freetype的python实现测试
应用背景
python上面的opencv的puttext用不了中文，于是使用到了freetype可以在ubuntu系统的opencv上写中文。安装准备
freetype-2.6.5.tar.gz //安装中文字库
freetype-py-master.tar.gz //python的安装接口
测试代码实现
#! /usr/bin/env python
# -*- coding: utf-8 -*-
'''
##################################################
# tools #
#------------------------------------------------#
# draw chinese text using freetype on python2.x # #
# 2017.4.12 #
##################################################
'''
import numpy as np
import freetype
import copy
import pdb
class put_chinese_text(object):
def __init__(self, ttf):
self._face = freetype.Face(ttf)
def draw_text(self, image, pos, text, text_size, text_color):
'''
draw chinese(or not) text with ttf
:param image: image(numpy.ndarray) to draw text
:param pos: where to draw text
:param text: the context, for chinese should be unicode type
:param text_size: text size
:param text_color:text color
:return: image
'''
self._face.set_char_size(text_size * 64)
metrics = self._face.size
ascender = metrics.ascender/64.0
#descender = metrics.descender/64.0
#height = metrics.height/64.0
#linegap = height - ascender + descender
ypos = int(ascender)
if not isinstance(text, unicode):
text = text.decode('utf-8')
img = self.draw_string(image, pos[0], pos[1]+ypos, text, text_color)
return img
def draw_string(self, img, x_pos, y_pos, text, color):
'''
draw string
:param x_pos: text x-postion on img
:param y_pos: text y-postion on img
:param text: text (unicode)
:param color: text color
:return: image
'''
prev_char = 0
pen = freetype.Vector()
pen.x = x_pos << 6 # div 64
pen.y = y_pos << 6
hscale = 1.0
matrix = freetype.Matrix(int(hscale)*0x10000L, int(0.2*0x10000L),\
int(0.0*0x10000L), int(1.1*0x10000L))
cur_pen = freetype.Vector()
pen_translate = freetype.Vector()
image = copy.deepcopy(img)
for cur_char in text:
self._face.set_transform(matrix, pen_translate)
self._face.load_char(cur_char)
kerning = self._face.get_kerning(prev_char, cur_char)
pen.x += kerning.x
slot = self._face.glyph
bitmap = slot.bitmap
cur_pen.x = pen.x
cur_pen.y = pen.y - slot.bitmap_top * 64
self.draw_ft_bitmap(image, bitmap, cur_pen, color)
pen.x += slot.advance.x
prev_char = cur_char
return image
def draw_ft_bitmap(self, img, bitmap, pen, color):
'''
draw each char
:param bitmap: bitmap
:param pen: pen
:param color: pen color e.g.(0,0,255) - red
:return: image
'''
x_pos = pen.x >> 6
y_pos = pen.y >> 6
cols = bitmap.width
rows = bitmap.rows
glyph_pixels = bitmap.buffer
for row in range(rows):
for col in range(cols):
if glyph_pixels[row*cols + col] != 0:
img[y_pos + row][x_pos + col][0] = color[0]
img[y_pos + row][x_pos + col][1] = color[1]
img[y_pos + row][x_pos + col][2] = color[2]
if __name__ == '__main__':
# just for test
import cv2
# file = open('class.txt','r')
#line = file.readline()
img = np.zeros([300,300,3])
color_ = (0,255,0)
pos = (3, 3)
text_size = 24
ft = put_chinese_text('/home/jing/hqzy/Demo/楷体_GB2312.ttf')
image = ft.draw_text(img, pos, "你好的", text_size, color_)
cv2.imshow('ss', image)
cv2.waitKey(0)