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#!/usr/bin/env python
# -*- coding: utf-8 -*-
# -----------------------------------------------------------------------------
#
# pycairo/cairocffi-based FreeType example - Copyright 2017 Hin-Tak Leung
# Distributed under the terms of the new BSD license.
#
# rewrite of the numply,matplotlib-based example from Nicolas P. Rougier
#
# -----------------------------------------------------------------------------
#
# Direct translation of example 1 from the freetype tutorial:
# http://www.freetype.org/freetype2/docs/tutorial/step1.html
#
# Except we uses FreeType's own trigonometric functions instead of those
# from the system/python's math library.
from cairo import Context, ImageSurface, FORMAT_A8
from bitmap_to_surface import make_image_surface
from freetype.raw import *
from PIL import Image
WIDTH, HEIGHT = 640, 480
image = ImageSurface(FORMAT_A8, WIDTH, HEIGHT)
ctx = Context(image)
def to_c_str(text):
''' Convert python strings to null terminated c strings. '''
cStr = create_string_buffer(text.encode(encoding='UTF-8'))
return cast(pointer(cStr), POINTER(c_char))
def draw_bitmap( bitmap, x, y):
global image, ctx
# cairo does not like zero-width surface
if (bitmap.width > 0):
glyph_surface = make_image_surface(bitmap)
ctx.set_source_surface(glyph_surface, x, y)
ctx.paint()
def main():
library = FT_Library()
matrix = FT_Matrix()
face = FT_Face()
pen = FT_Vector()
filename= 'Vera.ttf'
text = 'Hello World !'
num_chars = len(text)
# FT_Angle is a 16.16 fixed-point value expressed in degrees.
angle = FT_Angle(25 * 65536)
# initialize library, error handling omitted
error = FT_Init_FreeType( byref(library) )
# create face object, error handling omitted
error = FT_New_Face( library, to_c_str(filename), 0, byref(face) )
# set character size: 50pt at 100dpi, error handling omitted
error = FT_Set_Char_Size( face, 50 * 64, 0, 100, 0 )
slot = face.contents.glyph
# set up matrix
matrix.xx = FT_Cos( angle )
matrix.xy = - FT_Sin( angle )
matrix.yx = FT_Sin( angle )
matrix.yy = FT_Cos( angle )
# the pen position in 26.6 cartesian space coordinates; */
# start at (300,200) relative to the upper left corner */
pen.x = 200 * 64;
pen.y = ( HEIGHT - 300 ) * 64
for n in range(num_chars):
# set transformation
FT_Set_Transform( face, byref(matrix), byref(pen) )
# load glyph image into the slot (erase previous one)
charcode = ord(text[n])
index = FT_Get_Char_Index( face, charcode )
FT_Load_Glyph( face, index, FT_LOAD_RENDER )
# now, draw to our target surface (convert position)
draw_bitmap( slot.contents.bitmap,
slot.contents.bitmap_left,
HEIGHT - slot.contents.bitmap_top )
# increment pen position
pen.x += slot.contents.advance.x
pen.y += slot.contents.advance.y
FT_Done_Face(face)
FT_Done_FreeType(library)
image.flush()
image.write_to_png("example_1-cairo.png")
Image.open("example_1-cairo.png").show()
if __name__ == '__main__':
main()
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