In Python, how can I draw to a pixel on the screen directly?

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I'm wanting to do something like the following:

...
pixel[0,0] = [ 254, 0, 0 ] # Draw R at pixel x0y0
pixel[2,1] = [ 0, 254, 0 ] # Draw G at pixel x2y1
pixel[4,2] = [ 0, 0, 254 ] # Draw B at pixel x4y2
...

I hope to display many different configurations of pixels and colours in a short space of time -- writing to an intermediary file would be too expensive.

How should I best go about achieving this goal in Python?

Direct answer:

This can only be done with OS-specific APIs. Some OSes does not allow changing pixels on the screen directly.

On Windows, you can use pywin32 libraries to get screen's device context with dc = GetDC(0) call, then paint pixels with SetPixel(dc, x, y, color).

import win32gui
import win32api

dc = win32gui.GetDC(0)
red = win32api.RGB(255, 0, 0)
win32gui.SetPixel(dc, 0, 0, red)  # draw red at 0,0

Of course, what you paint this way can be erased at any moment.

Right answer:

Painting pixel by pixel is the slowest way to paint something. For example, on Windows, creating an image in memory then painting it in one operation is order of magnitude faster than painting with SetPixel.

If you need speed, use some user interface library for python, for example, Tkinter module or PyQt. Create a window and image in memory, then paint the image on the window. If you need to manipulate pixels, manipulate them in the image and repaint every time.

I have Python and I want to draw graphics at the pixel-by-pixel level , A pixel is the smallest little square that can by displayed on your screen. A Point object, like each of the graphical objects that can be drawn on a GraphWin , has a method [1] draw . Return to the directory window for the Python examples​. Nevertheless, from time to time, we do want to break out of our mundane shape drawing existence and deal with the pixels on the screen directly. Processing provides this functionality via the pixels array. We are familiar with the idea of each pixel on the screen having an X and Y position in a two dimensional window.

Im not sure if I get your question right, but I believe you should investigate some framework or middleware that give you an access to screen. I would say PyGame or Pyglet or maybe even Panda. It may be overkill a bit because Pygame and Panda is a framework that let you develop game while Pyglet is wrapper to Opengl in python, but it will let you control pixels, windows and similar with easy.

2.4. Graphics, Create a window and draw a pixel in it, subject to the following: the window is 320 x szMessErrGc: .asciz "Can not create graphics context.\n" For instance: Multi-dimensional Lists? Sometimes you need more than on dimension to a list. In Python you can achieve this by creating a list of lists! For instance for our pixel art project we want to store each pixel on a line within a list: e.g.: We can then store all these lines into a list.

Although it does not exactely what you say (paint "by pixel"), I like to use Python, GTK and Cairo.

In this case, you create a GTK Window, add a DrawingArea, create a Cairo context, and do paint operations.

The difference is that you have a continuous canvas with floating-point coordinates, and instead of pixels you draw geometric shapes with strokes and fills. You could even draw rectangles one-pixel-sized, and fill them, but that would not be so fast.

Also, you can take any raster object (image, pixbuffer) and render it at once. Then you could generate images in a fast sequence, and render its pixels all at once, similar to a movie.

A working example can be seen in a previous answer here (second snippet): quickest way to get started with cairo

Draw a pixel, 15 pixels in the direction it is facing, drawing a line as it moves. This function should be used when turtle is used as a standalone tool for doing graphics. All methods of TurtleScreen/Screen also exist as functions, i.e. as part of the There can be a turtle.cfg file in the directory where turtle is stored and an additional one​  line () draws a straight line connecting each point, polygon () draws a polygon where each point is connected, and point () draws a point of 1 pixel at each point.

I recommend you the Pygame library. It is a cross-platform library well suited for general computer graphics, and game development. Check here some examples of Pygame in action.

The library is pretty simple yet powerful. You can draw in a Window, and in fullscreen as well.

turtle — Turtle graphics, Before we deal with the details of the animation, we need to increment the bodysize we created the illusion of a moving object by drawing the ball on the screen, then This is particularly inefficient - every pixel on the screen has to be updated rectangles straight onto the screen, leaving the remaining pixels unchanged. I'd like to get down and dirty with the pixels. Basically, I want this: screen = somegraphicslib.Screen() screen.draw_pixel( x=1, y=2, rgb=(10,10,10) ) # a bunch more pixel magic screen.refresh() That's it. Make screen. Place pixels. Paint screen. GOTO 10. I realise that this is a very caveman-esque feature set, but I'd appreciate any help you

Python for Rookies: A First Course in Programming, When you create an image on the display, you should cover the entire screen; If you don't draw over every pixel, you will get an unpleasant strobing effect  def drawPoint(x,y,color): s = pygame.Surface((1,1)) # the object surface 1 x 1 pixel (a point!) s.fill(color) # color as (r,g,b); e.g. (100,20,30) # now get an object 'rectangle' from the object surface and place it at position x,y r,r.x,r.y = s.get_rect(),x,y screen.blit(s,r) # link the object rectangle to the object surface

Beginning Game Development with Python and Pygame: From Novice to , It is rarely necessary to draw pixels one at a time because there are more you run Listing 4-7 you will see the screen slowly fill up with random-colored dots;  PImage img; // Declare a variable of type PImage void setup() { size(320,240); // Make a new instance of a PImage by loading an image file img = loadImage("mysummervacation.jpg"); } void draw() { background(0); // Draw the image to the screen at coordinate (0,0) image(img,0,0); }

Beginning Python Games Development, Second Edition: With PyGame, This tutorial is for Processing's Python Mode. Loading images in draw() may result in slow performance as well as "Out of Memory" errors. We are familiar with the idea of each pixel on the screen having an X and Y position in a two pixel from a source image and written a new pixel to the Processing window directly. The main idea behind the solution is GetPixel from screen is slow, and you can't fix that. But as you need some pixels, you can get a bunch of them all at once. The time that it took to get 64 pixels was 98 times faster.

Comments
  • You generally don't want to write to "the screen", you want to write to a window. Python doesn't include any built-in packages for interacting with a window, you'll need to choose and install something.
  • @MarkRansom - Right. A borderless window would also be acceptable.
  • If you knew how to to this writing to file, you can write to memory using cStringIO, although I don't think that's the case.
  • @Mark Ransom: With tkinter, you can create and display windows. Built-in.
  • Related: How to display text on the screen without a window using Python
  • Do you know how to do the same on ubuntu?
  • How can I undo a pixel drawn using win32gui.SetPixel ?
  • Some people also like to play around with things, not caring if there already exists a library that will do it 100 times faster.