From edc6e254f31e94ba0da5a7adb534bc0ad411c035 Mon Sep 17 00:00:00 2001
From: Stefano Ceccherini <stefano.ceccherini@gmail.com>
Date: Thu, 1 Jul 2004 06:16:00 +0000
Subject: [PATCH] Fixed the outstanding BRegion bug. It turned out that
 rects_intersect() returned true in some cases when called with an invalid
 clipping_rect. Added an ASSERT() call to BRegion::_AddRect(), which would've
 saved my day. Added some comments

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@8246 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 headers/private/interface/clipping.h | 22 +++++++++++++++++++++-
 src/kits/interface/Region.cpp        |  3 ++-
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/headers/private/interface/clipping.h b/headers/private/interface/clipping.h
index fc38cd515e..af9e7ddde8 100644
--- a/headers/private/interface/clipping.h
+++ b/headers/private/interface/clipping.h
@@ -12,6 +12,8 @@
 	calculations).
 */
 
+
+// Returns the union of the given rects.
 static inline clipping_rect
 union_rect(clipping_rect r1, clipping_rect r2)
 {
@@ -43,6 +45,7 @@ sect_rect(clipping_rect r1, clipping_rect r2)
 }
 
 
+// Adds the given offsets to the given rect.
 static inline void
 offset_rect(clipping_rect &rect, int32 x, int32 y)
 {
@@ -53,13 +56,15 @@ offset_rect(clipping_rect &rect, int32 x, int32 y)
 }
 
 
+// Converts the given clipping_rect to a BRect
 static inline BRect
 to_BRect(clipping_rect rect)
 {
-	return BRect(rect.left, rect.top, rect.right, rect.bottom);
+	return BRect((float)rect.left, (float)rect.top, (float)rect.right, (float)rect.bottom);
 }
 
 
+// Converts the given BRect to a clipping_rect.
 static inline clipping_rect
 to_clipping_rect(BRect rect)
 {
@@ -74,6 +79,7 @@ to_clipping_rect(BRect rect)
 }
 
 
+// Checks if the given point lies in the given rect's area
 static inline bool
 point_in(clipping_rect rect, int32 px, int32 py)
 {
@@ -84,6 +90,7 @@ point_in(clipping_rect rect, int32 px, int32 py)
 }
 
 
+// Same as above, but it accepts a BPoint parameter
 static inline bool
 point_in(clipping_rect rect, BPoint pt)
 {
@@ -94,6 +101,7 @@ point_in(clipping_rect rect, BPoint pt)
 }
 
 
+// Checks if the rect is valid
 static inline bool
 valid_rect(clipping_rect rect)
 {
@@ -103,14 +111,25 @@ valid_rect(clipping_rect rect)
 }
 
 
+// Checks if the two rects intersect.
 static inline bool
 rects_intersect(clipping_rect rectA, clipping_rect rectB)
 {
+	// TODO: should we skip that check and let the caller do this
+	// kind of work ?
+	if (!valid_rect(rectA) || !valid_rect(rectB))
+		return false;
+
+	// TODO: Is there a better algorithm ? 
+	// the one we used is faster than
+	// ' return valid_rect(sect_rect(rectA, rectB)); ', though.
+
 	return !(rectA.left > rectB.right || rectA.top > rectB.bottom
 			|| rectA.right < rectB.left || rectA.bottom < rectB.top);
 }
 
 
+// Returns the width of the given rect.
 static inline int32
 rect_width(clipping_rect rect)
 {
@@ -118,6 +137,7 @@ rect_width(clipping_rect rect)
 }
 
 
+// Returns the height of the given rect.
 static inline int32
 rect_height(clipping_rect rect)
 {
diff --git a/src/kits/interface/Region.cpp b/src/kits/interface/Region.cpp
index da1fe04d99..4214cb11e0 100644
--- a/src/kits/interface/Region.cpp
+++ b/src/kits/interface/Region.cpp
@@ -435,7 +435,8 @@ BRegion::_AddRect(clipping_rect rect)
 {
 	ASSERT(count >= 0);
 	ASSERT(data_size >= 0);
-	
+	ASSERT(valid_rect(rect));
+
 	// Should we just reallocate the memory and
 	// copy the rect ?
 	bool addRect = true;