PROPixx Demo 2 -- Drawing dots at 1440 Hz
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This demo is a simple demonstration of the PROPixx's 1440 Hz sequencer. We display twelve white dots around the center of the screen, cycling at a rate of 1440 Hz. The demo ends when a key is pressed.

Currently, there is no graphics card capable of drawing individual frames at this refresh rate. To achieve this rate, the PROPixx uses a "sequencer" to break up a single 1920 x 1080, 120 Hz RGB video signal into 12 multiple frames displayed in sequence. First, the 1920 x 1080 image is divided into four 960 x 540 images, or "quadrants", which are magnified to full screen. Next, each 8-bit RGB color channel is converted to grayscale and displayed separately. The order of appearance is Q1 red, Q2 red, Q3 red, Q4 red, and then this order is repeated for G and B channels. 


.. image:: Quad12xStill.*
  :width: 500
  :align: center

To create our stimuli, we determine target locations as if they were full resolution, full screen. The helper script ``convertToQuadrant`` reassigns and rescales the target positon to the correct quadrant. Depending on the frame, we draw our targets as either full red, full green or full blue. 

A screen running in 120 Hz mode will display the twelve dots on the same frame, in the correct quadrant and with the correct color profile. Here is a demonstration, albeit slowed down:

.. image:: 1440HzDemoFullHD.*
  :width: 300
  :align: center

The PROPixx in 1440 Hz mode will display the four quadrants in sequence, starting with red and repeating for green and blue. The image will be full screen, grayscale:

.. image:: 1440HzDemo.*
  :width: 300
  :align: center

.. literalinclude:: ../DatapixxToolbox/DatapixxDemos/PPxDraw1440HzDots.m
   :language: matlab
   :emphasize-lines: 46, 47, 79, 86, 93, 100, 109, 116, 123, 130, 139, 146, 153, 160, 179-180, 185-199 
   :linenos: