Drawing a polygon in pygame [duplicate] - python

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Drawing polygons in pygame using list
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Closed last month.
i am jaison i like to build an application for land survey process. for that i need to plot points in a canvas for a given gsi file. for example
the points be
a. .b
c. .d .e
these are the 5 points and i need to develop a tool to connect these points by line. while closing a boundry by like connecting points acdba. give it a parcel_id and other details like land owner, tax payment etc. save these details for feature query.
in real time the points will be more than 100000. and i need the canvas should have pan and zoom property.
friends i like to do this project in python using pygame. is it possible to do.
i am a newbie to python.
please need help.

Pygame is absolutely a good tool for this.
Look into using a pygame.surface object, and the pygame.draw module.
http://www.pygame.org/docs/ref/
If you need anything more complicated than dots, pygame.sprite is a relatively well developed module as well.

http://www.pygame.org/docs/ref/draw.html#pygame.draw.polygon
This is the function for drawing polygons in pygame. You can draw straight to screen or to a separate surface. I am not sure how fast it is with lots of points, you might want to split up what your drawing into smaller segments and just display what you need.
If you do need to show the whole polygon I would look into some way of compressing the amount of points to only get the general shape

Related

Simple animation in Python using wxPython objects

I'm writing a gravity simulator in Python 2.7 and at the moment I finished the mathematical part. I'm trying to find a way to display the results while the simulation is running, it should consist of some colored circles representing the various bodies and optionally some curved lines to represent orbits, that can be shown or hidden while the simulation is running.
I pictured a way to obtain this result, but I can't seem to find a way to even start.
My idea is to use wxPython. The window should be divided into four sectors (2x2), the first three contain the simulation viewed in the XY, XZ and YZ planes, while the last contains the controls (start/stop simulation, show/hide orbits, ...).
The controls should not be a problem, I just need a way to display the animation. So how can I display moving circles and curved lines using wxPython objects? Which objects should I use? I don't need much more than a couple names, the rest should follow easily.
I know that an animation purely with wxPython will probably require some multithreading, I'm already prepared for that. I also want to stress that I need the animation to be shown while the simulation is running, not after, because the simulation has no definite end at the moment: I don't know when to stop it if I don't see the results first.
If it's somehow useful, I'm using Ubuntu Linux 17.10.
Edit: Since I was asked to choose one approach, I discarded Matplotlib because it requires two different windows. Hope this helps.

Simple animations in Python 2.7 [duplicate]

This question already has answers here:
simple animation using tkinter
(2 answers)
Closed 6 years ago.
In Python 2.7, I want to display some simple graphics, such as a red square moving around on a blue window. On every frame, I want to update the position of the square, and render the new window. I am looking for something simple and lightweight.
I have seen people use matplotlib for drawing shapes, but I don't want to have to deal with axes and data points. I have also seen pygame suggested, but this seems to heavyweight for what I want, as I do not want to create a game, just a simple animation.
So what I really want is something where on every frame, I just indicate the colour of every pixel on an image, and then display that image. What are some good suggestions?
Tkinter is not good for setting individual pixels. If you want to move rectangles or ovals though (a small oval will look like a pixel, but it doesn't scale for updating a whole image).
def update(x,y):
canvas.delete('all')
canvas.create_rectangle(x-1,y-1,x+1,y+1)
You can, of course, be more judicious, saving the return value of the rectangle and then only clear the appropriate elements. Or you can move existing elements directly as Bryan points out. As he explains elsewhere Tkinter of course, supports drawing images, ovals, and a slew of other things. Here's a canonical source edit: that is old and not canoncial This one's slightly better For a general source on animating with a timer loop, here's Bryan agian
Bryan also noted that you can work with pixels directly You can do that with PhotoImage.
Array-Like Pixel Access Without Graphical Extensions
A robust module like pygame will be the most scalable option. However, I've had success (in educational settings only) writing graphics engines by modifying the elements of a numpy array and then displaying it as an image (you also need this link to display the images).
This lets you do pixel level modifications; since it's relatively trivial to write C-extensions that modify numpy arrays, you can prototype fast image processing doing custom manipulations. While I've written whole graphics engines using just tkinter this way, again I can only reccomend it for educational purposes.
Otherwise, just bite the bullet and pull in openGl or pygame. You'll save yourself a ton of time in the long run.
Summary
Very simple animations can be done right in tkinter
For educational purposes, you can do arbitrary graphics with numpy and tkinter
For rhobust animations, check out a full library (openGl, matplotlib, pygame) that suits your needs (graphical rendering, statistical graphing, game development, etc.)

