PixelKit

Live Graphics for iOS, macOS and tvOS
Runs on RenderKit, powered by Metal

PixelKit combines custom shaders, metal performance shaders, core image filters and vision to create tools for real-time rendering.

Examples: Camera Effects - Green Screen
Info: Coordinate Space - Blend Operators - Effect Convenience Funcs - High Bit Mode


CameraPIX	DepthCameraPIX	ImagePIX	VideoPIX	ScreenCapturePIX	StreamInPIX	SlopePIX


ColorPIX	CirclePIX	RectanglePIX	PolygonPIX	ArcPIX	LinePIX	GradientPIX	StackPIX


NoisePIX	TextPIX	MetalPIX	TwirlPIX	FeedbackPIX	DelayPIX	SharpenPIX	StreamOutPIX


LevelsPIX	BlurPIX	EdgePIX	ThresholdPIX	QuantizePIX	TransformPIX	KaleidoscopePIX


ChannelMixPIX	ChromaKeyPIX	CornerPinPIX	ColorShiftPIX	FlipFlopPIX	RangePIX	StarPIX


SepiaPIX	ConvertPIX	ReducePIX	ClampPIX	FreezePIX	FlarePIX	AirPlayPIX	RecordPIX


BlendPIX	CrossPIX	LookupPIX	DisplacePIX	RemapPIX	ReorderPIX	ResolutionPIX	CropPIX


BlendsPIX	LumaLevelsPIX	LumaBlurPIX	LumaTransformPIX	TimeMachinePIX	ArrayPIX

Install

Swift Package

.package(url: "https://github.com/heestand-xyz/PixelKit", from: "3.0.0")

Setup

SwiftUI

import SwiftUI
import PixelKit

struct ContentView: View {
    
    @StateObject var circlePix = CirclePIX()
    @StateObject var blurPix = BlurPIX()
    
    var body: some View {
        PixelView(pix: blurPix)
            .onAppear {
                blurPix.input = circlePix
                blurPix.radius = 0.25
            }
    }
}

UIKit

import UIKit
import PixelKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let circlePix = CirclePIX()

        let blurPix = BlurPIX()
        blurPix.input = circlePix
        blurPix.radius = 0.25

        let finalPix: PIX = blurPix
        finalPix.view.frame = view.bounds
        view.addSubview(finalPix.view)
    }
}

Resolution

In PixelKit all PIXs have a resolution. Some PIXs have defined resolutions (default to .auto) and some PIXs have derived resolutions.

The .auto resolution will fill up the view and get the correct resolution based on the view size. If a view is 100x100 points, the resolution will be 200x200 pixels on macOS and 300x300 pixels on iPhone.

Import the resolution package to work with resolutions:

import Resolution

You can multiply and divide resolutions with a CGFloat or Int.

There are predefined resolutions like ._1080p & ._4K.

Rendered Image

.renderedImage // UIImage or NSImage
.renderedTexture // MTLTexture

Example: Camera Effects

import SwiftUI
import PixelKit

class ViewModel: ObservableObject {
    
    let camera: CameraPIX
    let levels: LevelsPIX
    let colorShift: ColorShiftPIX
    let blur: BlurPIX
    let circle: CirclePIX
    
    let finalPix: PIX
    
    init() {
        
        camera = CameraPIX()
        camera.cameraResolution = ._1080p

        levels = LevelsPIX()
        levels.input = camera
        levels.brightness = 1.5
        levels.gamma = 0.5

        colorShift = ColorShiftPIX()
        colorShift.input = levels
        colorShift.saturation = 0.5

        blur = BlurPIX()
        blur.input = colorShift
        blur.radius = 0.25

        circle = CirclePIX(at: .square(1080))
        circle.radius = 0.45
        circle.backgroundColor = .clear

        finalPix = blur & (camera * circle)
    }
}

struct ContentView: View {
    
    @StateObject var viewModel = ViewModel()
    
    var body: some View {
        PixelView(pix: viewModel.finalPix)
    }
}

This can also be done with Effect Convenience Funcs:

let pix = CameraPIX().pixBrightness(1.5).pixGamma(0.5).pixSaturation(0.5).pixBlur(0.25)

