New, hopefully better, implementation of PART drawing

[rrdtool.git] / src / rrd_gfx.c

diff --git a/src/rrd_gfx.c b/src/rrd_gfx.c
index 724a074..1a45439 100644 (file)
--- a/src/rrd_gfx.c
+++ b/src/rrd_gfx.c
@@ -15,6 +15,7 @@
 #include <png.h>
 #include <ft2build.h>
 #include FT_FREETYPE_H
+#include <math.h>
 
 #include "rrd_gfx.h"
 
@@ -107,6 +108,52 @@ gfx_node_t   *gfx_new_area   (gfx_canvas_t *canvas,
 
   return node;
 }
+/* create an arc section (2*M_PI is full circle) */
+gfx_node_t   *gfx_arc_sect   (gfx_canvas_t *canvas, 
+                             double centerx, double centery,
+                             double radiusx, double radiusy,
+                             double start, double end,
+                             gfx_color_t color) {
+
+  gfx_node_t *node;
+  ArtVpath *vec;
+  int counter;
+  double position;
+
+/* 20 is too low, 100 is overkill */
+#define AMOUNT_OF_VECTORS 50
+
+  node = gfx_new_node(canvas,GFX_AREA);
+  if (node == NULL) return NULL;
+  vec = art_new(ArtVpath, AMOUNT_OF_VECTORS+4);
+  if (vec == NULL) return NULL;
+
+  vec[0].code = ART_MOVETO;
+  vec[0].x = centerx;
+  vec[0].y = centery;
+
+  for (counter=0;counter<=AMOUNT_OF_VECTORS;) {
+    position=start + counter*(end-start)/AMOUNT_OF_VECTORS;
+
+    counter++;
+    vec[counter].code = ART_LINETO;
+    vec[counter].x = centerx + sin(position)*radiusx;
+    vec[counter].y = centery - cos(position)*radiusy;
+  }
+
+  vec[AMOUNT_OF_VECTORS+2].code = ART_LINETO;
+  vec[AMOUNT_OF_VECTORS+2].x = centerx;
+  vec[AMOUNT_OF_VECTORS+2].y = centery;
+
+  vec[AMOUNT_OF_VECTORS+3].code = ART_END;
+  
+  node->points = AMOUNT_OF_VECTORS+4;
+  node->points_max = AMOUNT_OF_VECTORS+4;
+  node->color = color;
+  node->path  = vec;
+
+  return node;
+}
 
 /* add a point to a line or to an area */
 int           gfx_add_point  (gfx_node_t *node,