qbmphandler.cpp

奇趣公司比较新的qt/emd版本

/****************************************************************************
**
** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file.  Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
** http://trolltech.com/products/qt/licenses/licensing/opensource/
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
** or contact the sales department at [e-mail].
**
** In addition, as a special exception, Trolltech gives you certain
** additional rights. These rights are described in the Trolltech GPL
** Exception version 1.0, which can be found at
** http://www.trolltech.com/products/qt/gplexception/ and in the file
** GPL_EXCEPTION.txt in this package.
**
** In addition, as a special exception, Trolltech, as the sole copyright
** holder for Qt Designer, grants users of the Qt/Eclipse Integration
** plug-in the right for the Qt/Eclipse Integration to link to
** functionality provided by Qt Designer and its related libraries.
**
** Trolltech reserves all rights not expressly granted herein.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/

#include "private/qbmphandler_p.h"

#ifndef QT_NO_IMAGEFORMAT_BMP

#include <qimage.h>
#include <qvariant.h>
#include <qvector.h>

static void swapPixel01(QImage *image)        // 1-bpp: swap 0 and 1 pixels
{
    int i;
    if (image->depth() == 1 && image->numColors() == 2) {
        register uint *p = (uint *)image->bits();
        int nbytes = image->numBytes();
        for (i=0; i<nbytes/4; i++) {
            *p = ~*p;
            p++;
        }
        uchar *p2 = (uchar *)p;
        for (i=0; i<(nbytes&3); i++) {
            *p2 = ~*p2;
            p2++;
        }
        QRgb t = image->color(0);                // swap color 0 and 1
        image->setColor(0, image->color(1));
        image->setColor(1, t);
    }
}

/*
    QImageIO::defineIOHandler("BMP", "^BM", 0,
                               read_bmp_image, write_bmp_image);
*/

/*****************************************************************************
  BMP (DIB) image read/write functions
 *****************************************************************************/

const int BMP_FILEHDR_SIZE = 14;                // size of BMP_FILEHDR data

QDataStream &operator>>(QDataStream &s, BMP_FILEHDR &bf)
{                                                // read file header
    s.readRawData(bf.bfType, 2);
    s >> bf.bfSize >> bf.bfReserved1 >> bf.bfReserved2 >> bf.bfOffBits;
    return s;
}

QDataStream &operator<<(QDataStream &s, const BMP_FILEHDR &bf)
{                                                // write file header
    s.writeRawData(bf.bfType, 2);
    s << bf.bfSize << bf.bfReserved1 << bf.bfReserved2 << bf.bfOffBits;
    return s;
}


const int BMP_OLD  = 12;                        // old Windows/OS2 BMP size
const int BMP_WIN  = 40;                        // new Windows BMP size
const int BMP_OS2  = 64;                        // new OS/2 BMP size

const int BMP_RGB  = 0;                                // no compression
const int BMP_RLE8 = 1;                                // run-length encoded, 8 bits
const int BMP_RLE4 = 2;                                // run-length encoded, 4 bits
const int BMP_BITFIELDS = 3;                        // RGB values encoded in data as bit-fields


QDataStream &operator>>(QDataStream &s, BMP_INFOHDR &bi)
{
    s >> bi.biSize;
    if (bi.biSize == BMP_WIN || bi.biSize == BMP_OS2) {
        s >> bi.biWidth >> bi.biHeight >> bi.biPlanes >> bi.biBitCount;
        s >> bi.biCompression >> bi.biSizeImage;
        s >> bi.biXPelsPerMeter >> bi.biYPelsPerMeter;
        s >> bi.biClrUsed >> bi.biClrImportant;
    }
    else {                                        // probably old Windows format
        qint16 w, h;
        s >> w >> h >> bi.biPlanes >> bi.biBitCount;
        bi.biWidth  = w;
        bi.biHeight = h;
        bi.biCompression = BMP_RGB;                // no compression
        bi.biSizeImage = 0;
        bi.biXPelsPerMeter = bi.biYPelsPerMeter = 0;
        bi.biClrUsed = bi.biClrImportant = 0;
    }
    return s;
}

