LFile::LoadBitmapResize
#include "ltwrappr.h"
virtual L_INT LFile::LoadBitmapResize(nDestWidth, nDestHeight, nDestBits, uFlags, nOrder, pLoadOptions, pFileInfo)
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L_INT nDestWidth; |
/* new width of the image */ |
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L_INT nDestHeight; |
/* new height of the image */ |
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L_INT nDestBits; |
/* resulting bitmap pixel depth */ |
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L_UINT32 uFlags; |
/* flags */ |
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L_INT nOrder; |
/* color order for 16-, 24-, 32-, 48, and 64-bit bitmaps */ |
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pLOADFILEOPTION pLoadOptions; |
/* pointer to optional extended load options */ |
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pFILEINFO pFileInfo; |
/* pointer to a structure */ |
Loads an image file into the class object's associated bitmap, resizing the bitmap as it loads, to the desired width, height, and bits per pixel. The file can be in any supported image file format and bits per pixel, whether compressed or uncompressed.
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Parameter |
Description |
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nDestWidth |
New width of the image. |
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nDestHeight |
New height of the image. |
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nDestBits |
Resulting bitmap pixel depth. The following are valid values: |
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Value |
Meaning |
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0 |
Keep the original file's pixel depth (Do not convert). A special note about loading 12 and 16-bit grayscale images. |
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1 to 8 |
The specified bits per pixel in the resultant bitmap |
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12 |
12 bits per pixel in the resultant bitmap. |
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16 |
16 bits per pixel in the resultant bitmap |
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24 |
24 bits per pixel in the resultant bitmap |
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32 |
32 bits per pixel in the resultant bitmap |
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48 |
48 bits per pixel in the resultant bitmap |
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64 |
64 bits per pixel in the resultant bitmap |
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uFlags |
Flag that indicates the type of resizing to use. Possible values are: |
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Value |
Meaning |
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SIZE_NORMAL |
[0x0] Normal resizing. |
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SIZE_RESAMPLE |
[0x2] Linear interpolation resizing. |
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SIZE_BICUBIC |
[0x4] Bicubic interpolation resizing. |
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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: |
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Value |
Meaning |
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ORDER_RGB |
[0] Red, green, and blue color order in memory |
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ORDER_BGR |
[1] Blue, green, and red color order in memory |
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ORDER_GRAY |
[2] 12 or 16-bit grayscale image. 12 and 16-bit grayscale images are only supported in the Document/Medical toolkits. |
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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. |
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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 supported in the Document/Medical toolkits only. |
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pLoadOptions |
Pointer to a LOADFILEOPTION structure that contains optional extended load options. Pass NULL to use the default load options. |
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pFileInfo |
Pointer to a FILEINFO structure. This structure may contain file information used in loading an image, or it may be updated with information about the file being loaded. |
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If nothing is known about the file, pass NULL for this parameter, or declare a variable of type FILEINFO and set the FILEINFO.Flags to 0, then pass the address of the FILEINFO structure in this parameter. In this case, if the address of a FILEINFO structure is passed, the FILEINFO structure will be updated with the results of LFile::GetInfo. |
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If only the file type is known, set pFileInfo.Format to the file type and set pFileInfo.Flags to FILEINFO_FORMATVALID. This can also be done if LFile::GetInfo has been called previously, but values that affect the size of the image loaded have been changed (for example, by calling LFileSettings::SetPCDResolution or LFileSettings::SetWMFResolution). In this case the FILEINFO structure pointed to by pFileInfo will be updated with the results of LFile::GetInfo. |
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If LFile::GetInfo has been called prior to calling this function, and no changes have been made to the contents of the structure filled by LFile::GetInfo, then the address of the filled FILEINFO structure can be passed for this parameter. In this case, the FILEINFO.Flags member should be set to FILEINFO_INFOVALID. The LFile::GetInfo function will set the FILEINFO.Flags to FILEINFO_INFOVALID. In this case the load will be faster since this function does not have to query the file filters for the file type. |
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Note: Local variables are not initialized (since they are placed on the stack). So if you have a FILEINFO structure as a local variable, the value of its Flags parameter is undefined, possibly having FILEINFO_INFOVALID or FILEINFO_FORMATVALID set. That is why it is important to initialize FILEINFO.Flags before passing the address of the FILEINFO structure to the function. |
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Returns
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SUCCESS |
The function was successful. |
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< 1 |
An error occurred. Refer to Return Codes. |
Comments
This function resizes a file as it loads, to the desired width, height, and bits per pixel. Note that the original file is not completely loaded into memory. This function is ideal for sampling large images (i.e. generating a thumbnail) without the memory overhead of loading the large file itself.
For supported formats, refer to Summary of All Supported Image File Formats.
Required DLLs and Libraries
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LTFIL 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
Example
/* This sample loads and resizes an image to 400 pixels high.
The width of the bitmap is determined by the aspect ratio.
Bicubic interpolation is used in the resize.
The bitmap is loaded at the original bits per pixel. */
L_INT LoadBitmapResized(LFile & LeadFile, LBitmapBase & Bitmap,
L_TCHAR * pszFile)
{
LeadFile.SetBitmap(&Bitmap);
LeadFile.SetFileName(pszFile);
return LeadFile.LoadBitmapResize(0,
400, 0, SIZE_BICUBIC, ORDER_BGR, NULL, NULL);
}