From 9b7b00ac24333e2aafe5187a542dcd500d765234 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wim.taymans@gmail.com>
Date: Thu, 17 Oct 2002 21:36:20 +0000
Subject: Some cleanups, fix for the blending code

Original commit message from CVS:
Some cleanups, fix for the blending code
---
 gst/smpte/paint.c | 144 +++++++++++++++++++++++++++---------------------------
 1 file changed, 71 insertions(+), 73 deletions(-)

(limited to 'gst/smpte/paint.c')

diff --git a/gst/smpte/paint.c b/gst/smpte/paint.c
index 51eecebd..07cffc4f 100644
--- a/gst/smpte/paint.c
+++ b/gst/smpte/paint.c
@@ -204,44 +204,46 @@ gst_smpte_paint_triangle_linear (guint32 *dest, gint stride,
   }
 }
 
-
-void 
-draw_line (guint32* dest, gint stride, int x, int y, int x2, int y2, int col) 
+static void 
+draw_bresenham_line (guint32 *dest, gint stride, 
+		     gint x0, gint y0, 
+		     gint x1, gint y1, 
+		     guint32 col)
 {
-  gboolean yLonger=FALSE;
-  int incrementVal, endVal;
-  gdouble decInc;
-  int shortLen=y2-y;
-  int longLen=x2-x;
-  gdouble j=0.0;
-  int i;
-
-  if (abs(shortLen)>abs(longLen)) {
-    int swap=shortLen;
-    shortLen=longLen;
-    longLen=swap;
-    yLonger=TRUE;
+  gint dx = abs (x1 - x0);
+  gint dy = abs (y1 - y0);
+  gint x_incr, y_incr;
+  gint i, dpr, dpru, P, indep;
+
+  dest = dest + y0 * stride + x0;
+
+  x_incr = SIGN (x1 - x0);
+  y_incr = SIGN (y1 - y0) * stride;
+	
+  if (dx >= dy)	{           
+    dpr = dy << 1;
+    i = dx;
+    indep = x_incr;
+  }
+  else {
+    dpr = dx << 1;
+    i = dy;
+    indep = y_incr;
   }
 
-  endVal=longLen;
-  if (longLen<0) {
-    incrementVal=-1;
-    longLen=-longLen;
-  } 
-  else incrementVal=1;
-   
-  if (longLen==0) decInc=(gdouble)shortLen;
-  else decInc = ((gdouble)shortLen/(gdouble)longLen);
-  
-  if (yLonger) {
-    for (i=0;i!=endVal;i+=incrementVal) {
-      *(dest+(x+(int)j) + (y+i)*stride) = col;
-      j+=decInc;
-    }
-  } else {
-    for (i=0;i!=endVal;i+=incrementVal) {
-      *(dest+(x+i) + (y+(int)j)*stride) = col;
-      j+=decInc;
+  dpru = dpr - (i << 1);
+  P = dpr - i;
+
+  for (; i >= 0; i--) {
+    *dest = col;
+
+    if (P > 0) { 
+      dest += x_incr;
+      dest += y_incr;
+      P += dpru;
+    } else {
+      dest += indep;
+      P += dpr;
     }
   }
 }
@@ -255,44 +257,41 @@ gst_smpte_paint_triangle_clock (guint32 *dest, gint stride,
   gint i;
   gint sign;
   gfloat angle, angle_s, angle_e;
+  gfloat len1;
 
   angle_s = 0.0;
   angle_e = acos (((x1-x0) * (x2-x0) + (y1-y0) * (y2-y0))/
 		    (sqrt ((x1-x0) * (x1-x0) + (y1-y0) * (y1-y0)) * 
 		     sqrt ((x2-x0) * (x2-x0) + (y2-y0) * (y2-y0))));
 
-  if (x1 == x2) {
-    gfloat len1 = sqrt ((x1-x0) * (x1-x0) + (y1-y0) * (y1-y0));
+  len1 = sqrt ((x1-x0) * (x1-x0) + (y1-y0) * (y1-y0));
 
+  if (x1 == x2) {
     sign = SIGN (y2 - y1);
 
-    for (i=y1; i != y2+sign; i+=sign) {
-      gfloat len2 = sqrt ((x1-x0) * (x1-x0) + (i-y0) * (i-y0));
-      
-      if (y1==i)
+    for (i = y1; i != (y2 + sign); i += sign) {
+      if (y1 == i)
 	angle = 0;
       else
-        angle = acos (((x1-x0) * (x2-x0) + (y1-y0) * (i-y0))/ (len1 * len2)) / angle_e;
+        angle = acos (((x1-x0) * (x2-x0) + (y1-y0) * (i-y0)) / 
+			(len1 * sqrt ((x1-x0) * (x1-x0) + (i-y0) * (i-y0)))) / angle_e;
 
