dibapi.cpp

用内存设备上下文实现图像选中区域 的判断

//  dibapi.cpp
//
//  Source file for Device-Independent Bitmap (DIB) API.  Provides
//  the following functions:
//
//  PaintDIB()          - Painting routine for a DIB
//  CreateDIBPalette()  - Creates a palette from a DIB
//  FindDIBBits()       - Returns a pointer to the DIB bits
//  DIBWidth()          - Gets the width of the DIB
//  DIBHeight()         - Gets the height of the DIB
//  PaletteSize()       - Gets the size required to store the DIB's palette
//  DIBNumColors()      - Calculates the number of colors
//                        in the DIB's color table
//  CopyHandle()        - Makes a copy of the given global memory block
//
// This is a part of the Microsoft Foundation Classes C++ library.
// Copyright (C) 1992-1998 Microsoft Corporation
// All rights reserved.
//
// This source code is only intended as a supplement to the
// Microsoft Foundation Classes Reference and related
// electronic documentation provided with the library.
// See these sources for detailed information regarding the
// Microsoft Foundation Classes product.

#include "stdafx.h"
#include "dibapi.h"
#include <io.h>
#include <errno.h>
#include <math.h>
#include <direct.h>

/*
 * Dib Header Marker - used in writing DIBs to files
 */
#define DIB_HEADER_MARKER   ((WORD) ('M' << 8) | 'B')

/*************************************************************************

  Function:  ReadDIBFile (CFile&)

   Purpose:  Reads in the specified DIB file into a global chunk of
			 memory.

   Returns:  A handle to a dib (hDIB) if successful.
			 NULL if an error occurs.

  Comments:  BITMAPFILEHEADER is stripped off of the DIB.  Everything
			 from the end of the BITMAPFILEHEADER structure on is
			 returned in the global memory handle.

*************************************************************************/


HDIB WINAPI ReadDIBFile(LPCTSTR pszFileName )
{
	BITMAPFILEHEADER bmfHeader;
	DWORD dwBitsSize;
	HDIB hDIB;
	LPSTR pDIB;
	HANDLE hFile;
	DWORD nBytesRead;

	/*
	 * get length of DIB in bytes for use when reading
	 */
	hFile =  CreateFile(
	pszFileName,    // pointer to name of the file
	GENERIC_READ,   // access (read-write) mode
	FILE_SHARE_READ,    // share mode
	NULL,   // pointer to security descriptor
	OPEN_EXISTING,  // how to create
	FILE_ATTRIBUTE_NORMAL,  // file attributes
	NULL    // handle to file with attributes to copy
   );


	dwBitsSize = GetFileSize(hFile,NULL);

	/*
	 * Go read the DIB file header and check if it's valid.
	 */
	// attempt an asynchronous read operation
	if(! ReadFile(hFile, (LPSTR)&bmfHeader, sizeof(bmfHeader), &nBytesRead,
		 NULL))
		return NULL;

	if (bmfHeader.bfType != DIB_HEADER_MARKER)
		return NULL;

	/*
	 * Allocate memory for DIB
	 */
	hDIB = (HDIB) ::GlobalAlloc(GMEM_MOVEABLE | GMEM_ZEROINIT, dwBitsSize);
	if (hDIB == 0)
	{
		return NULL;
	}
	pDIB = (LPSTR) ::GlobalLock((HGLOBAL) hDIB);

	/*
	 * Go read the bits.
	 */
	if(!ReadFile(hFile, (LPSTR)pDIB, dwBitsSize - sizeof(BITMAPFILEHEADER), &nBytesRead, NULL))
	{
		::GlobalUnlock((HGLOBAL) hDIB);
		::GlobalFree((HGLOBAL) hDIB);
		return NULL;
	}
	::GlobalUnlock((HGLOBAL) hDIB);
	CloseHandle(hFile);
	return hDIB;
}

