CMYK Colors - Mac Catalyst

import Foundation
import IMGLYEngine

@MainActor
func cmykColors(engine: Engine) async throws {
  let scene = try engine.scene.create()

  let page = try engine.block.create(.page)
  try engine.block.setWidth(page, value: 800)
  try engine.block.setHeight(page, value: 600)
  try engine.block.appendChild(to: scene, child: page)

  // CMYK components (c, m, y, k) and tint all range from 0.0 to 1.0.
  let cmykCyan = Color.cmyk(c: 1.0, m: 0.0, y: 0.0, k: 0.0, tint: 1.0)
  let cmykMagenta = Color.cmyk(c: 0.0, m: 1.0, y: 0.0, k: 0.0, tint: 1.0)
  let cmykYellow = Color.cmyk(c: 0.0, m: 0.0, y: 1.0, k: 0.0, tint: 1.0)
  let cmykBlack = Color.cmyk(c: 0.0, m: 0.0, y: 0.0, k: 1.0, tint: 1.0)

  // Create a graphic block, attach a color fill, then assign a CMYK color.
  // The same setColor call works for any CMYK value.
  for cmykColor in [cmykCyan, cmykMagenta, cmykYellow, cmykBlack] {
    let block = try engine.block.create(.graphic)
    try engine.block.setShape(block, shape: engine.block.createShape(.rect))
    try engine.block.setWidth(block, value: 150)
    try engine.block.setHeight(block, value: 150)
    try engine.block.appendChild(to: page, child: block)

    let fill = try engine.block.createFill(.color)
    try engine.block.setFill(block, fill: fill)
    try engine.block.setColor(fill, property: "fill/color/value", color: cmykColor)
  }

  // The tint value scales color intensity without changing the CMYK components.
  // On screen, a tint below 1.0 is rendered as transparency.
  let tintedBlock = try engine.block.create(.graphic)
  try engine.block.setShape(tintedBlock, shape: engine.block.createShape(.rect))
  try engine.block.appendChild(to: page, child: tintedBlock)
  let tintedFill = try engine.block.createFill(.color)
  try engine.block.setFill(tintedBlock, fill: tintedFill)

  let cmykHalfMagenta = Color.cmyk(c: 0.0, m: 1.0, y: 0.0, k: 0.0, tint: 0.5)
  try engine.block.setColor(tintedFill, property: "fill/color/value", color: cmykHalfMagenta)

  // Enable the stroke and set its width before applying a CMYK color.
  let strokeBlock = try engine.block.create(.graphic)
  try engine.block.setShape(strokeBlock, shape: engine.block.createShape(.rect))
  try engine.block.appendChild(to: page, child: strokeBlock)

  try engine.block.setStrokeEnabled(strokeBlock, enabled: true)
  try engine.block.setStrokeWidth(strokeBlock, width: 8)
  let cmykStrokeColor = Color.cmyk(c: 0.8, m: 0.2, y: 0.0, k: 0.1, tint: 1.0)
  try engine.block.setColor(strokeBlock, property: "stroke/color", color: cmykStrokeColor)

  // Enable the drop shadow before applying a CMYK color.
  let shadowBlock = try engine.block.create(.graphic)
  try engine.block.setShape(shadowBlock, shape: engine.block.createShape(.rect))
  try engine.block.appendChild(to: page, child: shadowBlock)

  try engine.block.setDropShadowEnabled(shadowBlock, enabled: true)
  let cmykShadowColor = Color.cmyk(c: 0.0, m: 0.0, y: 0.0, k: 0.6, tint: 0.8)
  try engine.block.setColor(shadowBlock, property: "dropShadow/color", color: cmykShadowColor)

  // getColor returns a Color enum. Use pattern matching to inspect the CMYK components.
  let readBlock = try engine.block.create(.graphic)
  try engine.block.setShape(readBlock, shape: engine.block.createShape(.rect))
  try engine.block.appendChild(to: page, child: readBlock)
  let readFill = try engine.block.createFill(.color)
  try engine.block.setFill(readBlock, fill: readFill)

  let cmykOrange = Color.cmyk(c: 0.0, m: 0.5, y: 1.0, k: 0.0, tint: 1.0)
  try engine.block.setColor(readFill, property: "fill/color/value", color: cmykOrange)

  let retrievedColor: Color = try engine.block.getColor(readFill, property: "fill/color/value")
  if case let .cmyk(c, m, y, k, tint) = retrievedColor {
    print("CMYK Color - C: \(c), M: \(m), Y: \(y), K: \(k), Tint: \(tint)")
  }

