bitmaploaddoc.cpp

本原码主要介绍了如何在arm处理器上针对24位真彩位图的处理的方法

// bitmaploadDoc.cpp : implementation of the CBitmaploadDoc class
//

#include "stdafx.h"
#include "bitmapload.h"

#include "bitmaploadDoc.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CBitmaploadDoc

IMPLEMENT_DYNCREATE(CBitmaploadDoc, CDocument)

BEGIN_MESSAGE_MAP(CBitmaploadDoc, CDocument)
	//{{AFX_MSG_MAP(CBitmaploadDoc)
		// NOTE - the ClassWizard will add and remove mapping macros here.
		//    DO NOT EDIT what you see in these blocks of generated code!
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CBitmaploadDoc construction/destruction

CBitmaploadDoc::CBitmaploadDoc()
{
	// TODO: add one-time construction code here
	pBitmapPixels = NULL;
	bm_width = -1;
	bm_height = -1;
}

CBitmaploadDoc::~CBitmaploadDoc()
{
	if (pBitmapPixels != NULL)
		delete [] pBitmapPixels;
	pBitmapPixels = NULL;

	bm_width = -1;
	bm_height = -1;
}

BOOL CBitmaploadDoc::OnNewDocument()
{
	if (!CDocument::OnNewDocument())
		return FALSE;

	// TODO: add reinitialization code here
	// (SDI documents will reuse this document)
	DeleteContents();

	return TRUE;
}



/////////////////////////////////////////////////////////////////////////////
// CBitmaploadDoc serialization

void CBitmaploadDoc::Serialize(CArchive& ar)
{
	if (ar.IsStoring())
	{
		// TODO: add storing code here
	}
	else
	{
		// TODO: add loading code here
	}
}

/////////////////////////////////////////////////////////////////////////////
// CBitmaploadDoc diagnostics

#ifdef _DEBUG
void CBitmaploadDoc::AssertValid() const
{
	CDocument::AssertValid();
}

void CBitmaploadDoc::Dump(CDumpContext& dc) const
{
	CDocument::Dump(dc);
}
#endif //_DEBUG

/////////////////////////////////////////////////////////////////////////////
// CBitmaploadDoc commands

void CBitmaploadDoc::DeleteContents() 
{
	// TODO: Add your specialized code here and/or call the base class
	if (pBitmapPixels != NULL)
		delete [] pBitmapPixels;
	pBitmapPixels = NULL;

	bm_width = -1;
	bm_height = -1;

	CDocument::DeleteContents();
}

BOOL CBitmaploadDoc::OnOpenDocument(LPCTSTR lpszPathName) 
{
//	if (!CDocument::OnOpenDocument(lpszPathName))
//		return FALSE;
	
	// TODO: Add your specialized creation code here
	DeleteContents();
	LoadBitmap24(lpszPathName);
	if (pBitmapPixels == NULL)
		TRACE0("It is NULL\n");
	UpdateAllViews(NULL);

	return TRUE;
}

BOOL CBitmaploadDoc::LoadBitmap24(const char * fn)
{
    FILE * fp;
    BYTE r, g, b;
    BITMAPFILEHEADER bmFileHdr;
    BITMAPINFO bmInfo;
    int EndByte = 1;
    BOOL bDone = FALSE;
    WORD * temp;
	WORD * t2;

    // open file to read
    fp = fopen(fn, "rb");

    // read BITMAPFILEHEADER
    fread((char *)&bmFileHdr, sizeof(BITMAPFILEHEADER), 1, fp);

    // you read BITMAPINFOHEADER and RGBQUAD separately or together by
    // read them into
    // BITMAPINFO structure. When RGBQUAD is not empty (bitmap is 16 colors
    // or 256 colors)
    // You must read these two structures separately.
    fread((char *)&bmInfo, sizeof(BITMAPINFO), 1, fp);

    // check the bitmap info. If it is not 24 bit, and uncompressed,
    //and the colors used and are important is
    // not 0. return FALSE.
    if (bmInfo.bmiHeader.biBitCount != 24 ||
        bmInfo.bmiHeader.biCompression != 0 ||
        (bmInfo.bmiHeader.biClrUsed != 0 && bmInfo.bmiHeader.biClrImportant != 0))
    {
        fclose(fp);
		AfxMessageBox("This does nto appear to be a 24-bit uncompressed bitmap.");
        return FALSE;
    }

    // get the width and height of the bitmap.
    bm_width = (WORD)bmInfo.bmiHeader.biWidth;
    bm_height = (WORD)bmInfo.bmiHeader.biHeight;

	if (bm_width > 800 || bm_height > 600)
	{
        fclose(fp);
		AfxMessageBox("This bitmap is way to big. Bitmap shouldn't be larger than 800X600.");
        return FALSE;
	}

    // set new file pointer position at 54 from the begin of the
    //file. (0 to 53 are used to store
    // BITMAPFILEINFO, and BITMAPINFOHEADER.
    fseek(fp, bmFileHdr.bfOffBits, SEEK_SET);

    // start the mathematicall calculation for junk bytes.
    if ((bmInfo.bmiHeader.biSizeImage - bm_width * bm_height * 3) == 0)
    {
        EndByte = 0; // only when there is no junk bytes
    }
    else 
    {
        // find junk bytes.
        EndByte = (bmFileHdr.bfSize - 54 - bm_width * bm_height * 3) / bm_height; 
    }

    // create 2 empty arrays. One to store pixels from the file,
    // the other is used to invert the array.
    temp = new WORD[bm_width * bm_height];
    pBitmapPixels = new WORD[bm_width * bm_height];
    int count = bm_width * bm_height - 1;

    // read the pixels.
    while (!feof(fp))
    {
        // read scan line
        for (int i = 0; i < bm_width; i++)
        {
            // since the bitmap is inverted stored, color byte Blue is always
            // the first
            if (!feof(fp))
            {
                fread((BYTE *)&b, sizeof(BYTE), 1, fp);
            }
            else
            {
                // this is true only when the file is totally corrupted.
                bDone = TRUE;
                break;
            }
            // Then we read the Green byte.
            if (!feof(fp))
            {
                fread((BYTE *)&g, sizeof(BYTE), 1, fp);
            }
            else
            {
                // this is true only when the file is totally corrupted.
                bDone = TRUE;
                break;
            }
            // Finally the Red byte.
            if (!feof(fp))
            {
                fread((BYTE *)&r, sizeof(BYTE), 1, fp);
            }
            else
            {
                // this is true only when the file is totally corrupted.
                bDone = TRUE;
                break;
            }

            // convert 24 bit color (3 bytes for R, G, B) into 16 bit,
            //5-6-5 format WORD pixel.
            temp[count] =
              (WORD)((((WORD)r&0xf8)<<8)|(((WORD)g&0xfc)<<3)|(((WORD)b&0xf8)>>3));
            count--; // counter operation for pixel index.
        }

        // When the for loop is done, one scan line is completed.
        // This is where you skip the junk bytes. If you don't do
        // that, the end result will be distorted image.
        // Not good.
        if (!bDone)
        {
            fseek(fp, EndByte, SEEK_CUR);
        }
        else
        {
            break;
        }
    }

    // We do another inversion of the array.
    count = 0;
    for (int y = 0; y < bm_height; y++)
    {
        for (int x = bm_width - 1; x > -1; x--)
        {
            t2 = temp + y * bm_width + x;
            pBitmapPixels[count] = *t2;
            count++;
        }
    }
    delete [] temp; // when done, the old array is discarded.

    fclose(fp); // close file

    return TRUE; // return success.
}