Python tKinter box dragging v1.0

'''
December 23, 2019

This is an example ( using Python 3.7 / tKinter on Win10 x64 ) application that allows scrolling a canvas and dragging boxes on a canvas.

The canvas visible area is 300 x 300 px, but the scrollable area is 600 x 600 px.

This program demonstrates obtaining the final canvas shape object position, and altering it as desired.
    The boxes snap to a grid that is 30px vertically and 100px horizontally.


'''

import tkinter as tk
from tkinter import ttk
from functools import partial


root = tk.Tk()
root.title( "Scroll/Drag Canvas Example 1.0" )
window_width = 900
window_height = 700
root.minsize(window_width, window_height)
window_position_x = 20
window_position_y = 20
root.geometry('%dx%d+%d+%d' % (window_width, window_height, window_position_x, window_position_y))
root.resizable(True, True)
window_test_color = '#%02x%02x%02x' % (160, 160, 160)
root.config(bg=window_test_color)

label_test_color = '#%02x%02x%02x' % (255, 180, 180)

# @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
# Below is the scrolling functionality (working)

canvas_test_color = '#%02x%02x%02x' % (100, 160, 100)
canvas1 = tk.Canvas(master=root, width=300, height=300, scrollregion=(0,0,600,600), bg=canvas_test_color)
canvas1.place(x=30, y=30)

hbar1 = tk.Scrollbar(master=root,orient=tk.HORIZONTAL)
hbar1.place(x=30, y=360, width=200, height=30)

vbar1 = tk.Scrollbar(master=root,orient=tk.VERTICAL)
vbar1.place(x=360, y=30, width=30, height=200)



def function_hbar1_movement(event, *args):
    option1 = False
    if option1 == True:
        argList = []
        for x in args:
            argList.append(x)
        print (argList)
    canvas1.xview(event, *args)

def function_vbar1_movement(event, *args):
    option2 = False
    if option2 == True:
        argList = []
        for x in args:
            argList.append(x)
        print (argList)
    canvas1.yview(event, *args)



def function_hbar1_set(event, *args):
    option1 = False
    if option1 == True:
        argList = []
        for x in args:
            argList.append(x)
        print (argList)
    hbar1.set(event, *args)

def function_vbar1_set(event, *args):
    option2 = False
    if option2 == True:
        argList = []
        for x in args:
            argList.append(x)
        print (argList)

    vbar1.set(event, *args)



#hbar1.config(command=canvas1.xview)
#vbar1.config(command=canvas1.yview)
hbar1.config(command=function_hbar1_movement)
vbar1.config(command=function_vbar1_movement)

#canvas1.config(xscrollcommand=hbar1.set, yscrollcommand=vbar1.set)
canvas1.config(xscrollcommand=function_hbar1_set, yscrollcommand=function_vbar1_set)

# @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@






def show_canvas_scroll_values(event):
    canvas = event.widget
    x = canvas.canvasx(event.x)
    y = canvas.canvasy(event.y)
    #print canvas.find_closest(x, y)
    canvas_hposition_label.config(text=x)
    canvas_vposition_label.config(text=y)

#canvas1.bind('<Configure>', show_canvas_scroll_values)


# @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
# This section is just four labels to read out the canvas scroll values
# and the last-dragged-box actual xy values, on the 600x600 canvas area.

xpos=430
ypos=50
vspacer425 = 30
someLabel = tk.Label(master=root, text="canvas vertical scroll:")
someLabel.place(x=xpos, y=ypos)
xpos=570
canvas_hposition_label = tk.Label(master=root, text="???", bg=label_test_color)
canvas_hposition_label.place(x=xpos, y=ypos)

xpos=430
ypos=ypos + vspacer425
someLabel = tk.Label(master=root, text="canvas horizontal scroll:")
someLabel.place(x=xpos, y=ypos)
xpos=570
canvas_vposition_label = tk.Label(master=root, text="???", bg=label_test_color)
canvas_vposition_label.place(x=xpos, y=ypos)

xpos=430
ypos=ypos + vspacer425 + vspacer425
someLabel = tk.Label(master=root, text="box xpos:")
someLabel.place(x=xpos, y=ypos)
xpos=530
box_xposition_label = tk.Label(master=root, text="???", bg=label_test_color)
box_xposition_label.place(x=xpos, y=ypos)

xpos=430
ypos=ypos + vspacer425
someLabel = tk.Label(master=root, text="box ypos:")
someLabel.place(x=xpos, y=ypos)
xpos=530
box_yposition_label = tk.Label(master=root, text="???", bg=label_test_color)
box_yposition_label.place(x=xpos, y=ypos)



# @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
# this just draws the grid on the canvas.
    # canvas1 scroll region is 600 x 600

def draw_test_lines_on_canvas():
    tcolor1 = '#%02x%02x%02x' % (0, 0, 0)
    vspacing = 30
    hspacing = 100
    loopcount = 0
    tValue = vspacing
    while loopcount < 20:
        canvas1.create_line(0, tValue, 600, tValue, fill=tcolor1)
        tValue += vspacing
        loopcount += 1
    loopcount = 0
    tValue = hspacing
    while loopcount < 7:
        canvas1.create_line(tValue, 0, tValue, 600, fill=tcolor1)
        tValue += hspacing
        loopcount += 1

draw_test_lines_on_canvas()

# @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
# Below is the code for putting the 3 boxes on the canvas, and dragging them.

