LFile::LoadLayer

#include "ltwrappr.h"

virtual L_INT LFile::LoadLayer(nBitsPerPixel, nOrder, nLayer, pLayerInfo=NULL, pLoadOptions=NULL)

L_INT nBitsPerPixel;	/* resulting bitmap pixel depth */
L_INT nOrder;	/* color order for 16-, 24-, 32-, 48, and 64-bit bitmaps */
L_INT nLayer;	/* index of the layer to load */
pLAYERINFO pLayerInfo;	/* pointer to a structure */
pLOADFILEOPTION pLoadOptions;	/* pointer to optional extended load options */

Loads the specified layer from the class object's associated bitmap. Currently only PSD files support layers.

Parameter	Description
nBitsPerPixel	Resulting bitmap pixel depth. The following are valid values:
	Value	Meaning
	0	Keep the original file's pixel depth (Do not convert).
	1 to 8	The specified bits per pixel in the resultant bitmap
	12	12 bits per pixel in the resultant bitmap.
	16	16 bits per pixel in the resultant bitmap
	24	24 bits per pixel in the resultant bitmap
	32	32 bits per pixel in the resultant bitmap
	48	48 bits per pixel in the resultant bitmap
	64	64 bits per pixel in the resultant bitmap
nOrder	Color order for 16-, 24-, 32-, 48-, and 64-bit bitmaps. If the resultant bitmap is less than 16 bits per pixel, this will have no effect since palletized images have no order. The following are valid values:
	Value	Meaning
	ORDER_RGB	[0] Red, green, and blue color order in memory
	ORDER_BGR	[1] Blue, green, and red color order in memory
	ORDER_GRAY	[2] 12 or 16-bit grayscale image. 12 and 16-bit grayscale images are only supported in the Document/Medical toolkits.
	ORDER_RGBORGRAY	[3] Load the image as red, green, blue OR as a 12 or 16-bit grayscale image. 12 and 16-bit grayscale images are supported in the Document/Medical toolkits only.
	ORDER_BGRORGRAY	[4] Load the image as blue, green, red OR as a 12 or 16-bit grayscale image. 12 and 16-bit grayscale images are Document/Medical toolkits Imaging editions only.
nLayer	Index of the layer to load. This index is zero-based. Pass 0 to load the first layer, 1 to load the second layer, etc.
pLayerInfo	Pointer to a LAYERINFO structure to be updated with information about the loaded layer. Pass NULL for this parameter if layer information is not needed. If this parameter contains a valid pointer to a LAYERINFO structure, the lSize member should be set to the sizeof (LAYERINFO) before calling this function.
pLoadOptions	Pointer to optional extended load options. Pass NULL to use the default load options.

Returns

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

Comments

Support for 12 and 16-bit grayscale images is only available in the Document/Medical toolkits.

Currently, only the PSD file format supports layers.

This function works similarly to the LFile::Load function, except that it loads only a layer from a file. It loads the layer specified in nLayer.

Before calling this function, you may need to get or set file information, such as the number of layers on the file. Refer to Getting and Setting File Information.

The number of layers in a file is indicated in FILEINFO.Layers. If FILEINFO.Layers is 0, the file does not contains any layers and this function should not be called.

Since the function allocates storage to hold the image, it is up to you to free this storage by calling LBitmapBase::Free.

Required DLLs and Libraries

LTFIL
Exif 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.

See Also

Functions:	LFile::Load, LFile::GetInfo, LFile::SaveWithLayers, Class Members
Topics:	Raster Image Functions: Loading Files
	Loading and Saving Images

Example

L_INT LFile__LoadLayerExample(LFile & File, LBitmapBase & Bitmap, L_TCHAR * pszFile, L_INT nLayer)
{
   L_INT nRet;
   FILEINFO FileInfo;
   File.SetBitmap(&Bitmap);
   File.SetFileName(pszFile);
   nRet = File.GetInfo(&FileInfo, sizeof(FILEINFO));
   if(nRet != SUCCESS)
      return nRet;
   if (FileInfo.Layers)
   {
      if (FileInfo.Layers > nLayer)
      {
         nRet  =  File.LoadLayer(0, ORDER_BGRORGRAY, nLayer);
         if(nRet!=SUCCESS)
         {
           LBase::DisplayErrorFromList();
           return nRet;
         }
      }
      else
         MessageBox(NULL, TEXT("Invalid layer index!"), TEXT("Testing"), MB_OK);
   }
   else
      MessageBox(NULL, TEXT("No layers in the file!"), TEXT("Testing"), MB_OK);
   return SUCCESS;
}