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L_PerspectiveBitmap

Summary

Gives a bitmap a 3-D effect, as if it exists on a flat plane and has been skewed into a different shape.

Syntax

#include "l_bitmap.h"

L_LTIMGSFX_API L_INT L_PerspectiveBitmap(pBitmap, pPoints, crBkgColor, uFlags)

Parameters

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle referencing the bitmap to be changed.

POINT * pPoints

Pointer to an array of points that determines the new locations of the image corners. It should contain four points; points at indices 0, 1, 2 and 3 determine the new locations of left-top, right-top, left-bottom and right-bottom image corners respectively.

COLORREF crBkgColor

Background color.

L_UINT uFlags

Flag that indicates how to create the background. Possible values are:

Value	Meaning
PERSPECTIVE_IMAGE	[0x0001] Use the same image as the background.
PERSPECTIVE_COLOR	[0x0002] Fill the back ground with `crBkgColor`.

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.

The new locations for the image corners should keep the relative relation between corners. For example, the point at index 1 should be to the right of point at index 0 and above the point at index 3. Also, the point at index 2 should be to the left of the point at index 3 and below the point at index 0 and so on. All new locations should remain inside the image.

To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.

This function supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available in the Document and Medical Imaging toolkits.

If the bitmap has a region, this function works only on the region. If the bitmap does not have a region, this function works on the entire bitmap.

This function does not support 32-bit grayscale images. It returns the error code ERROR_GRAY32_UNSUPPORTED if a 32-bit grayscale image is passed to this function.

Perspective Function - Before

Perspective Function - After

View additional platform support for this Perspective function.

Required DLLs and Libraries

LTIMGSFX
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 example loads a bitmap, and applies the 3D perspective effect

L_INT PerspectiveBitmapExample(L_VOID) 
{ 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap; 
   POINT pNewLocations[4]; 
 
   /* Load the bitmap, keeping the bits per pixel of the file */ 
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("Sample1.CMP")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   pNewLocations[0].x = LeadBitmap.Width * 3 / 9; 
   pNewLocations[0].y = LeadBitmap.Height * 1 / 12; 
   pNewLocations[1].x = LeadBitmap.Width * 3 / 4; 
   pNewLocations[1].y = LeadBitmap.Height * 2 / 12; 
   pNewLocations[2].x = LeadBitmap.Width * 2 / 10; 
   pNewLocations[2].y = LeadBitmap.Height * 8 / 10; 
   pNewLocations[3].x = LeadBitmap.Width * 10 / 11; 
   pNewLocations[3].y = LeadBitmap.Height * 7 / 10; 
 
   /*Apply the filter*/ 
   nRet = L_PerspectiveBitmap(&LeadBitmap, pNewLocations, RGB(255, 255, 255), PERSPECTIVE_IMAGE); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   nRet = L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("Result.BMP")), &LeadBitmap, FILE_BMP, 24, 0, NULL); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   //free bitmap 
   if (LeadBitmap.Flags.Allocated) 
      L_FreeBitmap(&LeadBitmap); 
 
   return SUCCESS; 
}