def canvas1_remember(event, *args):
    global canvas1_former_pos
    canvas1_former_pos = event.x, event.y
    #tList = ""
    #for n in args:
    #    tList = tList + str(n) + ", "
    #print ("args = " + tList)
    #x = event.x # <--------------- this is just giving the direct (window) coords of the mouse-down.
    #y = event.y # <--------------- this is just giving the direct (window) coords of the mouse-down.
    #canvas = event.widget
    #x = canvas.canvasx(event.x) #<------------ This is giving the scrolled canvas xy coords of the mouse click.
    #y = canvas.canvasy(event.y) #<------------ This is giving the scrolled canvas xy coords of the mouse click.
    #print ("mouse-down:" + str(canvas.find_closest(x, y))) #<------ this is finding the closest tagged item.
    #print ("mouse-down:" + str(x) + ", " + str(y))



canvas1.bind('<Button>', canvas1_remember)



def on_mouse1_release(box, event):
    global stored_box
    global canvas1_former_pos
    #canvas1.move(stored_box, -10, -10)
    #stored_box.gettags()
    #itemInfo = canvas1.coords(stored_tags[0])
    print ("mouse released from box")
    stored_tags = canvas1.gettags(box)
    sItems = []
    for n in stored_tags:
        sItems.append(n)
    print ( "tag = " + str(sItems[0]))
    #print (stored_box)

    # Below is showing the ending drag position.
    itemInfo = canvas1.coords(stored_tags[0]) # <-------- this gets the tag itself
    #print (itemInfo[0]) # = x (string/float format)
    #print (itemInfo[1]) # = y
    #print (itemInfo[2]) # = x + width
    #print (itemInfo[3]) # = y + height
    print (str(itemInfo[0]) + "," + str(itemInfo[1]) + "," + str(itemInfo[2]) + "," + str(itemInfo[3]))

    # (Here is where the item's coordinates would be checked for legit settings)
    newxval = check_x_coordinate(str(itemInfo[0]))
    newyval = check_y_coordinate(str(itemInfo[1]))

    canvas1.move(sItems[0], newxval, newyval) # <------ this moves the whole item by tag name, the specified coordinates

    # Below is showing the ending position after 10,10 move.
    itemInfo = canvas1.coords(stored_tags[0]) # <-------- this gets the tag itself
    #print (itemInfo[0]) # = x (string/float format)
    #print (itemInfo[1]) # = y
    #print (itemInfo[2]) # = x + width
    #print (itemInfo[3]) # = y + height
    print (str(itemInfo[0]) + "," + str(itemInfo[1]) + "," + str(itemInfo[2]) + "," + str(itemInfo[3]))

    #new_x = canvas1_former_pos[0] = newxval
    #new_y = canvas1_former_pos[1] = newyval
    new_x = newxval
    new_y = newyval
    canvas1_former_pos = new_x, new_y


def check_x_coordinate(xValue):
    num_xValue = float(xValue)
    if num_xValue <= 0:
        num_xValue = (num_xValue * -1) # This is checking for a negative x position, and returning it to zero if it exists.
        return num_xValue
    else:
        remainder = num_xValue % 100
        return (remainder * -1)


def check_y_coordinate(yValue):
    num_yValue = float(yValue)
    if num_yValue <= 0:
        num_yValue = (num_yValue * -1) # This is checking for a negative y position, and returning it to zero if it exists.
        return num_yValue
    else:
        remainder = num_yValue % 30
        return (remainder * -1)





stored_box = "" # <------- this stores the item ID number, which is just a string of an int value.
stored_tags = [] # <------ this stores the item tag that you assigned, as item[0]


def ondrag(box, event):
    global stored_box
    global canvas1_former_pos
    #global stored_tags
    stored_box = box
    canvas1.tag_raise(box)
    #print ("box = " + str(box)) # <--------- this is showing the ID number
    #stored_tags = canvas1.gettags(box)
    #sItems = ""
    #for n in stored_tags:
    #    sItems = sItems + n + ", "
    #print ("tag = " + sItems) # <----------- this returns the single tag, and the string "current"
    canvas1.move(box, event.x-canvas1_former_pos[0], event.y-canvas1_former_pos[1]) # This line allows dragging the box in x and y.
    #canvas1.move(box, event.x-canvas1_former_pos[0], 0) # This line only allows dragging the box in the x dimension (left and right along whatever row it is already in).
    canvas1_remember(event)



def add_box(x_pos, y_pos, color, thisTag):
    box = canvas1.create_rectangle(x_pos, y_pos, x_pos+dragBox_width, y_pos+dragBox_height, outline="black", fill=color, tags=(thisTag))
    canvas1.tag_bind(box, '<B1-Motion>', partial(ondrag, box))
    canvas1.tag_bind(box, '<ButtonRelease-1>', partial(on_mouse1_release, box)) # <ButtonRelease-1>
    '''
    https://stackoverflow.com/questions/2679418/how-to-get-the-coordinates-of-an-object-in-a-tkinter-canvas

    Note about above: whenever you create an item on a canvas, the canvas returns the item ID number.
    So that just needs to be kept with each shift object, and then you have a way to query all the block positions
    and correct them if they don't fall on the snap-to grid spacing.
    '''



canvas1_former_pos = 0,0
dragBox_width = 80
dragBox_height = 20

add_box(80, 100, 'red', 'shiftbox1')
add_box(80, 200, 'green', 'shiftbox2')
add_box(200, 200, 'blue', 'shiftbox3')


# @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@


root.mainloop()