png_set_compression_level 1693 3rdparty/libpng/png.h PNG_EXPORT(69, void, png_set_compression_level,
png_set_compression_level  400 modules/imgcodecs/src/grfmt_png.cpp                         png_set_compression_level( png_ptr, compression_level );
png_set_compression_level  407 modules/imgcodecs/src/grfmt_png.cpp                         png_set_compression_level(png_ptr, Z_BEST_SPEED);