delphi 打印Trichedit|笨鱼技术网

Problem/Question/Abstract:

How to print a TRichEdit upside down

Answer:

Below are the 4 base orientations, but TXForm (in windows.pas) gives you the ability to turn the world to any degree. World transformations are interesting in that they raise the prospect of working in code with portrait objects and simply turning the world, rather than turning the objects individually to conform to the world - which I have been doing up until now.

Note: This does not work for Win9x.

{ ... }
type
TWorldOrientation = (woPortrait, woLandscape, woInversePortrait,
woInverseLandscape);

function GetWorldOrientation(APageRect: TRect; AOrientation: TWorldOrientation):
TXForm;
begin
case AOrientation of
    woPortrait:
      begin
        Result.eM11 := 0;
        Result.eM12 := 0;
        Result.eM21 := 0;
        Result.eM22 := 0;
        Result.eDX := APageRect.Left;
        Result.eDY := APageRect.Top;
      end;
    woLandscape:
      begin
        Result.eM11 := 0;
        Result.eM12 := -1;
        Result.eM21 := 1;
        Result.eM22 := 0;
        Result.eDX := APageRect.Left;
        Result.eDY := APageRect.Bottom;
      end;
    woInversePortrait:
      begin
        Result.eM11 := -1;
        Result.eM12 := 0;
        Result.eM21 := 0;
        Result.eM22 := -1;
        Result.eDX := APageRect.Right;
        Result.eDY := APageRect.Bottom;
      end;
    woInverseLandscape:
      begin
        Result.eM11 := 0;
        Result.eM12 := 1;
        Result.eM21 := -1;
        Result.eM22 := 0;
        Result.eDX := APageRect.Right;
        Result.eDY := APageRect.Top;
      end;
end;
end;

Examples:

procedure TForm1.FormCreate(Sender: TObject);
begin
{Apparently you need to initialise before using the first time otherwise the
canvas doesn't appear to paint properly}
Windows.SetGraphicsMode(Self.Canvas.Handle, GM_ADVANCED);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
R: TRect;
begin
R := Rect(20, 20, 200, 200);
PrintText(Self.Canvas, Self.ClientRect, R, 'I am portrait', 0, woPortrait);
PrintText(Self.Canvas, Self.ClientRect, R, 'I am landscape', 0, woLandscape);
PrintText(Self.Canvas, Self.ClientRect, R, 'We are inverse portrait' + #13#10 +
'As are we', 0, woInversePortrait);
PrintText(Self.Canvas, Self.ClientRect, R, 'We are inverse landscape.' + #13#10 +
'Us to', DT_RIGHT, woInverseLandscape);
end;

procedure TForm1.Button2Click(Sender: TObject);
var
R: TRect;
begin
if OpenDialog1.Execute then
begin
    RichEdit1.Lines.LoadFromFile(OPenDialog1.FileName);
    R := Rect(10, 10, 200, 300);
    PrintRichText(Self.Canvas, Self.ClientRect, R, RichEdit1, Screen.PixelsPerInch,
      Screen.PixelsPerInch, woPortrait);
    PrintRichText(Self.Canvas, Self.ClientRect, R, RichEdit1, Screen.PixelsPerInch,
      Screen.PixelsPerInch, woLandscape);
    PrintRichText(Self.Canvas, Self.ClientRect, R, RichEdit1, Screen.PixelsPerInch,
      Screen.PixelsPerInch, woInverseLandscape);
    PrintRichText(Self.Canvas, Self.ClientRect, R, RichEdit1, Screen.PixelsPerInch,
      Screen.PixelsPerInch, woInversePortrait);
end;
end;