Wednesday, March 14, 2012

Touchscreen Delay

One of the things we can't control in stylus design is delay or latency in touchscreen systems. Several customers have emailed us saying they thought the drawing point for a stylus should always be right in the centre of the contact area. Unfortunately there is a delay between the actual touch and the appearance of the line on the touchscreen device, particularly apparent when drawing a line quickly.

Microsoft has been researching how significant this is. They have found that with today's touchscreens there is about a 100 millisecond (ms) lag. This happens whether we use a finger or a stylus, and is noticeable when we are quickly sketching curved or zigzag lines – the line appears a few millimeters behind the centre point of the finger or stylus.

Here is the video Microsoft Research posted:
http://youtu.be/vOvQCPLkPt4

They demonstrate in the video that a delay of 1 ms would be ideal. The human eye cannot detect that small a lag, and at that point you "feel like ink is coming from your finger" – a real physical connection with the screen. Unfortunately they estimate this technology may be as much as 10 years away. Until then we have to either put up with the delay, or simply slow down our drawing.

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