Add rtgrpblib_draw_circular_arc

Signed-off-by: Mattias Andrée <maandree@kth.se>

4 files changed, 75 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index 1db2138..322c783 100644
--- a/Makefile
+++ b/Makefile
@@ -21,6 +21,7 @@ OBJ =\
 	lines.o\
 	sorting.o\
 	rtgrpblib_create_raster.o\
+	rtgrpblib_draw_circular_arc.o\
 	rtgrpblib_draw_linear_bezier.o\
 	rtgrpblib_draw_quadratic_bezier.o\
 	rtgrpblib_draw_cubic_bezier.o\
diff --git a/demo.c b/demo.c
index 76473e7..6157fbd 100644
--- a/demo.c
+++ b/demo.c
@@ -26,11 +26,16 @@ main(void)
 		{35, 15},
 		{20, 25},
 		{5, 15}
-#else
+#elif 0
 		{5.25, 5.25},
 		{35.75, 5.25},
 		{35.75, 25.75},
 		{5.25, 25.75}
+#else
+		/* for circular arch*/
+		{20, 15},
+		{15, 10},
+		{100 * M_PI/180, 400 * M_PI/180}
 #endif
 	};
 
@@ -46,9 +51,21 @@ main(void)
 #elif 0
 	rtgrpblib_draw_quadratic_bezier(raster, P(2), P(3), P(0));
 	rtgrpblib_draw_linear_bezier(raster, P(0), P(2));
-#else
+#elif 0
 	rtgrpblib_draw_cubic_bezier(raster, P(0), P(1), P(2), P(3));
 	rtgrpblib_draw_linear_bezier(raster, P(3), P(0));
+#else
+	rtgrpblib_draw_circular_arc(raster, P(0), P(1), P(2));
+	rtgrpblib_draw_linear_bezier(raster,
+	                             points[0].x + points[1].x * cos(points[2].y),
+	                             points[0].y + points[1].y * sin(points[2].y),
+	                             points[0].x,
+	                             points[0].y);
+	rtgrpblib_draw_linear_bezier(raster,
+	                             points[0].x,
+	                             points[0].y,
+	                             points[0].x + points[1].x * cos(points[2].x),
+	                             points[0].y + points[1].y * sin(points[2].x));
 #endif
 
 	rtgrpblib_fill_shapes(image, width, raster);
diff --git a/librifunktionsteckensnittsglyfrasteriseringsprogrambiblioteket.h b/librifunktionsteckensnittsglyfrasteriseringsprogrambiblioteket.h
index 0fceece..fffeae7 100644
--- a/librifunktionsteckensnittsglyfrasteriseringsprogrambiblioteket.h
+++ b/librifunktionsteckensnittsglyfrasteriseringsprogrambiblioteket.h
@@ -30,4 +30,11 @@ void rtgrpblib_draw_cubic_bezier(RTGRPBLIB_RASTER *restrict raster,
                                  double x3, double y3,
                                  double x4, double y4);
 
+void rtgrpblib_draw_circular_arc(RTGRPBLIB_RASTER *restrict raster,
+                                 double x0, double y0,
+                                 double semiwidth, double semiheight,
+                                 double start, double end);
+
+/* TODO add support for outlining */
+
 #endif
diff --git a/rtgrpblib_draw_circular_arc.c b/rtgrpblib_draw_circular_arc.c
new file mode 100644
index 0000000..f30fde7
--- /dev/null
+++ b/rtgrpblib_draw_circular_arc.c
@@ -0,0 +1,48 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+
+void
+rtgrpblib_draw_circular_arc(RASTER *restrict raster, double x0, double y0,
+                            double semiwidth, double semiheight, double start, double end)
+{
+	double inc, v, x, y, prevX, prevY;
+
+	if (start == end)
+		return;
+
+	/* TODO precalculate intersection with raster box */
+
+	inc = fmax(semiwidth, semiheight);
+	inc *= 2 * M_PI;
+	inc *= end - start;
+	inc = raster->draftness / inc;
+
+	v = start;
+	prevX = x0 + semiwidth * cos(start);
+	prevY = y0 + semiheight * sin(start);
+
+	for (; (v += inc) < end; prevX = x, prevY = y) {
+		x = x0 + semiwidth * cos(v);
+		y = y0 + semiheight * sin(v);
+		rtgrpblib_draw_linear_bezier(raster, prevX, prevY, x, y);
+	}
+
+	x = x0 + semiwidth * cos(end);
+	y = y0 + semiheight * sin(end);
+	rtgrpblib_draw_linear_bezier(raster, prevX, prevY, x, y);
+}
+
+
+#else
+
+
+int
+main(void)
+{
+	return 0; /* TODO add test */
+}
+
+
+#endif