Strange cut outs when drawing a simple circle

beginners
#1

Hello,

I’m drawing a simple circle using this piece of code:

  
  
ofSetColor(255);  
ofSetLineWidth(50.0f);  
ofSetCircleResolution(100);  
ofNoFill();  
ofCircle(ofGetWidth() / 2, ofGetHeight() / 2, 200.0f);

It shows up like this:

Has anyone seen this before? If I reduce the line width to a lower number (1, 2) it seems to draw ok.

I’m running this code in the emptyExample on OS X 10.8.4 with openFrameworks 0.7.4.

Kind regards,
Harry Vermeulen

1 Like
#2

This isnt something I am super familiar with, but i have seen similar discussions around on the forums. I think it just comes down to how opengl does 2D vector graphics. You might have more luck with a different renderer, either Cairo or ShivaVG, there are addons for them

https://github.com/bgstaal/ofxShivaVG
https://github.com/bgstaal/ofxCairo

Here are some threads i found searching for ‘smooth vector’

http://forum.openframeworks.cc/t/how-to-smooth-joints-when-calling-ofsetlinewidth/7278/0
http://forum.openframeworks.cc/t/ofxshivavg-smooth-2d-graphics-in-of/12574/0

#3

Thank you for your reaction.

I’m not able to get the ofxShivaVG add-on to work. First it’s bugging me about GLFW.h not being present, which I’ve now downloaded, compiled and linked. However now it’s bugging me with this more errors in ofPath.

–
Nevermind! Downloaded the 0.7.4 branch at: https://github.com/bgstaal/ofxShivaVG/tree/0.7.4 which works like a charm!

#4

any idea if ofxShivaVG is working wiht 0.8.1 or 0.8.0?
I am trying with 10.9 and Xcode 5 without any success.

There’s any other (GL and fast) addon or something to get smooth lines?