C++ T2::get_row方法代码示例

inline int import_image(T2 const& im_in,
                             WebPPicture & pic,
                             bool alpha)
{
    image<typename T2::pixel> const& data = im_in.data();
    std::size_t width = im_in.width();
    std::size_t height = im_in.height();
    std::size_t stride = sizeof(typename T2::pixel_type) * width;
    if (data.width() == width &&
        data.height() == height)
    {
        if (alpha)
        {
            return WebPPictureImportRGBA(&pic, data.bytes(), static_cast<int>(stride));
        }
        else
        {
    #if (WEBP_ENCODER_ABI_VERSION >> 8) >= 1
            return WebPPictureImportRGBX(&pic, data.bytes(), static_cast<int>(stride));
    #else
            return WebPPictureImportRGBA(&pic, data.bytes(), static_cast<int>(stride));
    #endif
        }
    }
    else
    {
        // need to copy: https://github.com/mapnik/mapnik/issues/2024
        image_rgba8 im(width,height);
        for (unsigned y = 0; y < height; ++y)
        {
            typename T2::pixel_type const * row_from = im_in.get_row(y);
            image_rgba8::pixel_type * row_to = im.get_row(y);
            std::copy(row_from, row_from + width, row_to);
        }
        if (alpha)
        {
            return WebPPictureImportRGBA(&pic, im.bytes(), static_cast<int>(stride));
        }
        else
        {
    #if (WEBP_ENCODER_ABI_VERSION >> 8) >= 1
            return WebPPictureImportRGBX(&pic, im.bytes(), static_cast<int>(stride));
    #else
            return WebPPictureImportRGBA(&pic, im.bytes(), static_cast<int>(stride));
    #endif
        }
    }
}

void save_as_jpeg(T1 & file,int quality, T2 const& image)
{
    struct jpeg_compress_struct cinfo;
    struct jpeg_error_mgr jerr;

    int width=image.width();
    int height=image.height();

    cinfo.err = jpeg_std_error(&jerr);
    jpeg_create_compress(&cinfo);

    cinfo.dest = (struct jpeg_destination_mgr *)(*cinfo.mem->alloc_small)
        ((j_common_ptr) &cinfo, JPOOL_PERMANENT, sizeof(jpeg_detail::dest_mgr));
    jpeg_detail::dest_mgr * dest = reinterpret_cast<jpeg_detail::dest_mgr*>(cinfo.dest);
    dest->pub.init_destination = jpeg_detail::init_destination;
    dest->pub.empty_output_buffer = jpeg_detail::empty_output_buffer;
    dest->pub.term_destination = jpeg_detail::term_destination;
    dest->out = &file;

    //jpeg_stdio_dest(&cinfo, fp);
    cinfo.image_width = width;
    cinfo.image_height = height;
    cinfo.input_components = 3;
    cinfo.in_color_space = JCS_RGB;
    jpeg_set_defaults(&cinfo);
    jpeg_set_quality(&cinfo, quality,1);
    jpeg_start_compress(&cinfo, 1);
    JSAMPROW row_pointer[1];
    JSAMPLE* row=reinterpret_cast<JSAMPLE*>( ::operator new (sizeof(JSAMPLE) * width*3));
    while (cinfo.next_scanline < cinfo.image_height)
    {
        const unsigned* imageRow=image.get_row(cinfo.next_scanline);
        int index=0;
        for (int i=0;i<width;++i)
        {
            row[index++]=(imageRow[i])&0xff;
            row[index++]=(imageRow[i]>>8)&0xff;
            row[index++]=(imageRow[i]>>16)&0xff;
        }
        row_pointer[0] = &row[0];
        (void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
    }
    ::operator delete(row);

    jpeg_finish_compress(&cinfo);
    jpeg_destroy_compress(&cinfo);
}

void save_as_webp(T1& file,
                  T2 const& image,
                  WebPConfig const& config,
                  bool alpha)
{
    if (WebPValidateConfig(&config) != 1)
    {
        throw std::runtime_error("Invalid configuration");
    }

    WebPPicture pic;
    if (!WebPPictureInit(&pic))
    {
        throw std::runtime_error("version mismatch");
    }
    pic.width = image.width();
    pic.height = image.height();
    int ok = 0;
#if (WEBP_ENCODER_ABI_VERSION >> 8) >= 1
    pic.use_argb = !!config.lossless;
    // lossless fast track
    if (pic.use_argb)
    {
        pic.colorspace = static_cast<WebPEncCSP>(pic.colorspace | WEBP_CSP_ALPHA_BIT);
        if (WebPPictureAlloc(&pic)) {
            ok = 1;
            const int width = pic.width;
            const int height = pic.height;
            for (int y = 0; y < height; ++y) {
                typename T2::pixel_type const * row = image.get_row(y);
                for (int x = 0; x < width; ++x) {
                    const unsigned rgba = row[x];
                    unsigned a = (rgba >> 24) & 0xff;
                    unsigned r = rgba & 0xff;
                    unsigned g = (rgba >> 8 ) & 0xff;
                    unsigned b = (rgba >> 16) & 0xff;
                    const uint32_t argb = (a << 24) | (r << 16) | (g << 8) | (b);
                    pic.argb[x + y * pic.argb_stride] = argb;
                }
            }
        }

void save_as_png(T1 & file,
                T2 const& image,
                png_options const& opts)

