Tkinter Does Not Suck

Tkinter doesn’t suck!Honest!

Saturday, 7 November 2009

“What GUI toolkit should I use?”

– random poster in random forum


wxWindows!


import wx

class Application(wx.Frame): def __init__(self, parent): wx.Frame.__init__(self, parent, -1, 'My GUI', size=(300, 200)) panel = wx.Panel(self) sizer = wx.BoxSizer(wx.VERTICAL) panel.SetSizer(sizer) txt = wx.StaticText(panel, -1, 'Hello, world') sizer.Add(txt, 0, wx.TOP|wx.LEFT, 20) self.Centre() self.Show(True)

app = wx.App(0)Application(None)app.MainLoop()


pyGTK


import gtk

window = gtk.Window()label = gtk.Label("Hello, world")window.add(label)window.show_all()gtk.main()


PyQt!


import sysimport PyQt4.Qt as qt

a=qt.QApplication(sys.argv)w=qt.QLabel("Hello, world")w.show()a.exec_()


“whatever you do...


...don’t use Tkinter!”


“Tkinter sucks!”


import Tkinter as tk

root = tk.Tk()tk.Label(root, text="Hello, world").pack()root.mainloop()


“yeah, OMG, Tkinter sucks!”


I disagree


1. it’s simple to use

- rich base widget set- which is not verbose- automatic packing


2. it’s always there

on Windows & OS X

-- on Linuxes you might need to install an optional package


3. it’s mature

first release 19918.0 released August 19998.5 released December 2007


how I discovered thisI had this project that I wanted to be click-to-run, but needed to select a file

Looked for a cross-platform “file dialog” solution and found some hacks

Then I noticed a reference to Tkinter, and lo and behold...


filename = tkFileDialog.askopenfilename(parent=root, filetypes=[('ReStructuredText Files', '.rst .txt'), ('All Files', '.*')], title='Select your presentation file')


well, if it can do that...

what about the program’s command-line options?


self.root = tk.Tk()frame = Tk.Frame(self.root)frame.pack()

Tk.Label(frame, text='Bruce, the Presentation Tool!').pack()

self.fullscreen = Tk.IntVar()Tk.Checkbutton(frame, text='Fullscreen?', variable=self.fullscreen).pack() # screen selectiondisplay = pyglet.window.get_platform().get_default_display()N = len(display.get_screens())self.screen = Tk.IntVar(0)if N > 1: for n in range(N): Tk.Radiobutton(frame, text="Display on screen %d"%(n+1), variable=self.screen, value=n).pack()

self.timer = Tk.IntVar()Tk.Checkbutton(frame, text='Show Timer?', variable=self.timer).pack()self.page_count = Tk.IntVar()Tk.Checkbutton(frame, text='Show Page Count?', variable=self.page_count).pack()self.bullet_mode = Tk.IntVar()Tk.Checkbutton(frame, text='Run in Bullet Mode?', variable=self.bullet_mode).pack()self.source = Tk.IntVar()Tk.Checkbutton(frame, text='Display source in console?', variable=self.source).pack()

Tk.Button(frame, text='Play Presentation', command=self.go).pack()


specific Tkinter gripes


1. it’s not pretty


1. it’s not pretty1. it doesn’t look native,2. fonts are not anti-aliased


2. extending is tricky


native look and feel(since Tk 8.0, 1999)



(much improved in Tk 8.5, 2008)



(much improved in Tk 8.5, 2008)

(“less ugly but not perfect”)


truetype / opentype fonts

(since Tk 8.5)


1. Simple to use


Widgets




demo image display

label properties: foreground, background, font, ???




No point showing the other three lines in other examples


from PIL import Image, ImageTkimage = ImageTk.PhotoImage(Image.open('kitten.jpg'))tk.Label(root, image=image).pack()


def pressed(): print 'You pressed me!'

tk.Button(root, text='Press me!', command=pressed).pack()


entry = tk.Entry(root)entry.pack()entry.insert(0, 'some text')


value = tk.IntVar()tk.Checkbutton(root, text='Checked?', variable=value).pack()


value = tk.IntVar()for n in range(4): tk.Radiobutton(root, value=n text="Selection %d"%(n+1), variable=value).pack()


value = tk.StringVar(value='One')tk.OptionMenu(root, value, 'One', 'Two', 'Three').pack()

10 minutes


listbox = tk.Listbox(root)listbox.pack()listbox.insert(tk.END, "a list entry")for item in ‘one two three four’.split(): listbox.insert(tk.END, item)


text = tk.Text(root)text.pack()text.insert(tk.END, '''some textmore text''')

also allows:- embedding of images and widgets- searching- tagging (identification, useful for properties)- styles


scale = tk.Scale(root, from_=0, to=100)scale.pack()


w = tk.Canvas(root, width=200, height=100)w.pack()w.create_line(0, 0, 200, 100)w.create_line(0, 100, 200, 0, fill="red", dash=(4, 4))w.create_rectangle(50, 25, 150, 75, fill="blue")

- line (with arrows), arc, image, oval, polygon, rectangle, text, widgets- outline, fill- scrollable (limitable)- picking (with closest)


1. Simple to use


Packing


rows or columns

the pack manager packs into rows or columns

the default is column, centered.


