imagbmp.cpp

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                    ((wxUint8)palette->GetPixel(data[pixel],
                                                data[pixel+1],
                                                data[pixel+2]) << 4) |
                    (((x+1) > width)
                     ? 0
                     : ((wxUint8)palette->GetPixel(data[pixel+3],
                                                   data[pixel+4],
                                                   data[pixel+5]) ))    );
#else
                // FIXME: what should this be? use some std palette maybe?
                buffer[x/2] = 0;
#endif // wxUSE_PALETTE
            }
        }
        else if ( format == wxBMP_1BPP ) // 1 bpp in "color"
        {
            for (x = 0; x < width; x+=8)
            {
                pixel = 3*(y*width + x);

#if wxUSE_PALETTE
                buffer[x/8] = (wxUint8)(
                                           ((wxUint8)palette->GetPixel(data[pixel], data[pixel+1], data[pixel+2]) << 7) |
                    (((x+1) > width) ? 0 : ((wxUint8)palette->GetPixel(data[pixel+3], data[pixel+4], data[pixel+5]) << 6)) |
                    (((x+2) > width) ? 0 : ((wxUint8)palette->GetPixel(data[pixel+6], data[pixel+7], data[pixel+8]) << 5)) |
                    (((x+3) > width) ? 0 : ((wxUint8)palette->GetPixel(data[pixel+9], data[pixel+10], data[pixel+11]) << 4)) |
                    (((x+4) > width) ? 0 : ((wxUint8)palette->GetPixel(data[pixel+12], data[pixel+13], data[pixel+14]) << 3)) |
                    (((x+5) > width) ? 0 : ((wxUint8)palette->GetPixel(data[pixel+15], data[pixel+16], data[pixel+17]) << 2)) |
                    (((x+6) > width) ? 0 : ((wxUint8)palette->GetPixel(data[pixel+18], data[pixel+19], data[pixel+20]) << 1)) |
                    (((x+7) > width) ? 0 : ((wxUint8)palette->GetPixel(data[pixel+21], data[pixel+22], data[pixel+23])     ))    );
#else
                // FIXME: what should this be? use some std palette maybe?
                buffer[x/8] = 0;
#endif // wxUSE_PALETTE
            }
        }
        else if ( format == wxBMP_1BPP_BW ) // 1 bpp B&W colormap from red color ONLY
        {
            for (x = 0; x < width; x+=8)
            {
                pixel = 3*(y*width + x);

                buffer[x/8] = (wxUint8)(
                                          (((wxUint8)(data[pixel]   /128.)) << 7) |
                   (((x+1) > width) ? 0 : (((wxUint8)(data[pixel+3] /128.)) << 6)) |
                   (((x+2) > width) ? 0 : (((wxUint8)(data[pixel+6] /128.)) << 5)) |
                   (((x+3) > width) ? 0 : (((wxUint8)(data[pixel+9] /128.)) << 4)) |
                   (((x+4) > width) ? 0 : (((wxUint8)(data[pixel+12]/128.)) << 3)) |
                   (((x+5) > width) ? 0 : (((wxUint8)(data[pixel+15]/128.)) << 2)) |
                   (((x+6) > width) ? 0 : (((wxUint8)(data[pixel+18]/128.)) << 1)) |
                   (((x+7) > width) ? 0 : (((wxUint8)(data[pixel+21]/128.))     ))    );
            }
        }

        if ( !stream.Write(buffer, row_width) )
        {
            if (verbose)
                wxLogError(_("BMP: Couldn't write data."));
            delete[] buffer;
#if wxUSE_PALETTE
            delete palette;
#endif // wxUSE_PALETTE
            delete q_image;
            return false;
        }
    }
    delete[] buffer;
#if wxUSE_PALETTE
    delete palette;
#endif // wxUSE_PALETTE
    delete q_image;

    return true;
}


typedef struct
{
    unsigned char r, g, b;
}  _cmap;

bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
                             int bpp, int ncolors, int comp,
                             wxFileOffset bmpOffset, wxInputStream& stream,
                             bool verbose, bool IsBmp, bool hasPalette)
{
    wxInt32         aDword, rmask = 0, gmask = 0, bmask = 0;
    int             rshift = 0, gshift = 0, bshift = 0;
    int             rbits = 0, gbits = 0, bbits = 0;
    wxInt32         dbuf[4];
    wxInt8          bbuf[4];
    wxUint8         aByte;
    wxUint16        aWord;

