Draw text on an angle (rotated) in Python

Question

I am drawing text onto a numpy array image in Python (using a custom font). Currently I am converting the image to PIL, drawing the text and then converting back to a numpy

Answer 1

Using matplotlib, first visualize array and draw on it, get the raw data from the figure back. Pro: both tools are quite high level and let you deal with many details of the process. ax.annotate() offers flexibility for where and how to draw and set font properties, and plt.matshow() offers flexibility that lets you deal with aspects of array visualization.

import matplotlib.pyplot as plt
import scipy as sp

# make Data array to draw in
M = sp.zeros((500,500))

dpi = 300.0

# create a frameless mpl figure
fig, axes = plt.subplots(figsize=(M.shape[0]/dpi,M.shape[1]/dpi),dpi=dpi)
axes.axis('off')
fig.subplots_adjust(bottom=0,top=1.0,left=0,right=1)
axes.matshow(M,cmap='gray')

# set custom font
import matplotlib.font_manager as fm
ttf_fname = '/usr/share/fonts/truetype/ubuntu-font-family/Ubuntu-B.ttf'
prop = fm.FontProperties(fname=ttf_fname)

# annotate something
axes.annotate('ABC',xy=(250,250),rotation=45,fontproperties=prop,color='white')

# get fig image data and read it back to numpy array
fig.canvas.draw()
w,h = fig.canvas.get_width_height()
Imvals = sp.fromstring(fig.canvas.tostring_rgb(),dtype='uint8')
ImArray = Imvals.reshape((w,h,3))