C++ wxImage::CountColours方法代码示例

ImageDetailsDocument::ImageDetailsDocument(ImageDocument *parent)
    : wxDocument(parent)
{
    const wxImage image = parent->GetImage();

    m_size.x = image.GetWidth();
    m_size.y = image.GetHeight();
    m_numColours = image.CountColours();
    m_type = image.GetType();
    m_hasAlpha = image.HasAlpha();
}

bool MultiColorImage(wxImage& image)
{
    // return true if image contains at least one color that isn't a shade of gray
    int numpixels = image.GetWidth() * image.GetHeight();
    unsigned char* p = image.GetData();
    // p points to RGBRGB... (ie. no alpha data)
    for (int i = 0; i < numpixels; i++) {
        unsigned char r = *p++;
        unsigned char g = *p++;
        unsigned char b = *p++;
        if (r != g || g != b) {
            if (image.CountColours(2) <= 2) {
                // Golly 2.4 and older treated two-color icons as monochrome
                // so we need to convert the image to black-and-white
                image = image.ConvertToMono(r, g, b);
                return false;   // grayscale image
            } else {
                return true;    // multi-color image
            }
        }
    }
    return false;   // grayscale image
}

bool wxGIFHandler::DoSaveFile(const wxImage& image, wxOutputStream *stream,
    bool WXUNUSED(verbose), bool first, int delayMilliSecs, bool loop,
    const wxRGB *pal, int palCount, int maskIndex)
{
    const unsigned long colorcount = image.CountColours(256+1);
    bool ok = colorcount && (colorcount <= 256);
    if (!ok)
    {
        return false;
    }

    int width = image.GetWidth();
    int height = image.GetHeight();
    wxCHECK_MSG( width && height, false, wxS("can't save 0-sized file") );

    int width_even = width + ((width % 2) ? 1 : 0);

    if (first)
    {
        ok = wxGIFHandler_WriteHeader(stream, width, height, loop,
            pal, palCount);
    }

    ok = ok
        && wxGIFHandler_WriteComment(stream,
            image.GetOption(wxIMAGE_OPTION_GIF_COMMENT))
        && wxGIFHandler_WriteControl(stream, maskIndex, delayMilliSecs)
        && wxGIFHandler_WriteByte(stream, GIF_MARKER_SEP)
        && wxGIFHandler_WriteRect(stream, width, height);

    // local palette
    if (first)
    {
        // we already saved the (global) palette
        ok = ok && wxGIFHandler_WriteZero(stream);
    }
    else
    {
        const int bpp = wxGIFHandler_BitSize(palCount);
        wxUint8 b;

        b = 0x80;
        b |=(bpp - 1) << 5;
        b |=(bpp - 1);
        b &=~0x40; // clear interlaced

        ok = ok && wxGIFHandler_WriteByte(stream, b)
            && wxGIFHandler_WritePalette(stream, pal, palCount, bpp);
    }

    if (!ok)
    {
        return false;
    }

    if (!InitHashTable())
    {
        wxLogError(_("Couldn't initialize GIF hash table."));
        return false;
    }

    const wxUint8 *src = image.GetData();
    wxScopedArray<wxUint8> eightBitData(width);

    SetupCompress(stream, 8);

    m_pixelCount = height * width_even;
    for (int y = 0; y < height; y++)
    {
        m_pixelCount -= width_even;
        for (int x = 0; x < width; x++)
        {
            wxRGB rgb;
            rgb.red   = src[0];
            rgb.green = src[1];
            rgb.blue  = src[2];
            int index = wxGIFHandler_PaletteFind(rgb, pal, palCount);
            wxASSERT(index != wxNOT_FOUND);
            eightBitData[x] = (wxUint8)index;
            src+=3;
        }

        ok = CompressLine(stream, eightBitData.get(), width);
        if (!ok)
        {
            break;
        }
    }

    wxDELETE(m_hashTable);

    return ok;
}