ppi_from_ppm      312 3rdparty/libpng/pngget.c    return ppi_from_ppm(png_get_pixels_per_meter(png_ptr, info_ptr));
ppi_from_ppm      318 3rdparty/libpng/pngget.c    return ppi_from_ppm(png_get_x_pixels_per_meter(png_ptr, info_ptr));
ppi_from_ppm      324 3rdparty/libpng/pngget.c    return ppi_from_ppm(png_get_y_pixels_per_meter(png_ptr, info_ptr));