QDataStream &operator<<(QDataStream &s, const BMP_INFOHDR &bi)
{
    s << bi.biSize;
    s << bi.biWidth << bi.biHeight;
    s << bi.biPlanes;
    s << bi.biBitCount;
    s << bi.biCompression;
    s << bi.biSizeImage;
    s << bi.biXPelsPerMeter << bi.biYPelsPerMeter;
    s << bi.biClrUsed << bi.biClrImportant;
    return s;
}

static int calc_shift(int mask)
{
    int result = 0;
    while (!(mask & 1)) {
        result++;
        mask >>= 1;
    }
    return result;
}

static bool read_dib_fileheader(QDataStream &s, BMP_FILEHDR &bf)
{
    // read BMP file header
    s >> bf;
    if (s.status() != QDataStream::Ok)
        return false;

    // check header
    if (qstrncmp(bf.bfType,"BM",2) != 0)
        return false;

    return true;
}

static bool read_dib_infoheader(QDataStream &s, BMP_INFOHDR &bi)
{
    s >> bi;                                        // read BMP info header
    if (s.status() != QDataStream::Ok)
        return false;

    int nbits = bi.biBitCount;
    int comp = bi.biCompression;
    if (!(nbits == 1 || nbits == 4 || nbits == 8 || nbits == 16 || nbits == 24 || nbits == 32) ||
        bi.biPlanes != 1 || comp > BMP_BITFIELDS)
        return false;                                        // weird BMP image
    if (!(comp == BMP_RGB || (nbits == 4 && comp == BMP_RLE4) ||
        (nbits == 8 && comp == BMP_RLE8) || ((nbits == 16 || nbits == 32) && comp == BMP_BITFIELDS)))
         return false;                                // weird compression type

    return true;
}

static bool read_dib_body(QDataStream &s, const BMP_INFOHDR &bi, int offset, int startpos, QImage &image)
{
    QIODevice* d = s.device();
    if (d->atEnd())                                // end of stream/file
        return false;
#if 0
    qDebug("offset...........%d", offset);
    qDebug("startpos.........%d", startpos);
    qDebug("biSize...........%d", bi.biSize);
    qDebug("biWidth..........%d", bi.biWidth);
    qDebug("biHeight.........%d", bi.biHeight);
    qDebug("biPlanes.........%d", bi.biPlanes);
    qDebug("biBitCount.......%d", bi.biBitCount);
    qDebug("biCompression....%d", bi.biCompression);
    qDebug("biSizeImage......%d", bi.biSizeImage);
    qDebug("biXPelsPerMeter..%d", bi.biXPelsPerMeter);
    qDebug("biYPelsPerMeter..%d", bi.biYPelsPerMeter);
    qDebug("biClrUsed........%d", bi.biClrUsed);
    qDebug("biClrImportant...%d", bi.biClrImportant);
#endif
    int w = bi.biWidth,         h = bi.biHeight,  nbits = bi.biBitCount;
    int t = bi.biSize,         comp = bi.biCompression;
    int red_mask = 0;
    int green_mask = 0;
    int blue_mask = 0;
    int red_shift = 0;
    int green_shift = 0;
    int blue_shift = 0;
    int red_scale = 0;
    int green_scale = 0;
    int blue_scale = 0;

    int ncols = 0;
    int depth = 0;
    QImage::Format format;
    switch (nbits) {
        case 32:
        case 24:
        case 16:
            depth = 32;
            format = QImage::Format_RGB32;
            break;
        case 8:
        case 4:
            depth = 8;
            format = QImage::Format_Indexed8;
            break;
        default:
            depth = 1;
            format = QImage::Format_Mono;
    }

    if (bi.biHeight < 0)
        h = -h;                  // support images with negative height

    if (image.size() != QSize(w, h) || image.format() != format) {
        image = QImage(w, h, format);
        if (image.isNull())                        // could not create image
            return false;
    }

    if (depth != 32) {
        ncols = bi.biClrUsed ? bi.biClrUsed : 1 << nbits;
        image.setNumColors(ncols);
    }

    image.setDotsPerMeterX(bi.biXPelsPerMeter);
    image.setDotsPerMeterY(bi.biYPelsPerMeter);

    if (!d->isSequential())
        d->seek(startpos + BMP_FILEHDR_SIZE + bi.biSize); // goto start of colormap