in the beginning there is a container, and it is empty

we’re going to pack this container at the default tk.TOP


pack a button

tk.Button(root, text='Press me!').pack()


pack a button

tk.Button(root, text='Press me!').pack()tk.Button(root, text='Press me too!').pack()


pack a button

tk.Button(root, text='Press me!').pack()tk.Button(root, text='Press me too!').pack()tk.Button(root, text='And me!').pack()


pack on tk.LEFT instead

tk.Button(root, text='Press me!').pack(side=tk.LEFT)tk.Button(root, text='Press me too!').pack(side=tk.LEFT)tk.Button(root, text='And me!').pack(side=tk.LEFT)


pack on tk.RIGHT instead

tk.Button(root, text='Press me!').pack(side=tk.RIGHT)tk.Button(root, text='Press me too!').pack(side=tk.RIGHT)tk.Button(root, text='And me!').pack(side=tk.RIGHT)


more complex packing?


tk.Button(root, text='Press me!').pack()horizontal = tk.Frame(root)horizontal.pack()tk.Button(horizontal, text='Press me too!').pack(side=tk.LEFT)tk.Button(horizontal, text='Press me too!').pack(side=tk.LEFT)


grids


tk.Button(root, text='Press me!').grid(row=0, column=0)tk.Message(root, text='Press\nme\ntoo!').grid(row=1, column=0)tk.Button(root, text='And me!').grid(row=1, column=1)

those are tk.CENTER “sticky”

other options are the 9 points of the compass

pack() also allows the sticky side to be specified

see I snuck in the multiline “Message” widget there?


... or place


Widget values


widgets with a variablevariable = tk.IntVar()value = variable.get()variable.set(value)


text widgetsentry = tk.Entry()value = entry.get()entry.delete(0, tk.END)entry.insert(0, value)


list boxeslistbox = tk.Listbox(root)listbox.pack()for item in ‘one two three four’.split(): listbox.insert(tk.END, item)selected = list.curselection()


Styling


2 methods:1. direct2. themed (py2.6+, py3k+)


tk.Label(root, text="Hello, world!", background='black', foreground='white', font='Courier').pack()


tk.Button(root, text="Hello, world!", background='black', foreground='white', font='Courier').pack()

some limitations (sometimes depending on your theme)


Option 2: Themed


from [tT]kinter import ttk

lower-case “t” in py3k+

If you want it earlier you can install the tile extension


complementary

Though the themed widget commands work similarly to the originals, there are important differences.

Themed widgets are not a drop-in replacement.

In particular, themed widgets generally provide less options for customizing their appearance than regular Tk widgets (e.g. they will often not have options like "-background").

Such changes, if needed (and they should be needed much less often) must be done by defining new widget styles, using the facilities offered by the themed widget package.


Implementsbutton, checkbutton, entry, label, menubutton, radiobutton, scale,

scrollbar, frame, labelframe, panedwindow


Addedcombobox, notebook, progressbar, separator,

sizegrip


Not presentcanvas, listbox,

menu, spinbox, text

these aren’t really needed


“classes” and “styles”>>> from tkinter import ttk>>> l = ttk.Label('hello, world!')>>> l.winfo_class()'TLabel'>>> l['style']''


layout example (button)


>>> style = ttk.Style()>>> style.layout('TButton')[("Button.border", {"children": [("Button.focus", {"children": [("Button.spacing", {"children": [("Button.label", {"sticky": "nswe"})], "sticky": "nswe"})], "sticky": "nswe"})], "sticky": "nswe", "border": "1"})]


element options>>> style = ttk.Style()>>> style.element_options('Button.label')('-compound', '-space', '-text', '-font', '-foreground', '-underline', '-width', '-anchor', '-justify', '-wraplength', '-embossed', '-image', '-stipple', '-background')


style = ttk.Style()style.configure("Red.TLabel", foreground="red", font="Courier 32")ttk.Label(text="Test Styled", style="Red.TLabel").pack()ttk.Label(text="Test Unstyled").pack()


switching themesstyle = ttk.Style()current_theme = style.theme_use()new_theme = style.theme_create(...)style.theme_use(new_theme)


Events


bind(), unbind()def callback(event): print "clicked at", event.x, event.y

frame = Frame(root, width=100, height=100)frame.bind("<Button-1>", callback)


<modifier-type-detail>


mouse event types

mouse button <Button-1>, <Button-2>, <Button-3>

mouse drag <B1-Motion>

mouse release <ButtonRelease-1>, ...

double click <Double-Button-1>, ...

triple click <Triple-Button-1>, ...

mouse entered <Enter>

mouse left <Leave>


keyboard event types

focus <FocusIn>, <FocusOut>

specific keys <Enter>, <Delete>, <Left>, <Right>, ...

any key <Key>

any text a, b, 1, 2, ...

modified keys <Shift-Up>, <Alt-Enter>, <Control-Tab>, ...


special event types

configuration <Configure>

The widget changed size (or location, on some platforms). The new size is provided in the width and height attributes of the event object passed to the callback.


Canvas

w = tk.Canvas(root, width=400, height=300)w.pack()


w.create_line(0, 0, 400, 300)


w.create_line(0, 300, 400, 0,fill="red", dash=(4, 4))


w.create_rectangle(150, 125, 250, 175, outline="green", fill="blue")

specify corders, outline and fill colors


w.create_arc(50, 50, 200, 200, outline="blue", fill="green")


w.create_oval(200, 200, 250, 250, outline="blue", fill="green")


from PIL import Image, ImageTkimage = ImageTk.PhotoImage(Image.open('kitten.jpg'))w.create_image((0, 0), image=image, anchor=tk.NW)


Tips


self.attributes('-topmost', True)


Tkinter Does Not Suck

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