Flag of Portugal, created by Columbano Bordalo Pinheiro (1857–1929), officially adopted by Portuguese government in June 30th 1911 (in use since about November 1910). Color shades matching the RGB values officially reccomended here. (PMS values should be used for direct ink or textile; CMYK for 4-color offset printing on paper; this is an image for screen display, RGB should be used.)
Own work using: http://jorgesampaio.arquivo.presidencia.pt/pt/republica/simbolos/bandeiras/index.html#imgs

see construction sheet.
Columbano Bordalo Pinheiro (1910; generic design)
Vítor Luís Rodrigues; António Martins-Tuválkin (2004; this specific vector set: see sources)