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)