png_get_y_pixels_per_meter 2051 3rdparty/libpng/png.h PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
png_get_y_pixels_per_meter  324 3rdparty/libpng/pngget.c    return ppi_from_ppm(png_get_y_pixels_per_meter(png_ptr, info_ptr));