"Mouse droppings" on drawing small arcs

General Discussion Other

beriso

"Mouse droppings" on drawing small arcs

in General Discussion • Other • 8 months ago

Hello everybody,

I am using Processing 2.0b6 to draw a donut diagram. Each segment is drawn with a startAngle and an endAngle, using the arc command.

The problem: Sometimes, there are little dirt artefacts around very small segments, and I do not know where they are from and what I can do about it.

Screenshots:
Screenshot 1, Screenshot 2 (highlighted)

Has anybody an idea how I can get along?

Thanks in advance! :-))
beriso

Replies(4)

asimes

Re: "Mouse droppings" on drawing small arcs

8 months ago

If I had to guess, you are drawing a white circle that doesn't quite cover something underneath it due to using smooth(). It also might be that you are drawing a purple circle and then placing white segments with arc()?

It would be easier to determine with code if that is not the problem.

beriso

Re: "Mouse droppings" on drawing small arcs

8 months ago

Thank you for the reply!

I will try to outline what is done in the visualization:

In setup(), smooth() is called.
At the beginning of draw(), the canvas is cleared by using background(255, 255, 255)
zoomer.transform() is called (like described here)
For each donut diagram, drawDonut() is called

It determines startAngle and endAngle for each data segment
stroke() is called, with the color code, e.g. for purple, red, green, ...
noFill()
strokeCap(SQUARE);
strokeWeight(75)
arc(donutX, donutY, diameterInnerDonut, diameterInnerDonut, radians(segment.angleStart), radians(segment.angleEnd));

So there is nothing underneath anything but white canvas with a colored arc painted on it (and afterwards drawn some explanations, etc).

I still have no idea how to get rid of the "dirty drawing", calling noSmooth() instead of smooth() just makes everything look ugly. ;-)

rbrauer

Re: "Mouse droppings" on drawing small arcs

8 months ago

I believe it is probably caused by the span of the arc being smaller than your stroke weight. Instead of using strokes to draw your arcs, you could draw them all from the same coordinate starting with the largest diameter. Use noStroke() and fill with the corresponding color. After finishing all the arcs in each donut, draw a white circle from the same origin of an appropriate size to create the inner radius of the donut then draw the next one.

beriso

Re: Re: "Mouse droppings" on drawing small arcs

8 months ago

@ rbrauer: Ohhhh yeah, that's the solution!
It works now, the dirty drawing is gone.

Thank you two for your answers, especially rbrauer for the answer leading to the solution.

Top Reply