I can't display images longer (height) than about 30612 pixels high. I've read that there is a maximum height to canvas. I'd like to get the source file and extend that to 90 or 100k pixels in height. Conversely, I've seen suggested that a canvas may be buffered, if this is true, I have no clue how to implement it.. Any help is appreciated!
I am using code I found off Stack that is supposed to deal with large images, it does alright, but ultimately hit's the cavas height limit.
Canvas Limit
from tkinter import *
from PIL import ImageTk
from PIL import *
Image.MAX_IMAGE_PIXELS = None
class ScrolledCanvas(Frame):
def __init__(self, parent=None):
Frame.__init__(self, parent)
self.master.title("Spectrogram Viewer")
self.pack(expand=YES, fill=BOTH)
canv = Canvas(self, relief=SUNKEN)
canv.config(width=400, height=500)
# canv.config(scrollregion=(0,0,1000, 1000))
# canv.configure(scrollregion=canv.bbox('all'))
canv.config(highlightthickness=0)
sbarV = Scrollbar(self, orient=VERTICAL)
sbarH = Scrollbar(self, orient=HORIZONTAL)
sbarV.config(command=canv.yview)
sbarH.config(command=canv.xview)
canv.config(yscrollcommand=sbarV.set)
canv.config(xscrollcommand=sbarH.set)
sbarV.pack(side=RIGHT, fill=Y)
sbarH.pack(side=BOTTOM, fill=X)
canv.pack(side=LEFT, expand=YES, fill=BOTH)
self.im = Image.open("Test_3.tif")
width, height = self.im.size
canv.config(scrollregion=(0, 0, width, height))
self.im2 = ImageTk.PhotoImage(self.im)
self.imgtag = canv.create_image(0, 0, anchor="nw", image=self.im2)
ScrolledCanvas().mainloop()
I tried to put together a bigger image from displays of a grid of canvases. This looks like it might work, at least if you just want to display a big image. I have just tested with a small image and not paid any attention to memory or speed or anything...
from tkinter import *
from scrframe import VerticalScrolledFrame
root = Tk()
tiles = VerticalScrolledFrame(root) # Scrolled frame
tiles.grid()
tw = 90 # Tile width
th = 110 # Tile height
rows = 4 # Number of tiles/row
cols = 4 # Number of tiles/column
tile_list = [] # List of image tiles
img = PhotoImage(file='pilner.png')
for r in range(rows):
col_list = []
for c in range(cols):
tile = Canvas(tiles.interior, highlightthickness=0, bg='tan1',
width=tw, height=th)
tile.create_image(-c*tw, -r*th, image=img, anchor ='nw')
tile.grid(row=r, column=c)
col_list.append(tile)
tile_list.append(col_list)
root.mainloop()
Now, scrolling a frame seems to raise some problems, but there also seems to be solutions. I tried to use VerticalScrolledFrame as described in Python Tkinter scrollbar for frame and it works fine. As it only provides for a vertical scrollbar you'd have to implement horizontal scrollbar yourself. Maybe a few additional functions as scrolling with the mouse wheel, keyboard shortcuts or other would be useful.
I got the VerticalScrolledFrame from TKinter scrollable frame and modified it for Python 3.
This is the code I've come up with from several sources - Thanks to figbeam for all the help. Also, this is not pretty!!!! The button shows up in the center of the Tkinter window. If you'd like to modify this, please do.
from tkinter import *
from PIL import ImageTk as itk
from PIL import Image
import math
import numpy as np
Image.MAX_IMAGE_PIXELS = None #prevents the "photo bomb" warning from popping up. Have to have this for really large images.
#----------------------------------------------------------------------
# makes a simple window with a button right in the middle that let's you go "down" an image.
class MainWindow():
#----------------
def __init__(self, main):
# canvas for image
_, th, tw, rows, cols = self.getrowsandcols()
self.canvas = Canvas(main, width=tw, height=th)
self.canvas.grid(row=0, column=0)
# images
self.my_images = self.cropimages() # crop the really large image down into several smaller images and append to this list
self.my_image_number = 0 #
# set first image on canvas
self.image_on_canvas = self.canvas.create_image(0, 0, anchor = NW, image = self.my_images[self.my_image_number])
# button to change image
self.button = Button(main, text="DOWN", command=self.onDownButton)
self.button.grid(row=0, column=0)
#----------------
def getimage(self):
im = Image.open("Test_3.png") # import the image
im = im.convert("RGBA") # convert the image to color including the alpha channel (which is the transparency best I understand)
width, height = im.size # get the width and height
return width, height, im # return relevent variables/objects
def getrowsandcols(self):
width, height, im = self.getimage()
im = np.asarray(im) # Convert image to Numpy Array
tw = width # Tile width will equal the width of the image
th = int(math.ceil(height / 100)) # Tile height
rows = int(math.ceil(height / th)) # Number of tiles/row
cols = int(math.ceil(width / tw)) # Number of tiles/column
return im, th, tw, rows, cols #return selected variables
def cropimages(self):
self.my_images = [] # initialize list to hold Tkinter "PhotoImage objects"
im, th, tw, rows, cols = self.getrowsandcols() # pull in needed variables to crop the really long image
for r in range(rows): # loop row by row to crop all of the image
crop_im =im[r * th:((r * th) + th), 0:tw] # crop the image for the current row (r). (th) stands for tile height.
crop_im = Image.fromarray(crop_im) # convert the image from an Numpy Array to a PIL image.
crop_im = itk.PhotoImage(crop_im) # convert the PIL image to a Tkinter Photo Object (whatever that is)
self.my_images.append(crop_im) # Append the photo object to the list
crop_im = None
return self.my_images
def onDownButton(self):
# next image
self.my_image_number += 1 #every button pressed will
# return to first image
if self.my_image_number == len(self.my_images):
self.my_image_number = 0
# change image
self.canvas.itemconfig(self.image_on_canvas, image = self.my_images[self.my_image_number]) #attaches the image from the image list to the canvas
#----------------------------------------------------------------------
root = Tk()
MainWindow(root)
root.mainloop()
