p5

package module
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 Go to latest Published: Oct 21, 2022 License: BSD-3-Clause Imports: 34 Imported by: 0

README

p5

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p5 is a simple package that provides primitives resembling the ones exposed by the p5/processing library.

License

p5 is released under the BSD-3 license.

Documentation

Documentation for p5 is served by GoDev.

Contributing

Guidelines for contributing to go-p5 the same than for the Go project.

Installation

This project relies on Gio for the graphics parts. As Gio uses system libraries to display graphics, you need to install those for your system/OS for p5 to work properly. See Gio/install for details.

Example

package main

import (
	"image/color"
	"math"

	"github.com/go-p5/p5"
)

func main() {
	p5.Run(setup, draw)
}

func setup() {
	p5.Canvas(400, 400)
	p5.Background(color.Gray{Y: 220})
}

func draw() {
	p5.StrokeWidth(2)
	p5.Fill(color.RGBA{R: 255, A: 208})
	p5.Ellipse(50, 50, 80, 80)

	p5.Fill(color.RGBA{B: 255, A: 208})
	p5.Quad(50, 50, 80, 50, 80, 120, 60, 120)

	p5.Fill(color.RGBA{G: 255, A: 208})
	p5.Rect(200, 200, 50, 100)

	p5.Fill(color.RGBA{G: 255, A: 208})
	p5.Triangle(100, 100, 120, 120, 80, 120)

	p5.TextSize(24)
	p5.Text("Hello, World!", 10, 300)

	p5.Stroke(color.Black)
	p5.StrokeWidth(5)
	p5.Arc(300, 100, 80, 20, 0, 1.5*math.Pi)
}

img-hello

Documentation

Overview

Package p5 provides types and functions to draw geometrical shapes on a canvas, interact with the mouse and keyboard, with the aim to learn programming with a graphics aid.

p5 is inspired by Processing and its p5js port:

A very simple p5 program could look like: 

func main() {
    p5.Run(setup, draw)
}

func setup() {
    p5.Canvas(200, 200)
    p5.Background(color.Black)
}

func draw() {
    p5.Fill(color.White)
    p5.Square(10, 10, 50, 50)
}

p5 actually provides two set of APIs:

  • one closely following the p5js API, with global functions and hidden state,
  • another one based on the p5.Proc type that encapsulates state.

Index

Constants

This section is empty.

Variables

View Source 
var Event struct {
	Mouse struct {
		Pressed      bool
		PrevPosition struct {
			X float64
			Y float64
		}
		Position struct {
			X float64
			Y float64
		}
		Buttons Buttons
	}
}

Event is the current event pushed from the system.

Functions

func Arc 

func Arc(x, y, w, h float64, beg, end float64)

Arc draws an ellipsoidal arc centered at (x,y), with the provided width and height, and a path from the beg to end radians. Positive angles denote a counter-clockwise path.

func Background 

func Background(c color.Color)

Background defines the background color for the painting area. The default color is transparent.

func Bezier 

func Bezier(x1, y1, x2, y2, x3, y3, x4, y4 float64)

Bezier draws a cubic Bézier curve from (x1,y1) to (x4,y4) and two control points (x2,y2) and (x3,y3).

func Canvas 

func Canvas(w, h int)

Canvas defines the dimensions of the painting area, in pixels.

func Circle 

func Circle(x, y, d float64)

Circle draws a circle at (x,y) with a diameter d.

func Curve 

func Curve(x1, y1, x2, y2, x3, y3, x4, y4 float64)

Curve draws a curved line starting at (x2,y2) and ending at (x3,y3). (x1,y1) and (x4,y4) are the control points.

Curve is an implementation of Catmull-Rom splines.

func CurveTightness 

func CurveTightness(v float64)

CurveTightness determines how the curve fits to the Curve vertex points. CurveTightness controls the Catmull-Rom tau tension.

The default value is 0.

func DrawImage 

func DrawImage(img image.Image, x, y float64)

DrawImage draws the provided image at (x,y).

func Ellipse 

func Ellipse(x, y, w, h float64)

Ellipse draws an ellipse at (x,y) with the provided width and height.

func Fill 

func Fill(c color.Color)

Fill sets the color used to fill shapes.

func FrameCount 

func FrameCount() uint64

FrameCount returns the number of frames that have been displayed since the program started.

func IsLooping 

func IsLooping() bool

IsLooping checks whether p5 is continuously executing the code within Draw.

func Line 

func Line(x1, y1, x2, y2 float64)

Line draws a line between (x1,y1) and (x2,y2).

func LoadFonts 

func LoadFonts(fnt []text.FontFace)

LoadFonts sets the fonts collection to use for text.

func Loop 

func Loop()

By default, p5 continuously executes the code within Draw. Loop starts the draw loop again, if it was stopped previously by calling NoLoop.

func Matrix 

func Matrix(a, b, c, d, e, f float64)

Matrix sets the affine matrix transformation.

func NoLoop 

func NoLoop()

NoLoop stops p5 from continuously executing the code within Draw.

func PhysCanvas 

func PhysCanvas(w, h int, xmin, xmax, ymin, ymax float64)

PhysCanvas sets the dimensions of the painting area, in pixels, and associates physical quantities.

func Pop 

func Pop()

Pop restores the previous drawing style settings and transformations.

func Push 

func Push()

Push saves the current drawing style settings and transformations.

func Quad 

func Quad(x1, y1, x2, y2, x3, y3, x4, y4 float64)

Quad draws a quadrilateral, connecting the 4 points (x1,y1), (x2,y2), (x3,y3) and (x4,y4) together.

func Random 

func Random(min, max float64) float64

Random returns a pseudo-random number in [min,max). Random will produce the same sequence of numbers every time the program runs. Use RandomSeed with a seed that changes (like time.Now().UnixNano()) in order to produce different sequence of numbers.

func RandomGaussian 

func RandomGaussian(mean, stdDev float64) float64

RandomGaussian returns a random number fitting a Gaussian (normal) distribution.

func RandomSeed 

func RandomSeed(seed uint64)

RandomSeed changes the sequence of numbers generated by Random.

func ReadImage 

func ReadImage(fname string) (image.Image, error)

ReadImage reads a BMP, JPG, GIF, PNG or TIFF image from the provided path.

func Rect 

func Rect(x, y, w, h float64)

Rect draws a rectangle at (x,y) with width w and height h.

func Rotate 

func Rotate(angle float64)

Rotate rotates the graphical context by angle radians. Positive angles rotate counter-clockwise.

func Run 

func Run(setup, draw Func)

Run executes the user functions setup and draw. Run never exits.

func Scale 

func Scale(x, y float64)

Scale rescales the graphical context by x and y.

func Screenshot 

func Screenshot(fname string)

Screenshot saves the current canvas to the provided file. Supported file formats are: PNG, JPEG and GIF.

func Shear 

func Shear(x, y float64)

Shear shears the graphical context by the given x and y angles in radians.

func Square 

func Square(x, y, s float64)

Square draws a square at (x,y) with size s.

func Stroke 

func Stroke(c color.Color)

Stroke sets the color of the strokes.

func StrokeWidth 

func StrokeWidth(v float64)

StrokeWidth sets the size of the strokes.

func Text 

func Text(txt string, x, y float64)

Text draws txt on the screen at (x,y).

func TextFont 

func TextFont(fnt text.Font)

TextFont sets the text font.

func TextSize 

func TextSize(size float64)

TextSize sets the text size.

func Translate 

func Translate(x, y float64)

Translate applies a translation by x and y.

func Triangle 

func Triangle(x1, y1, x2, y2, x3, y3 float64)

Triangle draws a triangle, connecting the 3 points (x1,y1), (x2,y2) and (x3,y3) together.

Types

type Buttons 

type Buttons uint8

Buttons is a set of mouse buttons. 

const (
	ButtonLeft Buttons = 1 << iota
	ButtonRight
	ButtonMiddle
)

func (Buttons) Contain 

func (b Buttons) Contain(buttons Buttons) bool

Contain reports whether the set b contains all of the buttons.

type Func 

type Func func()

Func is the type of functions users provide to p5.

type Path 

type Path struct {
	// contains filtered or unexported fields
}

func (*Path) Close 

func (p *Path) Close()

Close closes the current path.

func (*Path) Cube 

func (p *Path) Cube(x1, y1, x2, y2, x3, y3 float64)

Cube draws a cubic Bézier curve from the current position to the (x3,y3) point, with the (x1,y1) and (x2,y2) control points.

func (*Path) End 

func (p *Path) End()

func (*Path) Quad 

func (p *Path) Quad(x1, y1, x2, y2 float64)

Quad draws a quadratic Bézier curve from the current position to the (x2,y2) point, with the (x1,y1) control point.

func (*Path) Vertex 

func (p *Path) Vertex(x, y float64)

type Proc 

type Proc struct {
	Setup Func
	Draw  Func
	Mouse Func
	// contains filtered or unexported fields
}

Proc is a p5 processor.

Proc runs the bound Setup function once before the event loop. Proc then runs the bound Draw function once per event loop iteration.

func NewProc 

func NewProc(w, h int) *Proc

func (*Proc) Arc 

func (p *Proc) Arc(x, y, w, h float64, beg, end float64)

Arc draws an ellipsoidal arc centered at (x,y), with the provided width and height, and a path from the beg to end radians. Positive angles denote a counter-clockwise path.

func (*Proc) Background 

func (p *Proc) Background(c color.Color)

Background defines the background color for the painting area. The default color is transparent.

func (*Proc) BeginPath 

func (p *Proc) BeginPath() *Path

func (*Proc) Bezier 

func (p *Proc) Bezier(x1, y1, x2, y2, x3, y3, x4, y4 float64)

Bezier draws a cubic Bézier curve from (x1,y1) to (x4,y4) and two control points (x2,y2) and (x3,y3)

func (*Proc) Canvas 

func (p *Proc) Canvas(w, h int)

Canvas defines the dimensions of the painting area, in pixels.

func (*Proc) Circle 

func (p *Proc) Circle(x, y, d float64)

Circle draws a circle at (x,y) with a diameter d.

func (*Proc) Curve 

func (p *Proc) Curve(x1, y1, x2, y2, x3, y3, x4, y4 float64)

Curve draws a curved line starting at (x2,y2) and ending at (x3,y3). (x1,y1) and (x4,y4) are the control points.

Curve is an implementation of Catmull-Rom splines.

func (*Proc) CurveTightness 

func (p *Proc) CurveTightness(v float64)

CurveTightness determines how the curve fits to the Curve vertex points. CurveTightness controls the Catmull-Rom tau tension.

The default value is 0.

func (*Proc) DrawImage 

func (p *Proc) DrawImage(img image.Image, x, y float64)

DrawImage draws the provided image at (x,y).

func (*Proc) Ellipse 

func (p *Proc) Ellipse(x, y, w, h float64)

Ellipse draws an ellipse at (x,y) with the provided width and height.

func (*Proc) Fill 

func (p *Proc) Fill(c color.Color)

Fill sets the color used to fill shapes.

func (*Proc) FrameCount 

func (p *Proc) FrameCount() uint64

FrameCount returns the number of frames that have been displayed since the program started.

func (*Proc) IsLooping 

func (p *Proc) IsLooping() bool

IsLooping checks if p5 is continuously executing the code within draw() or not.

func (*Proc) Line 

func (p *Proc) Line(x1, y1, x2, y2 float64)

Line draws a line between (x1,y1) and (x2,y2).

func (*Proc) LoadFonts 

func (p *Proc) LoadFonts(fnt []text.FontFace)

LoadFonts sets the fonts collection to use for text.

func (*Proc) Loop 

func (p *Proc) Loop()

By default, p5 continuously executes the code within draw(). Loop starts the draw loop again, if it was stopped previously by calling NoLoop().

func (*Proc) Matrix 

func (p *Proc) Matrix(a, b, c, d, e, f float64)

Matrix sets the affine matrix transformation.

func (*Proc) NoLoop 

func (p *Proc) NoLoop()

NoLoop stops p5 from continuously executing the code within draw().

func (*Proc) PhysCanvas 

func (p *Proc) PhysCanvas(w, h int, xmin, xmax, ymin, ymax float64)

PhysCanvas sets the dimensions of the painting area, in pixels, and associates physical quantities.

func (*Proc) Pop 

func (p *Proc) Pop()

Pop restores the previous drawing style settings and transformations.

func (*Proc) Push 

func (p *Proc) Push()

Push saves the current drawing style settings and transformations.

func (*Proc) Quad 

func (p *Proc) Quad(x1, y1, x2, y2, x3, y3, x4, y4 float64)

Quad draws a quadrilateral, connecting the 4 points (x1,y1), (x2,y2), (x3,y3) and (x4,y4) together.

func (*Proc) Random 

func (p *Proc) Random(min, max float64) float64

Random returns a pseudo-random number in [min,max). Random will produce the same sequence of numbers every time the program runs. Use RandomSeed with a seed that changes (like time.Now().UnixNano()) in order to produce different sequences of numbers.

func (*Proc) RandomGaussian 

func (p *Proc) RandomGaussian(mean, stdDev float64) float64

RandomGaussian returns a random number following a Gaussian distribution with the provided mean and standard deviation.

func (*Proc) RandomSeed 

func (p *Proc) RandomSeed(seed uint64)

RandomSeed changes the sequence of numbers generated by Random.

func (*Proc) ReadImage 

func (p *Proc) ReadImage(fname string) (img image.Image, err error)

ReadImage reads a BMP, JPG, GIF, PNG or TIFF image from the provided path.

func (*Proc) Rect 

func (p *Proc) Rect(x, y, w, h float64)

Rect draws a rectangle at (x,y) with width w and height h.

func (*Proc) Rotate 

func (p *Proc) Rotate(angle float64)

Rotate rotates the graphical context by angle radians. Positive angles rotate counter-clockwise.

func (*Proc) Run 

func (p *Proc) Run()

func (*Proc) Scale 

func (p *Proc) Scale(x, y float64)

Scale rescales the graphical context by x and y.

func (*Proc) Screenshot 

func (p *Proc) Screenshot(fname string) error

Screenshot saves the current canvas to the provided file. Supported file formats are: PNG, JPEG and GIF.

func (*Proc) Shear 

func (p *Proc) Shear(x, y float64)

Shear shears the graphical context by the given x and y angles in radians.

func (*Proc) Square 

func (p *Proc) Square(x, y, s float64)

Square draws a square at (x,y) with size s.

func (*Proc) Stroke 

func (p *Proc) Stroke(c color.Color)

Stroke sets the color of the strokes.

func (*Proc) StrokeWidth 

func (p *Proc) StrokeWidth(v float64)

StrokeWidth sets the size of the strokes.

func (*Proc) Text 

func (p *Proc) Text(txt string, x, y float64)

Text draws txt on the screen at (x,y).

func (*Proc) TextFont 

func (p *Proc) TextFont(fnt text.Font)

func (*Proc) TextSize 

func (p *Proc) TextSize(size float64)

TextSize sets the text size.

func (*Proc) Translate 

func (p *Proc) Translate(x, y float64)

Translate applies a translation by x and y.

func (*Proc) Triangle 

func (p *Proc) Triangle(x1, y1, x2, y2, x3, y3 float64)

Triangle draws a triangle, connecting the 3 points (x1,y1), (x2,y2) and (x3,y3) together.

Source Files

View all Source files

Directories

Path Synopsis
cmd
p5-run
example
anim-image
bouncing-bubbles
emfield
hello
mouse-pressed
sketch
snake
solar-system
wasm-p5-ex
internal
cmpimg
Package cmpimg compares the raw representation of images taking into account idiosyncracies related to their underlying format (SVG, PDF, PNG, ...).
 Package cmpimg compares the raw representation of images taking into account idiosyncracies related to their underlying format (SVG, PDF, PNG, ...).

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