Remeber to add NSCameraUsageDescription to your Info.plist

Example: Green Screen

import RenderKit import PixelKit

let cityImage = ImagePIX()
cityImage.image = UIImage(named: "city")

let supermanVideo = VideoPIX()
supermanVideo.load(fileNamed: "superman", withExtension: "mov")

let supermanKeyed = ChromaKeyPIX()
supermanKeyed.input = supermanVideo
supermanKeyed.keyColor = .green

let blendPix = BlendPIX()
blendPix.blendingMode = .over
blendPix.inputA = cityImage
blendPix.inputB = supermanKeyed

let finalPix: PIX = blendPix
finalPix.view.frame = view.bounds
view.addSubview(finalPix.view)

This can also be done with Blend Operators and Effect Convenience Funcs:

let pix = cityImage & supermanVideo.pixChromaKey(.green)

Example: Depth Camera

import RenderKit import PixelKit

let cameraPix = CameraPIX()
cameraPix.camera = .front

let depthCameraPix = DepthCameraPIX.setup(with: cameraPix)

let levelsPix = LevelsPIX()
levelsPix.input = depthCameraPix
levelsPix.inverted = true

let lumaBlurPix = cameraPix.pixLumaBlur(pix: levelsPix, radius: 0.1)

let finalPix: PIX = lumaBlurPix
finalPix.view.frame = view.bounds
view.addSubview(finalPix.view)

The DepthCameraPIX was added in PixelKit v0.8.4 and requires an iPhone X or newer.

Note to use the setup(with:filter:) method of DepthCameraPIX.
It will take care of orientation, color and enable depth on the CameraPIX.

To gain access to depth values ouside of the 0.0 and 1.0 bounds,
enable 16 bit mode like this: PixelKit.main.render.bits = ._16

Example: Multi Camera

let cameraPix = CameraPIX()
cameraPix.camera = .back

let multiCameraPix = MultiCameraPIX.setup(with: cameraPix, camera: .front)

let movedMultiCameraPix = multiCameraPix.pixScale(by: 0.25).pixTranslate(x: 0.375 * (9 / 16), y: 0.375)

let finalPix: PIX = camearPix & movedMultiCameraPix
finalPix.view.frame = view.bounds
view.addSubview(finalPix.view)

Note MultiCameraPIX requires iOS 13.

Coordinate Space

The PixelKit coordinate space is normailzed to the vertical axis (1.0 in height) with the origin (0.0, 0.0) in the center.
Note that compared to native UIKit and SwiftUI views the vertical axis is flipped and origin is moved, this is more convinent when working with graphics in PixelKit. A full rotation is defined by 1.0

Center: CGPoint(x: 0, y: 0)
Bottom Left: CGPoint(x: -0.5 * aspectRatio, y: -0.5)
Top Right: CGPoint(x: 0.5 * aspectRatio, y: 0.5)

Tip: Resolution has an .aspect property:
let aspectRatio: CGFloat = Resolution._1080p.aspect

Blend Operators

A quick and convenient way to blend PIXs
These are the supported BlendingMode operators:

`&`	`!&`	`+`	`-`	`*`	`**`	`!**`	`%`	`~`	`°`
.over	.under	.add	.subtract	.multiply	.power	.gamma	.difference	.average	cosine

`<>`	`><`	`++`	`--`	`<->`	`>-<`	`+-+`
.minimum	.maximum	.addWithAlpha	.subtractWithAlpha	inside	outside	exclusiveOr

let blendPix = (CameraPIX() !** NoisePIX(at: .fullHD(.portrait))) * CirclePIX(at: .fullHD(.portrait))

The default global blend operator fill mode is .fit, change it like this:
PIX.blendOperators.globalPlacement = .fill

