如何得到一memo的字体高度？
试了用memo1.font.height，但其值为负数，就算用绝对值也与实际不符，
如果用form1.font := memo1.font; 再用form1.canvas.TextHeight是可以得到，
有没有不借助其它组件的办法呢？
[解决办法]
字体高度正值是单元高度，为0是让Windows自定决定需多高，为负是实际图形部分高度
[解决办法]
The value of Height can be obtained from the point size using this formula:
Font.Height = -Font.Size * Font.PixelsPerInch / 72
When the Height property has a positive value, the Size property has a negative value. When the Size property has a positive value, the Height property has a negative value.
