From 06a978b8e3c0702b853069e627db41c51b3b11fd Mon Sep 17 00:00:00 2001
From: zeljko <zeljko@lazarus-ide.org>
Date: Mon, 30 Nov 2009 20:43:38 +0000
Subject: [PATCH] Qt: fix segfault when creating QRegion with negative width or
 height.Fixed implementation of GetRgnBox, so it doesn't ask for
 QRegion_boundingRect() if returned region type is ERROR or NULLREGION.

git-svn-id: trunk@22881 -
---
 lcl/interfaces/qt/qtobjects.pas | 15 +++++++++++++--
 lcl/interfaces/qt/qtwinapi.inc  |  9 ++++-----
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/lcl/interfaces/qt/qtobjects.pas b/lcl/interfaces/qt/qtobjects.pas
index 43466045a3..4fcf84b9e8 100644
--- a/lcl/interfaces/qt/qtobjects.pas
+++ b/lcl/interfaces/qt/qtobjects.pas
@@ -1631,7 +1631,7 @@ begin
   {$endif}
 
   // Creates the widget
-  if CreateHandle then Widget := QRegion_create;
+  if CreateHandle then Widget := QRegion_create();
 end;
 
 {------------------------------------------------------------------------------
@@ -1641,6 +1641,8 @@ end;
  ------------------------------------------------------------------------------}
 constructor TQtRegion.Create(CreateHandle: Boolean; X1,Y1,X2,Y2:Integer;
   Const RegionType: QRegionRegionType = QRegionRectangle);
+var
+  W, H: Integer;
 begin
   {$ifdef VerboseQt}
     WriteLn('TQtRegion.Create CreateHandle: ', dbgs(CreateHandle));
@@ -1649,7 +1651,16 @@ begin
   // Creates the widget
   // Note that QRegion_create expects a width and a height,
   // and not a X2, Y2 bottom-right point
-  if CreateHandle then Widget := QRegion_create(X1,Y1,X2-X1,Y2-Y1, RegionType);
+  if CreateHandle then
+  begin
+    W := X2 - X1;
+    H := Y2 - Y1;
+    if W < 0 then
+      W := 0;
+    if H < 0 then
+      H := 0;
+    Widget := QRegion_create(X1, Y1, W, H, RegionType);
+  end;
 end;
 
 constructor TQtRegion.Create(CreateHandle: Boolean; Poly: QPolygonH;
diff --git a/lcl/interfaces/qt/qtwinapi.inc b/lcl/interfaces/qt/qtwinapi.inc
index b3b9990711..59e7668cb5 100644
--- a/lcl/interfaces/qt/qtwinapi.inc
+++ b/lcl/interfaces/qt/qtwinapi.inc
@@ -2581,20 +2581,19 @@ var
   R: TRect;
 begin
   {$ifdef VerboseQtWinAPI}
-    WriteLn('[WinAPI TQtWidgetSet.GetRgnBox] possible wrong implementation !');
+  writeln('Trace:> [WinAPI GetRgnBox] Handle: ' + dbghex(RGN));
   {$endif}
   Result := SIMPLEREGION;
-  If lpRect <> nil then
+  if lpRect <> nil then
     lpRect^ := Rect(0,0,0,0);
-  If Not IsValidGDIObject(RGN) then
+  if not IsValidGDIObject(RGN) then
     Result := ERROR
   else
   begin
     Result := TQtRegion(RGN).GetRegionType;
-    If lpRect <> nil then
+    if not (Result in [ERROR, NULLREGION]) and (lpRect <> nil) then
     begin
       QRegion_boundingRect(TQtRegion(RGN).Widget, @R);
-
       with lpRect^ do
       begin
         Left   := R.Left;