qbmphandler.cpp

奇趣公司比较新的qt/emd版本

                if (w & 1)                        // the last nibble
                    *p = *b >> 4;
            }
        }
        delete [] buf;
    }

    else if (nbits == 8) {                        // 8 bit BMP image
        if (comp == BMP_RLE8) {                // run length compression
            int x=0, y=0;
            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)
                            // Protection
                            if ((uint)x >= (uint)w)
                                x = w-1;
                            if ((uint)y >= (uint)h)
                                y = h-1;

                            {
                                quint8 tmp;
                                d->getChar((char *)&tmp);
                                x += tmp;
                                d->getChar((char *)&tmp);
                                y += tmp;
                            }
                            p = data + (h-y-1)*bpl + x;
                            break;
                        default:                // absolute mode
                            // Protection
                            if (p + b > endp)
                                b = endp-p;

                            if (d->read((char *)p, b) != b)
                                return false;
                            if ((b & 1) == 1)
                                d->getChar(0);        // align on word boundary
                            x += b;
                            p += b;
                    }
                } else {                        // encoded mode
                    // Protection
                    if (p + b > endp)
                        b = endp-p;

                    char tmp;
                    d->getChar(&tmp);
                    memset(p, tmp, b); // repeat pixel
                    x += b;
                    p += b;
                }
            }
        } else if (comp == BMP_RGB) {                // uncompressed
            while (--h >= 0) {
                if (d->read((char *)data + h*bpl, bpl) != bpl)
                    break;
            }
        }
    }

    else if (nbits == 16 || nbits == 24 || nbits == 32) { // 16,24,32 bit BMP image
        register QRgb *p;
        QRgb  *end;
        uchar *buf24 = new uchar[bpl];
        int    bpl24 = ((w*nbits+31)/32)*4;
        uchar *b;
        int c;

        while (--h >= 0) {
            p = (QRgb *)(data + h*bpl);
            end = p + w;
            if (d->read((char *)buf24,bpl24) != bpl24)
                break;
            b = buf24;
            while (p < end) {
                c = *(uchar*)b | (*(uchar*)(b+1)<<8);
                if (nbits != 16)
                    c |= *(uchar*)(b+2)<<16;
                *p++ = qRgb(((c & red_mask) >> red_shift) * red_scale,
                                        ((c & green_mask) >> green_shift) * green_scale,
                                        ((c & blue_mask) >> blue_shift) * blue_scale);
                b += nbits/8;
            }
        }
        delete[] buf24;
    }

    if (bi.biHeight < 0) {
        // Flip the image
        uchar *buf = new uchar[bpl];
        h = -bi.biHeight;
        for (int y = 0; y < h/2; ++y) {
            memcpy(buf, data + y*bpl, bpl);
            memcpy(data + y*bpl, data + (h-y-1)*bpl, bpl);
            memcpy(data + (h-y-1)*bpl, buf, bpl);
        }
        delete [] buf;
    }

    return true;
}

// this is also used in qmime_win.cpp
bool qt_write_dib(QDataStream &s, QImage image)
{
    int        nbits;
    int        bpl_bmp;
    int        bpl = image.bytesPerLine();

    QIODevice* d = s.device();
    if (!d->isWritable())
        return false;

    if (image.depth() == 8 && image.numColors() <= 16) {
        bpl_bmp = (((bpl+1)/2+3)/4)*4;
        nbits = 4;
    } else if (image.depth() == 32) {
        bpl_bmp = ((image.width()*24+31)/32)*4;
        nbits = 24;
#ifdef Q_WS_QWS
    } else if (image.depth() == 1 || image.depth() == 8) {
        // Qt/E doesn't word align.
        bpl_bmp = ((image.width()*image.depth()+31)/32)*4;
        nbits = image.depth();
#endif
    } else {
        bpl_bmp = bpl;
        nbits = image.depth();
    }

    BMP_INFOHDR bi;
    bi.biSize               = BMP_WIN;                // build info header
    bi.biWidth               = image.width();
    bi.biHeight               = image.height();
    bi.biPlanes               = 1;
    bi.biBitCount      = nbits;
    bi.biCompression   = BMP_RGB;
    bi.biSizeImage     = bpl_bmp*image.height();
    bi.biXPelsPerMeter = image.dotsPerMeterX() ? image.dotsPerMeterX()
                                                : 2834; // 72 dpi default
    bi.biYPelsPerMeter = image.dotsPerMeterY() ? image.dotsPerMeterY() : 2834;
    bi.biClrUsed       = image.numColors();
    bi.biClrImportant  = image.numColors();
    s << bi;                                        // write info header
    if (s.status() != QDataStream::Ok)
        return false;

    if (image.depth() != 32) {                // write color table
        uchar *color_table = new uchar[4*image.numColors()];
        uchar *rgb = color_table;
        QVector<QRgb> c = image.colorTable();
        for (int i=0; i<image.numColors(); i++) {
            *rgb++ = qBlue (c[i]);
            *rgb++ = qGreen(c[i]);
            *rgb++ = qRed  (c[i]);
            *rgb++ = 0;
        }
        if (d->write((char *)color_table, 4*image.numColors()) == -1) {
            delete [] color_table;
            return false;
        }
        delete [] color_table;
    }

    if (image.format() == QImage::Format_MonoLSB)
        image = image.convertToFormat(QImage::Format_Mono);

    int y;

