add a simple draw_circle()

2 files changed, 19 insertions, 0 deletions

diff --git a/kms++util/inc/kms++util/kms++util.h b/kms++util/inc/kms++util/kms++util.h
index 8e45b0d..62ec663 100644
--- a/kms++util/inc/kms++util/kms++util.h
+++ b/kms++util/inc/kms++util/kms++util.h
@@ -22,6 +22,7 @@ void draw_yuv422_macropixel(IFramebuffer& buf, unsigned x, unsigned y, YUV yuv1,
 void draw_yuv420_macropixel(IFramebuffer& buf, unsigned x, unsigned y,
 				   YUV yuv1, YUV yuv2, YUV yuv3, YUV yuv4);
 void draw_rect(IFramebuffer &fb, uint32_t x, uint32_t y, uint32_t w, uint32_t h, RGB color);
+void draw_circle(IFramebuffer& fb, int32_t xCenter, int32_t yCenter, int32_t radius, RGB color);
 void draw_text(IFramebuffer& buf, uint32_t x, uint32_t y, const std::string& str, RGB color);
 
 void draw_color_bar(IFramebuffer& buf, int old_xpos, int xpos, int width);
diff --git a/kms++util/src/drawing.cpp b/kms++util/src/drawing.cpp
index 4e5c6c1..8885112 100644
--- a/kms++util/src/drawing.cpp
+++ b/kms++util/src/drawing.cpp
@@ -1,4 +1,6 @@
 
+#include <cmath>
+
 #include <kms++/kms++.h>
 #include <kms++util/kms++util.h>
 
@@ -198,6 +200,22 @@ void draw_rect(IFramebuffer &fb, uint32_t x, uint32_t y, uint32_t w, uint32_t h,
 	}
 }
 
+void draw_horiz_line(IFramebuffer& fb, uint32_t x1, uint32_t x2, uint32_t y, RGB color)
+{
+	for (uint32_t x = x1; x <= x2; ++x)
+		draw_rgb_pixel(fb, x, y, color);
+}
+
+void draw_circle(IFramebuffer& fb, int32_t xCenter, int32_t yCenter, int32_t radius, RGB color)
+{
+	int32_t r2 = radius * radius;
+
+	for (int y = -radius; y <= radius; y++) {
+		int32_t x = (int)(sqrt(r2 - y * y) + 0.5);
+		draw_horiz_line(fb, xCenter - x, xCenter + x, yCenter - y, color);
+	}
+}
+
 static bool get_char_pixel(char c, uint32_t x, uint32_t y)
 {
 #include "font_8x8.h"