PIL draw.text() MUCH slower than display.text()

[ThomasBurgess2000]

I'm writing a script that updates the screen with every keypress, which I am able to do using PIL on the 128x32 OLED but is far too slow on this display.

I want to use this:

draw.text((x, top+0), copy_of_output[:first_line], font=font, fill=black)
draw.text((x, top+(line_height)), copy_of_output[first_line:second_line], font=font, fill=black)
draw.text((x, top+(line_height)*2), copy_of_output[second_line:], font=font, fill=black)
disp.image(image)
disp.show()

but it is SUPER slow (~1 sec lag between keypresses). This, on the other hand, is way faster with almost no discernible lag:

disp.text(copy_of_output[:first_line], x, top+0, 0, size=FONTSIZE)
disp.text(copy_of_output[first_line:second_line], x, top+(line_height), 0, size=FONTSIZE)
disp.text(copy_of_output[second_line:], x, top+(line_height)*2, 0, size=FONTSIZE)
disp.show()

But I cannot use all the benefits of PIL, like choosing font. Is there a way to optimize PIL to run faster on this display?

[makermelissa]

Hi, this library is for the Sharp Memory display which is only available in 400x240 and 168x144. I'd like to address the issue, but want to make sure you're using the correct library with the correct display first.

[ThomasBurgess2000]

Hi Melissa, yes, I am using the 400x240 display. I just referred to the 128x32 OLED to show that I have been able to get this code to work quickly on a different device, so that it is clear the difference in speed is the device and not merely unoptimized code.

[ThomasBurgess2000]

Here is the whole of the code that is acting super slow:

import time
import subprocess
import board
import busio
import digitalio
from PIL import Image, ImageDraw, ImageFont

import keyboard
import string
import curses

# 400x240 Sharp Memory disp
import adafruit_sharpmemorydisplay
spi = busio.SPI(board.SCK, MOSI=board.MOSI)
scs = digitalio.DigitalInOut(board.D6)
disp = adafruit_sharpmemorydisplay.SharpMemoryDisplay(spi, scs, 400, 240)
disp.fill(1)
disp.show()
FONTSIZE = 42
#font = ImageFont.truetype("usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", FONTSIZE)
font = ImageFont.truetype("RobotoMono.ttf", FONTSIZE)

# Make sure to create image with mode '1' for 1-bit color.
width = disp.width
height = disp.height
BLACK = 0
WHITE = 255

# Splash screen (removed until get image with correct dimensions)
# image = Image.open(r'piskel.png')
# image = image.convert('1')
# disp.image(image)
# disp.show()
# time.sleep(3)

image = Image.new('1', (width, height))

# Get drawing object to draw on image.
draw = ImageDraw.Draw(image)
draw.rectangle((0, 0, width, height), outline=WHITE, fill=WHITE)
# Draw some shapes.
# First define some constants to allow easy resizing of shapes.
padding = -2
top = padding
bottom = height-padding
# Move left to right keeping track of the current x position for drawing shapes.
x = 0

#The version of the string that is saved to file
outputstring = ""
#The version of the string that is disped
copy_of_output = ""
black = "black"
white = "white"
#FUNCTIONS

modifier = 0
every_21 = 0

location_x = 0

first_line = 16
second_line = 32
third_line = 48
fourth_line = 64
fifth_line = 80
sixth_line = 96
line_height = 35

def main(stdscr):
    #stdscr.nodelay(True)
    print("disp output: " + copy_of_output + "\n")
    print("Saved output: " + outputstring + "\n")
    return stdscr.getch()

def fontchooser():
    return ("Nothing")

def linewriter(copy_of_output,string_adj_len):

