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LBitmapBase::CombineBitmapWarp

Summary

Combines image data from the source bitmap (the slave) and the destination bitmap (the master), using a perspective warp.

Syntax

#include "ltwrappr.h"

virtual L_INT LBitmapBase::CombineBitmapWarp (nDst, pBitmapSrc, nSrc, nSrcWidth, nSrcHeight, uFlags)

Parameters

POINT nDst

An array of POINT structures that contain the four points that define the warp area in the destination bitmap.

LBitmapBase * pBitmapSrc

Pointer to the bitmap object referencing the source bitmap. This is the slave bitmap, which is combined with the destination bitmap.

POINT nSrc

POINT structure that contains the point of origin of the source bitmap. This is the upper left corner. This point, along with nSrcWidth and nSrcHeight define the area of the source bitmap to be warped.

L_INT nSrcWidth

The width of the area in the source bitmap to be warped to the destination bitmap. This value, along with ptSrc and nSrcHeight define the area of the source bitmap to be warped.

L_INT nSrcHeight

The height of the area in the source bitmap to be warped to the destination bitmap. This value, along with ptSrc and nSrcWidth define the area of the source bitmap to be warped.

L_UINT uFlags

Flags that indicate the type of interpolation to use, if interpolation is used. Possible values are:

Value	Meaning
0	No interpolation
CBW_BILINEAR	Bilinear interpolation. This value is only valid if the bits per pixel of the image is 1-bit, 8-bit grayscale, 12-bit without a lookup table, 16-bit without a lookup table, or 24-, 32-, 48-, or 64-bit.

Returns

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

Comments

You can warp the entire source bitmap, or a portion of the source bitmap. To warp a portion of the source bitmap, set ptSrc, nSrcWidth and nSrcHeight accordingly. To warp the entire source bitmap, set the following:

ptSrc.x = 0;
ptSrc.y = 0;
nSrcWidth = pBitmapSrc.BitmapWidth;
nSrcHeight = pBitmapSrc.BitmapHeight;

The warp area in the destination bitmap is specified in nDst. The polygon specified in nDst must:

be concave.
fit entirely on the destination bitmap.

If either of these conditions is FALSE, this function will return an error.

The ordering of the points in nDst can affect the resulting warp. For example, if the source bitmap is the following:

then ordering the points in nDst as shown below results in the following warp:

while ordering the points in nDst as shown below, results in the following warp:

Required DLLs and Libraries

LTKRN
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

L_INT LBitmapBase__CombineBitmapWarpExample(LBitmap *pMaster,LBitmap *pSlave) 
{ 
  
   L_INT nRet;  
   POINT ptSrc = {0,0}; 
   POINT aptsDest[4]=  
   { 
      {100,100}, 
      {200,75}, 
      {200,250}, 
      {100,200} 
   }; 
 
   //load images as 24-bit, so we don't have to worry about palettes 
   pMaster->Load(MAKE_IMAGE_PATH(TEXT("Image1.cmp")), 24, ORDER_BGR, NULL, NULL);  
   pSlave->Load(MAKE_IMAGE_PATH(TEXT("Image1.cmp")), 24, ORDER_BGR, NULL, NULL);  
 
  nRet =pMaster->CombineBitmapWarp(aptsDest,  
                                     pSlave,  
                                     ptSrc,  
                                     pSlave->GetWidth(), pSlave->GetHeight(), 
                                     CBW_BILINEAR); 
  if(nRet !=SUCCESS) 
     return nRet; 
 
   nRet =pMaster->Save(MAKE_IMAGE_PATH(TEXT("output.jpg")), FILE_JPEG, 0, 2, 0, NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet =pMaster->Free(); 
   if(nRet !=SUCCESS) 
      return nRet; 
   nRet =pSlave->Free(); 
   if(nRet !=SUCCESS) 
      return nRet; 
 
   return SUCCESS; 
}