That would depend on what else you are asking it to do. About 15 years ago PIC-Pong was done using a PIC16C71 that produced NTSC-like output (256 line non-interlaced) directly via bit-banging in addition to running the code to play Pong, including the necessary character generation for the text.He could use average hobbyist microcontroller to render 100x100 pixels anything above that is too much for MCU.For full screen resolution you would need something with much bigger processing power.
http://tinyvga.com/avr-isa-vgaYou really need a video generator circuit.
You put data in its memory and it displays it for you.
I remember many years ago using a simple PC graphics card directly by poking data into its memory.
Here is PIC doing CGA: http://tinyvga.com/pic-vgaThe Maximite is a PIC microcontroller project which gives a VGA output for a 480 x 432 color display directly no using video generator circuitry beyond a few resistors and a connector.
I have not examined the source code to discover what high level language it is written in, but it certainly could be done in C/C++.