How to Think Like a Computer Scientist: Learning with Python 2nd Edition/GASP

Graphics API for Students of Python: GASP

Introduction

Describe gasp here...

(0, 0) is at the bottom left of the window. The window is 640 pixels by 480, by default. (You can make it a different size if you want to.) Coordinates are given in units of one pixel.

All functions that take coordinates take them as a tuple (x, y).

Colors

To access the color module GASP has to offer. Call color.* where * is the color you wish to call. For example: ` color.BLACK ` This is the color black. Check out the gasp color refrence chart to see all of the available color options.

The Essentials

These are the essentials. ` from gasp import * ` imports the gasp module, begin_graphics() starts the graphics window, and end_graphics() quits the graphics window and ends the program. It's dead simple, but also dead necessary.

Graphics Functions

begin_graphics()

This creates a graphics window with the dimensions 800x600, a title of My Game , and a background color of yellow. With no arguments you get a white 640x480 graphics window titled Gasp .

width

The width of the window in pixels.

height

The windows height in pixels.

title

A string that will be the title of the window.

background

It is the background of the graphics window. It can either be a color or an image

end_graphics()

Ends a graphics window.

clear_screen()

Clears everything off of the graphics window. It looks like a new graphcs window as if you just called begin_graphics().

remove_from_screen()

removes those objects from the screen

obj

A screen object of a list of screen_objects you would like to remove from the screen

Screen Objects

The objects that you will be displayed in your graphics window. You can manipulate these objects using the screen object methods

Plot

It puts a dot on the screen.

pos

The coordinate on the screen that you wish to plot.

color

The color you wish the dot to be.

size

An integer that determines the size the of the dot

Line

Creates a line on the screen.

start

The starting coordinate of the line.

end

The coordinate at which the line will end.

color

The color of the line

Box

This creates a Box on the screen

center

A coordinate where the center of your box will be.

width

The width in pixels of the box.

height

The height of the box in pixels.

filled

A boolean value that determines if your box will be filled

color

The color of your box.

thickness

The thickness in pixels of your box's lines.

Polygon

Creates a polygon on the screen

points

A list of coordinates that is each point on the polygon. The must be more than two items in the list

filled

A boolean value. If it is False the polygon will not be filled. Else, the polygon will not be filled

color

The color of the polygon's lines

thickness

An integer that determines the thickness of the lines.

Circle

Draws a circle, its center is a set of coordinates, and the radius is in pixels. It defaults to not being filled and the color black.

center

The circle's center coordinate.

width

An integer that is the radius of the circle

filled

A boolean value that determines if your circle will be filled

color

The color of your circle.

thickness

The thickness in pixels of the circles lines.

Arc

Creates an arc on the screen.

center

A coordinate that is the center of the arc.

radius

An integer that is the distance between the center and the outer edge of the arc.

start_angle

The start angle in degrees of the arc

end_angle

The end angle in degrees of your arc

filled

A boolean value that if True it fills the arc

color

The color the arc

thickness

The thickness in pixels of the arc

Oval

Puts an oval on the screen wherever you want.

center

The center coordinate of the Oval

width

The width in pixels of the oval

height

The height of the oval in pixels

filled

A boolean value determining if the oval will be filles or not.

color

The oval's color

thickness

The thickness of the ovals lines

Image

Loads an image onto the screen. If you only pass a width and not a height it automatically scales the height to fit the width you passed it. It behaves likewise when you pass just a height.

file_path

The path to the image

center

The center coordinates of the image

width

The width of the image in pixels. If width equals None then it defaults to the image file's width

height

The height of the image in pixels. If no height is passed it defaults to the image file's height

Screen Object Methods

The methods that manipulates screen objects

move_to()

Move a screen object to a pos

obj

A screen object you wish to move.

pos

The coordinate on the screen that the object will move to

move_by()

Move a screen object relative to it's position

obj

The screen object you wish to move

dx

How much the object will move in the 'x' direction. Positive or negative.

dy

How much the object will move in the 'y' direction. A pixel value.

rotate_to()

Rotate an object to an angle

obj

The screen object that will be rotated

angle

The angle in degrees that the object will be rotated to

rotate_by()

Rotate an object a certain degree.

obj

The screen object you wish to rotate

angle

The degree that the object will be rotate. Can be positive or negative.

Text

Text()

Puts text on the screen

text

A string of the text that will be displayed

pos

The center coordinate of the text

color

The color of the text

size

The font size

Mouse

mouse_position()

Returns the current mouse coordinate

mouse_buttons()

returns a dictionary of the buttons state. There is a 'left', 'middle', and 'right' key.

Keyboard

keys_pressed()

returns a list of all of the keys pressed at that moment.

Gasp Tools

screen_shot

Saves a screenshot of the current graphics screen to a png file.

filename

The file path relative to the current directory that the image will be written to.