Delphi XE2 之 FireMonkey 入门(6) TLine、TEllipse、TCircle、TPie、TArc、TRectangle、TRoundRect、TCalloutRectangle

它们都是继承自 TShape 类, 共同拥有如下属性:

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Fill            : TBrush;      //填充
Stroke          : TBrush;      //边线(画笔)
StrokeThickness : Single;      //厚度(边线宽度)
StrokeCap       : TStrokeCap;  //线帽样式, TStrokeCap (枚举)类型
StrokeDash      : TStrokeDash; //虚线样式, TStrokeDash(枚举)类型
StrokeJoin      : TStrokeJoin; //拐点结合样式, TStrokeJoin(枚举)类型
ShapeRect       : TRectF;      //可填充范围的矩形(相对于当前图形)

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TLine 用不着 Fill, 但增加了 LineType 属性(TLineType 枚举类型);

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procedure TForm1.Button1Click(Sender: TObject);
begin
  Line1.LineType := TLineType.ltDiagonal; //斜线
  Line2.LineType := TLineType.ltTop;      //横线
  Line3.LineType := TLineType.ltLeft;     //竖线
end;

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TElipse 和 TCircle 没有新属性, 应该也用不着 StrokeCap、StrokeJoin.

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procedure TForm1.Button1Click(Sender: TObject);
begin
  Ellipse1.StrokeDash := TStrokeDash.sdDot; //虚线样式
  Circle1.Fill.Kind := TBrushKind.bkNone;   //取消填充
end;

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TArc 和 TPie 增加了 StartAngle、EndAngle 属性.

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TRectangle 增加了控制圆角的 XRadius、YRadius 属性、控制边线的 Sides 属性、控制四个角的 Corners、CornerType 属性;

TRoundRect 只加了 Corners 属性; 看来要做更随意的圆角矩形得用 TRectangle 而不是 TRoundRect.

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procedure TForm1.Button1Click(Sender: TObject);
begin
  Rectangle1.Position.X := 50;
  Rectangle1.Position.Y := 10;
  Rectangle1.Width := 100;
  Rectangle1.Height := 120;
  Rectangle1.StrokeThickness := 16;
  Rectangle1.Fill.Color := $80FF0000;
  Rectangle1.Stroke.Color := $800000FF;

  Rectangle1.XRadius := 8;
  Rectangle1.YRadius := 8;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  Rectangle2.Position.X := 350;
  Rectangle2.Position.Y := 10;
  Rectangle2.Width := 100;
  Rectangle2.Height := 120;
  Rectangle2.StrokeThickness := 4;
  Rectangle2.Fill.Color := claRed;
  Rectangle2.Stroke.Color := claBlack;

  Rectangle2.CornerType := TCornerType.ctBevel;
  Rectangle2.Corners := [TCorner.crBottomLeft, TCorner.crBottomRight];
  Rectangle2.Sides := [TSide.sdBottom, TSide.sdRight];

  //关于 Corners 和 Sides 还有两个非常方便的常量: AllCorners、AllSides
end;

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TCalloutRectangle 很有意思, 矩形外带一个三角, 应该是用于图形化的注释.

给它增加的 CalloutWidth、CalloutLength、CalloutPosition、CalloutOffset 四个属性都是用于控制三角的.

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procedure TForm1.Button1Click(Sender: TObject);
begin
  CalloutRectangle1.Width := 200;
  CalloutRectangle1.Height := 150;
  CalloutRectangle1.CalloutPosition := TCalloutPosition.cpBottom;
  CalloutRectangle1.CalloutWidth := CalloutRectangle1.Width / 4;
  CalloutRectangle1.CalloutLength := CalloutRectangle1.Height / 2;
  CalloutRectangle1.CalloutOffset := -CalloutRectangle1.Width / 2;
end;

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这其中需要进一步学习的是 Fill、Stroke 属性, 它们都是 TBrush 类型, 会涉及到 TBitmap、TBitmapObject、TCanvas 等等.

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