A circular progress bar in Python based on phastmike's Vala widget

pygtk-circular-progress.py

#!/usr/bin/env python 
#
# pygtk-circular-progress.py
# based on https://github.com/phastmike/vala-circular-progress-bar
# Copyright (C) 2020 Reuben pygtk.posting@gmail.com
# 
# pygtk-circular-progress is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# 
# pygtk-circular-progress is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License along
# with this program.  If not, see <http://www.gnu.org/licenses/>.

import cairo
import gi
gi.require_version("Gtk", "3.0")
gi.require_version('PangoCairo', '1.0')
from gi.repository import Gtk, Gdk, GObject, Pango, PangoCairo
import os, sys, math

class CircularProgressBar (Gtk.Bin):
	
	min_diameter = 80
	line_width = 1
	percentage = 0
	center_fill_color = "#adadad"
	radius_fill_color = "#d3d3d3"
	progress_fill_color = "#4a90d9"
	center_filled = False
	radius_filled = False
	font = "URW Gothic"
	line_cap = cairo.LineCap.BUTT

	def __init__ (self):
		Gtk.Bin.__init__(self)

	def calculate_radius (self) :
		width = float(self.get_allocated_width ()) / 2
		height = (float(self.get_allocated_height ()) / 2) - 1
		return int(min(width, height)) 

	def calculate_diameter (self) :
		return 2 * self.calculate_radius ()

	def do_get_request_mode (self) :
		return Gtk.SizeRequestMode.CONSTANT_SIZE

	def do_get_preferred_width (self) :
		d = self.calculate_diameter ()
		min_w = self.min_diameter
		if d > self.min_diameter :
			natural_w = d
		else :
			natural_w = self.min_diameter
		return d, natural_w

	def do_get_preferred_height (self) :
		d = self.calculate_diameter ()
		min_h = self.min_diameter
		if d > self.min_diameter :
			natural_h = d
		else :
			natural_h = self.min_diameter
		return d, natural_h

	def do_draw (self, cr) :
		w = h = 0
		delta = 0
		color = Gdk.RGBA ()
		layout = PangoCairo.create_layout (cr) 
		desc = Pango.FontDescription() 
		
		cr.save ()

		color = Gdk.RGBA ()

		center_x = self.get_allocated_width () / 2
		center_y = self.get_allocated_height () / 2
		radius =  self.calculate_radius ()
		d = radius - self.line_width
		delta = radius - self.line_width / 2
		if d < 0 :
			delta = 0
			self.line_width = radius
		
		color = Gdk.RGBA ()
		cr.set_line_cap  (self.line_cap)
		cr.set_line_width (self.line_width)

		# Center Fill
		if self.center_filled == True:
			cr.arc (center_x, center_y, delta, 0, 2 * math.pi)
			color.parse (self.center_fill_color)
			Gdk.cairo_set_source_rgba (cr, color)
			cr.fill ()

		# Radius Fill
		if self.radius_filled == True:
			cr.arc (center_x, center_y, delta, 0, 2 * math.pi)
			color.parse (self.radius_fill_color)
			Gdk.cairo_set_source_rgba (cr, color)
			cr.stroke ()

		# Progress Fill
		progress = float(self.percentage)
		if progress > 0:
			cr.arc (center_x,
					center_y,
					delta, 
					1.5  * math.pi,
					(1.5 + progress * 2 ) * math.pi)
			color.parse (self.progress_fill_color)
			Gdk.cairo_set_source_rgba (cr, color)
			cr.stroke ()

		# Textual information
		context = self.get_style_context ()
		context.save ()
		context.add_class (Gtk.STYLE_CLASS_TROUGH)
		color = context.get_color (context.get_state ())
		Gdk.cairo_set_source_rgba (cr, color)

		# Percentage
		layout = PangoCairo.create_layout (cr)
		layout.set_text (str(int(self.percentage * 100.0)), -1)
		desc = Pango.FontDescription.from_string (self.font + " 24")
		layout.set_font_description (desc)
		PangoCairo.update_layout (cr, layout)
		w, h = layout.get_size () 
		cr.move_to (center_x - ((w / Pango.SCALE) / 2), center_y - 27 )
		PangoCairo.show_layout (cr, layout)

		# Units indicator ('PERCENT')
		layout.set_text ("PERCENT", -1)
		desc = Pango.FontDescription.from_string (self.font + " 8")
		layout.set_font_description (desc)
		PangoCairo.update_layout (cr, layout)
		w, h = layout.get_size () 
		cr.move_to (center_x - ((w / Pango.SCALE) / 2), center_y + 13)
		PangoCairo.show_layout (cr, layout)

		context.restore ()
		cr.restore ()

GObject.type_register(CircularProgressBar)

class GUI (Gtk.Window):
	def __init__(self):
		Gtk.Window.__init__(self)
		pb = CircularProgressBar()
		# have a peek at line 32-41 for all settings
		pb.percentage = .38
		pb.line_width = 3
		pb.radius_filled = True
		pb.center_filled = True
		self.connect('destroy', self.on_window_destroy)
		self.add(pb)
		self.show_all()

	def on_window_destroy(self, window):
		Gtk.main_quit()

def main():
	app = GUI()
	Gtk.main()
		
if __name__ == "__main__":
	sys.exit(main())