Paints a particular overlay. Use this function to paint overlays that are not automatically painted.


#include "ltwrappr.h"

virtual L_INT LPaint::PaintDCOverlay (nIndex, uROP3=SRCCOPY)


L_INT nIndex

The index of the overlay used for painting. The overlay should have a bitmap. If the overlay is embedded into a bitmap bitplane, make sure you create an overlay bitmap prior to calling this function. This index is zero-based.


The Windows ROP code that determines how the destination rectangle is updated. This parameter takes the same codes as the Windows BitBlt function. For ordinary painting, use SRCCOPY.


Value Meaning
SUCCESS The function was successful.
< 1 An error occurred. Refer to Return Codes.


This function will paint an overlay bitmap. For more information on the paint rectangles, see LPaint::PaintDC. LPaint::PaintDC will paint all the overlays that have the AutoRepaint flag attribute set. The overlays are painted in ascending index order: overlay 0 is painted first, then overlay 1, etc.

Use this function to manually paint an overlay. For example, if you want to change the order in which the overlays are painted, you can disable their AutoRepaint flag and call LPaint::PaintDCOverlay directly.

Another situation in which you might want to call this function is when you want to temporarily make an overlay top-most. In this case, you would call LPaint::PaintDCOverlay after LPaint::PaintDC. To permanently make an overlay top-most, it is recommended you change its index and give it the highest defined index.

The overlay bitmaps 1 pixels are painted with the overlay Color. The overlay bitmaps 0 pixels are considered transparent.

For more information on the overlay attributes (including the AutoRepaint flag and the Color), see the Overlay Overview topic.

Required DLLs and Libraries


Win32, x64.

See Also




This example assumes plBitmap contains overlays. It will make it look as if overlay 0 is topmost.
The example also assumes hDC and pDest have been initialized elsewhere.

L_INT LPaint__PaintDCOverlayExample(HDC hDC, LBitmapBase* plBitmap) 
   L_INT nRet; 
   LPaint MyPaint(plBitmap, hDC);  
   nRet = MyPaint.PaintDC(SRCCOPY);  
   if(nRet != SUCCESS) 
      return nRet; 
   nRet = MyPaint.PaintDCOverlay(0, SRCCOPY);  
   if(nRet != SUCCESS) 
      return nRet; 
   /* Now overlay 0 is topmost (it covers all the other overlays) */ 
   return SUCCESS; 

Help Version 22.0.2023.2.2
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.

LEADTOOLS Raster Imaging C++ Class Library Help