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How to properly use grid in tkinter

Time:10-14

I'm pasting the all the code I have been working on for a "strip Chart". I can provide the original code I've taken it from if there is interest. The code works well and generates a chart as expected, but the grid layout is strange. The buttons and label updates are all in awkwardly shaped "spaces". My assumption is the main canvas area takes up a large portion of the frame (window?), so when other widgets are added to the grid they are placed in accordance with the larger canvas window.

Is there a way to either subset the canvas frame/window that is doing the plotting so it doesn't affect the sizes of the other widgets? Or is there a generally better way to place everything together?

Let me know if I need to clarify anything.

Thanks!

EDIT

Here is an image of the GUI. First, the main plotting canvas is in grid(row=1,col=1). When I put the buttons to the right of the figure they are in the same row=1, but now in columns 2 and 3, respectively. Since the row height is so large, the buttons are placed in the center of that row. A similar thing happens with the column width of the buttons when looking at "Ch_A" and "Ch_B" labels.

Ideally, I would like the buttons and the associated "Channel Labels" to be neatly organized around each other. Is there a best practice way to go about this?

Strip Chart

EDIT

# (c) MIT License Copyright 2014 Ronald H Longo
# Please reuse, modify or distribute freely.

from collections import OrderedDict
import tkinter as tk
from tkinter import Label, ttk


# convert rate axis label to something useful and not too large...
def ratestr(f):
    if (f >= 1e6):
        return('{:.1f} MHz'.format(f/1000000.0))
    elif (f >= 1e3):
        return('{:.1f} kHz'.format(f/1000.0))
    else:
        return('{:.1f} Hz'.format(f))

class StripChart( tk.Frame ):
   def __init__( self, parent, scale, historySize, trackColors, *args, **opts ):
      # Initialize
      super().__init__( parent, *args, **opts )
      self._trackHist   = OrderedDict() # Map: TrackName -> list of canvas objID 
      self._trackColor  = trackColors   # Map: Track Name -> color
      #Set Scaling
      self._chartHeight = scale   1
      self._chartLength = historySize * 2  # Stretch for readability
      self.max_x = self._chartLength
      self.max_y = self._chartHeight -1

      #Create main canvas
      self._canvas = tk.Canvas( self, height=self._chartHeight   50,
                                width=self._chartLength, background='black' )
      # self._canvas.grid( sticky=tk.N tk.S tk.E tk.W )
      self._canvas.grid(row=1, column=1)
      self._canvas.create_text(6,50,text="Total Counts")

      #Labeling
      self.Ch_A = Label(self)
      self.Ch_A.grid(row=0, column=2)
      self.Ch_B = Label(self)
      self.Ch_B.grid(row=0, column=3)
      self.Ch_C = Label(self)
      self.Ch_C.grid(row=0, column=4)
      self.Ch_D = Label(self)
      self.Ch_D.grid(row=0, column=5)
      self.channel_labels = [self.Ch_A, self.Ch_B, self.Ch_C, self.Ch_D]
      # _y_label.grid(row=0, column=0)
      
      # Draw horizontal to divide plot from tick labels
      x,  y  = 0, self._chartHeight   2
      x2, y2 = self._chartLength, y
      self._baseLine = self._canvas.create_line( x, y, x2, y2, fill='white' )

    # create axis labels
      self.maxy = Label(self, text=ratestr(self.max_y), font=("Arial", 15), width=8)
      self.maxy.grid(column=0,row=0)

      self.midy = Label(self, text=ratestr(self.max_y/2), font=("Arial", 15), width=8)
      self.midy.grid(column=0,row=1)


      self.midx = Label(self, text="Seconds", font=("Arial", 15), width=6)
      self.midx.grid(column=1,row=2)


      
      # Init track def and histories lists
      self._trackColor.update( { 'tick':'white', 'tickline':'white',
                                 'ticklabel':'white' } )
      for trackName in self._trackColor.keys():
         self._trackHist[ trackName ] = [ None for x in range(historySize) ]

      #Make stop button
      self.Button1 = ttk.Button(master=self, text= "Quit", command=quit)
      self.Button1.grid(row=1,column=2)
      #Collect Data Button
      self.Button2 = ttk.Button(self, text="Collect Data" )
      self.Button2.grid(row=1, column=3)

   def plotValues( self, **vals ):
      row_val = 0
      for trackName, trackHistory in self._trackHist.items():

         self._canvas.delete( trackHistory.pop(0) )# Remove left-most canvas objs
         self._canvas.move( trackName, -2, 0 )# Scroll canvas objs 2 pixels left
         # Plot the new values
         
         try:
            val = vals[ trackName ]
            x = self._chartLength
            y = self._chartHeight - val #Makes random value maxy -> y=0
            color = self._trackColor[ trackName ]
            
            objId = self._canvas.create_line( x, y, x 1, y, fill=color,
                                              width=3, tags=trackName )
            trackHistory.append( objId )
            row_val  = 1

         except:

            trackHistory.append( None )


   def makeLabels(self, **vals):
      for x, l in zip(vals,self.channel_labels): #change your for loops to this
         l.configure(text = x  ": "  str(vals[x]), fg=self._trackColor[x])
         #l['text'] = x   ": "   str(vals[x])
         # l.after(1,self.makeLabels(**vals))


   def drawTick( self, text=None, **lineOpts ):
      # draw vertical tick line
      x = self._chartLength
      y = 1
      x2 = x
      y2 = self._chartHeight
      color = self._trackColor[ 'tickline' ]
      
      objId = self._canvas.create_line( x, y, x2, y2, fill=color,
                                        tags='tick', **lineOpts )
      self._trackHist[ 'tickline' ].append( objId )
      