    if string_adj_len <= first_line:
        draw.text((x, top+0), copy_of_output, font=font, fill=black)
    elif string_adj_len <= second_line:
        draw.text((x, top+0), copy_of_output[:first_line], font=font, fill=black)
        draw.text((x, top+(line_height)), copy_of_output[first_line:], font=font, fill=black)
    elif string_adj_len <= third_line:
        draw.text((x, top+0), copy_of_output[:first_line], font=font, fill=black)
        draw.text((x, top+(line_height)), copy_of_output[first_line:second_line], font=font, fill=black)
        draw.text((x, top+(line_height)*2), copy_of_output[second_line:], font=font, fill=black)
    # Changes distance from top to prevent last line from going off of screen
    elif string_adj_len <= fourth_line:
        draw.text((x, top+0), copy_of_output[:first_line], font=font, fill=black)
        draw.text((x, top+(line_height)), copy_of_output[first_line:second_line], font=font, fill=black)
        draw.text((x, top+(line_height)*2), copy_of_output[second_line:third_line], font=font, fill=black)
        draw.text((x, top+(line_height)*3), copy_of_output[third_line:], font=font, fill=black)
    elif string_adj_len <= fifth_line:
        draw.text((x, top+0), copy_of_output[:first_line], font=font, fill=black)
        draw.text((x, top+(line_height)), copy_of_output[first_line:second_line], font=font, fill=black)
        draw.text((x, top+(line_height)*2), copy_of_output[second_line:third_line], font=font, fill=black)
        draw.text((x, top+(line_height)*3), copy_of_output[third_line:fourth_line], font=font, fill=black)
        draw.text((x, top+(line_height)*4), copy_of_output[fourth_line:], font=font, fill=black)
    elif string_adj_len <= sixth_line:
        draw.text((x, top+0), copy_of_output[:first_line], font=font, fill=black)
        draw.text((x, top+(line_height)), copy_of_output[first_line:second_line], font=font, fill=black)
        draw.text((x, top+(line_height)*2), copy_of_output[second_line:third_line], font=font, fill=black)
        draw.text((x, top+(line_height)*3), copy_of_output[third_line:fourth_line], font=font, fill=black)
        draw.text((x, top+(line_height)*4), copy_of_output[fourth_line:fifth_line], font=font, fill=black)
        draw.text((x, top+(line_height)*5), copy_of_output[fifth_line:], font=font, fill=black)

while True:
    # This is the section that logs keypresses for the whole running of the program...might need to move it to a separate section though if line_writer becomes its own "app"
    keypress = curses.wrapper(main)
    #print ("key:", keypress)
    if (keypress == curses.KEY_ENTER or keypress == 10 or keypress == 13):
        outputstring = outputstring + "\n"
        if len(copy_of_output) <= first_line:
            modifier = first_line - len(copy_of_output)
        else:
            modifier = first_line - (len(copy_of_output)%first_line)
        i = 0
        while i < modifier:
            copy_of_output = copy_of_output + " "
            print (i)
            i += 1
    elif (keypress <= 255 and keypress >= 0):
        outputstring = outputstring + chr(keypress)
        copy_of_output = copy_of_output + chr(keypress)
    elif (keypress == 256 or keypress == curses.KEY_BACKSPACE):
        outputstring = outputstring[:-1]
        copy_of_output = copy_of_output[:-1]
        if ((len(copy_of_output)//first_line-1) - (len(copy_of_output) % first_line-1)) == 1:
            copy_of_output = copy_of_output.rstrip()
    draw.rectangle((0,0,width,height),outline=0,fill=white)
    if (len(copy_of_output)>sixth_line):
        copy_of_output = copy_of_output[first_line:]
    linewriter(copy_of_output,len(copy_of_output))
    disp.image(image)
    disp.show()

Again, by replacing any PIL functions like draw.text() with driver functions like disp.text() it runs with a nearly sub-10ms response time, but by using the PIL functions it can take about a second to draw each character.

[makermelissa]

Thanks for that. I think that should be enough information to reproduce.

[sparkster98]

I too am having trouble with Pils ImageDraw.Draw ... .text. Im getting a 4ms lag in python on a completely different type of project. As in, its the Pil module itself. Ill be investing a work around.

[makermelissa]

Pillow must have fixed the issue because the problematic code is running fine.