再學GDI+[50]: 路徑

本例效果圖:

代碼檔案:unit Unit1;
interface
uses
　Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
　Dialogs, StdCtrls, Grids;
type
　TForm1 = class(TForm)
　　StringGrid1: TStringGrid;
　　procedure FormCreate(Sender: TObject);
　　procedure FormPaint(Sender: TObject);
　　procedure StringGrid1SelectCell(Sender: TObject; ACol, ARow: Integer;
　　　var CanSelect: Boolean);
　end;
var
　Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
procedure TForm1.FormCreate(Sender: TObject);
begin
　StringGrid1.Align := alRight;
　StringGrid1.FixedCols := 0;
　StringGrid1.ColCount := 3;
　StringGrid1.ColWidths[0] := 25;
　StringGrid1.ColWidths[1] := 25;
　StringGrid1.ColWidths[2] := 80;
　StringGrid1.DefaultRowHeight := 20;
　StringGrid1.Cells[0,0] := 'X';
　StringGrid1.Cells[1,0] := 'Y';
　StringGrid1.Cells[2,0] := '點類型';
end;
procedure TForm1.FormPaint(Sender: TObject);
var
　g: TGPGraphics;
　p: TGPPen;
　path: TGPGraphicsPath;
　points: array of TGPPoint;
　types: PByte;
　typestr: string;
　i: Integer;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　p := TGPPen.Create(aclRed);
　path := TGPGraphicsPath.Create;
　path.StartFigure;
　path.AddRectangle(MakeRect(30,20,90,40));
　path.AddEllipse(MakeRect(30,80,90,180));
　path.CloseFigure;
　g.DrawPath(p, path);
　SetLength(points, path.GetPointCount);
　GetMem(types, path.GetPointCount);
　path.GetPathPoints(PGPPoint(points), Length(points));
　path.GetPathTypes(types, Length(points));
　StringGrid1.RowCount := Length(points) + 1;
　for i := 0 to Length(points) - 1 do
　begin
　　case types^ of
　　　$00 : typestr := '路徑起始點';
　　　$01 : typestr := '直線點';
　　　$03 : typestr := '貝塞爾線點';
　　　$07 : typestr := '遮蓋點';
　　　$10 : typestr := '虛線點';
　　　$20 : typestr := '路徑標記';
　　　$80 : typestr := '子路徑結束點';
　　end;
　　StringGrid1.Cells[0, i+1] := IntToStr(points[i].X);
　　StringGrid1.Cells[1, i+1] := IntToStr(points[i].Y);
　　StringGrid1.Cells[2, i+1] := typestr;
　　Inc(types);
　end;
　Dec(types, Length(points));
　FreeMem(types);
　types := nil;
　path.Free;
　p.Free;
　g.Free;
end;
procedure TForm1.StringGrid1SelectCell(Sender: TObject; ACol, ARow: Integer;
　var CanSelect: Boolean);
var
　x,y: Integer;
begin
　x := StrToIntDef(StringGrid1.Cells[0,ARow], 0);
　y := StrToIntDef(StringGrid1.Cells[1,ARow], 0);
　Repaint;
　Canvas.Brush.Color := clBlue;
　Canvas.FillRect(Bounds(x-3,y-3,6,6));
　Text := Format('%d,%d',[x,y]);
end;
end.