From 21622f66e740841458dbebddac1f83c7f55a1985 Mon Sep 17 00:00:00 2001
From: ask <ask@lazarus-ide.org>
Date: Sat, 16 Jun 2012 10:06:57 +0000
Subject: [PATCH] TAChart: Introduce ZeroRect constant

git-svn-id: trunk@37664 -
---
 components/tachart/tachartlistbox.pas | 4 ++--
 components/tachart/tachartutils.pas   | 1 +
 components/tachart/tagraph.pas        | 4 ++--
 components/tachart/tanavigation.pas   | 2 +-
 components/tachart/test/UtilsTest.pas | 2 +-
 5 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/components/tachart/tachartlistbox.pas b/components/tachart/tachartlistbox.pas
index 9d12f5b3d2..ac7272cf96 100644
--- a/components/tachart/tachartlistbox.pas
+++ b/components/tachart/tachartlistbox.pas
@@ -218,8 +218,8 @@ procedure TChartListbox.CalcRects(
 var
   w, x: Integer;
 begin
-  ACheckBoxRect := Rect(-1, -1, -1, -1);
-  ASeriesIconRect := Rect(-1, -1, -1, -1);
+  ACheckBoxRect := ZeroRect;
+  ASeriesIconRect := ZeroRect;
   w := GetSystemMetrics(SM_CYMENUCHECK);
   x := 2;
   if cloShowCheckboxes in Options then begin
diff --git a/components/tachart/tachartutils.pas b/components/tachart/tachartutils.pas
index 5f598c6a5d..372f3418de 100644
--- a/components/tachart/tachartutils.pas
+++ b/components/tachart/tachartutils.pas
@@ -250,6 +250,7 @@ const
     '%4:.9g' // smsXValue
   );
   ZeroDoublePoint: TDoublePoint = (X: 0; Y: 0);
+  ZeroRect: TRect = (Left: 0; Top: 0; Right: 0; Bottom: 0);
   EmptyDoubleRect: TDoubleRect = (coords: (0, 0, 0, 0));
   EmptyExtent: TDoubleRect =
     (coords: (Infinity, Infinity, NegInfinity, NegInfinity));
diff --git a/components/tachart/tagraph.pas b/components/tachart/tagraph.pas
index c126b9da44..4c389298e8 100644
--- a/components/tachart/tagraph.pas
+++ b/components/tachart/tagraph.pas
@@ -1001,7 +1001,7 @@ var
   a: TRectArray absolute Result;
   s: TBasicChartSeries;
 begin
-  Result := Rect(0, 0, 0, 0);
+  Result := ZeroRect;
   for s in Series do
     if s.Active then
       s.UpdateMargins(ADrawer, Result);
@@ -1171,7 +1171,7 @@ begin
 
   // There is a cyclic dependency: extent -> visible marks -> margins.
   // We recalculate them iteratively hoping that the process converges.
-  CalculateTransformationCoeffs(Rect(0, 0, 0, 0));
+  CalculateTransformationCoeffs(ZeroRect);
   cr := FClipRect;
   for tries := 1 to 10 do begin
     axisMargin := AxisList.Measure(CurrentExtent);
diff --git a/components/tachart/tanavigation.pas b/components/tachart/tanavigation.pas
index 9c71d3b576..3acd7fb27f 100644
--- a/components/tachart/tanavigation.pas
+++ b/components/tachart/tanavigation.pas
@@ -265,7 +265,7 @@ begin
   FFullExtentPen.OnChange := @ChartExtentChanged;
   FLogicalExtentPen := TPen.Create;
   FLogicalExtentPen.OnChange := @ChartExtentChanged;
-  FLogicalExtentRect := Rect(0, 0, 0, 0);
+  FLogicalExtentRect := ZeroRect;
   Width := DEF_WIDTH;
   Height := DEF_HEIGHT;
   FAllowDragNavigation := true;
diff --git a/components/tachart/test/UtilsTest.pas b/components/tachart/test/UtilsTest.pas
index 199ce88902..2e361b778b 100644
--- a/components/tachart/test/UtilsTest.pas
+++ b/components/tachart/test/UtilsTest.pas
@@ -190,7 +190,7 @@ procedure TGeometryTest.TestExpandRect;
 var
   r: TRect;
 begin
-  r := Rect(0, 0, 0, 0);
+  r := ZeroRect;
   ExpandRect(r, Point(1, 2));
   AssertEquals(Rect(0, 0, 1, 2), r);
   ExpandRect(r, Point(-5, -6));