[solved] Can't us GetDataLineStart and Move why ?

[bubulemaster]

Hi,

I look about GetDataLineStart() and I would like use Move to copy fast a picture to another picture.

All picture is TBitmap 24 bits per pixel color.

When I use a code like below :

Code: [Select]

type
  TRGBArray = array[word] of TRGBTriple ;
  pRGBArray = ^TRGBArray ;

procedure ....
var
    // Source image
    lSrc : TLazIntfImage ;
    // Destination image
    lDst : TLazIntfImage ;
    // Source line
    lSrcLine : pRGBArray ;
    // Destination line
    lDstLine : pRGBArray ;
begin
       // PixelFormat := pf24bit

        // For each line of source
        for lLineIndex := 0 to lSrc.Height - 1 do
        begin
            lSrcLine := lSrc.GetDataLineStart(lLineIndex) ;
            lDstLine := lDst.GetDataLineStart(lLineIndex) ;

            Move(lSrcLine, lDstLine, lSrc.Width * 3) ; // * 3 -> for 24 bits
        end ;
end ;

First time (lLineIndex  = 0) is ok, but the second time (lLineIndex = 1), I receive a SIGSEGV on first GetDataLineStart().

Ok, it doesn't work. But I just want understand why.
It's two pointer on differents memories.

Someone can explain me ?

Thanks you.

[ludob]

Move(lSrcLine, lDstLine, lSrc.Width * 3)

This copies the contents of lSrcLine to lDstLine for lSrc.Width * 3 bytes. So you copy lSrcLine to lDstLine and overwrite a big chunk of the stack in doing so. What you want to do is to copy the memory pointed to by lSrcLine to the memory pointed to by lDstLine:

Code: [Select]

Move(lSrcLine^, lDstLine^, lSrc.Width * 3)

[bubulemaster]

Ok, thank.

I don't know where I saw the methode Move(pointer,pointer, integer).

I read the source code of freepascal and I see

Code: [Select]

Procedure Move(const source;var dest;count:SizeInt);
I'm so stupid sorry !