    // allocate space for palette if needed:
    _cmap *cmap;

    if ( bpp < 16 )
    {
        cmap = new _cmap[ncolors];
        if ( !cmap )
        {
            if (verbose)
                wxLogError(_("BMP: Couldn't allocate memory."));
            return false;
        }
    }
    else
        cmap = NULL;

    // destroy existing here instead of:
    image->Destroy();
    image->Create(width, height);

    unsigned char *ptr = image->GetData();

    if ( !ptr )
    {
        if ( verbose )
            wxLogError( _("BMP: Couldn't allocate memory.") );
        if ( cmap )
            delete[] cmap;
        return false;
    }

    // Reading the palette, if it exists:
    if ( bpp < 16 && ncolors != 0 )
    {
        unsigned char* r = new unsigned char[ncolors];
        unsigned char* g = new unsigned char[ncolors];
        unsigned char* b = new unsigned char[ncolors];
        for (int j = 0; j < ncolors; j++)
        {
            if (hasPalette)
            {
                stream.Read(bbuf, 4);
                cmap[j].b = bbuf[0];
                cmap[j].g = bbuf[1];
                cmap[j].r = bbuf[2];

                r[j] = cmap[j].r;
                g[j] = cmap[j].g;
                b[j] = cmap[j].b;
            }
            else
            {
                //used in reading .ico file mask
                r[j] = cmap[j].r =
                g[j] = cmap[j].g =
                b[j] = cmap[j].b = ( j ? 255 : 0 );
            }
        }

#if wxUSE_PALETTE
        // Set the palette for the wxImage
        image->SetPalette(wxPalette(ncolors, r, g, b));
#endif // wxUSE_PALETTE

        delete[] r;
        delete[] g;
        delete[] b;
    }
    else if ( bpp == 16 || bpp == 32 )
    {
        if ( comp == BI_BITFIELDS )
        {
            int bit = 0;
            stream.Read(dbuf, 4 * 3);
            rmask = wxINT32_SWAP_ON_BE(dbuf[0]);
            gmask = wxINT32_SWAP_ON_BE(dbuf[1]);
            bmask = wxINT32_SWAP_ON_BE(dbuf[2]);
            // find shift amount (Least significant bit of mask)
            for (bit = bpp-1; bit>=0; bit--)
            {
                if (bmask & (1 << bit))
                    bshift = bit;
                if (gmask & (1 << bit))
                    gshift = bit;
                if (rmask & (1 << bit))
                    rshift = bit;
            }
            // Find number of bits in mask (MSB-LSB+1)
            for (bit = 0; bit < bpp; bit++)
            {
                if (bmask & (1 << bit))
                    bbits = bit-bshift+1;
                if (gmask & (1 << bit))
                    gbits = bit-gshift+1;
                if (rmask & (1 << bit))
                    rbits = bit-rshift+1;
            }
        }
        else if ( bpp == 16 )
        {
            rmask = 0x7C00;
            gmask = 0x03E0;
            bmask = 0x001F;
            rshift = 10;
            gshift = 5;
            bshift = 0;
            rbits = 5;
            gbits = 5;
            bbits = 5;
        }
        else if ( bpp == 32 )
        {
            rmask = 0x00FF0000;
            gmask = 0x0000FF00;
            bmask = 0x000000FF;
            rshift = 16;
            gshift = 8;
            bshift = 0;
            rbits = 8;
            gbits = 8;
            bbits = 8;
        }
    }

    /*
     * Reading the image data
     */
    if ( IsBmp )
        stream.SeekI(bmpOffset); // else icon, just carry on

    unsigned char *data = ptr;

    /* set the whole image to the background color */
    if ( bpp < 16 && (comp == BI_RLE4 || comp == BI_RLE8) )
    {
        for (int i = 0; i < width * height; i++)
        {
            *ptr++ = cmap[0].r;
            *ptr++ = cmap[0].g;
            *ptr++ = cmap[0].b;
        }
        ptr = data;
    }

    int linesize = ((width * bpp + 31) / 32) * 4;

