From ccb3dbd5c949c165913737f7ad5016803abb9fca Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Sun, 5 Apr 2015 10:32:11 -0600
Subject: [PATCH] NX circular drawing.  Reduce computations; line caps needed
 only on every other line segment

---
 nuttx/libnx/nx/nx_drawcircle.c            | 15 +++++++++++++--
 nuttx/libnx/nxtk/nxtk_drawcircletoolbar.c | 14 ++++++++++++--
 nuttx/libnx/nxtk/nxtk_drawcirclewindow.c  | 14 ++++++++++++--
 3 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/nuttx/libnx/nx/nx_drawcircle.c b/nuttx/libnx/nx/nx_drawcircle.c
index ea279a45d..ab2c85ea9 100644
--- a/nuttx/libnx/nx/nx_drawcircle.c
+++ b/nuttx/libnx/nx/nx_drawcircle.c
@@ -113,6 +113,7 @@ int nx_drawcircle(NXWINDOW hwnd, FAR const struct nxgl_point_s *center,
 {
   struct nxgl_point_s pts[NCIRCLE_POINTS];
   FAR struct nxgl_vector_s vector;
+  bool capped;
   int i;
   int ret;
 
@@ -122,17 +123,27 @@ int nx_drawcircle(NXWINDOW hwnd, FAR const struct nxgl_point_s *center,
 
   /* Draw each pair of points as a vector */
 
+  capped = false;
   for (i = POINT_0p0; i < POINT_337p5; i++)
     {
+      /* Draw one line segment */
+
       vector.pt1.x = pts[i].x;
       vector.pt1.y = pts[i].y;
       vector.pt2.x = pts[i+1].x;
       vector.pt2.y = pts[i+1].y;
-      ret = nx_drawline(hwnd, &vector, width, color, true);
+
+      ret = nx_drawline(hwnd, &vector, width, color, capped);
       if (ret != OK)
         {
           return ret;
         }
+
+      /* Every other line segment needs to have a circular line caps to join
+       * cleanly with the surround lines segments without line caps.
+       */
+
+      capped = !capped;
     }
 
   /* The final, closing vector is a special case */
@@ -141,5 +152,5 @@ int nx_drawcircle(NXWINDOW hwnd, FAR const struct nxgl_point_s *center,
   vector.pt1.y = pts[POINT_337p5].y;
   vector.pt2.x = pts[POINT_0p0].x;
   vector.pt2.y = pts[POINT_0p0].y;
-  return nx_drawline(hwnd, &vector, width, color, true);
+  return nx_drawline(hwnd, &vector, width, color, capped);
 }
diff --git a/nuttx/libnx/nxtk/nxtk_drawcircletoolbar.c b/nuttx/libnx/nxtk/nxtk_drawcircletoolbar.c
index 3aab9fd6e..390e0e5b5 100644
--- a/nuttx/libnx/nxtk/nxtk_drawcircletoolbar.c
+++ b/nuttx/libnx/nxtk/nxtk_drawcircletoolbar.c
@@ -113,6 +113,7 @@ int nxtk_drawcircletoolbar(NXTKWINDOW hfwnd, FAR const struct nxgl_point_s *cent
 {
   struct nxgl_point_s pts[NCIRCLE_POINTS];
   FAR struct nxgl_vector_s vector;
+  bool capped;
   int i;
   int ret;
 
@@ -124,15 +125,24 @@ int nxtk_drawcircletoolbar(NXTKWINDOW hfwnd, FAR const struct nxgl_point_s *cent
 
   for (i = POINT_0p0; i < POINT_337p5; i++)
     {
+      /* Draw one line segment */
+
       vector.pt1.x = pts[i].x;
       vector.pt1.y = pts[i].y;
       vector.pt2.x = pts[i+1].x;
       vector.pt2.y = pts[i+1].y;
-      ret = nxtk_drawlinetoolbar(hfwnd, &vector, width, color, true);
+
+      ret = nxtk_drawlinetoolbar(hfwnd, &vector, width, color, capped);
       if (ret != OK)
         {
           return ret;
         }
+
+      /* Every other line segment needs to have a circular line caps to join
+       * cleanly with the surround lines segments without line caps.
+       */
+
+      capped = !capped;
     }
 
   /* The final, closing vector is a special case */
@@ -141,5 +151,5 @@ int nxtk_drawcircletoolbar(NXTKWINDOW hfwnd, FAR const struct nxgl_point_s *cent
   vector.pt1.y = pts[POINT_337p5].y;
   vector.pt2.x = pts[POINT_0p0].x;
   vector.pt2.y = pts[POINT_0p0].y;
-  return nxtk_drawlinetoolbar(hfwnd, &vector, width, color, true);
+  return nxtk_drawlinetoolbar(hfwnd, &vector, width, color, capped);
 }
diff --git a/nuttx/libnx/nxtk/nxtk_drawcirclewindow.c b/nuttx/libnx/nxtk/nxtk_drawcirclewindow.c
index 38435d943..dadf4f41f 100644
--- a/nuttx/libnx/nxtk/nxtk_drawcirclewindow.c
+++ b/nuttx/libnx/nxtk/nxtk_drawcirclewindow.c
@@ -113,6 +113,7 @@ int nxtk_drawcirclewindow(NXTKWINDOW hfwnd, FAR const struct nxgl_point_s *cente
 {
   struct nxgl_point_s pts[NCIRCLE_POINTS];
   FAR struct nxgl_vector_s vector;
+  bool capped;
   int i;
   int ret;
 
@@ -124,15 +125,24 @@ int nxtk_drawcirclewindow(NXTKWINDOW hfwnd, FAR const struct nxgl_point_s *cente
 
   for (i = POINT_0p0; i < POINT_337p5; i++)
     {
+      /* Draw one line segment */
+
       vector.pt1.x = pts[i].x;
       vector.pt1.y = pts[i].y;
       vector.pt2.x = pts[i+1].x;
       vector.pt2.y = pts[i+1].y;
-      ret = nxtk_drawlinewindow(hfwnd, &vector, width, color, true);
+
+      ret = nxtk_drawlinewindow(hfwnd, &vector, width, color, capped);
       if (ret != OK)
         {
           return ret;
         }
+
+      /* Every other line segment needs to have a circular line caps to join
+       * cleanly with the surround lines segments without line caps.
+       */
+
+      capped = !capped;
     }
 
   /* The final, closing vector is a special case */
@@ -141,5 +151,5 @@ int nxtk_drawcirclewindow(NXTKWINDOW hfwnd, FAR const struct nxgl_point_s *cente
   vector.pt1.y = pts[POINT_337p5].y;
   vector.pt2.x = pts[POINT_0p0].x;
   vector.pt2.y = pts[POINT_0p0].y;
-  return nxtk_drawlinewindow(hfwnd, &vector, width, color, true);
+  return nxtk_drawlinewindow(hfwnd, &vector, width, color, capped);
 }