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--- tkinter_calc_ii [2024/04/20 00:34] – created appledog
+++ tkinter_calc_ii [2024/04/20 00:53] (current) – appledog
@@ Line 1: / Line 1: @@
 = TKInter Calc II
+== Themed Widgets
+Use ttk.button() //etc.// whenever possible. That's because ttk is the newest version. tk.button() and others are old, don't use them unless ttk. doesn't work.
 == Binding
+For example, you may wish to bind a key to a button. This helps you streamline the control of an application. If you just have two input methods there could be a problem with things like arrows and backspace or delete messing up the calculator window.
 <Code:Python>
+import tkinter as tk
+from tkinter import ttk
+def press_eq(event):
+    print('Equals key pressed.')
+root = tk.Tk()
+button1 = ttk.Button(root, text='=')
+button1.bind('<KeyPress-Return>', press_eq)
+button1.focus()
+button1.pack(expand=True)
+root.mainloop()
+</Code>
+=== Binding Mouse
+Observe carefully that <Button> and <Button-1> events are both the same event, but one has a specifier. Events such as <KeyPress> and <KeyPress-Enter> are discussed on some sites such as [[https://www.pythontutorial.net/tkinter/tkinter-event-binding/]].
+<Code:Python>
+import tkinter
+root = tkinter.Tk()
+def right_click_handler(event):
+    # event.num == 2 is MOUSE.
+    if event.num == 2:
+        print("RIGHT CLICK")
+root.bind("<Button-1>", lambda x: print("LEFT CLICK"))
+root.bind("<Button>", right_click_handler)
+root.mainloop()
+</Code>
+Here, a lambda is used to handle left clicks with <Button-1> while the more general <Button> handles both left and right, but uses <Code:Python>event.num == 2</Code> to determine right click vs. left click, so it could handle both if needed.
+== Dragging
+To capture a click-and-drag event use any of the <B1-Motion> (left-click), <B2-Motion> (right click) or <B3-Motion> (middle mouse button click). Note that Note that when dragging outside of an element the event still fires.
+<Code:Python>
+import tkinter
+root = tkinter.Tk()
+label = tkinter.Label(root, text="HEY")
+label.pack()
+def drag_handler(event):
+print(event.x, event.y)
+label.bind("<B1-Motion>", drag_handler)
+root.mainloop()
+</Code>
+=== Hovering
+Hovering over an element sends out two events in sequence, <Enter> and <Leave>
+<Code:Python>
+import tkinter
+root = tkinter.Tk()
+label = tkinter.Label(root, text="HELLO", bg="white", fg="navy")
+label.bind("<Enter>", lambda event: event.widget.config(bg="navy", fg="white"))
+label.bind("<Leave>", lambda event: event.widget.config(bg="white", fg="navy"))
+label.pack()
+root.mainloop()
 </Code>