    /* BMPs are stored upside down */
    for ( int line = (height - 1); line >= 0; line-- )
    {
        int linepos = 0;
        for ( int column = 0; column < width ; )
        {
            if ( bpp < 16 )
            {
                linepos++;
                aByte = stream.GetC();
                if ( bpp == 1 )
                {
                    for (int bit = 0; bit < 8 && column < width; bit++)
                    {
                        int index = ((aByte & (0x80 >> bit)) ? 1 : 0);
                        ptr[poffset] = cmap[index].r;
                        ptr[poffset + 1] = cmap[index].g;
                        ptr[poffset + 2] = cmap[index].b;
                        column++;
                    }
                }
                else if ( bpp == 4 )
                {
                    if ( comp == BI_RLE4 )
                    {
                        wxUint8 first;
                        first = aByte;
                        aByte = stream.GetC();
                        if ( first == 0 )
                        {
                            if ( aByte == 0 )
                            {
                                if ( column > 0 )
                                    column = width;
                            }
                            else if ( aByte == 1 )
                            {
                                column = width;
                                line = -1;
                            }
                            else if ( aByte == 2 )
                            {
                                aByte = stream.GetC();
                                column += aByte;
                                linepos = column * bpp / 4;
                                aByte = stream.GetC();
                                line -= aByte; // upside down
                            }
                            else
                            {
                                int absolute = aByte;
                                wxUint8 nibble[2] ;
                                int readBytes = 0 ;
                                for (int k = 0; k < absolute; k++)
                                {
                                    if ( !(k % 2 ) )
                                    {
                                        ++readBytes ;
                                        aByte = stream.GetC();
                                        nibble[0] = (wxUint8)( (aByte & 0xF0) >> 4 ) ;
                                        nibble[1] = (wxUint8)( aByte & 0x0F ) ;
                                    }
                                    ptr[poffset    ] = cmap[nibble[k%2]].r;
                                    ptr[poffset + 1] = cmap[nibble[k%2]].g;
                                    ptr[poffset + 2] = cmap[nibble[k%2]].b;
                                    column++;
                                    if ( k % 2 )
                                        linepos++;
                                }
                                if ( readBytes & 0x01 )
                                    aByte = stream.GetC();
                            }
                        }
                        else
                        {
                            wxUint8 nibble[2] ;
                            nibble[0] = (wxUint8)( (aByte & 0xF0) >> 4 ) ;
                            nibble[1] = (wxUint8)( aByte & 0x0F ) ;

                            for ( int l = 0; l < first && column < width; l++ )
                            {
                                ptr[poffset    ] = cmap[nibble[l%2]].r;
                                ptr[poffset + 1] = cmap[nibble[l%2]].g;
                                ptr[poffset + 2] = cmap[nibble[l%2]].b;
                                column++;
                                if ( l % 2 )
                                    linepos++;
                            }
                        }
                    }
                    else
                    {
                        for (int nibble = 0; nibble < 2 && column < width; nibble++)
                        {
                            int index = ((aByte & (0xF0 >> nibble * 4)) >> (!nibble * 4));
                            if ( index >= 16 )
                                index = 15;
                            ptr[poffset] = cmap[index].r;
                            ptr[poffset + 1] = cmap[index].g;
                            ptr[poffset + 2] = cmap[index].b;
                            column++;
                        }
                    }
                }
                else if ( bpp == 8 )
                {
                    if ( comp == BI_RLE8 )
                    {
                        unsigned char first;
                        first = aByte;
                        aByte = stream.GetC();
                        if ( first == 0 )
                        {
                            if ( aByte == 0 )
                            {
                                /* column = width; */
                            }
                            else if ( aByte == 1 )
                            {
                                column = width;
                                line = -1;
                            }
                            else if ( aByte == 2 )
                            {
                                aByte = stream.GetC();
                                column += aByte;
                                linepos = column * bpp / 8;
                                aByte = stream.GetC();
                                line += aByte;
                            }
                            else
                            {
                                int absolute = aByte;

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