TCanvas

TPaintBox，图片最终显示类

类似ios的图形上下文。

procedure TForm1.Button1Click(Sender: TObject);

var

canvas: TCanvas;

pic: TPicture;

map: TBitmap;

i: integer;

color: TColor;

begin

color := RGB(Random(255),Random(255),Random(255));

map := TBitmap.Create;

map.Width := 100;

map.Height := 100;

for i:=0 to 99 do

begin

map.Canvas.MoveTo(0,i);

map.Canvas.Pen.Color := color;

map.Canvas.LineTo(100,i);

end;

PaintBox1.Canvas.Draw(0,0,map);

map.Free;

end;

procedure TForm1.FormPaint(Sender: TObject);

var

wid,hei: integer;

begin

inherited;

bit := TJPEGImage.Create;

bit.LoadFromFile('D:\vcl\timg.jpg');

//  Canvas.Draw(0,0,bit);

wid := 100;

hei := wid*bit.Height div bit.Width;

Canvas.StretchDraw(Rect(10,10,wid,hei),bit);

end;