CLAMP divisions

and go back to clamping in test as well.

Note that there are various other cases, blend_dodge() for example,
where we can end up dividing by zero.

Conflicts:

	pixman/pixman-combine-float.c

1 files changed, 44 insertions, 15 deletions

diff --git a/pixman/pixman-combine-float.c b/pixman/pixman-combine-float.c
index 9617e240..bd190901 100644
--- a/pixman/pixman-combine-float.c
+++ b/pixman/pixman-combine-float.c
@@ -159,55 +159,84 @@ typedef enum
     ONE_MINUS_INV_SA_OVER_DA
 } combine_factor_t;
 
+#define CLAMP(f)					\
+    (((f) < 0)? 0 : (((f) > 1.0) ? 1.0 : (f)))
+
+#define IS_ZERO(f) ((f) == 0.0f) /* FIXME? */
+
 static force_inline float
 get_factor (combine_factor_t factor, float sa, float da)
 {
+    float f = -1;
+
     switch (factor)
     {
     case ZERO:
-	return 0.0f;
+	f = 0.0f;
+	break;
 
     case ONE:
-	return 1.0f;
+	f = 1.0f;
+	break;
 
     case SRC_ALPHA:
-	return sa;
+	f = sa;
+	break;
 
     case DEST_ALPHA:
-	return da;
+	f = da;
+	break;
 
     case INV_SA:
-	return 1 - sa;
+	f = 1 - sa;
+	break;
 
     case INV_DA:
-	return 1 - da;
+	f = 1 - da;
+	break;
 
     case SA_OVER_DA:
-	return da <= sa ? 1.0f : sa / da;
+	f = IS_ZERO (da)? 1.0f : sa / da;
+	f = CLAMP (f);
+	break;
 
     case DA_OVER_SA:
-	return sa <= da ? 1.0f : da / sa;
+	f = IS_ZERO (sa) ? 1.0f : da / sa;
+	f = CLAMP (f);
+	break;
 
     case INV_SA_OVER_DA:
-	return da <= 1.0f - sa ? 1.0f : (1.0f - sa) / da;
+	f = IS_ZERO (da) ? 1.0f : (1.0f - sa) / da;
+	f = CLAMP (f);
+	break;
 
     case INV_DA_OVER_SA:
-	return sa <= 1.0f - da ? 1.0f : (1.0f - da) / sa;
+	f = IS_ZERO (sa) ? 1.0f : (1.0f - da) / sa;
+	f = CLAMP (f);
+	break;
 
     case ONE_MINUS_SA_OVER_DA:
-	return da <= sa ? 0.0f : 1.0f - sa / da;
+	f = IS_ZERO (da) ? 0.0f : 1.0f - sa / da;
+	f = CLAMP (f);
+	break;
 
     case ONE_MINUS_DA_OVER_SA:
-	return sa <= da ? 0.0f : 1.0f - da / sa;
+	f = IS_ZERO (sa) ? 0.0f : 1.0f - da / sa;
+	f = CLAMP (f);
+	break;
 
     case ONE_MINUS_INV_DA_OVER_SA:
-	return sa <= 1.0f - da ? 0.0f : 1.0f - (1.0f - da) / sa;
+	f = IS_ZERO (sa) ? 0.0f : 1.0f - (1.0f - da) / sa;
+	f = CLAMP (f);
+	break;
 
     case ONE_MINUS_INV_SA_OVER_DA:
-	return da <= 1.0f - sa ? 0.0f : 1.0f - (1.0f - sa) / da;
+	f = IS_ZERO (da) ? 0.0f : 1.0f - (1.0f - sa) / da;
+	f = CLAMP (f);
+	break;
     }
 
-    return -1;
+    return f;
 }
 
 #define MAKE_PD_COMBINERS(name, a, b)					\