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L_PaintRgnDC

Summary

Paints the bitmap region to a device context. This function works the same as L_PaintDC, except that only the bitmap region is painted.

Syntax

#include "l_bitmap.h"

L_LTDIS_API L_INT L_PaintRgnDC(hDC, pBitmap, pSrc, pClipSrc, pDst, pClipDst, uROP3)

Parameters

L_HDC hDC

Handle to a device context, such as a screen, to use as the display surface. The mapping mode of the device context must be MM_TEXT.

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle referencing the bitmap that has the region.

L_RECT* pSrc

Pointer to the Windows RECT structure that specifies the part of the bitmap to use as the display source.

The coordinates in the RECT structure are relative to the bitmap. You can pass NULL to use the default, which matches the bitmap.

L_RECT* pClipSrc

Pointer to the Windows RECT structure that specifies the portion of the display source to paint. Generally, this is used for updating the display when part of the source bitmap has changed.

The coordinates in the RECT structure are relative to the bitmap. You can pass NULL to use the default, which matches the bitmap.

L_RECT* pDst

Pointer to the Windows RECT structure that determines how the source rectangle is scaled and how the image is positioned in the device context.

The coordinates in the RECT structure are relative to the device context. There is no default for this parameter. You must specify the RECT structure.

L_RECT* pClipDst

Pointer to the Windows RECT structure that specifies the portion of the display rectangle to paint. Generally, this is used for updating changes in the display surface, such as when a user moves another window, uncovering a part of the image that had been covered up.

The coordinates in the RECT structure are relative to the device context. You can pass NULL to use the default, which matches the device context. In most cases, however, you should use the rectangle returned by the Windows WM_PAINT message.

L_UINT32 uROP3

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.

Returns

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

Required DLLs and Libraries

LTDIS
For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Platforms

Win32, x64.

Example

For a complete sample code, refer to the FEATURE3 example.
This example shows the minimum requirements for painting the current region of a bitmap using the bitmap’s palette.

L_INT PaintRgnDCExample(L_HWND hWnd, pBITMAPHANDLE LeadBitmap) 
{ 
   L_INT    nRet; 
   HDC      hdc;                    /* Device context for the current window */ 
   RECT     rLeadDest;              /* Destination rectangle for painting */ 
   HPALETTE hSavedPalette = NULL;   /* Temporary copy of the current system palette */ 
   HPALETTE hOurPalette = NULL;     /* The palette that we will use to paint */ 
 
   /* Get the device context */ 
   hdc = GetDC(hWnd); 
 
   /* Set the destination rectangle to be the same as the bitmap. 
   Other painting rectangles can take defaults. */ 
   SetRect(&rLeadDest, 0, 0, BITMAPWIDTH(LeadBitmap), BITMAPHEIGHT(LeadBitmap)); 
 
   /* Create the palette that we will use to paint */ 
   hOurPalette = L_CreatePaintPalette(hdc, LeadBitmap); 
 
   /* Select our palette and save the old one */ 
   hSavedPalette = SelectPalette(hdc, hOurPalette, FALSE); 
 
   /* Realize our palette */ 
   RealizePalette(hdc); 
 
   /* Paint the image */ 
   nRet = L_PaintRgnDC(hdc,   /* Device context */ 
      LeadBitmap,             /* Bitmap handle */ 
      NULL,                   /* Default source rectangle */ 
      NULL,                   /* Default source clip area */ 
      &rLeadDest,             /* Destination rectangle */ 
      NULL,                   /* Default destination clipping rectangle */ 
      SRCCOPY);               /* ROP3 code for a Normal Paint */ 
 
   /* Restore the old palette */ 
   SelectPalette(hdc, hSavedPalette, FALSE); 
 
   /* Release the device context */ 
   ReleaseDC(hWnd, hdc); 
 
   return nRet; 
}