blessed

Positioning

Offsets may be a number, a percentage (e.g. 50%), or a keyword (e.g. center).

Dimensions may be a number, or a percentage (e.g. 50%).

Positions are treated almost exactly the same as they are in CSS/CSSOM when an element has the position: absolute CSS property.

When an element is created, it can be given coordinates in its constructor:

var box = blessed.box({
  left: 'center',
  top: 'center',
  bg: 'yellow',
  width: '50%',
  height: '50%'
});

This tells blessed to create a box, perfectly centered relative to its parent, 50% as wide and 50% as tall as its parent.

Percentages can also have offsets applied to them:

  ...
  height: '50%-1',
  left: '45%+1',
  ...

To access the calculated offsets, relative to the parent:

console.log(box.left);
console.log(box.top);

To access the calculated offsets, absolute (relative to the screen):

console.log(box.aleft);
console.log(box.atop);

Overlapping offsets and dimensions greater than parents’

This still needs to be tested a bit, but it should work.