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I am writing a spell-checker with a simple window that has a Rich Edit control inside it. What I need to do is to retrieve the text that is displayed inside the rich-edit and NOT the whole text that is loaded inside it. For example, you have a 1MB text file loaded into the rich-edit but you just want to retrieve the text that is currently being displayed in the rich-edit's rectangular window. How can I do that?

The second question is about locating specific words inside the current list-view's frame. For example, after I retrieve the contents of the current view of the rich-edit as a string, I am going to have to highlight it within the rich-edit to state that for example, it is a misspelled word. Does anybody have any idea how I can do that? What message(s) should I send to the rich edit control?

Thanks in advance.

Thanks that was really useful. The problem is how I should find out what texts are displayed in the current rectangular frame of the rich-edit? Suppose you have loaded a whole bunch of text into the rich-edit and you have scrolled down the text using the scroll-bar while your cursor is still at the first line. How can you find what page you are at and retrieve the texts in that page into a buffer?

EM_GETSCROLLPOS is only supported with Rich Edit 3.0 :shock:

I believe that's how you retrieve the selected text not the text in view  8) The text I have here is not selected and why should it be? The user scrolls down to the bottom of the rich edit and then I will have to find the text that is seen. I tried the EM_CHARFROMPOS message but it is not that accurate. Sometimes when a line is in the view, it does not give you the starting position. You have to scroll all the way down to the next line somehow to get the line before  :O

Oh by the way, I also found this message which is useful EM_GETFIRSTVISIBLELINE

You're overcomplicating things and not following what I meant.
I've given you the list of messages and parts of the sequence of sending them, not the whole solution. And hinted where to look, to also find EM_POSFROMCHAR.
It wouldn't be fun for any of us to just give the whole sequence, would it :). But at least you're exploring correctly so far, except for the wrong (too inconvenient) GetTextMetrics detour :P.
Another hint: it's all extremely easy, with just several messages in a sequence and point-subtracting/adding. And then overloading the richedit-class to paint in the appropriate places.

Okay I did it! Finally. Sorry but the code is written in Delphi. Since it is all Win32 API, I think it wouldn't hurt if I put it here so that others, maybe having the same problem, could use it:

procedure TForm1.Button1Click(Sender: TObject);
Var
  Buffer              : PChar;
  RichRect            : TRect;
  TextRange           : TTextRangeA;
  UpperLeftPoint,
  BottomRightPoint    : TPointL;
  FirstCharacterIndex,
  LastCharacterIndex  : Cardinal;
Const
  HEAP_ZERO_MEMORY    = $00000008;
begin
(* Get the Rich Edit's rectangular area *)
SendMessage(RichEdit1.Handle, EM_GETRECT, 0, lParam(@RichRect));
(* Now try to set the upper leftmost point and get the character index of that point *)
UpperLeftPoint.x := RichRect.Left;
UpperLeftPoint.y := RichRect.Top;
(* Get the upper leftmost character index in view *)
FirstCharacterIndex := SendMessage(RichEdit1.Handle, EM_CHARFROMPOS, 0,
                                   lParam(@UpperLeftPoint));
(* Now try to get the character index at the bottom rightmost point *)
BottomRightPoint.x := RichRect.Right - RichRect.Left;
BottomRightPoint.y := RichRect.Bottom - RichRect.Top;
LastCharacterIndex := SendMessage(RichEdit1.Handle, EM_CHARFROMPOS, 0,
                                  lParam(@BottomRightPoint));
(* Set the character index at the top leftmost position *)
TextRange.chrg.cpMin := FirstCharacterIndex;
(* The character index of the bottom rightmost character *)
TextRange.chrg.cpMax := LastCharacterIndex;
(* Allocate a buffer *)
Buffer := HeapAlloc(GetProcessHeap, HEAP_ZERO_MEMORY,
                    LastCharacterIndex - FirstCharacterIndex  + 1);
(* Set the buffer in the structure *)
TextRange.lpstrText := Buffer;
(* Get the range of text *)
SendMessage(RichEdit1.Handle, EM_GETTEXTRANGE, 0, lParam(@TextRange));
(* Celebrate my glory! *)
MessageBox(Form1.Handle, Buffer, nil, MB_ICONINFORMATION);
(* Release the buffer *)
HeapFree(GetProcessHeap, 0, Buffer);
end;

That's right. Thanks for pointing that out. I will modify the code. By the way, thanks to both of you for helping me with this.

Thanks :oops: What I have to do now though is to highlight words in the rich edit. I think what I have to do is to retrieve the text from the current view with the code I posted above, then search for words in the buffer. Find which one of the words are not in the dictionary. Then get their index and somehow highlight them. Here we go again. Another puzzle  :mad:

To be able to retrieve the number of lines that are visible in the current view of a rich-edit, I am doing this:

1) Find the number of characters in the current view.
2) I go through each line in the current view, and retrieve that line's number of characters. I add 2 to the length for CR and LF.
3) I will subtract that from the total number of characters in the view.
4) I will do that until there are no more characters left.

Does anybody know of another way of doing this which could perhaps be faster?