Draw a path with variable width in iOS

Question

I am working on a writing application, My writing is working fine, but what I want to implement is variable stroke width, so that the writing is very realistic

Answer 1

The answer to how to reverse the width behaviour and (and even the same question as yours) is right there in the link that you posted. All I did was to search for the word "width"

The question (my highlighting is not part of the quote):

The final version of this seems to work opposite of the first version. I would like to have the line thicker as the user moves slower and not thinner. Where do I change the code to inverse the final varying thickness to perform or like a pen? Meaning the slower the user moves the thicker or more ink the pen puts down... Thanks! Great tutorials, btw...

And the answer:

thanks for the great tutorial!

with these changes i got the opposite line width cahnge effect:

#define CAPACITY 100
#define FF 20.0
#define LOWER 0.01
#define UPPER 1.5

float frac1 = clamp(FF/len_sq(pointsBuffer[i], pointsBuffer[i+1]), LOWER, UPPER); // ................. (4)
float frac2 = clamp(FF/len_sq(pointsBuffer[i+1], pointsBuffer[i+2]), LOWER, UPPER);
float frac3 = clamp(FF/len_sq(pointsBuffer[i+2], pointsBuffer[i+3]), LOWER, UPPER);

Another search in the same link for the text "float frac1 =" shows that this change should be applied to lines 76-78 (somewhere inside touchesMoved:withEvent: in the code from the article)

Answer 2

In your touchesBegan: method, UItouch is supplied.
UITouch has below instance functions,

– locationInView:
– previousLocationInView:

And below property

@property(nonatomic, readonly) NSTimeInterval timestamp

From the above, i think you can easily calculate velocity.I didn't go through any of mentioned links.I just want to give you an idea of how to calculate velocty based on touch object.