Taiwan’s Quanta Computer Inc will start mass production of Apple Inc’s first smartwatch in July, according to a source familiar with the matter, as the tech giant tries to prove it can still innovate against rival Samsung Electronics Co Ltd. The watch, which remains unnamed but which company followers have dubbed the iWatch, will be Apple’s first foray into a niche product category that many remain skeptical about, especially as to whether it can drive profits amid cooling growth in tech gadgets. Apple will introduce a smartwatch with a display that likely measures 2.5 inches diagonally and is slightly rectangular, one of the sources said. The source added that the watch face will protrude slightly from the band, creating an arched shape, and will feature a touch interface and wireless charging capabilities.