highlighting a line of text

[shankle]

The following code does not work.
Attempting to highlight a line of text by making the background light blue
and the text white. Same as what Hutch does in the Qeditor.
Line of text already exists that I want to highlight.
Have searched for info on this to no avail.


        LOCAL hWnd:HWND,  pt:POINT, iMsg:UINT     

       .ELSEIF iMsg==WM_LBUTTONDOWN
          invoke GetDC,hWnd
          mov hdc, eax
          invoke GetCursorPos, addr pt                   
          invoke ScreenToClient, hWnd, addr pt       
          invoke SetPixel, hdc, pt.x+1, pt.y+1, 00ffff00h
          invoke SetBkMode, hdc, OPAQUE
          invoke SetBkColor, hdc, 00ffff00h  ; light blue
          invoke InvalidateRect, hWnd, NULL, TRUE
          invoke UpdateWindow, hWnd                   
          invoke ReleaseDC, hWnd, hdc                                         
     

[dedndave]

you may want to provide a method of highlighting a line in the WM_PANT handler
set a line number to highlight - then, when you paint, perform the highlighting

my understanding is, once text is drawn, it stays the color it is
to highlight it, it may need to be re-drawn with the appropriate color(s)

you can use the system colors COLOR_HIGHLIGHT and COLOR_HIGHLIGHTTEXT
that way, the colors that have been selected by the user (theme) are used

[hutch--]

Jack,

In a rich edit control, the control itself does it. These are the API messages sent to set a line as hilighted.

Code Select Expand


        mov li, FUNC(SendMessage,hEdit,EM_LINEINDEX,cnt,0)
        m2m cr.cpMin, li
        m2m cr.cpMax, li
        invoke SendMessage,hEdit,EM_EXSETSEL,0,ADDR cr
        invoke SendMessage,hEdit,EM_EXGETSEL,0,ADDR cr
        mov ll, FUNC(SendMessage,hEdit,EM_LINELENGTH,cr.cpMin,0)
        add cr.cpMax, eax
        invoke SendMessage,hEdit,EM_EXSETSEL,0,ADDR cr


[shankle]

Thanks Hutch for the example.
Since this is my 1st venture into rich edit controls I think I need something like
Rich edit for dummies.
I can't follow your ex.
If you have the time:
What is "FUNC"?
I assume L1 is a dbl word.
Is "cr" a struct and where can I find it?
Do I need to include something to run Rich Edit in my program?

My only source is "C Petzolds Programming windows 95".

[fearless]

MSDN is worth searching for the various structures or messages to use:

EM_EXSETSEL message: http://msdn.microsoft.com/en-us/library/windows/desktop/bb788001%28v=vs.85%29.aspx

CHARRANGE structure: http://msdn.microsoft.com/en-us/library/windows/desktop/bb787885%28v=vs.85%29.aspx

So in hutches example, he declares a variable of type CHARRANGE, which is itself a structure as defined in the above link

If your declaring it in your .data section your would probably do so like this:

Code Select Expand

.data
cr     CHARRANGE <>

However if your using it in a procedure and want to only use this as a temporary variable you can make it a local variable and declare it like so:

Code Select Expand

LOCAL cr:CHARRANGE

FUNC is a macro - shorthand if you like - that calls a function or procedure and returns the value in eax, so in the example used:

Code Select Expand


mov li, FUNC(SendMessage,hEdit,EM_LINEINDEX,cnt,0)
is the same as the following (perhaps handier to do in one line once you know how - personal preference tho if you use macros):

Code Select Expand

Invoke SendMessage, hEdit, EM_LINEINDEX, cnt, 0
mov li, eax ; value of sendmessage is returned in eax, and we store it in a local or global var called li - short for line index

the variable li is a dword (you are right in assuming this). It is easier to manipulate and store the result from eax to a variable of the same size as the register we are using.
m2m is a macro to move the line index value into your cr variable min and max part (both of which are dword/long values)

Hope that helps

[shankle]

Thank you Fearless for a very good explanation. It's much appreciated.
Yes I will pursue the info on the Microsoft site.

Two more items in Hutch's code:
   "cnt" and "LL"
What's in cnt and how is it defined. Thought that param should be null in a SendMessage.
LL never seems to be used or is it a typo?

Am I right in assuming I have to create a child window to get this code to work?