copied more doxygen comments from drawing.dox back to source code

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@6421 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

1 files changed, 39 insertions, 0 deletions

diff --git a/src/fl_arci.cxx b/src/fl_arci.cxx
index 9cc64f6f3..69425554c 100644
--- a/src/fl_arci.cxx
+++ b/src/fl_arci.cxx
@@ -25,6 +25,11 @@
 //     http://www.fltk.org/str.php
 //
 
+/**
+  \file fl_arci.cxx
+  \brief Utility functions for drawing circles using integers
+*/
+
 // "integer" circle drawing functions.  These draw the limited
 // circle types provided by X and NT graphics.  The advantage of
 // these is that small ones draw quite nicely (probably due to stored
@@ -44,6 +49,28 @@
 #  include <config.h>
 #endif
 
+/**
+  Draw ellipse sections using integer coordinates.
+  
+  These functions match the rather limited circle drawing code provided by X
+  and WIN32. The advantage over using fl_arc with floating point coordinates
+  is that they are faster because they often use the hardware, and they draw
+  much nicer small circles, since the small sizes are often hard-coded bitmaps.
+
+  If a complete circle is drawn it will fit inside the passed bounding box.
+  The two angles are measured in degrees counterclockwise from 3'oclock and
+  are the starting and ending angle of the arc, a2 must be greater or equal
+  to a1.
+
+  fl_arc() draws a series of lines to approximate the arc. Notice that the
+  integer version of fl_arc() has a different number of arguments than the
+  double version fl_arc(double x, double y, double r, double start, double a)
+
+  \param[in] x,y,w,h bounding box of complete circle
+  \param[in] a1,a2 start and end angles of arc measured in degrees
+             counter-clockwise from 3 o'clock.  a2 must be greater
+	     than or equal to a1.
+*/
 void fl_arc(int x,int y,int w,int h,double a1,double a2) {
   if (w <= 0 || h <= 0) return;
 #ifdef WIN32
@@ -78,6 +105,18 @@ void fl_arc(int x,int y,int w,int h,double a1,double a2) {
 #endif
 }
 
+/**
+  Draw filled ellipse sections using integer coordinates.
+  
+  Like fl_arc, but fl_pie() draws a filled-in pie slice.
+  This slice may extend outside the line drawn by fl_arc;
+  to avoid this use w - 1 and h - 1.
+
+  \param[in] x,y,w,h bounding box of complete circle
+  \param[in] a1,a2 start and end angles of arc measured in degrees
+             counter-clockwise from 3 o'clock.  a2 must be greater
+	     than or equal to a1.
+*/
 void fl_pie(int x,int y,int w,int h,double a1,double a2) {
   if (w <= 0 || h <= 0) return;
 #ifdef WIN32