This paper presents a readout integrated circuit of pixel architecture called MPIX (Multithreshold PIXels), designed for CdTe pixel detectors used in high-energy X-ray imaging applications. The MPIX IC of the area of 9.6 mm x 20.3 mm is designed in a CMOS 130 nm process. The IC core is a matrix of 96 x 192 square-shaped pixels of 100 µm pitch. Each pixel contains an analog front-end, four independently working discriminators, and four 12-bit ripple counters. Such pixel architecture allows photon processing one by one and selecting the X-ray photons according to their energy (X-ray color imaging).