Drawing with canvas/zh CN

leo_tecnologica@yahoo.com.ar 发布 —— Leonardo Gabriel Calautti

Line (x1, y1, x2, y2)-> 从(x1,y1)到(x2,y2)画线

Rectangle (x1, y1, x2, y2)-> 从(x1,y1)点到(x2,y2)点画矩形

Ellipse (x1, y1, x2, y2)-> 从(x1,y1)点到(x2,y2)点画椭圆

<figure> <img src="canvas2.png" title="canvas2.png" /> <figcaption>canvas2.png</figcaption> </figure>

如，下面的代码，将绘制对角线，在Button1Click间：

procedure TForm1.Button1Click(Sender: TObject);
begin
  canvas.Line(0,0, form1.Width,form1.Height);
  canvas.Line(0,form1.height,form1.width,0);
end;

如何绘制矩形和椭圆在里面使用Rectangle和Ellipse；在调用Brush和Pen时，使用color设置颜色，该属性给绘制对象填充、线条的颜色。在绘制前，顺序很重要：

 canvas.Brush.color:= clred;
 canvas.Ellipse(195, 117, 205, 128);
 canvas.Brush.color:= clblue;
 canvas.Rectangle (192, 130,208,160);
 canvas.Brush.color:= clgreen;
 Canvas.Rectangle (187, 130,191,162);
 canvas.Brush.color:= clyellow;
 Canvas.Rectangle (209, 130,213,162);
 canvas.Brush.color:= clmaroon;
 Canvas.Rectangle (193,161,199,200);
 canvas.Brush.color:= clpurple;
 Canvas.Rectangle (201,161,207,200);

如果按着步骤，你可以做到：

<figure> <img src="canvas3.png" title="canvas3.png" /> <figcaption>canvas3.png</figcaption> </figure>

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From the Free Pascal wiki, page "Drawing with canvas/zh CN", as it stood on 2020-02-14 after a change by Trev, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.