* Implemented the Wu Anti-Aliased line drawing algorithm. Soon the canvas DrawLine will start using it.

* Created a very quick and simple Wu Line example.

2 files changed, 181 insertions, 0 deletions

diff --git a/examples/gui/wulinetest/wuline_test.lpi b/examples/gui/wulinetest/wuline_test.lpi
new file mode 100644
index 00000000..4929958e
--- /dev/null
+++ b/examples/gui/wulinetest/wuline_test.lpi
@@ -0,0 +1,54 @@
+<?xml version="1.0"?>
+<CONFIG>
+  <ProjectOptions>
+    <PathDelim Value="/"/>
+    <Version Value="6"/>
+    <General>
+      <Flags>
+        <SaveOnlyProjectUnits Value="True"/>
+      </Flags>
+      <SessionStorage Value="InProjectDir"/>
+      <MainUnit Value="0"/>
+      <IconPath Value="./"/>
+      <TargetFileExt Value=""/>
+    </General>
+    <VersionInfo>
+      <ProjectVersion Value=""/>
+    </VersionInfo>
+    <PublishOptions>
+      <Version Value="2"/>
+      <IgnoreBinaries Value="False"/>
+      <IncludeFileFilter Value="*.(pas|pp|inc|lfm|lpr|lrs|lpi|lpk|sh|xml)"/>
+      <ExcludeFileFilter Value="*.(bak|ppu|ppw|o|so);*~;backup"/>
+    </PublishOptions>
+    <RunParams>
+      <local>
+        <FormatVersion Value="1"/>
+        <LaunchingApplication PathPlusParams="/usr/X11R6/bin/xterm -T 'Lazarus Run Output' -e $(LazarusDir)/tools/runwait.sh $(TargetCmdLine)"/>
+      </local>
+    </RunParams>
+    <RequiredPackages Count="1">
+      <Item1>
+        <PackageName Value="fpgui_package"/>
+      </Item1>
+    </RequiredPackages>
+    <Units Count="1">
+      <Unit0>
+        <Filename Value="wuline_test.lpr"/>
+        <IsPartOfProject Value="True"/>
+        <UnitName Value="wuline_test"/>
+      </Unit0>
+    </Units>
+  </ProjectOptions>
+  <CompilerOptions>
+    <Version Value="5"/>
+    <CodeGeneration>
+      <Generate Value="Faster"/>
+    </CodeGeneration>
+    <Other>
+      <CustomOptions Value="-FUunits
+"/>
+      <CompilerPath Value="$(CompPath)"/>
+    </Other>
+  </CompilerOptions>
+</CONFIG>
diff --git a/examples/gui/wulinetest/wuline_test.lpr b/examples/gui/wulinetest/wuline_test.lpr
new file mode 100644
index 00000000..e1a04f7d
--- /dev/null
+++ b/examples/gui/wulinetest/wuline_test.lpr
@@ -0,0 +1,127 @@
+program wuline_test;
+
+{$mode objfpc}{$H+}
+
+uses
+  {$IFDEF UNIX}{$IFDEF UseCThreads}
+  cthreads,
+  {$ENDIF}{$ENDIF}
+  Classes, SysUtils, gfxbase, fpgfx, gui_form, gui_button, math,
+  gfx_imgfmt_bmp, gfx_wuline;
+
+type
+
+  { TMainForm }
+
+  TMainForm = class(TfpgForm)
+  private
+    btnGo: TfpgButton;
+    procedure btnGoClicked(Sender: TObject);
+    procedure DrawSpokes(phase: double);
+    procedure DrawSpiral;
+  public
+    constructor Create(AOwner: TComponent); override;
+  end;
+
+{ TMainForm }
+
+procedure TMainForm.btnGoClicked(Sender: TObject);
+begin
+  Canvas.BeginDraw;
+
+//  DrawWuCircle(Canvas, 200, 200, 50, clBlue);
+//  DrawSpiral;
+
+  DrawSpokes(0);
+
+//  WuLine(Canvas, Point(10, 35), Point(280, 180), clBlack);
+//  Canvas.SetColor(clBlack);
+//  Canvas.DrawLine(10, 45, 280, 190);
+
+  Canvas.EndDraw;
+end;
+
+// Generates spokes. Animates them using phase.
+procedure TMainForm.DrawSpokes(phase: double);
+var
+  x1, y1, x2, y2: integer;
+  theta: double;
+  img: TfpgImage;
+begin
+  Canvas.BeginDraw;
+
+  theta := phase;
+  while theta < (360+phase) do
+  begin
+		x1 := trunc(100.0*cos(theta*3.14/180.0)+355.0);
+		y1 := trunc(-100.0*sin(theta*3.14/180.0)+155.0);
+
+		x2 := trunc(20.0*cos(theta*3.14/180.0)+355.0);
+		y2 := trunc(-20.0*sin(theta*3.14/180.0)+155.0);
+
+		WuLine(Canvas, Point(x1, y1), Point(x2, y2), clBlack);
+		Canvas.DrawLine(x2-240, y2, x1-240, y1);
+
+    theta := theta + 10;
+  end;
+  Canvas.EndDraw;
+end;
+
+procedure TMainForm.DrawSpiral;
+var
+  Theta: double;
+  X1, Y1, X2, Y2: integer;
+begin
+  X1 := 300;
+  Y1 := 100;
+  Theta := 0;
+  Canvas.BeginDraw;
+  while Theta < 15 * 3.1415926535 do
+  begin
+    X2 := trunc(X1 + Cos(Theta) * Theta);
+    Y2 := trunc(Y1 + Sin(Theta) * Theta);
+    WuLine(Canvas, Point(X1, Y1), Point(X2, Y2), clBlack);
+    Theta := Theta + 0.2;
+    X1 := X2;
+    Y1 := Y2;
+  end;
+  Canvas.EndDraw;
+end;
+
+constructor TMainForm.Create(AOwner: TComponent);
+begin
+  inherited Create(AOwner);
+  WindowTitle := 'fpGUI Wu Anti-Aliased Line test';
+  WindowPosition := wpScreenCenter;
+  Width := 600;
+  Height := 400;
+  
+  btnGo := TfpgButton.Create(self);
+  with btnGo do
+  begin
+    SetPosition(4, 4, 90, 24);
+    Text := 'GO';
+    OnClick := @btnGoClicked;
+  end;
+end;
+
+
+procedure MainProc;
+var
+  frm: TMainForm;
+begin
+  fpgApplication.Initialize;
+  frm := TMainForm.Create(nil);
+  try
+    frm.Show;
+    fpgApplication.Run;
+  finally
+    frm.Free;
+  end;
+end;
+
+
+begin
+  MainProc;
+end.
+