PIL - font kerning

[carsn]

Hey all,

anybody know, if there´s a way to specify the kerning of a font, when
you draw text with PIL?

I´d like to achieve the same effect that you get, when you set a
negative kerning in Gimp/Photshop - ie. reduce the spacing between
glyphs.

Can PIL do that or do I use another lib for that?

Thx for any pointers & some nice xmas days to U all!
carsten

 

[Ivan Illarionov]

Hey all,

anybody know, if there$B!-(Bs a way to specify the kerning of a font, when
you draw text with PIL?

I$B!-(Bd like to achieve the same effect that you get, when you set a
negative kerning in Gimp/Photshop - ie. reduce the spacing between
glyphs.

Can PIL do that or do I use another lib for that?

Thx for any pointers & some nice xmas days to U all!
carsten

No. PIL can't do that. I suggest combination of cairo/pango/pangocairo
(pycairo and pygtk packages).

Ivan

 

[Ivan Illarionov]

No. PIL can't do that. I suggest combination of cairo/pango/pangocairo
(pycairo and pygtk packages).

Ivan

I found a little helper function that does what you want (and more)

import cairo
import pango
import pangocairo

def draw_text(surface, context, text, font="sans 14", position=None,
color=None,
box_width=None,
alignment=pango.ALIGN_CENTER,
line_spacing=None, letter_spacing=None,
extra_kerning=None):
if color is None:
color = (0.0, 0.0, 0.0)
context.set_source_rgb(*color)
pc = pangocairo.CairoContext(context)
layout = pc.create_layout()
layout.set_text(text)
layout.set_font_description(pango.FontDescription(font))
if box_width: layout.set_width(box_width)
layout.set_alignment(alignment)
if line_spacing: layout.set_spacing(spacing)
alist = pango.AttrList()
if letter_spacing:
alist.insert(pango.AttrLetterSpacing(letter_spacing, 0, len
(text)))
if extra_kerning:
for pos, kern in extra_kerning.iteritems():
alist.insert(pango.AttrLetterSpacing(kern, pos, pos
+1))
layout.set_attributes(alist)
if position is None:
width, height = surface.get_width(), surface.get_height()
w, h = layout.get_pixel_size()
position = (width/2.0 - w/2.0, height/2.0 - h/2.0)
context.move_to(*position)
pc.show_layout(layout)

And example usage:

surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
context = cairo.Context(surface)
draw_text(surface, context, 'Hello world!',
font="sans 52", color=(.25,.28,.33),
letter_spacing=-6000,
extra_kerning={0:-9000, 1:-1000, 6:6000, 7:-15000, 8:5000,
9:-7000})

surface.write_to_png("hello.png")

 

[carsn]

I found a little helper function that does what you want (and more)

import cairo
import pango
import pangocairo

def draw_text(surface, context, text, font="sans 14", position=None,
color=None,
box_width=None,
alignment=pango.ALIGN_CENTER,
line_spacing=None, letter_spacing=None,
extra_kerning=None):
if color is None:
color = (0.0, 0.0, 0.0)
context.set_source_rgb(*color)
pc = pangocairo.CairoContext(context)
layout = pc.create_layout()
layout.set_text(text)
layout.set_font_description(pango.FontDescription(font))
if box_width: layout.set_width(box_width)
layout.set_alignment(alignment)
if line_spacing: layout.set_spacing(spacing)
alist = pango.AttrList()
if letter_spacing:
alist.insert(pango.AttrLetterSpacing(letter_spacing, 0, len
(text)))
if extra_kerning:
for pos, kern in extra_kerning.iteritems():
alist.insert(pango.AttrLetterSpacing(kern, pos, pos
+1))
layout.set_attributes(alist)
if position is None:
width, height = surface.get_width(), surface.get_height()
w, h = layout.get_pixel_size()
position = (width/2.0 - w/2.0, height/2.0 - h/2.0)
context.move_to(*position)
pc.show_layout(layout)

And example usage:

surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
context = cairo.Context(surface)
draw_text(surface, context, 'Hello world!',
font="sans 52", color=(.25,.28,.33),
letter_spacing=-6000,
extra_kerning={0:-9000, 1:-1000, 6:6000, 7:-15000, 8:5000,
9:-7000})

surface.write_to_png("hello.png")

Works great, thanks a lot!!