p5

package module
Version: v0.9.0 Latest Latest
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Published: Jun 29, 2021 License: BSD-3-Clause Imports: 35 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 added in v0.6.0

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 added in v0.8.0

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 added in v0.8.0

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 added in v0.9.0

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 added in v0.8.0

func FrameCount() uint64

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

func IsLooping added in v0.8.0

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 Loop added in v0.8.0

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 added in v0.7.0

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

Matrix sets the affine matrix transformation.

func NoLoop added in v0.8.0

func NoLoop()

NoLoop stops p5 from continuously executing the code within Draw.

func PhysCanvas added in v0.8.0

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 added in v0.6.0

func Pop()

Pop restores the previous drawing style settings and transformations.

func Push added in v0.6.0

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 added in v0.8.0

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 added in v0.8.0

func RandomGaussian(mean, stdDev float64) float64

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

func RandomSeed added in v0.8.0

func RandomSeed(seed uint64)

RandomSeed changes the sequence of numbers generated by Random.

func ReadImage added in v0.9.0

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 added in v0.6.0

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 added in v0.6.0

func Scale(x, y float64)

Scale rescales the graphical context by x and y.

func Screenshot added in v0.3.0

func Screenshot(fname string)

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

func Shear added in v0.7.0

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 added in v0.2.0

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 TextSize

func TextSize(size float64)

TextSize sets the text size.

func Translate added in v0.6.0

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 added in v0.5.0

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

func (*Path) Close added in v0.5.0

func (p *Path) Close()

Close closes the current path.

func (*Path) Cube added in v0.5.0

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 added in v0.5.0

func (p *Path) End()

func (*Path) Quad added in v0.5.0

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 added in v0.5.0

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 (*Proc) Arc added in v0.2.0

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 added in v0.2.0

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

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

func (*Proc) BeginPath added in v0.5.0

func (p *Proc) BeginPath() *Path

func (*Proc) Bezier added in v0.6.0

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 added in v0.2.0

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 added in v0.8.0

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 added in v0.8.0

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 added in v0.9.0

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 added in v0.2.0

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

Fill sets the color used to fill shapes.

func (*Proc) FrameCount added in v0.8.0

func (p *Proc) FrameCount() uint64

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

func (*Proc) IsLooping added in v0.8.0

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) Loop added in v0.8.0

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 added in v0.7.0

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

Matrix sets the affine matrix transformation.

func (*Proc) NoLoop added in v0.8.0

func (p *Proc) NoLoop()

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

func (*Proc) PhysCanvas added in v0.8.0

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 added in v0.6.0

func (p *Proc) Pop()

Pop restores the previous drawing style settings and transformations.

func (*Proc) Push added in v0.6.0

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 added in v0.8.0

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 added in v0.8.0

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 added in v0.8.0

func (p *Proc) RandomSeed(seed uint64)

RandomSeed changes the sequence of numbers generated by Random.

func (*Proc) ReadImage added in v0.9.0

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 added in v0.6.0

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 added in v0.6.0

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

Scale rescales the graphical context by x and y.

func (*Proc) Screenshot added in v0.3.0

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 added in v0.7.0

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 added in v0.2.0

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

Stroke sets the color of the strokes.

func (*Proc) StrokeWidth added in v0.2.0

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) TextSize

func (p *Proc) TextSize(size float64)

TextSize sets the text size.

func (*Proc) Translate added in v0.6.0

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.

Directories

Path Synopsis
cmd
example
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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