Using the CSS Font-stretch property
Here is an example of making a font to be condenced or extended with font stretch. In Antenna House Formatter, percentage and numerical values are extended as specifiable values. i.e. font-stretch: 50%;

Absolute keyword values have the following ordering, from narrowest to widest :

  1. ultra-condensed
  2. extra-condensed
  3. condensed
  4. semi-condensed
  5. normal
  6. semi-expanded
  7. expanded
  8. extra-expanded
  9. ultra-expanded

font-family: serif;

  1. Peaceful World.
  2. Peaceful World.
  3. Peaceful World.
  4. Peaceful World.
  5. Peaceful World.
  6. Peaceful World.
  7. Peaceful World.
  8. Peaceful World.
  9. Peaceful World.
  1. Peaceful World.
  2. Peaceful World.
  3. Peaceful World.
  4. Peaceful World.
  5. Peaceful World.
  6. Peaceful World.
  7. Peaceful World.
  8. Peaceful World.
  9. Peaceful World.

The relative keyword values :

  1. normal
  2. wider
  3. wider*wider
  4. narrower
  5. narrower*narrower

font-family: serif;

  1. Peaceful World.
  2. Peaceful World.
  3. Peaceful World.
  4. Peaceful World.
  5. Peaceful World.

font-family: sans-serif;

  1. Peaceful World.
  2. Peaceful World.
  3. Peaceful World.
  4. Peaceful World.
  5. Peaceful World.

The percentage keyword values :

  1. 50%
  2. 75%
  3. 100%
  4. 150%
  5. 200%

font-family: serif;

  1. Peaceful World.
  2. Peaceful World.
  3. Peaceful World.
  4. Peaceful World.
  5. Peaceful World.

font-family: sans-serif;

  1. Peaceful World.
  2. Peaceful World.
  3. Peaceful World.
  4. Peaceful World.
  5. Peaceful World.

The number keyword values :

  1. 0.5
  2. 0.75
  3. 1.0
  4. 1.5
  5. 2.0

font-family: serif;

  1. Peaceful World.
  2. Peaceful World.
  3. Peaceful World.
  4. Peaceful World.
  5. Peaceful World.
  1. Peaceful World.
  2. Peaceful World.
  3. Peaceful World.
  4. Peaceful World.
  5. Peaceful World.