L_SizeBitmapInterpolate

#include "l_bitmap.h"

L_LTIMGCOR_API L_INT L_SizeBitmapInterpolate(pBitmap, nWidth, nHeight, uFlags)

Resizes a bitmap to a new width and height.

Parameters

pBITMAPHANDLE pBitmap

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

L_INT nWidth

Value that represents the new width, in pixels.

L_INT nHeight

Value that represents the new height, in pixels.

L_UINT uFlags

Flag that determines the resizing behavior. Possible values are:

Value Meaning
SIZE_NORMAL [0x0000] Resize normally. This is the fastest, but can cause aliasing.
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 high-quality image. This is slower than SIZE_BILINEAR.
SIZE_TRIANGLE [0x0005] Use Triangular-peaked weighting average to produce a high-quality image.
SIZE_HERMITE [0x0006] Use Hermite interpolation to produce a good quality image better than Bresenham interpolation but not as good as Bilinear interpolation. (using a cubic spline as is done when using Hermite interpolation is slower than when using Bilinear interpolation).
SIZE_BELL [0x0007] Use bell interpolation to produce a high-quality image. This filter blurs the image at the same time it resizes. If you want performance similar to bicubic filtering but your source image is noisy, use this one.
SIZE_QUADRATIC_B_SPLINE [0x0008] Use Quadratic B-Spline interpolation to produce a smooth quality image but one that is not as good as one produced using Cubic B-Spline interpolation. This is faster than SIZE_CUBIC_B_SPLINE.
SIZE_CUBIC_B_SPLINE [0x0009] Use Cubic B-Spline interpolation to produce a very smooth quality image (very blurry). This is one step further than the 'Bell Filter'. This type of interpolation is a bit slower and generates an image with more blur but it has less noise. This method is faster than SIZE_BICUBIC.
SIZE_BOXFILTER [0x00A] Use Box filter for results equivalent to Nearest Neighbor on Upsampling, and average pixels on Downsampling. This gives best result for images with single pixel lines.
SIZE_LANCZOS [0x000B] Use Lanczos interpolation using Sinc (sinx/x) to produce a high-quality image. Provides the best quality but it is rather slow.
SIZE_MICHELL [0x000C] Use Michel interpolation to produce a smooth quality image although not as smooth as one produced using Quadratic B-Spline interpolation. It is slower than SIZE_BICUBIC.
SIZE_COSINE [0x000D] Use a Cosine function in the interpolation to produce a good quality image.
SIZE_CATROM [0x000E] Use CatmullRom interpolation to produce a high-quality image. It is slower than SIZE_BICUBIC but faster than SIZE_LANCZOS.
SIZE_QUADRATIC [0x000F] Use QUADRATIC interpolation to produce a high-quality image although it is not as good quality as one produced using Bilinear interpolation. It is slower than SIZE_BICUBIC.
SIZE_CUBIC_CONVOLUTION [0x0010] Use Cubic Convolution interpolation to produce a high-quality image with enhanced image edges. It is slower than SIZE_BICUBIC.
SIZE_BILINEAR [0x0011] Use Linear interpolation and averaging to produce a high-quality image. It is fast but slower than SIZE_NORMAL and SIZE_BRESENHAM
SIZE_BRESENHAM [0x0012] Use Bresenham interpolation and averaging to produce a good quality image (better than SIZE_NORMAL). This is slower than SIZE_NORMAL but faster than SIZE_BILINEAR.

Returns

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

Comments

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 Document and Medical Imaging toolkits.

To see a visual comparison among these methods, showing speed and result of 500% enlargement, click  here.

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

Required DLLs and Libraries

Platforms

Win32, x64, Linux.

See Also

Functions

Topics

Example

This example changes a bitmap to half its previous size

L_INT SizeBitmapInterpolatepExample(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("sample5.cmp")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if(nRet != SUCCESS) 
      return nRet; 
   /* Change the size of the bitmap */ 
   nRet = L_SizeBitmapInterpolate(&LeadBitmap, LeadBitmap.Width / 2, LeadBitmap.Height / 2, SIZE_LANCZOS); 
   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; 
} 

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