/*************************************************************************
 *
 * PaintDIB()
 *
 * Parameters:
 *
 * HDC hDC          - DC to do output to
 *
 * LPRECT lpDCRect  - rectangle on DC to do output to
 *
 * HDIB hDIB        - handle to global memory with a DIB spec
 *                    in it followed by the DIB bits
 *
 * LPRECT lpDIBRect - rectangle of DIB to output into lpDCRect
 *
 * CPalette* pPal   - pointer to CPalette containing DIB's palette
 *
 * Return Value:
 *
 * BOOL             - TRUE if DIB was drawn, FALSE otherwise
 *
 * Description:
 *   Painting routine for a DIB.  Calls StretchDIBits() or
 *   SetDIBitsToDevice() to paint the DIB.  The DIB is
 *   output to the specified DC, at the coordinates given
 *   in lpDCRect.  The area of the DIB to be output is
 *   given by lpDIBRect.
 *
 ************************************************************************/

BOOL WINAPI PaintDIB(HDC     hDC,
					LPRECT  lpDCRect,
					HDIB    hDIB,
					LPRECT  lpDIBRect,
					HPALETTE hPal)
{
	LPSTR    lpDIBHdr;            // Pointer to BITMAPINFOHEADER
	LPSTR    lpDIBBits;           // Pointer to DIB bits
	BOOL     bSuccess=FALSE;      // Success/fail flag
	HPALETTE hOldPal=NULL;        // Previous palette

	/* Check for valid DIB handle */
	if (hDIB == NULL)
		return FALSE;

	/* Lock down the DIB, and get a pointer to the beginning of the bit
	 *  buffer
	 */
	lpDIBHdr  = (LPSTR) ::GlobalLock((HGLOBAL) hDIB);
	lpDIBBits = ::FindDIBBits(lpDIBHdr);

	// Get the DIB's palette, then select it into DC
	// Select as background since we have
	// already realized in forground if needed
	hOldPal = ::SelectPalette(hDC, hPal, TRUE);

	/* Make sure to use the stretching mode best for color pictures */
	::SetStretchBltMode(hDC, COLORONCOLOR);

	/* Determine whether to call StretchDIBits() or SetDIBitsToDevice() */
	if ((RECTWIDTH(lpDCRect)  == RECTWIDTH(lpDIBRect)) && (RECTHEIGHT(lpDCRect) == RECTHEIGHT(lpDIBRect)))
	{
		bSuccess = ::SetDIBitsToDevice(hDC,                    // hDC
			lpDCRect->left,             // DestX
			lpDCRect->top,              // DestY
			RECTWIDTH(lpDCRect),        // nDestWidth
			RECTHEIGHT(lpDCRect),       // nDestHeight
//          RECTWIDTH(lpDIBRect),           // wSrcWidth
//          RECTHEIGHT(lpDIBRect),          // wSrcHeight
			lpDIBRect->left,            // SrcX
			(int)DIBHeight(lpDIBHdr) -
			lpDIBRect->top -
			RECTHEIGHT(lpDIBRect),   // SrcY
			0,                          // nStartScan
			(WORD)DIBHeight(lpDIBHdr),  // nNumScans
			lpDIBBits,                  // lpBits
			(LPBITMAPINFO)lpDIBHdr,     // lpBitsInfo
			DIB_RGB_COLORS);            // wUsage
	}
	else
	{
		bSuccess = ::StretchDIBits(hDC,                          // hDC
			lpDCRect->left,                 // DestX
			lpDCRect->top,                  // DestY
			RECTWIDTH(lpDCRect),            // nDestWidth
			RECTHEIGHT(lpDCRect),           // nDestHeight
//          RECTWIDTH(lpDIBRect),           // wSrcWidth
//          RECTHEIGHT(lpDIBRect),          // wSrcHeight
			lpDIBRect->left,                // SrcX
			lpDIBRect->top,                 // SrcY
			RECTWIDTH(lpDIBRect),           // wSrcWidth
			RECTHEIGHT(lpDIBRect),          // wSrcHeight
			lpDIBBits,                      // lpBits
			(LPBITMAPINFO)lpDIBHdr,         // lpBitsInfo
			DIB_RGB_COLORS,                 // wUsage
			SRCCOPY);                       // dwROP
	}

   ::GlobalUnlock((HGLOBAL) hDIB);

