If I got it right, I may use WinBeginPaint() ... WinEndPaint()
without having to wait for the receipt of a WM_PAINT message.
I want to make use of this in order to avoid repainting the
complete client area of my terminal type window when text has
to be scrolled upwards. Instead I indend to copy the concerned
window area using GpiBitBlt(), which should be a lot faster.
Unfortunately nothing happens when I call GpiBitBlt(). Maybe
somebody finds the reason:


void  TVioWindow :: ScrollUp ( int  leftCol,
                               int  topRow,
                               int  rightCol,
                               int  bottomRow,
                               int  count,
                               int  attr )
{
  int  row,
       lastRow,
       chCount,
       dstPos,
       srcPos;

  if ( bottomRow >= maxRows )
    bottomRow = maxRows - 1;

  if ( rightCol >= maxCols )
    rightCol = maxCols - 1;

  dstPos  = maxCols * topRow + leftCol;      // Ziel-Offset
  srcPos  = dstPos + maxCols * count;        // Quell-Offset
  chCount = rightCol - leftCol + 1;          // Zeichen pro Zeile
  lastRow = bottomRow + 1 - count;

  for ( row = topRow; row <= lastRow; row++, count-- )
  {
    memcpy ( textBuf + dstPos, textBuf + srcPos, chCount );
    memcpy ( attrBuf + dstPos, attrBuf + srcPos, chCount );

    srcPos += maxCols;
    dstPos += maxCols;
  }

  while ( row < bottomRow )
  {
    memset ( textBuf + dstPos, ' ',  chCount );
    memset ( attrBuf + dstPos, attr, chCount );

    dstPos += maxCols;
    row++;
  }

  POINTL  ptlArray [3];
  HPS     hps;

  // -----------------------------------------------------
  // Ziel links unten
  // -----------------------------------------------------
  ptlArray [0].x = leftCol * charWidth;
  ptlArray [0].y = clientHeight - (bottomRow - count + 1) * charHeight;

  // -----------------------------------------------------
  // Ziel rechts oben
  // -----------------------------------------------------
  ptlArray [1].x = (rightCol + 1) * charWidth - 1;
  ptlArray [1].y = clientHeight - topRow * charHeight;

  // -----------------------------------------------------
  // Quelle links unten
  // -----------------------------------------------------
  ptlArray [2].x = ptlArray [0].x;
  ptlArray [2].y = clientHeight - (bottomRow + 1) * charHeight;

  hps = WinBeginPaint ( hWindow, NULLHANDLE, NULL );
  if ( NULLHANDLE != hps )
  {
    GpiBitBlt ( hps,              // Ziel
                hps,              // Quelle
                3L,               // Anzahl Eintr�ge in ptlArray
                ptlArray,         // Punkt-Array
                ROP_SRCCOPY,      // Kopier-Modus
                BBO_IGNORE );

    // ---------------------------------------------------
    // Den Rest mit dem angegebenen Attribut f�llen
    // ---------------------------------------------------
    RECTL  rect;

    rect.xLeft   = ptlArray [0].x;
    rect.xRight  = ptlArray [1].x;
    rect.yTop    = ptlArray [1].y;
    rect.yBottom = ptlArray [2].y;

    WinFillRect ( hps, &rect, BGColorFromAttr (attr) );
    WinEndPaint ( hps );
  }
}


BGColorFromAttr() and FGColorFromAttr() simply calculate the OS/2
color table index from a video attribute using bit shifts (There
is nothing wrong with these macros). "textBuf" and "attrBuf" are
arrays of "maxCols" * "maxRows" bytes.


Tschuess, Steffen


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