There is also a white flowered variety, and I used to have a pink one too, but it died out one winter.
Flowering will be best in full sun, but I have some in a considerable amount of shade that still produce some flowers. The white-flowered variety especially, really stands out in the shade.
Barleria cristata, also known as Philippine Violet, is a native of India and southeast Asia, and is recommended for USDA Zones 9-11. There may be some dieback on exposed plants during severe winters, but mine fared well at 26°F last winter. Even in colder locations, the plant could be grown as a fall-flowering perennial.