	/* Reselect old palette */
	if (hOldPal != NULL)
	{
		::SelectPalette(hDC, hOldPal, TRUE);
	}

   return bSuccess;
}

/*************************************************************************
 *
 * CreateDIBPalette()
 *
 * Parameter:
 *
 * HDIB hDIB        - specifies the DIB
 *
 * Return Value:
 *
 * HPALETTE         - specifies the palette
 *
 * Description:
 *
 * This function creates a palette from a DIB by allocating memory for the
 * logical palette, reading and storing the colors from the DIB's color table
 * into the logical palette, creating a palette from this logical palette,
 * and then returning the palette's handle. This allows the DIB to be
 * displayed using the best possible colors (important for DIBs with 256 or
 * more colors).
 *
 ************************************************************************/


BOOL WINAPI CreateDIBPalette(HDIB hDIB, HPALETTE* pPal)
{
	LPLOGPALETTE lpPal;      // pointer to a logical palette
	HANDLE hLogPal;          // handle to a logical palette
	HPALETTE hPal = NULL;    // handle to a palette
	int i;                   // loop index
	WORD wNumColors;         // number of colors in color table
	LPSTR lpbi;              // pointer to packed-DIB
	LPBITMAPINFO lpbmi;      // pointer to BITMAPINFO structure (Win3.0)
	LPBITMAPCOREINFO lpbmc;  // pointer to BITMAPCOREINFO structure (old)
	BOOL bWinStyleDIB;       // flag which signifies whether this is a Win3.0 DIB
	BOOL bResult = FALSE;

	/* if handle to DIB is invalid, return FALSE */

	if (hDIB == NULL)
	  return FALSE;

   lpbi = (LPSTR) ::GlobalLock((HGLOBAL) hDIB);

   /* get pointer to BITMAPINFO (Win 3.0) */
   lpbmi = (LPBITMAPINFO)lpbi;

   /* get pointer to BITMAPCOREINFO (old 1.x) */
   lpbmc = (LPBITMAPCOREINFO)lpbi;

   /* get the number of colors in the DIB */
   wNumColors = ::DIBNumColors(lpbi);

   if (wNumColors != 0)
   {
		/* allocate memory block for logical palette */
		hLogPal = ::GlobalAlloc(GHND, sizeof(LOGPALETTE)
									+ sizeof(PALETTEENTRY)
									* wNumColors);

		/* if not enough memory, clean up and return NULL */
		if (hLogPal == 0)
		{
			::GlobalUnlock((HGLOBAL) hDIB);
			return FALSE;
		}

		lpPal = (LPLOGPALETTE) ::GlobalLock((HGLOBAL) hLogPal);

		/* set version and number of palette entries */
		lpPal->palVersion = PALVERSION;
		lpPal->palNumEntries = (WORD)wNumColors;

		/* is this a Win 3.0 DIB? */
		bWinStyleDIB = IS_WIN30_DIB(lpbi);
		for (i = 0; i < (int)wNumColors; i++)
		{
			if (bWinStyleDIB)
			{
				lpPal->palPalEntry[i].peRed = lpbmi->bmiColors[i].rgbRed;
				lpPal->palPalEntry[i].peGreen = lpbmi->bmiColors[i].rgbGreen;
				lpPal->palPalEntry[i].peBlue = lpbmi->bmiColors[i].rgbBlue;
				lpPal->palPalEntry[i].peFlags = 0;
			}
			else
			{
				lpPal->palPalEntry[i].peRed = lpbmc->bmciColors[i].rgbtRed;
				lpPal->palPalEntry[i].peGreen = lpbmc->bmciColors[i].rgbtGreen;
				lpPal->palPalEntry[i].peBlue = lpbmc->bmciColors[i].rgbtBlue;
				lpPal->palPalEntry[i].peFlags = 0;
			}
		}

		/* create the palette and get handle to it */
		hPal = (HPALETTE)::CreatePalette((LPLOGPALETTE)lpPal);
		::GlobalUnlock((HGLOBAL) hLogPal);
		::GlobalFree((HGLOBAL) hLogPal);
		*pPal = hPal;
	}

	::GlobalUnlock((HGLOBAL) hDIB);

	return (NULL != pPal);
}

/*************************************************************************
 *
 * FindDIBBits()
 *
 * Parameter:
 *
 * LPSTR lpbi       - pointer to packed-DIB memory block
 *
 * Return Value:
 *
 * LPSTR            - pointer to the DIB bits
 *
 * Description:
 *
 * This function calculates the address of the DIB's bits and returns a
 * pointer to the DIB bits.