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L_SizeBitmap

Summary

Resizes a bitmap to a new width and height.

Syntax

#include "l_bitmap.h"

L_LTKRN_API L_INT L_SizeBitmap(pBitmap, nWidth, nHeight, uFlags)

Parameters

pBITMAPHANDLE pBitmap

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

L_INT nWidth

New width in pixels.

L_INT nHeight

New height in pixels.

L_UINT uFlags

Flags that control the behavior when resizing the bitmap. Use one of the following:

Value	Meaning
SIZE_NORMAL	[0x0000] Resize normally.
SIZE_FAVORBLACK	[0x0001] (Document and Medical Imaging toolkits) Preserve black objects when making the image smaller. This option affects only 1-bit, black-and-white images, where it prevents the disappearance of thin lines. You can use a bitwise OR (	) to combine this flag with another one. For example, SIZE_RESAMPLE \| SIZE_FAVORBLACK causes color images to be resampled, but applies the favor-black option to 1-bit, black-and-white images.
SIZE_RESAMPLE	[0x0002] Use linear interpolation and averaging to produce a higher-quality image.
SIZE_BICUBIC	[0x0004] Use bicubic interpolation and averaging to produce a higher quality image. This is slower than SIZE_RESAMPLE.
SIZE_SCALETOGRAY	[0x0008] (Document and Medical Imaging toolkits). Use interpolation to display black and white images using shades of gray when the image is resized. This improves the readability when the image is scaled up or down. The generated image is 8-bit grayscale, so this option should be used only for black and white images.
SIZE_OLD_RESAMPLE	[0x0010] Use the old resample algorithm from LEADTOOLS 14.5.
SIZE_PREMULTIPLYALPHA	[0x0020] Premultiply the alpha channel values when performing resize.

Returns

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

Comments

This function keeps the same bitmap handle and resizes the bitmap that it references. If you want to keep the original-size bitmap along with the resized bitmap, use the L_ResizeBitmap function.

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

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, Linux.

Example

For complete sample code, refer to the FEATURE2
example.
This example changes a bitmap to half its previous size.

L_INT SizeBitmapExample(L_VOID) 
{ 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle to hold the loaded image */ 
 
   /* Load the bitmap, at its own bits per pixel */ 
   nRet = L_LoadBitmap (MAKE_IMAGE_PATH(TEXT("ImageProcessingDemo\\Image3.cmp")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if(nRet != SUCCESS) 
      return nRet; 
   /* Change the size of the bitmap */ 
   nRet = L_SizeBitmap (&LeadBitmap, LeadBitmap.Width / 2, LeadBitmap.Height / 2, SIZE_NORMAL); 
   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; 
 
   if(LeadBitmap.Flags.Allocated) 
      L_FreeBitmap(&LeadBitmap);   
   return SUCCESS; 
}