Problem with -debug annotate

[dreamcatcher]

The option -debug annotate gives a false information:

Code: Select all

convert -debug annotate  xc: -font "/usr/share/fonts/opentype/Arsenal-Regular.otf -annotate" 0 "A" null: 2>&1 | grep "Metrics:"

---> With A (Uppercase letter):
Metrics: text: A; width: 6.71875; height: 15; ascent: 12; descent: -4; max advance: 22; bounds: 0.28125,0 6.54688,8; origin: 7,0; pixels per em: 12,12; underline position: -1.5625; underline thickness: 0.78125
The height-value is 15 pixel

But:

Code: Select all

convert -debug annotate  xc: -font "/usr/share/fonts/opentype/Arsenal-Regular.otf" -annotate 0 "a" null: 2>&1 | grep "Metrics:"

---> With a (Lowercase letter):
Metrics: text: a; width: 5.60938; height: 15; ascent: 12; descent: -4; max advance: 22; bounds: 0.390625,0 5.46875,6; origin: 6,0; pixels per em: 12,12; underline position: -1.5625; underline thickness: 0.78125
The height-value is 15 pixel

The height-value is the same. I don't agree with this result. "A" is higher than "a". What's wrong?