Multiline text line height not being calculated correctly

The line height isn't being calculated correctly for ImageDraw's multiline_text() function [1]. It's making an assumption that a capital "A" is as large as the font can be. However, if I use the word "Apple" you'll notice that the "p" in word creates a different text size.

The issue

Current code

line_spacing = self.textsize('A', font=font)[1] + spacing

• https://github.com/python-pillow/Pillow/blob/master/PIL/ImageDraw.py#L269

>>> self.textsize('A', font=font)[1]
170
>>> self.textsize('APPLE', font=font)[1]
170
>>> self.textsize('Apple', font=font)[1]
244 // <-- problem

How the text correctly looks on the web

How the image is rendered via pillow (incorrect line height)

Proposed Change

import string
...
line_spacing = self.textsize(string.ascii_letters, font=font)[1] + spacing

Gets characters above and below the text baseline. Use every upper and lower letter in the alphabet since you'll notice in the font above, the lower case "l" is the character with the highest point.

When that change is made, you'll see the correct text height in the image:

[1] https://github.com/python-pillow/Pillow/blob/master/PIL/ImageDraw.py#L269

Start in PIL/ImageDraw.py at the multiline_text implementation and reproduce the reported textsize results with the example font and strings. Check how line_spacing is derived from glyph bounds, then verify that multiline rendering accounts for both ascenders and descenders without excessive spacing.