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L_ColorBitmapRgn

Summary

Highlights a region by displaying a filled, color representation of the region.

Syntax

#include "l_bitmap.h"

L_LTDIS_API L_INT L_ColorBitmapRgn(hDC, pBitmap, pXForm, crRgnColor)

Parameters

L_HDC hDC

Handle to a device context where the image is displayed and where the frame is to appear.

pBITMAPHANDLE pBitmap

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

pRGNXFORM pXForm

Pointer to an RGNXFORM structure that LEADTOOLS uses to translate between display coordinates and bitmap coordinates.

If you specify NULL in this parameter, the scalar fields default to 1, the offsets default to 0, and the view perspective defaults to the bitmap's view perspective.

L_COLORREF crRgnColor

Color value to be XORed with colors within a region to determine the new colors for displaying the region. The color corresponding to a particular part of the region is determined as follows:

Region Color Displayed = (color of pixel in region) XOR (crRgnColor)

Returns

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

Comments

This function does not support signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this function.

This function is particularly useful when displaying regions with black and white images. All black pixels in a region are displayed with color crRgnColor, and all white pixels are displayed ~(crRgnColor). For example, suppose that crRgnColor is light green (BGR 0x80FF40). All black pixels in the region are displayed as crRgnColor. All white pixels in the region are displayed as 0xFFFFFF XOR 0x80FF40 = 0x7F00BF, which is purple.

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

The following should be part of the WM_PAINT processing.

L_INT ColorBitmapRgnExample(L_HWND hWnd, pBITMAPHANDLE pBitmap) 
{ 
   L_INT    nRet; 
   HDC      hdcDraw; 
   COLORREF crRgnColor = RGB(255, 0, 0); 
 
   if (L_BitmapHasRgn(pBitmap)) 
   { 
      hdcDraw = GetDC(hWnd); 
      nRet = L_ColorBitmapRgn(hdcDraw, pBitmap, NULL, crRgnColor); 
      if (nRet != SUCCESS) 
         return nRet; 
 
      ReleaseDC(hWnd, hdcDraw); 
   } 
 
   return SUCCESS; 
}