コード例 #1
0
ファイル: png_reader.cpp プロジェクト: Vanuan/mapnik
void png_reader<T>::read(unsigned x0, unsigned y0,image_data_32& image)
{
    stream_.clear();
    stream_.seekg(0, std::ios_base::beg);

    png_structp png_ptr = png_create_read_struct
        (PNG_LIBPNG_VER_STRING,0,0,0);

    if (!png_ptr)
    {
        throw image_reader_exception("failed to allocate png_ptr");
    }

    // catch errors in a custom way to avoid the need for setjmp
    png_set_error_fn(png_ptr, png_get_error_ptr(png_ptr), user_error_fn, user_warning_fn);

    png_infop info_ptr;
    png_struct_guard sguard(&png_ptr,&info_ptr);
    info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr) throw image_reader_exception("failed to create info_ptr");

    png_set_read_fn(png_ptr, (png_voidp)&stream_, png_read_data);
    png_read_info(png_ptr, info_ptr);

    if (color_type_ == PNG_COLOR_TYPE_PALETTE)
        png_set_expand(png_ptr);
    if (color_type_ == PNG_COLOR_TYPE_GRAY && bit_depth_ < 8)
        png_set_expand(png_ptr);
    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
        png_set_expand(png_ptr);
    if (bit_depth_ == 16)
        png_set_strip_16(png_ptr);
    if (color_type_ == PNG_COLOR_TYPE_GRAY ||
        color_type_ == PNG_COLOR_TYPE_GRAY_ALPHA)
        png_set_gray_to_rgb(png_ptr);

    // quick hack -- only work in >=libpng 1.2.7
    png_set_add_alpha(png_ptr,0xff,PNG_FILLER_AFTER); //rgba

    double gamma;
    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
        png_set_gamma(png_ptr, 2.2, gamma);

    if (x0 == 0 && y0 == 0 && image.width() >= width_ && image.height() >= height_)
    {

        if (png_get_interlace_type(png_ptr,info_ptr) == PNG_INTERLACE_ADAM7)
        {
            png_set_interlace_handling(png_ptr); // FIXME: libpng bug?
            // according to docs png_read_image
            // "..automatically handles interlacing,
            // so you don't need to call png_set_interlace_handling()"
        }
        png_read_update_info(png_ptr, info_ptr);
        // we can read whole image at once
        // alloc row pointers
        const std::unique_ptr<png_bytep[]> rows(new png_bytep[height_]);
        for (unsigned i=0; i<height_; ++i)
            rows[i] = (png_bytep)image.getRow(i);
        png_read_image(png_ptr, rows.get());
    }
    else
    {
        png_read_update_info(png_ptr, info_ptr);
        unsigned w=std::min(unsigned(image.width()),width_ - x0);
        unsigned h=std::min(unsigned(image.height()),height_ - y0);
        unsigned rowbytes=png_get_rowbytes(png_ptr, info_ptr);
        const std::unique_ptr<png_byte[]> row(new png_byte[rowbytes]);
        //START read image rows
        for (unsigned i = 0;i < height_; ++i)
        {
            png_read_row(png_ptr,row.get(),0);
            if (i >= y0 && i < (y0 + h))
            {
                image.setRow(i-y0,reinterpret_cast<unsigned*>(&row[x0 * 4]),w);
            }
        }
        //END
    }
    png_read_end(png_ptr,0);
}
コード例 #2
0
ファイル: png_reader.cpp プロジェクト: LeadsPlus/mapnik
void png_reader::read(unsigned x0, unsigned y0,image_data_32& image)
{
    FILE *fp=fopen(fileName_.c_str(),"rb");
    if (!fp) throw image_reader_exception("cannot open image file "+fileName_);

    png_structp png_ptr = png_create_read_struct
        (PNG_LIBPNG_VER_STRING,0,0,0);

    if (!png_ptr)
    {
        fclose(fp);
        throw image_reader_exception("failed to allocate png_ptr");
    }

    // catch errors in a custom way to avoid the need for setjmp
    png_set_error_fn(png_ptr, png_get_error_ptr(png_ptr), user_error_fn, user_warning_fn);

    png_infop info_ptr;
    try
    {
        info_ptr = png_create_info_struct(png_ptr);
        if (!info_ptr)
        {
            png_destroy_read_struct(&png_ptr,0,0);
            fclose(fp);
            throw image_reader_exception("failed to create info_ptr");
        }
    }
    catch (std::exception const& ex)
    {
        png_destroy_read_struct(&png_ptr,0,0);
        fclose(fp);
        throw;
    }

    png_set_read_fn(png_ptr, (png_voidp)fp, png_read_data);
    png_read_info(png_ptr, info_ptr);

    if (color_type_ == PNG_COLOR_TYPE_PALETTE)
        png_set_expand(png_ptr);
    if (color_type_ == PNG_COLOR_TYPE_GRAY && bit_depth_ < 8)
        png_set_expand(png_ptr);
    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
        png_set_expand(png_ptr);
    if (bit_depth_ == 16)
        png_set_strip_16(png_ptr);
    if (color_type_ == PNG_COLOR_TYPE_GRAY ||
        color_type_ == PNG_COLOR_TYPE_GRAY_ALPHA)
        png_set_gray_to_rgb(png_ptr);

    // quick hack -- only work in >=libpng 1.2.7
    png_set_add_alpha(png_ptr,0xff,PNG_FILLER_AFTER); //rgba

    double gamma;
    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
        png_set_gamma(png_ptr, 2.2, gamma);

    if (x0 == 0 && y0 == 0 && image.width() >= width_ && image.height() >= height_)
    {

        if (png_get_interlace_type(png_ptr,info_ptr) == PNG_INTERLACE_ADAM7)
        {
            png_set_interlace_handling(png_ptr); // FIXME: libpng bug?
            // according to docs png_read_image
            // "..automatically handles interlacing,
            // so you don't need to call png_set_interlace_handling()"
        }
        png_read_update_info(png_ptr, info_ptr);
        // we can read whole image at once
        // alloc row pointers
        boost::scoped_array<png_byte*> rows(new png_bytep[height_]);
        for (unsigned i=0; i<height_; ++i)
            rows[i] = (png_bytep)image.getRow(i);
        png_read_image(png_ptr, rows.get());
    }
    else
    {
        png_read_update_info(png_ptr, info_ptr);
        unsigned w=std::min(unsigned(image.width()),width_);
        unsigned h=std::min(unsigned(image.height()),height_);
        unsigned rowbytes=png_get_rowbytes(png_ptr, info_ptr);
        boost::scoped_array<png_byte> row(new png_byte[rowbytes]);
        //START read image rows
        for (unsigned i=0;i<height_;++i)
        {
            png_read_row(png_ptr,row.get(),0);
            if (i>=y0 && i<h)
            {
                image.setRow(i-y0,reinterpret_cast<unsigned*>(&row[x0]),w);
            }
        }
        //END
    }

    png_read_end(png_ptr,0);
    png_destroy_read_struct(&png_ptr, &info_ptr,0);
    fclose(fp);
}