  // Convert between sRGB and CMYK using the editor API. Conversions are not
  // perfectly reversible because the color gamuts differ.
  let rgbBlue = Color.rgba(r: 0.2, g: 0.4, b: 0.9, a: 1.0)
  let convertedCmyk = try engine.editor.convertColorToColorSpace(color: rgbBlue, colorSpace: .cmyk)
  print("RGB to CMYK conversion: \(convertedCmyk)")

  let cmykGreen = Color.cmyk(c: 0.7, m: 0.0, y: 1.0, k: 0.2, tint: 1.0)
  let convertedRgb = try engine.editor.convertColorToColorSpace(color: cmykGreen, colorSpace: .sRGB)
  print("CMYK to RGB conversion: \(convertedRgb)")

  // CMYK colors can be used in any gradient color stop.
  let gradientBlock = try engine.block.create(.graphic)
  try engine.block.setShape(gradientBlock, shape: engine.block.createShape(.rect))
  try engine.block.setWidth(gradientBlock, value: 320)
  try engine.block.setHeight(gradientBlock, value: 150)
  try engine.block.appendChild(to: page, child: gradientBlock)

  let gradientFill = try engine.block.createFill(.linearGradient)
  try engine.block.setFill(gradientBlock, fill: gradientFill)

  try engine.block.setGradientColorStops(
    gradientFill,
    property: "fill/gradient/colors",
    colors: [
      GradientColorStop(color: .cmyk(c: 1.0, m: 0.0, y: 0.0, k: 0.0, tint: 1.0), stop: 0.0),
      GradientColorStop(color: .cmyk(c: 0.0, m: 1.0, y: 0.0, k: 0.0, tint: 1.0), stop: 0.5),
      GradientColorStop(color: .cmyk(c: 0.0, m: 0.0, y: 1.0, k: 0.0, tint: 1.0), stop: 1.0),
    ],
  )
}

Work with CMYK colors in CE.SDK for professional print production workflows with support for color space conversion and tint control.

10 mins

estimated time

GitHub

CMYK (Cyan, Magenta, Yellow, Key/Black) is the standard color model for print production. Unlike sRGB, which is additive and designed for screens, CMYK uses subtractive color mixing to represent how inks combine on paper. CE.SDK represents CMYK as a case of the Color enum, so the same setColor and getColor APIs work across all color spaces.

This guide covers how to create CMYK colors, apply them to fills, strokes, and drop shadows, use the tint value, read colors back, convert between color spaces, and use CMYK in gradients.

Understanding CMYK Colors#

When to Use CMYK#

Use CMYK colors when preparing designs for commercial printing or when print service providers require CMYK values. Screen displays convert CMYK to RGB for preview, but exported PDFs preserve CMYK information for accurate print reproduction.

A CMYK color in CE.SDK has five properties:

c (Cyan): 0.0 to 1.0
m (Magenta): 0.0 to 1.0
y (Yellow): 0.0 to 1.0
k (Key/Black): 0.0 to 1.0
tint: 0.0 to 1.0 (controls overall color intensity, rendered as transparency on screen)

Creating CMYK Colors#

Create a CMYK color with Color.cmyk(c:m:y:k:tint:). Every component ranges from 0.0 to 1.0.

// CMYK components (c, m, y, k) and tint all range from 0.0 to 1.0.
let cmykCyan = Color.cmyk(c: 1.0, m: 0.0, y: 0.0, k: 0.0, tint: 1.0)
let cmykMagenta = Color.cmyk(c: 0.0, m: 1.0, y: 0.0, k: 0.0, tint: 1.0)
let cmykYellow = Color.cmyk(c: 0.0, m: 0.0, y: 1.0, k: 0.0, tint: 1.0)
let cmykBlack = Color.cmyk(c: 0.0, m: 0.0, y: 0.0, k: 1.0, tint: 1.0)

Applying CMYK Colors to Fills#

Apply a CMYK color to a color fill using engine.block.setColor(_:property:color:) on the fill with the "fill/color/value" property path.