Effect Convenience Funcs

.pixScaleResolution(to: ._1080p * 0.5) -> ResolutionPIX
.pixScaleResolution(by: 0.5) -> ResolutionPIX
.pixBrightness(0.5) -> LevelsPIX
.pixDarkness(0.5) -> LevelsPIX
.pixContrast(0.5) -> LevelsPIX
.pixGamma(0.5) -> LevelsPIX
.pixInvert() -> LevelsPIX
.pixOpacity(0.5) -> LevelsPIX
.pixBlur(0.5) -> BlurPIX
.pixEdge() -> EdgePIX
.pixThreshold(at: 0.5) -> ThresholdPIX
.pixQuantize(by: 0.5) -> QuantizePIX
.pixPosition(at: CGPoint(x: 0.5, y: 0.5)) -> TransformPIX
.pixRotatate(by: 0.5) -> TransformPIX
.pixRotatate(byRadians: .pi) -> TransformPIX
.pixRotatate(byDegrees: 180) -> TransformPIX
.pixScale(by: 0.5) -> TransformPIX
.pixKaleidoscope() -> KaleidoscopePIX
.pixTwirl(0.5) -> TwirlPIX
.pixSwap(.red, .blue) -> ChannelMixPIX
.pixChromaKey(.green) -> ChromaKeyPIX
.pixHue(0.5) -> ColorShiftPIX
.pixSaturation(0.5) -> ColorShiftPIX
.pixCrop(CGRect(x: 0.25, y 0.25, width: 0.5, height: 0.5)) -> CropPIX
.pixFlipX() -> FlipFlopPIX
.pixFlipY() -> FlipFlopPIX
.pixFlopLeft() -> FlipFlopPIX
.pixFlopRight() -> FlipFlopPIX
.pixRange(inLow: 0.0, inHigh: 0.5, outLow: 0.5, outHigh: 1.0) -> RangePIX
.pixRange(inLow: .clear, inHigh: .gray, outLow: .gray, outHigh: .white) -> RangePIX
.pixSharpen() -> SharpenPIX
.pixSlope() - > SlopePIX
.pixVignetting(radius: 0.5, inset: 0.25, gamma: 0.5) -> LumaLevelsPIX
.pixLookup(pix: pixB, axis: .x) -> LookupPIX
.pixLumaBlur(pix: pixB, radius: 0.5) -> LumaBlurPIX
.pixLumaLevels(pix: pixB, brightness: 2.0) -> LumaLevelsPIX
.pixDisplace(pix: pixB, distance: 0.5) -> DisplacePIX
.pixRemap(pix: pixB) -> RemapPIX

Keep in mind that these funcs will create new PIXs.
Be careful of overloading GPU memory, some funcs create several PIXs.

High Bit Mode

Some effects like DisplacePIX and SlopePIX can benefit from a higher bit depth.
The default is 8 bits. Change it like this: PixelKit.main.render.bits = ._16

Enable high bit mode before you create any PIXs.

Note resources do not support higher bits yet.
There is currently there is some gamma offset with resources.

MetalPIXs

let metalPix = MetalPIX(at: ._1080p, code:
    """
    pix = float4(u, v, 0.0, 1.0);
    """
)

let metalEffectPix = MetalEffectPIX(code:
    """
    float gamma = 0.25;
    pix = pow(input, 1.0 / gamma);
    """
)
metalEffectPix.input = CameraPIX()

let metalMergerEffectPix = MetalMergerEffectPIX(code:
    """
    pix = pow(inputA, 1.0 / inputB);
    """
)
metalMergerEffectPix.inputA = CameraPIX()
metalMergerEffectPix.inputB = ImagePIX("img_name")

let metalMultiEffectPix = MetalMultiEffectPIX(code:
    """
    float4 inPixA = inTexs.sample(s, uv, 0);
    float4 inPixB = inTexs.sample(s, uv, 1);
    float4 inPixC = inTexs.sample(s, uv, 2);
    pix = inPixA + inPixB + inPixC;
    """
)
metalMultiEffectPix.inputs = [ImagePIX("img_a"), ImagePIX("img_b"), ImagePIX("img_c")]

Uniforms:

var lumUniform = MetalUniform(name: "lum")
let metalPix = MetalPIX(at: ._1080p, code:
    """
    pix = float4(in.lum, in.lum, in.lum, 1.0);
    """,
    uniforms: [lumUniform]
)
lumUniform.value = 0.5

Notes:

To gain camera access, on macOS, check Camera in the App Sandbox in your Xcode project settings under Capabilities.

inspired by TouchDesigner created by Anton Heestand XYZ

eschmar / PixelKit