FLTK logo

[fltk.general] Drawing complex shapes - fl_arc

FLTK matrix user chat room
(using Element browser app)   FLTK gitter user chat room   GitHub FLTK Project   FLTK News RSS Feed  
  FLTK Apps      FLTK Library      Forums      Links     Login 
 All Forums  |  Back to fltk.general  ]
 
Previous Message ]New Message | Reply ]Next Message ]

Drawing complex shapes - fl_arc "'pvr... 08:11 Apr 10  
 
From the documentation:

void fl_arc(double x, double y, double r, double start, double end)

Add a series of points to the current path on the arc of a circle; you can get elliptical paths by using scale and rotate before calling fl_arc(). The center of the circle is given by x and y, and r is its radius. fl_arc() takes start and end angles that are measured in degrees counter-clockwise from 3 o'clock. If end is less than start then it draws the arc in a clockwise direction.

This infers that the two calls:
fl_arc(0, 0, radius, 90, 180);
fl_arc(0, 0, radius, 180, 90);
result in the same drawing - the arc selected is from 9 o'clock clockwise to 12 o'clock. And indeed they do.

I coded:
fl_arc(0, 0, radius, 180, 450);
to achieve what I wanted which was to draw an arc clockwise from 12 o'clock to 9 o'clock.

My concern is that this is not properly documented. Should I have drawn two separate arcs from 180 to 360 and 0 to 90?

I also noticed that the code
fl_start_polygon();
fl_vector(0,0);
fl_arc(0,0, radius, 180, 450);
fl_end_polygon();

actually worked to give me the 3/4 of the pie even though it is a concave shape.

Phil.

--
You received this message because you are subscribed to the Google Groups "fltk.general" group.
To unsubscribe from this group and stop receiving emails from it, send an email to fltkgeneral+unsubscribe@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/fltkgeneral/e2082917-db06-413f-a210-3b5393ce5550n%40googlegroups.com.
Direct Link to Message ]
 
     
Previous Message ]New Message | Reply ]Next Message ]
 
 

Comments are owned by the poster. All other content is copyright 1998-2024 by Bill Spitzak and others. This project is hosted by The FLTK Team. Please report site problems to 'erco@seriss.com'.