    if (ncols > 0) {                                // read color table
        uchar rgb[4];
        int   rgb_len = t == BMP_OLD ? 3 : 4;
        for (int i=0; i<ncols; i++) {
            if (d->read((char *)rgb, rgb_len) != rgb_len)
                return false;
            image.setColor(i, qRgb(rgb[2],rgb[1],rgb[0]));
            if (d->atEnd())                        // truncated file
                return false;
        }
    } else if (comp == BMP_BITFIELDS && (nbits == 16 || nbits == 32)) {
        if (d->read((char *)&red_mask, sizeof(red_mask)) != sizeof(red_mask))
            return false;
        if (d->read((char *)&green_mask, sizeof(green_mask)) != sizeof(green_mask))
            return false;
        if (d->read((char *)&blue_mask, sizeof(blue_mask)) != sizeof(blue_mask))
            return false;
        red_shift = calc_shift(red_mask);
        red_scale = 256 / ((red_mask >> red_shift) + 1);
        green_shift = calc_shift(green_mask);
        green_scale = 256 / ((green_mask >> green_shift) + 1);
        blue_shift = calc_shift(blue_mask);
        blue_scale = 256 / ((blue_mask >> blue_shift) + 1);
    } else if (comp == BMP_RGB && (nbits == 24 || nbits == 32)) {
        blue_mask = 0x000000ff;
        green_mask = 0x0000ff00;
        red_mask = 0x00ff0000;
        blue_shift = 0;
        green_shift = 8;
        red_shift = 16;
        blue_scale = green_scale = red_scale = 1;
    } else if (comp == BMP_RGB && nbits == 16) {
        blue_mask = 0x001f;
        green_mask = 0x03e0;
        red_mask = 0x7c00;
        blue_shift = 0;
        green_shift = 2;
        red_shift = 7;
        red_scale = 1;
        green_scale = 1;
        blue_scale = 8;
    }

    // offset can be bogus, be careful
    if (offset>=0 && startpos + offset > d->pos()) {
        if (!d->isSequential())
            d->seek(startpos + offset);                // start of image data
    }

    int             bpl = image.bytesPerLine();
    uchar *data = image.bits();

    if (nbits == 1) {                                // 1 bit BMP image
        while (--h >= 0) {
            if (d->read((char*)(data + h*bpl), bpl) != bpl)
                break;
        }
        if (ncols == 2 && qGray(image.color(0)) < qGray(image.color(1)))
            swapPixel01(&image);                // pixel 0 is white!
    }

    else if (nbits == 4) {                        // 4 bit BMP image
        int    buflen = ((w+7)/8)*4;
        uchar *buf    = new uchar[buflen];
        if (comp == BMP_RLE4) {                // run length compression
            int x=0, y=0, c, i;
            quint8 b;
            register uchar *p = data + (h-1)*bpl;
            const uchar *endp = p + w;
            while (y < h) {
                if (!d->getChar((char *)&b))
                    break;
                if (b == 0) {                        // escape code
                    if (!d->getChar((char *)&b) || b == 1) {
                        y = h;                // exit loop
                    } else switch (b) {
                        case 0:                        // end of line
                            x = 0;
                            y++;
                            p = data + (h-y-1)*bpl;
                            break;
                        case 2:                        // delta (jump)
                        {
                            quint8 tmp;
                            d->getChar((char *)&tmp);
                            x += tmp;
                            d->getChar((char *)&tmp);
                            y += tmp;
                        }

                            // Protection
                            if ((uint)x >= (uint)w)
                                x = w-1;
                            if ((uint)y >= (uint)h)
                                y = h-1;

                            p = data + (h-y-1)*bpl + x;
                            break;
                        default:                // absolute mode
                            // Protection
                            if (p + b > endp)
                                b = endp-p;

                            i = (c = b)/2;
                            while (i--) {
                                d->getChar((char *)&b);
                                *p++ = b >> 4;
                                *p++ = b & 0x0f;
                            }
                            if (c & 1) {
                                unsigned char tmp;
                                d->getChar((char *)&tmp);
                                *p++ = tmp >> 4;
                            }
                            if ((((c & 3) + 1) & 2) == 2)
                                d->getChar(0);        // align on word boundary
                            x += c;
                    }
                } else {                        // encoded mode
                    // Protection
                    if (p + b > endp)
                        b = endp-p;

                    i = (c = b)/2;
                    d->getChar((char *)&b);                // 2 pixels to be repeated
                    while (i--) {
                        *p++ = b >> 4;
                        *p++ = b & 0x0f;
                    }
                    if (c & 1)
                        *p++ = b >> 4;
                    x += c;
                }
            }
        } else if (comp == BMP_RGB) {                // no compression
            memset(data, 0, h*bpl);
            while (--h >= 0) {
                if (d->read((char*)buf,buflen) != buflen)
                    break;
                register uchar *p = data + h*bpl;
                uchar *b = buf;
                for (int i=0; i<w/2; i++) {        // convert nibbles to bytes
                    *p++ = *b >> 4;
                    *p++ = *b++ & 0x0f;
                }