如何绘制"非"彩色文字？

Question

我正在寻找一种用反色绘制文字的方法.对于形状,我们TPenMode可以将其设置为pmNot,但我们不能对文本执行此操作.我怎么能这样做呢？

Answer 1

这样做:

procedure DrawTextNOT(const hDC: HDC; const Font: TFont; const Text: string; const X, Y: integer);
begin
  with TBitmap.Create do
    try
      Canvas.Font.Assign(Font);
      with Canvas.TextExtent(Text) do
        SetSize(cx, cy);
      Canvas.Brush.Color := clBlack;
      Canvas.FillRect(Rect(0, 0, Width, Height));
      Canvas.Font.Color := clWhite;
      Canvas.TextOut(0, 0, Text);
      BitBlt(hDC, X, Y, Width, Height, Canvas.Handle, 0, 0, SRCINVERT);
    finally
      Free;
    end;
end;

例:

procedure TForm1.FormClick(Sender: TObject);
begin
  Canvas.Brush.Color := clRed;
  Canvas.FillRect(ClientRect);
  DrawTextNOT(Canvas.Handle, Canvas.Font, 'This is a test.', 20, 100);
//  DrawTextNOT(Canvas.Handle, Canvas.Font, 'This is a test.', 20, 100);
end;

您可能还想禁用ClearType.为此,我向您推荐以前的SO问题.