Drawing on touch event

Question

I'm making a drawing tool with UIView's touch events.

The problem is

touchesMoved event doesn't occur when trying to move very closely right after touch began.

so it's very difficult to draw 2~3 pixels line.

enter image description here See it's just one pixel.

But in iOS Simulator it works fine.

enter image description here

I thought it's device's problem But in SketchBookX(popular drawing app), works fine, too.

enter image description here

I'm not using UIScrollView or UIGuestureRocognizer.

Please help me to solve this problem.

I took some screenshots AND 'newbies are not allowed to post images..' X(

post screen shots in some online site and share the link if its that important for your question — Rohit Vipin Mathews, Mar 19 '12 at 09:25

score 0 · Accepted Answer · answered Apr 26 '12 at 10:27

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Oh FINALLY I found my fault!

enter image description here

If touch moves very short after 'touchesBegan', doesn't fire 'touchesMoved'.

But when 'touchesEnd' it gives moved point X(

It's little odd but finally i've done with it :)

answered Apr 26 '12 at 10:27

Minsu

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can you told me how can i draw in touch event ? i read that to draw you should use drawrec function ? – kartal May 22 '12 at 22:50

score 0 · Answer 2 · edited May 23 '17 at 12:30

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One thing is that on simulator input device is a mouse, where point of 'touch' is stricltly defined. Touchscreen works a bit different - 2-3px can be filtered as a noise.

People usually interpolate 'missing' pixels using UIBezierPath: see Increase frequency calls of touchesMoved

edited May 23 '17 at 12:30

Community

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answered Mar 19 '12 at 09:49

Rok Jarc

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I'm already using interpolation for very fast touch movement. But it can't solve my problem. Without any touchesMoved event, it's just nothing different with a pixel :( – Minsu Mar 19 '12 at 12:45

Drawing on touch event

2 Answers2