delphi - 将字形和 WordWrap 文本一起绘制

Question

我有一个 Canvas 、字形、文本和整数变量空间。我想根据 TRadioGroup 的 ItemIndex 将字形和文本绘制到 Canvas 上(例如，如果 ItemIndex = 1，则在文本的左侧绘制字形等)在任何情况下，必须在字形和文本之间插入空格作为空格。Glyph 和 Text 都必须在 Canvas 上居中，即使 Canvas 的宽度小于 Glyph 的宽度 + Text 的宽度。

我试图实现这个任务，但我对一些计算感到困惑。下面附上我的代码:

procedure TForm1.Button1Click(Sender: TObject);
var
  R1, R2: TRect;
  S: String;
  G, D: Integer;
  B, C: TBitmap;   
begin
  S := 'This is an example text to show how WordWrap works';
  B := TBitmap.Create;
  B.LoadFromFile('C:\g.bmp');

  C := TBitmap.Create;
  C.Width := 242;
  C.Height := 96;

  Form1.Repaint;
  Form1.Canvas.Brush.Color := clGreen;
  Form1.Canvas.FillRect(Rect(0, 0, TrackBar1.Position, C.Height));

  // left
  if RadioGroup1.ItemIndex = 0 then
    begin
      R1 := Rect(B.Width + TrackBar2.Position, 0, TrackBar1.Position, C.Height);
      Form1.Canvas.TextRect(R1, S, [tfWordBreak, tfNoClip, tfCenter, tfCalcRect]);

      Form1.Canvas.Brush.Color := clWebSkyBlue;
      R2 := Rect(B.Width + TrackBar2.Position, (C.Height - R1.Bottom) div 2, TrackBar1.Position, C.Height);
      Form1.Canvas.TextRect(R2, S, [tfWordBreak, tfNoClip, tfCenter]);

      Form1.Canvas.Draw((TrackBar1.Position - R1.Right - TrackBar2.Position) div 2, (C.Height - B.Height) div 2, B);
    end;

  //right
  if RadioGroup1.ItemIndex = 1 then
    begin
      R1 := Rect(B.Width + TrackBar2.Position, 0, TrackBar1.Position, C.Height);
      Form1.Canvas.TextRect(R1, S, [tfWordBreak, tfNoClip, tfCenter, tfCalcRect]);

      Form1.Canvas.Brush.Color := clWebSkyBlue;
      R2 := Rect(0, (C.Height - R1.Bottom) div 2, TrackBar1.Position - B.Width - TrackBar2.Position, C.Height);
      Form1.Canvas.TextRect(R2, S, [tfWordBreak, tfNoClip, tfCenter]);

      Form1.Canvas.Draw((TrackBar1.Position + R1.Right - (B.Width*2) + TrackBar2.Position) div 2, (C.Height - B.Height) div 2, B);
    end;

  //top
  if RadioGroup1.ItemIndex = 2 then
    begin
      R1 := Rect(0, B.Height + TrackBar2.Position, TrackBar1.Position, C.Height);
      Form1.Canvas.TextRect(R1, S, [tfWordBreak, tfNoClip, tfCenter, tfCalcRect]);

      G := B.Height + R1.Bottom - R1.Top;
      D := (C.Height - G) div 2;

      Form1.Canvas.Brush.Color := clWebSkyBlue;
      R2 := Rect(0, D + TrackBar2.Position, TrackBar1.Position, C.Height);
      Form1.Canvas.TextRect(R2, S, [tfWordBreak, tfNoClip, tfCenter]);

      Form1.Canvas.Draw((TrackBar1.Position - B.Width) div 2, D - TrackBar2.Position, B);
    end;

  //bottom
  if RadioGroup1.ItemIndex = 3 then
    begin
      R1 := Rect(0, B.Height + TrackBar2.Position, TrackBar1.Position, C.Height);
      Form1.Canvas.TextRect(R1, S, [tfWordBreak, tfNoClip, tfCenter, tfCalcRect]);

      G := B.Height + R1.Bottom - R1.Top;
      D := (C.Height + G) div 2;

      Form1.Canvas.Brush.Color := clWebSkyBlue;
      R2 := Rect(0, D - R1.Bottom - R1.Top + B.Height + TrackBar2.Position, TrackBar1.Position, C.Height);
      Form1.Canvas.TextRect(R2, S, [tfWordBreak, tfNoClip, tfCenter]);

      Form1.Canvas.Draw((TrackBar1.Position - B.Width) div 2, D + TrackBar2.Position, B);
    end;

  FreeAndNil(B);
end;

如何使用此代码:将两个 TrackBar 放到 Form 上，并将第一个 TrackBar 的最大值设置为 242，第二个设置为 10；将 TRadioGroup 放到 Form 上，并按照下一个顺序在其 Items 属性中设置 4 个项目:左、右、上、下。

因此，当选择“左侧”或“右侧”项目时，代码可以正确工作(正确 - 正如我所期望的)，但是当选择“顶部”或“底部”项目时，字形和文本绘制不正确。我的意思是，例如，我们选择项目“顶部”并单击 Button1。我们看到了什么？右图，Glyph 绘制在 Text 上(更多详细信息请参见图片)。不幸的是，我试图克服这一点，但没有成功:

那么，有什么方法可以改进这段代码吗？或者我应该用另一种方式来达到我的目标？

附注抱歉我的英语不好;)

编辑更新源代码。

Answer 1

您对顶部和底部的计算是错误的。并且您可以直接在位图 Canvas 上而不是在表单 Canvas 上绘图。这是修复后的版本:

  //top
  if RadioGroup1.ItemIndex = 2 then
    begin
      R1 := Rect(0, B.Height + TrackBar2.Position, TrackBar1.Position, C.Height);
      C.Canvas.TextRect(R1, S, [tfWordBreak, tfNoClip, tfCenter, tfCalcRect]);
      G := (C.Height div 2);
      // D is top for centered text rec + glyph size and spacing
      D := G + ((R1.Height + B.Height + Trackbar2.Position) div 2);
      C.Canvas.Brush.Color := clWebSkyBlue;
      R2 := Rect(0, D - R1.Height, TrackBar1.Position, D+R1.Height);
      C.Canvas.TextRect(R2, S, [tfWordBreak, tfNoClip, tfCenter]);
      C.Canvas.Draw((TrackBar1.Position - B.Width) div 2, R2.Top - B.Height - TrackBar2.Position, B);
    end;

  //bottom
  if RadioGroup1.ItemIndex = 3 then
    begin
      R1 := Rect(0, 0, TrackBar1.Position, C.Height);
      C.Canvas.TextRect(R1, S, [tfWordBreak, tfNoClip, tfCenter, tfCalcRect]);
      // G is absolute middle of draw canvas
      G := (C.Height div 2);
      // D is top for centered text rec + glyph size and spacing
      D := G - ((R1.Height + B.Height + Trackbar2.Position) div 2);
      C.Canvas.Brush.Color := clWebSkyBlue;
      R2 := Rect(0, D, TrackBar1.Position, D + R1.Height);
      C.Canvas.TextRect(R2, S, [tfWordBreak, tfNoClip, tfCenter]);
      C.Canvas.Draw((TrackBar1.Position - B.Width) div 2, R2.Bottom + TrackBar2.Position, B);
    end;