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L_HighQualityRotateBitmap

Summary

Rotates 1-bit (bitonal) images with high quality.

Syntax

#include "l_bitmap.h"

L_LTIMGCOR_API L_INT EXT_FUNCTION L_HighQualityRotateBitmap(pBitmap, nAngle, uFlags, crFill)

Parameters

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle that references the bitmap to rotate.

L_INT nAngle

Hundredths of degrees to rotate (+/-). This can be a number from 0 to 36,000. Positive values rotate the image in a clockwise direction, while negative values rotate the image in a counter-clockwise direction.

L_UINT uFlags

Flag that specifies whether to keep the resulting image the same size as the original image or to resize according to the rotation direction specified. Possible values are:

Value	Meaning
ROTATE_RESIZE	[0x0001] Size the resulting image.
HIGHQUALITYROTATE_HIGH	[0x0000] Rotate the image with high quality.(this is faster than best quality)
HIGHQUALITYROTATE_BEST	[0x0010] Rotate the image the image with the best quality.
HIGHQUALITYROTATE_CROP	[0x0000] Do not resize the image. Crop it.
HIGHQUALITYROTATE_RESIZE	[0x0001] Use high quality resize.

L_COLORREF crFill

A COLORREF value representing the color of the backgrounds. You can specify the value, such as the return value of the Windows RGB macro, or use the PALETTEINDEX macro to specify a palette color.

Returns

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

Comments

This function has the following features:

It works only with 1-bit images.
It uses the center of the image as the center of rotation.
It can rotate the image clockwise or counterclockwise up to 360 degrees in 1-degree increments.
It can resize the image to accommodate the rotated height and width, or it can retain the original height and width, cropping the bitmap as necessary.
It uses crFill as the background color to fill any new area created by the rotation.

If ROTATE_RESIZE is set, then the image is resized. Otherwise, the image is cropped.

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

Required DLLs and Libraries

LTIMGCOR
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

L_INT HighQualityRotateBitmapExample(L_VOID) 
{ 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle to hold the loaded image. */ 
 
   /* Load the bitmap, keeping the bits per pixel of the file */ 
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("OCR1.TIF")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   nRet = L_HighQualityRotateBitmap(&LeadBitmap, 2500, HIGHQUALITYROTATE_RESIZE | HIGHQUALITYROTATE_HIGH, RGB(255, 255, 255)); 
   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; 
}