Bug 400813. Prevent nsRect::Deflate from creating negative-sized rect…

…angles. r+sr=mats

gfx/src/nsRect.cpp

@@ -39,19 +39,6 @@
 #include "nsString.h"
 #include "nsIDeviceContext.h"
 
-#ifdef MIN
-#undef MIN
-#endif
-
-#ifdef MAX
-#undef MAX
-#endif
-
-#define MIN(a,b)\
-  ((a) < (b) ? (a) : (b))
-#define MAX(a,b)\
-  ((a) > (b) ? (a) : (b))
-
 // Containment
 PRBool nsRect::Contains(nscoord aX, nscoord aY) const
 {
@@ -85,19 +72,19 @@ PRBool nsRect::IntersectRect(const nsRect &aRect1, const nsRect &aRect2)
   nscoord  ymost2 = aRect2.YMost();
   nscoord  temp;
 
-  x = MAX(aRect1.x, aRect2.x);
-  y = MAX(aRect1.y, aRect2.y);
+  x = PR_MAX(aRect1.x, aRect2.x);
+  y = PR_MAX(aRect1.y, aRect2.y);
 
   // Compute the destination width
-  temp = MIN(xmost1, xmost2);
+  temp = PR_MIN(xmost1, xmost2);
   if (temp <= x) {
     Empty();
     return PR_FALSE;
   }
   width = temp - x;
 
   // Compute the destination height
-  temp = MIN(ymost1, ymost2);
+  temp = PR_MIN(ymost1, ymost2);
   if (temp <= y) {
     Empty();
     return PR_FALSE;
@@ -134,12 +121,12 @@ PRBool nsRect::UnionRect(const nsRect &aRect1, const nsRect &aRect2)
     nscoord ymost2 = aRect2.YMost();
 
     // Compute the origin
-    x = MIN(aRect1.x, aRect2.x);
-    y = MIN(aRect1.y, aRect2.y);
+    x = PR_MIN(aRect1.x, aRect2.x);
+    y = PR_MIN(aRect1.y, aRect2.y);
 
     // Compute the size
-    width = MAX(xmost1, xmost2) - x;
-    height = MAX(ymost1, ymost2) - y;
+    width = PR_MAX(xmost1, xmost2) - x;
+    height = PR_MAX(ymost1, ymost2) - y;
   }
 
   return result;
@@ -168,17 +155,17 @@ void nsRect::Deflate(nscoord aDx, nscoord aDy)
 {
   x += aDx;
   y += aDy;
-  width -= 2 * aDx;
-  height -= 2 * aDy;
+  width = PR_MAX(0, width - 2 * aDx);
+  height = PR_MAX(0, height - 2 * aDy);
 }
 
 // Deflate the rect by the specified margin
 void nsRect::Deflate(const nsMargin &aMargin)
 {
   x += aMargin.left;
   y += aMargin.top;
-  width -= aMargin.left + aMargin.right;
-  height -= aMargin.top + aMargin.bottom;
+  width = PR_MAX(0, width - aMargin.LeftRight());
+  height = PR_MAX(0, height - aMargin.TopBottom());
 }
 
 // scale the rect but round to smallest containing rect
@@ -252,19 +239,19 @@ PRBool nsIntRect::IntersectRect(const nsIntRect &aRect1, const nsIntRect &aRect2
   PRInt32  ymost2 = aRect2.YMost();
   PRInt32  temp;
 
-  x = MAX(aRect1.x, aRect2.x);
-  y = MAX(aRect1.y, aRect2.y);
+  x = PR_MAX(aRect1.x, aRect2.x);
+  y = PR_MAX(aRect1.y, aRect2.y);
 
   // Compute the destination width
-  temp = MIN(xmost1, xmost2);
+  temp = PR_MIN(xmost1, xmost2);
   if (temp <= x) {
     Empty();
     return PR_FALSE;
   }
   width = temp - x;
 
   // Compute the destination height
-  temp = MIN(ymost1, ymost2);
+  temp = PR_MIN(ymost1, ymost2);
   if (temp <= y) {
     Empty();
     return PR_FALSE;
@@ -301,12 +288,12 @@ PRBool nsIntRect::UnionRect(const nsIntRect &aRect1, const nsIntRect &aRect2)
     PRInt32 ymost2 = aRect2.YMost();
 
     // Compute the origin
-    x = MIN(aRect1.x, aRect2.x);
-    y = MIN(aRect1.y, aRect2.y);
+    x = PR_MIN(aRect1.x, aRect2.x);
+    y = PR_MIN(aRect1.y, aRect2.y);
 
     // Compute the size
-    width = MAX(xmost1, xmost2) - x;
-    height = MAX(ymost1, ymost2) - y;
+    width = PR_MAX(xmost1, xmost2) - x;
+    height = PR_MAX(ymost1, ymost2) - y;
   }
 
   return result;