Delphi TRichEdit.Perform（EM_FORMATRANGE，0，Longint（@fmtRange））;

Question

我想找到需要ResponseBody body = retrofitService.retrieveImageData().execute().body(); byte[] bytes = body.bytes(); Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length); 控件来呈现自身而不显示TRichEdit的高度。 我用这个代码

vertical scrollbar

当文档有几页（＆lt; 15 function RichEditHeight(var RE : TRichEdit; aForm : TForm) : integer; var fmtRange: TFormatRange; begin FillChar(fmtRange, SizeOf(fmtRange), 0); with fmtRange do begin hDC := aForm.canvas.Handle; hdcTarget := hDC; rc.left := 0; rc.right := (RE.ClientWidth * 1440) div screen.pixelsPerInch; rc.top := 0; rc.Bottom := MaxInt; rcPage := rc; chrg.cpMin := 0; chrg.cpMax := -1; end; RE.Perform(EM_FORMATRANGE, 0, Longint(@fmtRange)); result := round(fmtRange.rc.Bottom*screen.pixelsPerInch/1440); RE.Perform(EM_FORMATRANGE, 0, 0); end; ）时，结果就足够了。 但是有了更多的页面，rc.bottom似乎被转换，控件需要垂直滚动条。 问题是：执行代码中有一些限制吗？ 如果我手动（大约）增加rc.bottom然后控件呈现自己好，但这不是我想要的情况。

PS。如果重要的话，richedit组件实际上是一个TjvRichEdit。

这是一个可以重现问题的最小程序（即使是2页）

A4 portrait

表格

unit Unit32;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ComCtrls, winAPI.richedit, JvExStdCtrls, JvRichEdit, Vcl.ExtCtrls;

type
  TForm32 = class(TForm)
    ScrollBox1: TScrollBox;
    Button1: TButton;
    RichEdit1: TJvRichEdit;
    panel1: TPanel;
    OpenDialog1: TOpenDialog;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var Form32: TForm32;

implementation

{$R *.dfm}

function RichEditHeight(var RE : TjvRichEdit; aForm : TForm) : integer;
var fmtRange: TFormatRange;
begin
    FillChar(fmtRange, SizeOf(fmtRange), 0);
    with fmtRange do begin
    hDC := aForm.canvas.Handle;
    hdcTarget := hDC;
    rc.left := 0;
    rc.right := (RE.ClientWidth * 1440) div screen.pixelsPerInch;
    rc.top := 0;
    rc.Bottom := 500000;
    rcPage := rc;
    chrg.cpMin := 0;
    chrg.cpMax := -1;
    end;
    RE.Perform(EM_FORMATRANGE, 0, Longint(@fmtRange));
    result := round(fmtRange.rc.Bottom*screen.pixelsPerInch/1440);
    RE.Perform(EM_FORMATRANGE, 0, 0);
end;

procedure TForm32.Button1Click(Sender: TObject);
begin
with OpenDialog1 do
if execute then begin
    RichEdit1.lines.LoadFromFile(filename);
    panel1.height := RichEditHeight(RichEdit1,Form32);
end;
end;

end.

和RTF文档的结果（仅2页）

Answer 1

最后，解决方案非常简单！ TRichedit有onResizeRequest事件，其中控件的实际高度由rect参数给出