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L_PolarBitmap

#include "l_bitmap.h"

L_LTIMGSFX_API L_INT L_PolarBitmap(pBitmap, crFill, uFlags)

Converts the bitmap from rectangular to polar coordinates and vice versa.

Parameters

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle that references the bitmap on which to apply the effect.

The COLORREF value that specifies the fill color for any exposed areas. You can specify a COLORREF value, such as the return value of the Windows RGB macro, or you can use the PALETTEINDEX macro to specify a palette color.

L_UINT uFlags

Flags that indicate how to handle exposed areas and the type of conversion. You can use a bitwise OR (|) to specify one flag from each group.

The following are the flags that indicate how to handle exposed areas:

Value	Meaning
FILL_CLR	[0x0000] Fill any exposed areas with `crFill`.
FILL_RPT	[0x0001] Stretch the image edges to fill the exposed area.
FILL_NOCHG	[0x0002] Leave the exposed area as is, without changing it.

The following are the flags that indicate the conversion type:

Value	Meaning
CART_TO_POL	[0x0000] Convert the image from Cartesian (rectangular) coordinates to polar coordinates.
POL_TO_CART	[0x0010] Convert the image from polar coordinates to Cartesian (rectangular) coordinates.

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 converts a bitmap from Cartesian (rectangular) coordinates to polar coordinates or vice versa. Rectangular coordinates use the form (x, y) where x and y are the horizontal and vertical distances from the origin, respectively. Polar coordinates are in the form (r, ?) where r is the distance from the origin to the point and ? is the angle of the line the point makes with the positive x-axis. Polar coordinates use a grid made of concentric circles around the origin, along with lines that are rays radiating outward from the origin.

This function considers the positions of the images pixels as values in a polar coordinate system. Then it converts all the pixels in a line of the image into a circle around the center of the bitmap.

If the bitmap contains a region, the effect will be applied on the region only.

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.

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

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.

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.

Functions

Topics

Example

L_INT PolarBitmapExample(L_VOID) 
{ 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle for the image */ 
 
   /* Load a bitmap at its own bits per pixel */ 
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("sample5.cmp")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
 
   /* convert to polar coordinate */ 
   nRet = L_PolarBitmap (&LeadBitmap, 0, FILL_RPT | CART_TO_POL); 
   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; 
}