Introduction

pygameZoom is an extension to pygame that allows you to zoom into drawn figures without quality loss. It can be very useful for example when you want to play around with fractals or allow player of your 2D game zoom into the screen

Installation

pip install pygameZoom

Requirements

• pygame

How it works

pygameZoom sees canvas not as pixel grid but as coordinates system.

When using pygameZoom you can declare key point's of figures by using floats.

That means you can for example declare the center of a circle at (x=20.34, y=189.798).

It also allows you to draw very small objects like a line with starting point (0,0) and ending point (0.2, 0.2). Of course, you will not see it when you are zoomed out all the way but when you start to zoom in this tiny line will slowly get bigger.

Usage

First we need to import our dependencies.

import pygame
from pygameZoom import PygameZoom

In this tutorial I will be using object-oriented programming (OOP).

The first step to using pygameZoom is declaring an instance of pygameZoom object. It should be done in the constructor. Make sure to pass width and height to pygameZoom constructor.

class Window:
    def __init__(self):
        pygame.init()
        self.WIDTH, self.HEIGHT = 1000, 800
        self.WIN = pygame.display.set_mode((self.WIDTH, self.HEIGHT))
        self.CLOCK = pygame.time.Clock()
        self.FPS = 30
        self.run = True
        self.pygameZoom = PygameZoom(self.WIDTH, self.HEIGHT)
        self.pygameZoom.set_background((255, 0, 0))
        self.loop()

You can also set background color. It's black by default.

There is an option to change zoom strength by using this line in the constructor:

self.pygameZoom.set_zoom_strength(value)

Default value is 0.05 se feel free to play around with it.

Then we write basic loop method

def loop(self):
    while self.run:
        self.refresh_window()
        self.events()
        self.CLOCK.tick(self.FPS)
    pygame.quit()
    sys.exit()

'events' method to close our window:

def events(self):
    for e in pygame.event.get():
        if e.type == pygame.QUIT:
            self.run = False

And last but not least, refresh_window method:

def refresh_window(self):
    self.WIN.fill(0)
    #Draw shapes

    #End of draw shapes section
    self.pygameZoom.render(self.WIN, (100, 100))
    pygame.display.update()

We will get back to drawing shapes later in this tutorial.

Let me explain this line of code

self.pygameZoom.render(self.WIN, (0, 0))

This line adds generated surface to main window. The second parameter are coordinates, so the main window knows where to blit generated surface.

There is an alternative way to blit generated image:

self.WIN.blit(self.pygameZoom.generate_surface(),(0,0))

But this way is not recommended because it only works when we are blitting generated surface at (0,0) coordinates and width and height of pygameZoom canvas are the same as window's width and height.

So I recommend you to always use first method, that way pygameZoom knows where it's canvas is located, and it allows you to blit generated image at any coordinates on the screen.

Disabling zooming and dragging

You can disable zooming and dragging at any given time.

#Zooming
self.pygameZoom.allow_zooming(bool)
#Dragging
self.pygameZoom.allow_dragging(bool)

Where bool is either True or False.

When False user can't use corresponding feature

Let's take a look on how to draw shapes with pygameZoom.

To draw any of shapes listed bellow ad corresponding code to draw shapes section in refresh_window.

• Line

self.pygameZoom.draw_line(color, x1, y1, x2, y2, width)

Input data:

color = color of the line (RGB).

x1 = x coordinate of starting point

y1 = y coordinate of starting point

x2 = x coordinate of ending point

y2 = y coordinate of ending point

width = width of the line (default = 1)

Example:

self.pygameZoom.draw_line((255, 255, 255), 0, 0, 200, 200)

• Rectangle

self.pygameZoom.draw_rect(color, x, y, w, h, width)

Input data:

color = color of the line (RGB).

x1 = x coordinate of starting point

y1 = y coordinate of starting point

w = Width of the rectangle

h = Height of the rectangle

width = width of the border (default = 0). If the width=0, rectangle will be filled.

Example:

self.pygameZoom.draw_rect((255, 255, 255), 100, 100, 200.123, 200,5.567)

• Circle

self.pygameZoom.draw_circle(color, x, y, r, width)

Input data:

color = color of the line (RGB).

x1 = x coordinate of the center point

y1 = y coordinate of the center point

r = radius of the circle

width = width of the border (default = 0). If the width=0, circle will be filled.

Example:

self.pygameZoom.draw_circle((255, 255, 255), 100.5, 100.5, 50.9087,90)

• Ellipse

self.pygameZoom.draw_ellipse(color, rect, width)

Input data:

color = color of the line (RGB).

rect = Tuple with 4 values. (x1,y1,r1,r2).
    x = x coordinate of the center point
    y = y coordinate of the center point
    r1 = width of the ellipse
    r2 = height of the ellipse

width = width of the border (default = 0). If the width=0, ellipse will be filled.

Example:

self.pygameZoom.draw_ellipse((255, 255, 255), (100, 400.5, 80.123, 20),0)

• Polygon

self.pygameZoom.draw_polygon(color, points, width)

Input data:

color = color of the line (RGB).

points = array with tuples of 2. First value in each tuple is a x coordinate of the point. Second values is the y coordinate

width = width of the border (default = 0). If the width=0, ellipse will be filled.

Example:

self.pygameZoom.draw_polygon((255, 255, 255), [(0.653, 789.234), (100,100), (345, 890.2)],0)

Blitting images in pygameZoom

To blit an image add this line to draw shapes section:

image = pygame.image.load("image.jpg")
self.pygameZoom.blit(image, (x, y))

x and y are the coordinates of the top right corner.

Remember!!! When you zoom into blitted image, this image will slowly lose quality. Zooming without quality loss work only with shapes.

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Following a point

pygameZoom has a feature to follow any given point on canvas, it's useful for example when you want to zoom into moving object in your game.

self.pygameZoom.follow_point(x,y,zoom)

Where (x,y) are coordinates of followed point.

zoom - zoom while following

I recommend you to disable zooming and dragging while using this feature, because it gets buggy when user tries to zoom or drag while this feature is on

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Great se we finished writing our class. Don't forget to make an instance of Window class.

win = Window()

Thanks for using pygameZoom <3