-      draw_line (dest, stride,
+      draw_bresenham_line (dest, stride,
 		    x0, y0, x1, i, 
 		    (c2 * angle + c1 * (1.0-angle)));
     }
   }
   else if (y1 == y2) {
-    gfloat len1 = sqrt ((x1-x0) * (x1-x0) + (y1-y0) * (y1-y0));
-
     sign = SIGN (x2 - x1);
 
-    for (i=x1; i != x2+sign; i+=sign) {
-      gfloat len2 = sqrt ((i-x0) * (i-x0) + (y2-y0) * (y2-y0));
-
-      if (x1==i)
+    for (i = x1; i != (x2 + sign); i += sign) {
+      if (x1 == i)
 	angle = 0;
       else
-        angle = acos (((x1-x0) * (i-x0) + (y1-y0) * (y2-y0)) / (len1 * len2)) / angle_e;
+        angle = acos (((x1-x0) * (i-x0) + (y1-y0) * (y2-y0)) / 
+			(len1 * sqrt ((i-x0) * (i-x0) + (y2-y0) * (y2-y0)))) / angle_e;
 
-      draw_line (dest, stride,
+      draw_bresenham_line (dest, stride,
 		    x0, y0, i, y1, 
 		    (c2 * angle + c1 * (1.0-angle)));
     }
@@ -305,35 +304,34 @@ gst_smpte_paint_box_clock (guint32 *dest, gint stride,
 			   gint x1, gint y1, gint c1, 
 			   gint x2, gint y2, gint c2)
 {
-  gfloat angle_m;
+  gfloat angle_m, col_m;
+  gint xv, yv;
+
+  if (x1 == x0) { 
+    xv = x2;
+    yv = y1;
+  } else if (y1 == y0) {
+    xv = x1;
+    yv = y2;
+  }
+  else {
+    g_warning ("paint box clock: not supported");
+    return;
+  }
 
-  if (x1 == x0) {
-    angle_m = 2* acos (((x1-x0) * (x2-x0) + (y1-y0) * (y1-y0))/
+  angle_m = 2 * acos (((x1-x0) * (xv-x0) + (y1-y0) * (yv-y0))/
 		    (sqrt ((x1-x0) * (x1-x0) + (y1-y0) * (y1-y0)) * 
-		     sqrt ((x2-x0) * (x2-x0) + (y1-y0) * (y1-y0)))) / M_PI;
+		     sqrt ((xv-x0) * (xv-x0) + (yv-y0) * (yv-y0)))) / M_PI;
     
-    gst_smpte_paint_triangle_clock (dest, stride,
-		                  x0, y0, c0,
-		                  x1, y1, c1,
-		                  x2, y1, (c2 * angle_m + c1 * (1.0-angle_m)));
-    gst_smpte_paint_triangle_clock (dest, stride,
-		                  x0, y0, c0,
-		                  x2, y1, (c2 * angle_m + c1 * (1.0-angle_m)),
-		                  x2, y2, c2);
-  }
-  else if (y1 == y0) {
-    angle_m = 2* acos (((x1-x0) * (x1-x0) + (y1-y0) * (y2-y0))/
-		    (sqrt ((x1-x0) * (x1-x0) + (y1-y0) * (y1-y0)) * 
-		     sqrt ((x1-x0) * (x1-x0) + (y2-y0) * (y2-y0)))) / M_PI;
+  col_m = c2 * angle_m + c1 * (1.0-angle_m);
 
-    gst_smpte_paint_triangle_clock (dest, stride,
+  gst_smpte_paint_triangle_clock (dest, stride,
 		                  x0, y0, c0,
 		                  x1, y1, c1,
-		                  x1, y2, (c2 * angle_m + c1 * (1.0-angle_m)));
-    gst_smpte_paint_triangle_clock (dest, stride,
+		                  xv, yv, col_m);
+  gst_smpte_paint_triangle_clock (dest, stride,
 		                  x0, y0, c0,
-		                  x1, y2, (c2 * angle_m + c1 * (1.0-angle_m)),
+		                  xv, yv, col_m,
 		                  x2, y2, c2);
-  }
 }
 
-- 
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