Verify if given fonts are known and create an image to show them. Uses by default all the known fonts.

CheckFonts.py

import sys, os
import cairo
import commands

def truncate_chars(value, max_length): # thanks django!
    if len(value) <= max_length:
        return value
    truncd_val = value[:max_length]
    if value[max_length] != " ":
        rightmost_space = truncd_val.rfind(" ")
        if rightmost_space != -1:
            truncd_val = truncd_val[:rightmost_space]
    return truncd_val + "..."

# == Main =================================
image_path	= os.path.abspath("test_font.png")
fonts 		= sys.argv[1:]
offset 		= 40
known_fonts	= []

# get known fonts
out=commands.getoutput('fc-list').split('\n')
for line in out:
	line 	= line.split(':style=')
	font 	= line[0]
	# styles 	= line[1].split(' ')
	known_fonts.append(font)

_fonts = fonts or known_fonts

# init cairo
size    = (1200, offset*len(_fonts)+offset)
surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, size[0], size[1])
ctx     = cairo.Context(surface)
ctx.set_source_rgb(0,0,0)
ctx.set_font_size(30)
# background
ctx.set_source_rgb(255, 255, 255)
ctx.rectangle(0, 0, size[0], size[1])
ctx.fill()

for i, font in enumerate(_fonts):
	print "[%d] testing font %s" % (i+1, font)
	# if tested font is provided by user, we check if fonts are known by the OS
	if fonts:
		unknown = False
		if not font in known_fonts:
			unknown = True
			print "[%d]=====> font '%s' unknown !!" % (i+1, font)
	# drawing line
	if fonts and unknown: # colored in red if font is unknown
		ctx.set_source_rgb(255, 0, 0)
		ctx.rectangle(0, i*offset+0.25*offset, size[0], offset)
		ctx.fill()
	elif i%2:
		ctx.set_source_rgba(0, 25, 25,0.2)
		ctx.rectangle(0, i*offset+0.25*offset, size[0], offset)
		ctx.fill()
	ctx.set_source_rgb(0, 0, 0)
	ctx.select_font_face("Courier new", cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_NORMAL)
	ctx.move_to(0, i*offset+offset)
	ctx.show_text("%d %s" % (i+1, truncate_chars(font, 25)))
	ctx.select_font_face(font, cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_NORMAL)
	ctx.move_to(600, i*offset+offset)
	ctx.show_text(font)
# write the image file
surface.write_to_png(image_path)

print "%d fonts tested" % len(_fonts)
print "image created at '%s'" % (image_path)