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You can use the pen to display text as well as
lines. The display work is done by displayText:at: or
centerText:at: messages. In the following, one argument of
centerText:at: is a string to be printed, and the other specifies a
position just under the primitive meter.
The exact distance under the primitive meter is twice the
height of the font. To determine that height, you send a font
message to extract the current font instance associated with the pen, and
then you send a height message to determine the font instance's
height:
MeterGraphPane method definition • instance drawMeter | thePen meterWidth xLft yBot | meterWidth := self width * 3 // 4. xLft := self width - meterWidth // 2. yBot := self height // 2. thePen := self pen. thePen lineFrom: xLft @ yBot to: (xLft + meterWidth) @ yBot. thePen lineFrom: (xLft + (meterWidth // 2)) @ yBot to: (xLft + (meterWidth // 2)) @ (yBot - 10). thePen centerText: 'Untitled' at: ((self width) // 2) @ ((self height // 2) + (2 * thePen font height)).
Using the definition of drawMeter provided in this segment, you
produce the following display:
