Data
Composite
BufferedReaderHashMapPFontPGraphicsPImagePShaderPShapePVectorPrintWriterTableRowTableXMLstd::mapstd::vector
Array Functions
append()arrayCopy()concat()expand()reverse()shorten()sort()splice()subset()
Conversion
binary()hex()str()unbinary()unhex()
Primitive
color
String Functions
join()matchAll()match()nf()split()splitTokens()trim()
Input
Files
createInput()createReader()launch()loadBytes()loadJSONArray()loadJSONObject()loadStrings()loadTable()loadXML()parseJSONArray()parseJSONObject()parseXML()selectFolder()selectInput()
Time & Date
day()hour()millis()minute()month()second()year()
Keyboard
keykeyPressedkeyCodekeyReleased()keyPressed()keyTyped()
Mouse
mouseButtonmouseClicked()mouseDragged()mouseMoved()mousePressedmousePressed()mouseWheel()mouseReleased()mouseXmouseYpmouseXpmouseY
Constants
HALF_PIPIQUARTER_PITAUTWO_PI
Typography
Loading & Displaying
PFontcreateFont()loadFont()textFont()text()
Attributes
textAlign()textLeading()textMode()textSize()textWidth()
Metrics
textAscent()textDescent()
Rendering
PGraphicsblendMode()clip()createGraphics()hint()noClip()
Shaders
PShaderloadShader()resetShader()shader()
Image
PImagecreateImage()
Pixels
blend()copy()filter()get()loadPixels()mask()pixels[]set()updatePixels()
Loading & Displaying
image()imageMode()loadImage()noTint()tint()
Textures
texture()textureMode()textureWrap()
Shape
PShapecreateShape()loadShape()
2D Primitives
arc()circle()ellipse()line()point()quad()rect()square()triangle()
Vertex
beginContour()beginShape()bezierVertex()curveVertex()endContour()endShape()quadraticVertex()vertex()
Curves
bezierDetail()bezierPoint()bezierTangent()bezier()curveDetail()curvePoint()curveTangent()curveTightness()curve()
3D Primitives
box()sphere()sphereDetail()
Attributes
ellipseMode()rectMode()strokeCap()strokeJoin()strokeWeight()
Loading & Displaying
shape()shapeMode()
Math
PVector
Calculation
abs()ceil()constrain()dist()exp()floor()lerp()log()mag()map()max()min()norm()pow()round()sq()sqrt()
Trigonometry
acos()asin()atan2()atan()cos()degrees()radians()sin()tan()
Random
noise()noiseDetail()noiseSeed()randomGaussian()randomSeed()random()
Output
Files
PrintWritercreateOutput()createWriter()saveBytes()saveJSONArray()saveJSONObject()saveStrings()saveTable()saveXML()selectOutput()
Text Area
print()printArray()println()
Image
save()saveFrame()
Color
Creating & Reading
alpha()blue()brightness()color()green()hue()lerpColor()red()saturation()
Setting
background()clear()colorMode()fill()noFill()noStroke()stroke()
Lights Camera
Lights
ambientLight()directionalLight()lightFalloff()lightSpecular()lights()noLights()normal()pointLight()spotLight()
Material Properties
ambient()emissive()shininess()specular()
Camera
beginCamera()camera()endCamera()frustum()ortho()perspective()printCamera()printProjection()
Coordinates
modelX()modelY()modelZ()screenX()screenY()screenZ()
Transform
applyMatrix()popMatrix()printMatrix()pushMatrix()resetMatrix()rotateX()rotateY()rotateZ()rotate()scale()shearX()shearY()translate()
Structure
draw()exit()loop()noLoop()pop()popMatrix()popStyle()push()pushMatrix()pushStyle()redraw()setup()thread()delay()
Environment
cursor()deltaTimedisplayHeightdisplayWidthfocusedframeCountframeRateframeRate()fullScreen()heighthint()noCursor()noSmooth()pixelDensity()pixelHeightpixelWidthsize()smooth()widthwindowMoved()windowResizable()windowResize()windowResized()windowTitle()

alpha()

Color / Creating & Reading

Description

Extracts the alpha value from a color.

Syntax

float alpha(color c)

Parameters

NameTypeDescription
ccolorany color value

Returns

float

Related

redgreenblue

Under the Hood

Implementation in Processing.h / Processing.cpp:

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