    if (nbits == 1 || nbits == 8) {                // direct output
#ifdef Q_WS_QWS
        // Qt/E doesn't word align.
        int pad = bpl_bmp - bpl;
        char padding[4];
#endif
        for (y=image.height()-1; y>=0; y--) {
            if (d->write((char*)image.scanLine(y), bpl) == -1)
                return false;
#ifdef Q_WS_QWS
            if (d->write(padding, pad) == -1)
                return false;
#endif
        }
        return true;
    }

    uchar *buf        = new uchar[bpl_bmp];
    uchar *b, *end;
    register uchar *p;

    memset(buf, 0, bpl_bmp);
    for (y=image.height()-1; y>=0; y--) {        // write the image bits
        if (nbits == 4) {                        // convert 8 -> 4 bits
            p = image.scanLine(y);
            b = buf;
            end = b + image.width()/2;
            while (b < end) {
                *b++ = (*p << 4) | (*(p+1) & 0x0f);
                p += 2;
            }
            if (image.width() & 1)
                *b = *p << 4;
        } else {                                // 32 bits
            QRgb *p   = (QRgb *)image.scanLine(y);
            QRgb *end = p + image.width();
            b = buf;
            while (p < end) {
                *b++ = qBlue(*p);
                *b++ = qGreen(*p);
                *b++ = qRed(*p);
                p++;
            }
        }
        if (bpl_bmp != d->write((char*)buf, bpl_bmp)) {
            delete[] buf;
            return false;
        }
    }
    delete[] buf;
    return true;
}

// this is also used in qmime_win.cpp
bool qt_read_dib(QDataStream &s, QImage &image)
{
    BMP_INFOHDR bi;
    if (!read_dib_infoheader(s, bi))
        return false;
    return read_dib_body(s, bi, -1, -BMP_FILEHDR_SIZE, image);
}

QBmpHandler::QBmpHandler()
    : state(Ready)
{
}

bool QBmpHandler::readHeader()
{
    state = Error;

    QIODevice *d = device();
    QDataStream s(d);
    startpos = d->pos();

    // Intel byte order
    s.setByteOrder(QDataStream::LittleEndian);

    // read BMP file header
    if (!read_dib_fileheader(s, fileHeader))
        return false;

    // read BMP info header
    if (!read_dib_infoheader(s, infoHeader))
        return false;

    state = ReadHeader;
    return true;
}

bool QBmpHandler::canRead() const
{
    if (state == Ready) {
        if (!canRead(device()))
            return false;
        setFormat("bmp");
        return true;
    }
    return state != Error;
}

bool QBmpHandler::canRead(QIODevice *device)
{
    if (!device) {
        qWarning("QBmpHandler::canRead() called with 0 pointer");
        return false;
    }

    char head[2];
    if (device->peek(head, sizeof(head)) != sizeof(head))
        return false;

    return (qstrncmp(head, "BM", 2) == 0);
}

bool QBmpHandler::read(QImage *image)
{
    if (state == Error)
        return false;

    if (!image) {
        qWarning("QBmpHandler::read: cannot read into null pointer");
        return false;
    }

    if (state == Ready && !readHeader()) {
        state = Error;
        return false;
    }

    QIODevice *d = device();
    QDataStream s(d);

    // Intel byte order
    s.setByteOrder(QDataStream::LittleEndian);

    // read image
    if (!read_dib_body(s, infoHeader, fileHeader.bfOffBits, startpos, *image))
        return false;

    state = Ready;
    return true;
}

bool QBmpHandler::write(const QImage &img)
{
    QImage image = img;
    if (image.format() == QImage::Format_RGB16)
        image = image.convertToFormat(QImage::Format_RGB32);

    QIODevice *d = device();
    QDataStream s(d);
    BMP_FILEHDR bf;
    int bpl_bmp;
    int bpl = image.bytesPerLine();

    // Code partially repeated in qt_write_dib
    if (image.depth() == 8 && image.numColors() <= 16) {
        bpl_bmp = (((bpl+1)/2+3)/4)*4;
    } else if (image.depth() == 32) {
        bpl_bmp = ((image.width()*24+31)/32)*4;
    } else {
        bpl_bmp = bpl;
    }

    // Intel byte order
    s.setByteOrder(QDataStream::LittleEndian);

    // build file header
    memcpy(bf.bfType, "BM", 2);

    // write file header
    bf.bfReserved1 = 0;
    bf.bfReserved2 = 0;
    bf.bfOffBits = BMP_FILEHDR_SIZE + BMP_WIN + image.numColors() * 4;
    bf.bfSize = bf.bfOffBits + bpl_bmp*image.height();
    s << bf;

    // write image
    return qt_write_dib(s, image);
}

bool QBmpHandler::supportsOption(ImageOption option) const
{
    return option == Size;
}

QVariant QBmpHandler::option(ImageOption option) const
{
    if (option == Size) {
        if (state == Error)
            return QVariant();
        if (state == Ready && !const_cast<QBmpHandler*>(this)->readHeader())
            return QVariant();
        return QSize(infoHeader.biWidth, infoHeader.biHeight);
    }
    return QVariant();
}

void QBmpHandler::setOption(ImageOption option, const QVariant &value)
{
    Q_UNUSED(option);
    Q_UNUSED(value);
}

QByteArray QBmpHandler::name() const
{
    return "bmp";
}

#endif // QT_NO_IMAGEFORMAT_BMP