#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Needs freetype-py>=1.0
# The MIT License (MIT)
#
# Copyright (c) 2013 Daniel Bader (http://dbader.org)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
"""
References:
https://dbader.org/blog/monochrome-font-rendering-with-freetype-and-python
https://gist.github.com/dbader/5488053#file-fontdemo-py-L244
"""
from __future__ import absolute_import, division, print_function, unicode_literals
[docs]class Bitmap(object):
"""
A 2D bitmap image represented as a list of byte values. Each byte indicates the state
of a single pixel in the bitmap. A value of 0 indicates that the pixel is `off`
and any other value indicates that it is `on`.
"""
def __init__(self, width, height, pixels=None):
self.width = width
self.height = height
self.pixels = pixels or bytearray(width * height)
def __repr__(self):
"""Return a string representation of the bitmap's pixels."""
rows = ''
for y in range(self.height):
for x in range(self.width):
rows += '#' if self.pixels[y * self.width + x] else '.'
rows += '\n'
return rows
[docs] def bitblt(self, src, x, y):
"""Copy all pixels from `src` into this bitmap"""
srcpixel = 0
dstpixel = y * self.width + x
row_offset = self.width - src.width
for sy in range(src.height):
for sx in range(src.width):
self.pixels[dstpixel] = self.pixels[dstpixel] or src.pixels[srcpixel]
srcpixel += 1
dstpixel += 1
dstpixel += row_offset
[docs]class Glyph(object):
def __init__(self, pixels, width, height, top, advance_width):
self.bitmap = Bitmap(width, height, pixels)
self.top = top
self.descent = max(0, self.height - self.top)
self.ascent = max(0, max(self.top, self.height) - self.descent)
self.advance_width = advance_width
@property
def width(self):
return self.bitmap.width
@property
def height(self):
return self.bitmap.height
[docs] @staticmethod
def from_glyphslot(slot):
"""Construct and return a Glyph object from a FreeType GlyphSlot."""
pixels = Glyph.unpack_mono_bitmap(slot.bitmap)
width, height = slot.bitmap.width, slot.bitmap.rows
top = slot.bitmap_top
advance_width = slot.advance.x // 64
return Glyph(pixels, width, height, top, advance_width)
[docs] @staticmethod
def unpack_mono_bitmap(bitmap):
"""
Unpack a freetype FT_LOAD_TARGET_MONO glyph bitmap into a bytearray where each
pixel is represented by a single byte.
"""
data = bytearray(bitmap.rows * bitmap.width)
for y in range(bitmap.rows):
for byte_index in range(bitmap.pitch):
byte_value = bitmap.buffer[y * bitmap.pitch + byte_index]
num_bits_done = byte_index * 8
rowstart = y * bitmap.width + byte_index * 8
for bit_index in range(min(8, bitmap.width - num_bits_done)):
bit = byte_value & (1 << (7 - bit_index))
data[rowstart + bit_index] = 1 if bit else 0
return data
[docs]class Font(object):
def __init__(self, filename, size):
import freetype
self.face = freetype.Face(filename)
self.face.set_pixel_sizes(0, size)
[docs] def glyph_for_character(self, char):
import freetype
self.face.load_char(char, freetype.FT_LOAD_RENDER | freetype.FT_LOAD_TARGET_MONO)
return Glyph.from_glyphslot(self.face.glyph)
[docs] def render_character(self, char):
glyph = self.glyph_for_character(char)
return glyph.bitmap
[docs] def kerning_offset(self, previous_char, char):
kerning = self.face.get_kerning(previous_char, char)
return kerning.x // 64
[docs] def text_dimensions(self, text):
"""
Return (width, height, baseline) of `text` rendered in the current
font."""
width = 0
max_ascent = 0
max_descent = 0
previous_char = None
for char in text:
glyph = self.glyph_for_character(char)
max_ascent = max(max_ascent, glyph.ascent)
max_descent = max(max_descent, glyph.descent)
kerning_x = self.kerning_offset(previous_char, char)
width += max(glyph.advance_width + kerning_x, glyph.width + kerning_x)
previous_char = char
height = max_ascent + max_descent
return (width, height, max_descent)
[docs] def render_text(self, text, width=None, height=None, baseline=None):
if None in (width, height, baseline):
width, height, baseline = self.text_dimensions(text)
x = 0
previous_char = None
outbuffer = Bitmap(width, height)
for char in text:
glyph = self.glyph_for_character(char)
x += self.kerning_offset(previous_char, char)
y = height - glyph.ascent - baseline
outbuffer.bitblt(glyph.bitmap, x, y)
x += glyph.advance_width
previous_char = char
return outbuffer
[docs]def font_demo():
r"""
CommandLine:
python -m vtool.fontdemo font_demo --show
Example:
>>> # DISABLE_DOCTEST
>>> from vtool.fontdemo import * # NOQA
>>> result = font_demo()
>>> import utool as ut
>>> print(result)
>>> # xdoctest: +REQUIRES(--show)
>>> import wbia.plottool as pt
>>> ut.show_if_requested()
"""
filename = '/usr/share/fonts/truetype/freefont/FreeMono.ttf'
fnt = Font(filename, 12)
# Single characters
ch = fnt.render_character('e')
print(repr(ch))
# Multiple characters
txt = fnt.render_text('hello')
print(repr(txt))
# Kerning
print(repr(fnt.render_text('A1321')))
# Choosing the baseline correctly
print(repr(fnt.render_text('hello world')))
[docs]def get_text_test_img(text):
r"""
Args:
text (str):
CommandLine:
python -m vtool.fontdemo get_text_test_img --show
Example:
>>> # DISABLE_DOCTEST
>>> from vtool.fontdemo import * # NOQA
>>> import utool as ut
>>> text = 'A012'
>>> text_img = get_text_test_img(text)
>>> result = ('text_img = %s' % (ub.repr2(text_img),))
>>> print(result)
>>> # xdoctest: +REQUIRES(--show)
>>> import wbia.plottool as pt
>>> pt.imshow(text_img)
>>> ut.show_if_requested()
"""
filename = '/usr/share/fonts/truetype/freefont/FreeMono.ttf'
fnt = Font(filename, 24)
buf = fnt.render_text(text)
import numpy as np
img = np.array(buf.pixels)
text_img = img.reshape(buf.height, buf.width) * 255
return text_img
if __name__ == '__main__':
"""
CommandLine:
xdoctest -m vtool.fontdemo
"""
import xdoctest
xdoctest.doctest_module(__file__)