      # draw tick label
      if text is not None:
         x = self._chartLength
         y = self._chartHeight   10
         color = self._trackColor[ 'ticklabel' ]
         
         objId = self._canvas.create_text( x, y, text=text,
                                           fill=color, tags='tick' )
         self._trackHist[ 'ticklabel' ].append( objId )

      

   def configTrackColors( self, **trackColors ):
      # Change plotted data color
      for trackName, colorName in trackColors.items( ):
         self._canvas.itemconfigure( trackName, fill=colorName )
      
      # Change settings so future data has the new color
      self._trackColor.update( trackColors )


##########################
#
#        MAIN PROGRAM
#
##########################

if __name__ == '__main__':
   top = tk.Tk( )
   # style = ttk.Style(top)
   # style.theme_use('classic')
   scale_max = 600
   graph = StripChart( top, scale_max, 400, { 'Ch_A':'blue', 'Ch_B':'green', 'Ch_C':'red','Ch_D':'yellow' } )
   graph.grid( )
   
   val_A = 0
   val_B = 0
   val_C = 0
   val_D = 0
   delta = [ -4, -3, -2, -1, 0, 1, 2, 3, 4 ]  # randomly vary the values by one of these
   tickCount = 0
   
   def nextVal( current, lowerBound, upperBound ):
      from random import choice
      
      current  = choice( delta )
      if current < lowerBound:
         return lowerBound
      elif current > upperBound:
         return upperBound
      else:
         return current
   
   def plotNextVals( ): #Main function
      global val_A, val_B, val_C, val_D, tickCount
   
      if tickCount % 50 == 0:
         graph.drawTick( text=str(tickCount), dash=(1,4) )
         graph.makeLabels(Ch_A=val_A, Ch_B=val_B, Ch_C=val_C, Ch_D=val_D )
      tickCount  = 1
      
      val_A = nextVal( val_A, 0, scale_max )
      val_B = nextVal( val_B, 0, scale_max )
      val_C = nextVal( val_C, 0, scale_max )
      val_D = nextVal( val_D, 0, scale_max )

      graph.plotValues( Ch_A=val_A, Ch_B=val_B, Ch_C=val_C, Ch_D=val_D )
      
      changeColor = { 800: 'black',
        1200: 'yellow',
        1600: 'orange',
        2000: 'white',
        2400: 'brown',
        2800: 'blue' }
      if tickCount in changeColor:
         graph.configTrackColors( A=changeColor[tickCount] )
      
      top.after( 250, plotNextVals )#Repeats after 1000 ms

   top.after( 100, plotNextVals )
   top.mainloop( )

CodePudding user response:

If you use grid(..., sticky="N") then it moves element to top border (North)

      #Make stop button
      self.Button1 = ttk.Button(self, text= "Quit", command=quit)
      self.Button1.grid(row=1, column=2, sticky='N')
      
      #Collect Data Button
      self.Button2 = ttk.Button(self, text="Collect Data" )
      self.Button2.grid(row=1, column=3, sticky='N')

enter image description here

But buttons are in the same column as Ch_A, Ch_B so both elements in columns have the same width. You could put buttons or labels in Frame and put this frame in grid using also columnspan=4 and this frame (and buttons will not change width of labels

      self.frame_buttons = tk.Frame(self)
      self.frame_buttons.grid(row=1, column=2, sticky='N', columnspan=4)
      
      #Make stop button
      self.Button1 = ttk.Button(self.frame_buttons, text= "Quit", command=quit)
      self.Button1.grid(row=1, column=1)
      
      #Collect Data Button
      self.Button2 = ttk.Button(self.frame_buttons, text="Collect Data" )
      self.Button2.grid(row=1, column=2)

enter image description here

At this moment Ch_A, Ch_B don't depent on buttons. Because frame uses columnspan=4 so it is uses width of 4 columns and it is centered in this width. Frame doesn't use full width - there are free spaces on left and right.


If I use sticky='NEW' then frame will use full width but buttons (or rather columns) will not use this space. I added red background in frame to show it.

self.frame_buttons = tk.Frame(self, bg='red')
self.frame_buttons.grid(row=1, column=2, sticky='NEW', columnspan=4)

enter image description here


If I use .columnconfigure(..., weight=1) then I can reuse free space in existing column(s).

      self.frame_buttons = tk.Frame(self, bg='red')
      self.frame_buttons.grid(row=1, column=2, sticky='NEW', columnspan=4)
      self.frame_buttons.columnconfigure(1, weight=1)
      self.frame_buttons.columnconfigure(2, weight=1)

enter image description here

Sum of weight is 2 and first column has weight=1 so it uses 1/2 of free space and the same for second row. But I can use bigger value in weight to split free space in different way.


If I use sticky='WE' for buttons then buttons will use full size in columns. And this way button will have the same width

      self.frame_buttons = tk.Frame(self, bg='red')
      self.frame_buttons.grid(row=1, column=2, sticky='NEW', columnspan=4)
      self.frame_buttons.columnconfigure(1, weight=1)
      self.frame_buttons.columnconfigure(2, weight=1)
      
      #Make stop button
      self.Button1 = ttk.Button(self.frame_buttons, text= "Quit", command=quit)
      self.Button1.grid(row=1, column=1, sticky='WE')
      
      #Collect Data Button
      self.Button2 = ttk.Button(self.frame_buttons, text="Collect Data" )
      self.Button2.grid(row=1, column=2, sticky='WE')

enter image description here


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