[lazarus] Utilities in Graphic.pp

[Giuliano Colla]

The attached patch adds a couple of useful procedure to the graphics 
library, i.e. InflateRect and OffsetRect. They are derived from the 
Delphi counterparts, and are useful to increase or decrease the size of 
a rectangle, or to move it. This happens frequently when drawing in the 
client area of a component, and one has to take into account border 
width, or simulate the button up/down, etc.

Regards,
Giuliano Colla
Index: graphics.pp
===================================================================
--- graphics.pp	(revisione 9820)
+++ graphics.pp	(copia locale)
@@ -1310,6 +1310,9 @@
 function FPColorToTColor(const FPColor: TFPColor): TColor;
 function TColorToFPColor(const c: TColor): TFPColor;
 
+procedure InflateRect(var ARect: TRect; X, Y: Integer);
+procedure OffsetRect(var ARect: TRect; X, Y: Integer);
+
 // fonts
 procedure GetCharsetValues(Proc: TGetStrProc);
 function CharsetToIdent(Charset: Longint; var Ident: string): Boolean;
@@ -1679,6 +1682,27 @@
   Result.Alpha:=FPImage.alphaOpaque;
 end;
 
+procedure InflateRect(var ARect: TRect; X, Y: Integer);
+begin
+  with ARect do begin
+    Dec(Top, Y);
+    Inc(Bottom, Y);
+    Dec(Left, X);
+    Inc(Right, X);
+  end;
+end;
+
+procedure OffsetRect(var ARect: TRect; X, Y: Integer);
+begin
+  with ARect do begin
+    Inc(Left, X);
+    Inc(Top, Y);
+    Inc(Right, X);
+    Inc(Bottom, Y);
+  end;
+end;
+
+
 {$I graphicsobject.inc}
 {$I graphic.inc}
 {$I picture.inc}