// ********************************************************************** //
// ** This file was downloaded from Jeff Heaton's Source Code Examples ** //
// **                      www.heat-on.com/source                      ** //
// ********************************************************************** //
// Copyright 1999 by Jeff Heaton
// ********************************************************************** //
// Permission is granted for royaltyfree use in compiled form.  No 
// additional licensing is required.  This code may not be distributed 
// in source form without written premission by Jeff Heaton.  Generally
// I will grant it.  Just ask first. 
//
// Basically I do not care how you distribute this code in compiled form.
// But if your going to publish my source code somewhere I'd like to hear
// about it first.
// ********************************************************************** //

// SaveBitmap V1.0
// Written 1/14/1999 by Jeff Heaton
//
//  Write bitmap handles as bitmap files(.bmp).
//
// Windows provides many routines for working with bitmaps.  However there
// is no easy way to save one as a .bmp file.  The SaveBitmap routine can be
// used to save bitmap handles to disk.  This example uses the ErrorHandler
// example.

#include <windows.h>

// Function Name: ErrorHandler
// Parameters:
//		msg - Error message to display
// Returns:
//		Nothing.
// Purpose:
//		This function is used to report errors to the user.
// Author
//		Jeff Heaton
void ErrorHandler(char *msg)
{
	LPVOID lpMsgBuf;// The GetLastError error message
	char *complete;// Used to build complete error message
	
	
	FormatMessage( 
		FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,    NULL,
		GetLastError(),MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 
		(LPTSTR) &lpMsgBuf,    0,    NULL );

	complete = (char*)LocalAlloc( LMEM_FIXED,LocalSize(lpMsgBuf) + 2 + lstrlen(msg) );
	lstrcpy(complete,msg);
	lstrcat(complete,"\r\n");
	lstrcat(complete,(char*)lpMsgBuf);
	
	MessageBox( NULL, (const char *)complete, "Error", MB_OK|MB_ICONINFORMATION );
	LocalFree( lpMsgBuf );
	LocalFree( complete );
}


// Function Name: SaveBitmap
// Parameters:
//		name - Filename to save the bitmap to
//		bitmap - Bitmap handle to save
// Returns:
//		TRUE if successful.
// Purpose:
//		This is used to save a HBITMAP handle as a Windows .bmp file.
// Author
//		Jeff Heaton

BOOL SaveBitmap(char *name,HBITMAP bitmap)
{
	HDC hdcScreen;		// Device context of the screen
	HWND hwndScreen;	// Desktop window handle
	int i;				// Counts the number of scanlines
	BYTE *bits;			// Pointer to the bitmap's bits
	BITMAPINFOHEADER *info;	// Info structure about this bitmap
	HANDLE fp;			// A file handle
	BITMAPFILEHEADER finfo;	// File info header
	long ctsize,imgsize,pixels;// Various sizes needed to build the file
	DWORD dw;			// Doubleword return code
	char *ptr;			// Pointer used to write the opening BM
	
	hwndScreen=GetDesktopWindow();
	hdcScreen = GetDC( hwndScreen );

	info = (BITMAPINFOHEADER*)GlobalAlloc(GMEM_FIXED,sizeof(BITMAPFILEHEADER)+(1024*sizeof(RGBQUAD)));
	info->biSize = sizeof(BITMAPINFOHEADER);
	info->biBitCount = 0;

	i = GetDIBits( hdcScreen, // handle of device context 
			bitmap, // handle of bitmap 
			0,			// first scan line to set in destination bitmap 
			0,		// number of scan lines to copy 
			NULL, // address of array for bitmap bits 
			(BITMAPINFO*)info,		// address of structure with bitmap data 
			DIB_RGB_COLORS // RGB or palette index
			 );

	if( (info->biBitCount!=4) &&
		(info->biBitCount!=8) &&
		(info->biBitCount!=24) )
		info->biBitCount=24;
	info->biCompression=BI_RGB;


	pixels=info->biWidth*info->biHeight;
	switch(info->biBitCount)
	{
		case 4:ctsize=16;imgsize=pixels/2;break;
		case 8:ctsize=256;imgsize=pixels;break;
		case 16:ctsize=0;imgsize=pixels*2;break;
		case 24:ctsize=0;imgsize=pixels*3;break;
		case 32:ctsize=0;imgsize=pixels*4;break;
		default:
			ReleaseDC( hwndScreen,hdcScreen );
			return FALSE;
	}


	bits = (unsigned char*)GlobalAlloc(GMEM_FIXED,imgsize);

	i = GetDIBits( hdcScreen, // handle of device context 
			bitmap, // handle of bitmap 
			0,			// first scan line to set in destination bitmap 
			info->biHeight,		// number of scan lines to copy 
			bits, // address of array for bitmap bits 
			(BITMAPINFO*)info,		// address of structure with bitmap data 
			DIB_RGB_COLORS // RGB or palette index
			 );

	ptr = (char *)&finfo.bfType;
	ptr[0]='B';
	ptr[1]='M';

	finfo.bfOffBits=sizeof(BITMAPFILEHEADER)+
		sizeof(BITMAPINFOHEADER)+
		(sizeof(RGBQUAD)*ctsize);
	finfo.bfSize=finfo.bfOffBits+imgsize;
	finfo.bfReserved1=0;
    finfo.bfReserved2=0;       

	fp = CreateFile(name,// pointer to name of the file 
		GENERIC_WRITE, // access (read-write) mode 
		0, // share mode 
		NULL, // pointer to security attributes 
		CREATE_ALWAYS,// how to create
		FILE_ATTRIBUTE_NORMAL|FILE_FLAG_SEQUENTIAL_SCAN,// file attributes 
		NULL // handle to file with attributes to copy 
		);

	WriteFile(fp,&finfo,sizeof(BITMAPFILEHEADER),&dw,NULL);
	WriteFile(fp,info,sizeof(BITMAPINFOHEADER)+sizeof(RGBQUAD)*ctsize,&dw,NULL);
	WriteFile(fp,bits,imgsize,&dw,NULL);
	CloseHandle(fp);
	GlobalFree(info);
	GlobalFree(bits);

	ReleaseDC( hwndScreen,hdcScreen );
	return TRUE;
}