How to create a flood fill figure animation using python?

How to create flood fill figure animation using python?
I saw this image online and was wondering how to go about these types of animation. I think this is a very useful technique that can be used in maps, presentations, etc and was curious about it.
The image:
http://i.imgur.com/zaSxkLI.gif
I Researched these questions:
Flood Fill in Python
How to flood-fill part of a bitmap enclosed by a black border with my chosen color?
Python: floodfill algorithm for minesweeper
Flood Fill Algorithm Python
Looked at this resource:
http://inventwithpython.com/blog/2011/08/11/recursion-explained-with-the-flood-fill-algorithm-and-zombies-and-cats/
Questions:
Can you point me to working code that does this type of exercise?
Which libraries are considered standard to use now?
How does the logic behind the fill exercise work?
Can you point me to more information/resources (maybe the docs for the libraries)
How could I integrate this concept with matplotlib? Can you point me to an example?
Thank you so much!

2D Game Engine - Implementing a Camera

So I've been making a game using Python, specifically the PyGame module. Everything has been going fairly well (except Python's speed, am I right :P), and I've got a nice list of accomplishments from this, but I just ran into a... speedbump. Maybe a mountain. I'm not to sure yet. The problem is:
How do I go about implementing a Camera with my current engine?
That probably means nothing to you, though, so let me explain what my current engine is doing: I have a spritesheet that I use for all images. The map is made up of a double array of Tile objects, which fills up the display (800 x 640). The map also contains references to all Entity's and Particles. So now I want to create a a camera, so that the map object can be Larger than the display. To do this I've devised that I'll need some kind of camera that follows the player (with the player at the center of the screen). I've seen this implemented before in games, and even read a few other similar posts, but I need to also know Will I have to restructure all game code to work this in? My first attempt was to make all object move on the screen when the player moves, but I feel that there is a better way to do this, as this screws up collision detection and such.
So, if anyone knows any good references to problems like this, or a way to fix it, I'm all ears... er.. eyes.
Thanks
You may find this link to be of interest.
In essence, what you need to do is to distinguish between the "actual" coordinates, and the "display" coordinates of each object.
What you would do is do the bulk of the work using the actual coordinates of each entity in your game. If it helps, imagine that you have a gigantic screen that can show everything at once, and calculate everything as normal. It might help if you also designed the camera to be an entity, so that you can update the position of your camera just like any other object.
Once everything is updated, you go to the camera object, and determine what tiles, objects, particles, etc. are visible within the window, and convert their actual, world coordinates to the pixel coordinates you need to display them correctly.
If this is done correctly, you can also do things like scale and otherwise modify the image your camera is displaying without affecting gameplay.
In essence, you want to have a very clear distinction between gameplay and physics logic/code, and your rendering/display code, so your game can do whatever it wants, and you can render it however you want, with minimal crossover between the two.
So the good news is, you probably don't need to change anything about how your game itself works. The bad news is, you'll probably have to go in and rewrite your rendering/drawing code so that everything is drawn relative to the camera, not to the world.
Since I can't have a look into your code, I can't assess how useful this answer will be for you.
My approach for side scroller, moveable maps, etc. is to blit all tiles onto a pygame.Surface spanning the dimensions of the whole level/map/ etc. or at least a big chunk of it. This way I have to blit only one surface per frame which is already prepared.
For collision detection I keep the x/y values (not the entire rect) of the tiles involved in a separate list. Updating is then mainly shifting numbers around and not surfaces anymore.
Feel free to ask for more details, if you deem it useful :)

How to read pixel colours using Python turtle.py

I'm preparing exercises for school classes involving Python's turtle library.
The students are already drawing terrific pictures, but I want them to be able to detect existing pictures and colours in order to modify the behaviour of their program.
For example I would like to provide them with code which draws a maze using turtle, and then they can write the code to navigate the turtle around the maze (don't worry, I'll start simpler).
Is there a way to detect the colour of the pixels already drawn by the turtle?
Thanks!
Turtle uses Tkinter canvas, which you can get using turtle.getcanvas(), and according to this you cannot read the colour of a pixel without using a workaround of converting the canvas to a picture (bitmap) and read the bitmap.
You could try to keep an open array to work as the bitmap of your canvas and update it yourself as you draw new elements on the canvas, although that seems impractical unless the maze is simple and 'squary'.
I would use an array keep all x and y that is used for the maze in an array like stated above. Then have a size of a box around the turtle defined for detecting purposes.

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