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exercise_2/colmap-build/FreeImage/Examples/Generic/LoadFromHandle.cpp

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// ==========================================================
// Load From Handle Example
//
// Design and implementation by
// - Hervé Drolon
//
// This file is part of FreeImage 3
//
// COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
// THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
// OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
// CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
// THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
// SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
// PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
// THIS DISCLAIMER.
//
// Use at own risk!
// ==========================================================
// This example shows how to load a bitmap from a
// user allocated FILE pointer.
//
// Functions used in this sample :
// FreeImage_GetFormatFromFIF, FreeImage_GetFileTypeFromHandle, FreeImage_LoadFromHandle,
// FreeImage_GetFIFFromFilename, FreeImage_Save, FreeImage_Unload
// FreeImage_GetVersion, FreeImage_GetCopyrightMessage, FreeImage_SetOutputMessage
//
// ==========================================================
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include "FreeImage.h"
// ----------------------------------------------------------
/**
FreeImage error handler
@param fif Format / Plugin responsible for the error
@param message Error message
*/
void FreeImageErrorHandler(FREE_IMAGE_FORMAT fif, const char *message) {
printf("\n*** ");
if(fif != FIF_UNKNOWN) {
printf("%s Format\n", FreeImage_GetFormatFromFIF(fif));
}
printf(message);
printf(" ***\n");
}
// ----------------------------------------------------------
unsigned DLL_CALLCONV
myReadProc(void *buffer, unsigned size, unsigned count, fi_handle handle) {
return fread(buffer, size, count, (FILE *)handle);
}
unsigned DLL_CALLCONV
myWriteProc(void *buffer, unsigned size, unsigned count, fi_handle handle) {
return fwrite(buffer, size, count, (FILE *)handle);
}
int DLL_CALLCONV
mySeekProc(fi_handle handle, long offset, int origin) {
return fseek((FILE *)handle, offset, origin);
}
long DLL_CALLCONV
myTellProc(fi_handle handle) {
return ftell((FILE *)handle);
}
// ----------------------------------------------------------
int
main(int argc, char *argv[]) {
// call this ONLY when linking with FreeImage as a static library
#ifdef FREEIMAGE_LIB
FreeImage_Initialise();
#endif // FREEIMAGE_LIB
// initialize your own FreeImage error handler
FreeImage_SetOutputMessage(FreeImageErrorHandler);
// print version & copyright infos
printf(FreeImage_GetVersion());
printf("\n");
printf(FreeImage_GetCopyrightMessage());
printf("\n");
if(argc != 2) {
printf("Usage : LoadFromHandle <input file name>\n");
return 0;
}
// initialize your own IO functions
FreeImageIO io;
io.read_proc = myReadProc;
io.write_proc = myWriteProc;
io.seek_proc = mySeekProc;
io.tell_proc = myTellProc;
FILE *file = fopen(argv[1], "rb");
if (file != NULL) {
// find the buffer format
FREE_IMAGE_FORMAT fif = FreeImage_GetFileTypeFromHandle(&io, (fi_handle)file, 0);
if(fif != FIF_UNKNOWN) {
// load from the file handle
FIBITMAP *dib = FreeImage_LoadFromHandle(fif, &io, (fi_handle)file, 0);
// save the bitmap as a PNG ...
const char *output_filename = "test.png";
// first, check the output format from the file name or file extension
FREE_IMAGE_FORMAT out_fif = FreeImage_GetFIFFromFilename(output_filename);
if(out_fif != FIF_UNKNOWN) {
// then save the file
FreeImage_Save(out_fif, dib, output_filename, 0);
}
// free the loaded FIBITMAP
FreeImage_Unload(dib);
}
fclose(file);
}
// call this ONLY when linking with FreeImage as a static library
#ifdef FREEIMAGE_LIB
FreeImage_DeInitialise();
#endif // FREEIMAGE_LIB
return 0;
}