1 files changed, 143 insertions, 0 deletions
diff --git a/src/intcgm/ellipse.c b/src/intcgm/ellipse.c
new file mode 100644
index 0000000..8d6889c
--- /dev/null
+++ b/src/intcgm/ellipse.c
@@ -0,0 +1,143 @@
+#include <stdio.h>
+#include <math.h>
+
+#include <cd.h>
+
+#include "list.h"
+#include "types.h"
+#include "intcgm.h"
+#include "intcgm6.h"
+#include "ellipse.h"
+
+#ifndef PI
+#define PI 3.14159265358979323846
+#endif
+
+#define ANGMIN 0.00001
+
+/* Adjust the circle parametrization for the elipsis parametrization */
+double cgm_AdjArc ( double arc, double w, double h )
+{
+ double value;
+
+ if ((fabs(w*sin(arc))<1e-99) && (fabs(h*cos(arc))<1e-99))
+   value = 0.0;
+ else
+   value = atan2(w*sin(arc), h*cos(arc));
+
+ if ( arc >  PI  ) value += 2*PI;
+ if ( arc < -PI  ) value -= 2*PI;
+
+ return value;
+}
+
+
+/*  Desenha um arco de Elipse */
+
+void cgm_ElpArc ( double xc, double yc, double w, double h, double r, double a1,
+              double a2, int n, int tipo )
+
+{
+
+ /* Onde:
+
+  (xc,yc) Centro
+  (w,h)   Largura e altura (diametro na direcao dos eixos principais)
+  r       Inclinacao dos eixos principais com relacao x e y
+  a1,a2   Angulos incial e final do arco [-360,+360]
+             Note-se que o sentido e' dado pela diferenca a2-a1,
+             ou seja, 30 a 330 e' trigonometrico
+                      30 a -30 e' horario
+  n       Numero de segmentos da poligonal equivalente
+          (64 parece ser um bom numero)
+  tipo    0=aberto 1=fechado(torta) 2=fechado(corda) */
+
+  double da, c, s, sx, sy, ang, xant, yant;
+  double px, py, tx, ty, txant, tyant, dx, dy;
+  int i, inicio;
+
+/* Reduz de diametro a raio */
+
+  w = w/2;
+  h = h/2;
+
+/* Transforma graus em radianos e ajusta a os angulos da parametrizacao */
+
+  a1 = cgm_AdjArc(a1,w,h);
+
+  a2 = cgm_AdjArc(a2,w,h);
+
+  if ( a2>a1 )
+   ang = a2 - a1;
+  else
+   ang = 2*PI - ( a1 - a2 );
+
+/* Gera os pontos do arco centrado na origem com os eixos em x e y */
+
+  da = ang/n;
+  c  = cos(da);
+  s  = sin(da);
+  sx = -w*s/h;
+  sy = h*s/w;
+
+  if ( tipo==1 || tipo==2 )
+   {
+    long int cor;
+    cor = cgm_getcolor ( intcgm_fill_att.color );
+    cdCanvasSetForeground (intcgm_canvas,  cor );
+    cdCanvasBegin(intcgm_canvas,  cgm_setintstyle(intcgm_fill_att.int_style) );
+   }
+  else
+   {
+    long int cor;
+    int size = (int)floor(intcgm_line_att.width+.5);
+    cdCanvasLineStyle (intcgm_canvas,  intcgm_line_att.type );
+    cdCanvasLineWidth (intcgm_canvas,  size>0? size: 1 );
+    cor = cgm_getcolor ( intcgm_line_att.color );
+    cdCanvasSetForeground (intcgm_canvas,  cor );
+   }
+
+  dx = (fabs(r)>ANGMIN) ? sin(r) : 0;
+  dy = (fabs(r)>ANGMIN) ? cos(r) : 1;
+
+  xant  = w*cos(a1);
+  yant  = h*sin(a1);
+
+  txant = xc+dy*xant-dx*yant;   /* Inclina (se for o caso) e translada */
+  tyant = yc+dx*xant+dy*yant;   /* Inclina (se for o caso) e translada */
+
+  if ( tipo==1 )
+   {
+    cdCanvasVertex (intcgm_canvas,  cgm_vdcx2canvas(xc), cgm_vdcy2canvas(yc) );
+    cdCanvasVertex (intcgm_canvas,  cgm_vdcx2canvas(txant), cgm_vdcy2canvas(tyant) );
+    inicio = 2;
+   }
+  else if ( tipo==2 )
+   {
+    cdCanvasVertex (intcgm_canvas,  cgm_vdcx2canvas(txant), cgm_vdcy2canvas(tyant) );
+    inicio = 1;
+   }
+
+  for ( i=inicio; i<=(n+inicio-1); i++ )
+   {
+    px = c*xant+sx*yant;
+    py = sy*xant+c*yant;
+
+    tx = xc+dy*px-dx*py;       /* Inclina (se for o caso) e translada */
+    ty = yc+dx*px+dy*py;       /* Inclina (se for o caso) e translada */
+
+    if ( tipo==0 )
+     cdCanvasLine (intcgm_canvas,  cgm_vdcx2canvas(txant), cgm_vdcy2canvas(tyant), cgm_vdcx2canvas(tx), cgm_vdcy2canvas(ty) );
+    else
+     cdCanvasVertex (intcgm_canvas,  cgm_vdcx2canvas(tx), cgm_vdcy2canvas(ty) );
+
+    xant = px;
+    yant = py;
+    txant = tx;
+    tyant = ty;
+  }
+
+/* Desenha */
+
+  if ( tipo==1 || tipo==2 ) cdCanvasEnd(intcgm_canvas);
+}