>>我用canvas.pixles[x,y]总是获得 -1 你只能得到 canvas 範圍內的TColor, 幫助解釋得很清楚Read Pixels to learn the color on the drawing surface at a specific pixel position within the current clipping region. If the position is outside the clipping rectangle, reading the value of Pixels returns -1.>>2。我用canvas在form上画的东西,怎样才能最小化或挡住窗口后不被抹去? 在Form的OnPaint事件中再畫一次
procedure TForm1.Button1Click(Sender: TObject);
var
aCanvas: TCanvas;
aColor: TColor;
begin
aCanvas := TCanvas.Create;
aCanvas.Handle := GetDC(0);
aColor := aCanvas.Pixels[1, 1];
aCanvas.Free;
end;2.
在OnPaint事件中画
你只能得到 canvas 範圍內的TColor, 幫助解釋得很清楚Read Pixels to learn the color on the drawing surface at a specific pixel position within the current clipping region. If the position is outside the clipping rectangle, reading the value of Pixels returns -1.>>2。我用canvas在form上画的东西,怎样才能最小化或挡住窗口后不被抹去?
在Form的OnPaint事件中再畫一次