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LPaint::ColorRgn

Summary

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

Syntax

#include "ltwrappr.h"

virtual L_INT LPaint::ColorRgn(crRgnColor, pXForm =NULL)

Parameters

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).

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.

Returns

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

Comments

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
m_Bitmap is an object of type LBitmap and it contains a valid bitmap

L_INT LPaint_ColorRgnExample(LBitmap *pBitmap, HDC hDC) 
{ 
   L_INT nRet = 0; 
   LPaint MyPaint(pBitmap, hDC); 
   nRet = MyPaint.PaintDC(); 
   if(nRet != SUCCESS) 
      return nRet; 
                      
   if (pBitmap->HasRgn()) 
   { 
        nRet = MyPaint.ColorRgn(RGB(255,0,0), NULL); 
        if(nRet != SUCCESS) 
           return nRet; 
   } 
   return SUCCESS; 
}