Function temp_png_path

tests/EffectMask.cpp:35–40

using namespace openshot;

static std::string temp_png_path(const std::string& base) {
	std::stringstream path;
	path << QDir::tempPath().toStdString() << "/libopenshot_" << base << "_"
		 << getpid() << "_" << rand() << ".png";
	return path.str();
}

static std::string create_source_png(int w, int h, const QColor& color) {
	const std::string path = temp_png_path("source");