, when it clearly should have processed (creating an edge or a new node.)

I've attached two screenshots showing cases where this has happened. In When the screenshot was taken I'd let go of the screen and was looking at the screen for a few seconds with nothing happening.

[glen.low@…]

I would love to fix this one! Unfortunately it's an Apple bug in that occasionally the end of a touch isn't sent to the app. I've been thinking of several workarounds none of which are entirely satisfactory:

• I could set a timer to trigger the end if no motion is detected. But occasionally the user may be pausing with his finger to the screen and thus be surprised that the recognition went ahead.
• I could check to see if there was a trace left over when the user touches the screen, and try to recognize that. Unfortunately that means the node or edge could potentially change the entire layout of the graph, and invalidate the context of the user's current touch.

Hopefully they've fixed it in 2.2 although I haven't tested it there. I'll leave this ticket open for now until we have more suggestions as to what to do.

[dgsachs@…]

The screenshots and bug report are from an iPod running 2.2.

How about "timing out" the stroke if no motion is detected after some amount of time (a second or two)? It's not ideal, but it at least removes the visual oddity of an unrecognized stroke sitting on the screen. It'd be like the software saying "sorry, I didn't understand, try again."

At least then you avoid changing the graph when the user is being indecisive.

[glen.low@…]

The problem is another scenario: the user could still have his finger down while pausing in a stroke, and it would be weird for the shape to be recognized before he actually finished drawing.