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LFile::ReadLoadResolutions

Summary

Examines a FlashPix, PhotoCD, ECW, or JBIG file to determine which resolutions it contains.

Syntax

#include "ltwrappr.h"

virtual L_INT LFile::ReadLoadResolutions(pDimensions, pDimensionCount, pLoadFileOption=NULL)

Parameters

pDIMENSION pDimensions

Pointer to the array of DIMENSION structures to be updated with the available physical resolutions in the file. You can pass NULL if you only want to update the count variable.

L_INT * pDimensionCount

Address of the pDimensionCount variable to be updated with the number of available resolutions.

pLOADFILEOPTION pLoadFileOption

Pointer to optional extended load options. Pass NULL to use the default load options.

Returns

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

Comments

A FlashPix, PhotoCD, ECW, or JBIG file can may contain more than one copy of the same image, each at a different physical resolution (width and height in pixels). For PhotoCD files, the resolutions are fixed sizes, and you can use an older function (LFile::GetPCDResolution) to examine them. For FlashPix and JBIG files, which can contain images of various sizes, you must use this function to examine them. For ECW files you can only resample images to dimensions smaller than the original values for width/height, you can use this function to get the original dimensions.

You must allocate the array to be updated. One way to do this is to declare an array of the maximum size (29 elements). Another way is to call this function twice the first time with NULL in the pDimensions parameter, so that you can get the number of elements and allocate storage of the appropriate size.

After you get the available resolutions, you can use the LFileSettings::SetLoadResolution function to specify the one to be loaded.

Before you can call this function, you must set the filename for the class object.

Required DLLs and Libraries

LTFIL
File format DLLs
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

L_INT LFile__ReadLoadResolutionsExample( HWND hWnd) 
{ 
   L_INT nRet; 
   pDIMENSION     pDimensions = NULL; // Pointer to the array to be updated 
   L_INT          DimensionCount;// Number of physical resolutions   
   L_TCHAR         szMessage[256];// MessageBox string  
   L_UINT32       uWidth;        // Width variable to be updated   
   L_UINT32       uHeight;       // Height variable to be updated  
   L_INT          i;             // Loop counter  
   LFile          LeadFile ; 
   FILEINFO      FileInfo ; 
   LBitmapBase  LeadBitmap; 
 
   LeadFile.SetBitmap(&LeadBitmap) ; 
   LeadFile.SetFileName(MAKE_IMAGE_PATH(TEXT("Img0024.pcd"))) ; 
 
   nRet = LeadFile.GetInfo(&FileInfo, sizeof(FILEINFO)) ; 
   if(nRet != SUCCESS) 
      return nRet; 
 
   nRet = LeadFile.ReadLoadResolutions(NULL, &DimensionCount, NULL) ; 
   if(nRet != SUCCESS) 
      return nRet; 
 
   pDimensions = new DIMENSION[DimensionCount]; 
 
   // Fill the array  
   nRet = LeadFile.ReadLoadResolutions( pDimensions, &DimensionCount, NULL); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   // Display a message box that shows the available sizes 
   for(i = 0; i < DimensionCount; ++i) 
   { 
      wsprintf (szMessage,TEXT("%s\n%d x %d"), TEXT("Available dimensions:\n"), pDimensions[i].nWidth, pDimensions[i].nHeight); 
      MessageBox( NULL, szMessage, TEXT("File Information"), MB_OK ); 
   }    
 
   // Set the size to load, the smallest size in this case  
   nRet = LFileSettings::SetLoadResolution(FileInfo.Format, pDimensions[0].nWidth, pDimensions[0].nHeight); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   delete pDimensions; 
 
   // Get the dimensions that we just set and display them  
   nRet = LFileSettings::GetLoadResolution(FileInfo.Format, &uWidth, &uHeight); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   wsprintf (szMessage,TEXT("Size that will be loaded:\n\n%d x %d"), uWidth, uHeight); 
   MessageBox( NULL, szMessage, TEXT("File Information"), MB_OK ); 
 
   // Load the bitmap, keeping the bits per pixel of the file  
   nRet = LeadFile.Load (); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   // Update the paint palette to force a repaint  
   SendMessage (hWnd, WM_QUERYNEWPALETTE, 0, 0L); 
 
   return SUCCESS; 
}