get-text-extent

Gets the dimensions of a string drawn into this device context. The result is four real numbers:

• the total width of the text (depends on both the font and the text);
• the total height of the font (depends only on the font);
• the distance from the baseline of the font to the bottom of the descender (depends only on the font); and
• extra vertical space added to the font by the font designer (often zero; depends only on the font).

• (send a-dc get-text-extent string font big-chars?) -> four non-negative real numbers: width, height, descent, and ascent
      string : string
      font = #f : font% object or #f
      big-chars? = #f : boolean

  Returns the size of string at it would be drawn in the device context. The font argument specifies the font to use in measuring the text; if it is #f, the current font of the drawing area is used. (See also set-font.)

  If big-chars? is #t, then string is interpreted as a string or Unicode or 16-bit characters instead of an ASCII string, but such strings are not yet fully supported.