{
    png_voidp error_ptr=0;
    png_structp png_ptr=png_create_write_struct(PNG_LIBPNG_VER_STRING,
                                                error_ptr,0, 0);

    if (!png_ptr) return;

    // switch on optimization only if supported
#if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200) && defined(PNG_MMX_CODE_SUPPORTED)
    png_uint_32 mask, flags;
    flags = png_get_asm_flags(png_ptr);
    mask = png_get_asm_flagmask(PNG_SELECT_READ | PNG_SELECT_WRITE);
    png_set_asm_flags(png_ptr, flags | mask);
#endif
    png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_FILTER_NONE);
    png_infop info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr)
    {
        png_destroy_write_struct(&png_ptr,static_cast<png_infopp>(0));
        return;
    }
    jmp_buf* jmp_context = static_cast<jmp_buf*>(png_get_error_ptr(png_ptr));
    if (jmp_context)
    {
        png_destroy_write_struct(&png_ptr, &info_ptr);
        return;
    }
    png_set_write_fn (png_ptr, &file, &write_data<T1>, &flush_data<T1>);

    png_set_compression_level(png_ptr, opts.compression);
    png_set_compression_strategy(png_ptr, opts.strategy);
    png_set_compression_buffer_size(png_ptr, 32768);

    png_set_IHDR(png_ptr, info_ptr,image.width(),image.height(),8,
                 (opts.trans_mode == 0) ? PNG_COLOR_TYPE_RGB : PNG_COLOR_TYPE_RGB_ALPHA,PNG_INTERLACE_NONE,
                 PNG_COMPRESSION_TYPE_DEFAULT,PNG_FILTER_TYPE_DEFAULT);
    const std::unique_ptr<png_bytep[]> row_pointers(new png_bytep[image.height()]);
    for (unsigned int i = 0; i < image.height(); i++)
    {
        row_pointers[i] = const_cast<png_bytep>(reinterpret_cast<const unsigned char *>(image.get_row(i)));
    }
    png_set_rows(png_ptr, info_ptr, row_pointers.get());
    png_write_png(png_ptr, info_ptr, (opts.trans_mode == 0) ? PNG_TRANSFORM_STRIP_FILLER_AFTER : PNG_TRANSFORM_IDENTITY, nullptr);
    png_destroy_write_struct(&png_ptr, &info_ptr);
}

void save_as_png8_oct(T1 & file,
                      T2 const& image,
                      png_options const& opts)
{
    // number of alpha ranges in png8 format; 2 results in smallest image with binary transparency
    // 3 is minimum for semitransparency, 4 is recommended, anything else is worse
    const unsigned TRANSPARENCY_LEVELS = (opts.trans_mode==2||opts.trans_mode<0)?MAX_OCTREE_LEVELS:2;
    unsigned width = image.width();
    unsigned height = image.height();
    unsigned alphaHist[256];//transparency histogram
    unsigned semiCount = 0;//sum of semitransparent pixels
    unsigned meanAlpha = 0;

    if (opts.trans_mode == 0)
    {
        meanAlpha = 255;
    }
    else
    {
        for(int i=0; i<256; i++)
        {
            alphaHist[i] = 0;
        }
        for (unsigned y = 0; y < height; ++y)
        {
            for (unsigned x = 0; x < width; ++x)
            {
                unsigned val = U2ALPHA(static_cast<unsigned>(image.get_row(y)[x]));
                alphaHist[val]++;
                meanAlpha += val;
                if (val>0 && val<255)
                {
                    semiCount++;
                }
            }
        }
        meanAlpha /= width*height;
    }

    // transparency ranges division points
    unsigned limits[MAX_OCTREE_LEVELS+1];
    limits[0] = 0;
    limits[1] = (opts.trans_mode!=0 && alphaHist[0]>0)?1:0;
    limits[TRANSPARENCY_LEVELS] = 256;
    for(unsigned j=2; j<TRANSPARENCY_LEVELS; j++)
    {
        limits[j] = limits[1];
    }
    if (opts.trans_mode != 0)
    {
        unsigned alphaHistSum = 0;
        for(unsigned i=1; i<256; i++)
        {
            alphaHistSum += alphaHist[i];
            for(unsigned j=1; j<TRANSPARENCY_LEVELS; j++)
            {
                if (alphaHistSum<semiCount*(j)/4)
                {
                    limits[j] = i;
                }
            }
        }
    }
    // avoid too wide full transparent range
    if (limits[1]>256/(TRANSPARENCY_LEVELS-1))
    {
        limits[1]=256/(TRANSPARENCY_LEVELS-1);
    }
    // avoid too wide full opaque range
    if (limits[TRANSPARENCY_LEVELS-1]<212)
    {
        limits[TRANSPARENCY_LEVELS-1]=212;
    }
    if (TRANSPARENCY_LEVELS==2)
    {
        limits[1]=127;
    }
    // estimated number of colors from palette assigned to chosen ranges
    unsigned cols[MAX_OCTREE_LEVELS];
    // count colors
    if (opts.trans_mode == 0)
    {
        for (unsigned j=0; j<TRANSPARENCY_LEVELS; j++)
        {
            cols[j] = 0;
        }
        cols[TRANSPARENCY_LEVELS-1] = width * height;
    }
    else
    {
        for (unsigned j=0; j<TRANSPARENCY_LEVELS; j++)
        {
            cols[j] = 0;
            for (unsigned i=limits[j]; i<limits[j+1]; i++)
            {
                cols[j] += alphaHist[i];
            }
        }
    }

//.........这里部分代码省略.........