Author: Tomas Rutkauskas

Does anyone know of a component or a few lines of code, that could turn the 
contents of a TRichText field (WIN32 RTF) into a bitmap?

Answer:

Add this in the unit your are developing:


1   uses
2     RichText;
3   
4   {For this demo add a RichEdit and an Image Control set the RichEdit change event to 
5   the lower code}
6   
7   procedure
8     OutputRTFToBmp(RichHolder: TRichEdit; ImageHolder: TBitmap; itemwidth, 
9   itemheight: real);
10  var
11    Range: TFormatRange;
12    TextBoundary: TRect;
13  begin
14    {Setup the Height and Width of our output}
15    ImageHolder.width := round(itemwidth * screen.PixelsPerInch);
16    ImageHolder.height := round(itemheight * screen.PixelsPerInch);
17    {Set the Size of the Rich Edit}
18    textboundary := rect(0, 0, round(itemwidth * 1440), round(itemheight * 1440));
19    {Set the Range record}
20    range.hdc := ImageHolder.Canvas.handle;
21    range.hdctarget := ImageHolder.Canvas.handle;
22    range.rc := textboundary;
23    range.rcpage := textboundary;
24    {Start at character zero}
25    range.chrg.cpMin := 0;
26    {Display all Characters}
27    range.chrg.cpMax := -1;
28    {Ask RTF to Draw}
29    Sendmessage(RichHolder.handle, EM_FORMATRANGE, 1, longint(@range));
30    {Cleanup RTF Cache}
31    sendmessage(RichHolder.handle, EM_FORMATRANGE, 0, 0);
32  end;
33  
34  procedure TForm1.RichEdit1Change(Sender: TObject);
35  begin
36    OutputRTFToBmp(RichEdit1, Image1.picture.bitmap, 2, 2);
37    {Display new stuff, this will flicker so you will have to double buffer}
38    image1.refresh;
39  end;



I use it on Metafiles then you can scale it also.