// Create a graphic block, attach a color fill, then assign a CMYK color.
// The same setColor call works for any CMYK value.
for cmykColor in [cmykCyan, cmykMagenta, cmykYellow, cmykBlack] {
  let block = try engine.block.create(.graphic)
  try engine.block.setShape(block, shape: engine.block.createShape(.rect))
  try engine.block.setWidth(block, value: 150)
  try engine.block.setHeight(block, value: 150)
  try engine.block.appendChild(to: page, child: block)

  let fill = try engine.block.createFill(.color)
  try engine.block.setFill(block, fill: fill)
  try engine.block.setColor(fill, property: "fill/color/value", color: cmykColor)
}

The same method works for any Color case — .rgba, .cmyk, or .spot — so you do not need a separate code path for each color space.

Using the Tint Property#

The tint value scales the color’s intensity without changing its CMYK components. A tint of 1.0 applies the full color; 0.5 scales it down.

// The tint value scales color intensity without changing the CMYK components.
// On screen, a tint below 1.0 is rendered as transparency.
let tintedBlock = try engine.block.create(.graphic)
try engine.block.setShape(tintedBlock, shape: engine.block.createShape(.rect))
try engine.block.appendChild(to: page, child: tintedBlock)
let tintedFill = try engine.block.createFill(.color)
try engine.block.setFill(tintedBlock, fill: tintedFill)

let cmykHalfMagenta = Color.cmyk(c: 0.0, m: 1.0, y: 0.0, k: 0.0, tint: 0.5)
try engine.block.setColor(tintedFill, property: "fill/color/value", color: cmykHalfMagenta)

Applying CMYK to Strokes#

Enable the stroke and set its width, then assign a CMYK color to the "stroke/color" property on the block.

// Enable the stroke and set its width before applying a CMYK color.
let strokeBlock = try engine.block.create(.graphic)
try engine.block.setShape(strokeBlock, shape: engine.block.createShape(.rect))
try engine.block.appendChild(to: page, child: strokeBlock)

try engine.block.setStrokeEnabled(strokeBlock, enabled: true)
try engine.block.setStrokeWidth(strokeBlock, width: 8)
let cmykStrokeColor = Color.cmyk(c: 0.8, m: 0.2, y: 0.0, k: 0.1, tint: 1.0)
try engine.block.setColor(strokeBlock, property: "stroke/color", color: cmykStrokeColor)

Applying CMYK to Drop Shadows#

Enable the drop shadow, then assign a CMYK color to the "dropShadow/color" property. Configure offset and blur radius with the usual drop shadow APIs as needed.

// Enable the drop shadow before applying a CMYK color.
let shadowBlock = try engine.block.create(.graphic)
try engine.block.setShape(shadowBlock, shape: engine.block.createShape(.rect))
try engine.block.appendChild(to: page, child: shadowBlock)

try engine.block.setDropShadowEnabled(shadowBlock, enabled: true)
let cmykShadowColor = Color.cmyk(c: 0.0, m: 0.0, y: 0.0, k: 0.6, tint: 0.8)
try engine.block.setColor(shadowBlock, property: "dropShadow/color", color: cmykShadowColor)

Reading CMYK Colors#

engine.block.getColor(_:property:) returns a Color enum value. Use pattern matching to extract the CMYK components.

// getColor returns a Color enum. Use pattern matching to inspect the CMYK components.
let readBlock = try engine.block.create(.graphic)
try engine.block.setShape(readBlock, shape: engine.block.createShape(.rect))
try engine.block.appendChild(to: page, child: readBlock)
let readFill = try engine.block.createFill(.color)
try engine.block.setFill(readBlock, fill: readFill)

let cmykOrange = Color.cmyk(c: 0.0, m: 0.5, y: 1.0, k: 0.0, tint: 1.0)
try engine.block.setColor(readFill, property: "fill/color/value", color: cmykOrange)

let retrievedColor: Color = try engine.block.getColor(readFill, property: "fill/color/value")
if case let .cmyk(c, m, y, k, tint) = retrievedColor {
  print("CMYK Color - C: \(c), M: \(m), Y: \(y), K: \(k), Tint: \(tint)")
}

Swift’s exhaustive enum matching replaces the type-guard helpers used on other platforms. The associated values are available directly inside the matched case.

Converting Between Color Spaces#

Use engine.editor.convertColorToColorSpace(color:colorSpace:) with ColorSpace.cmyk or ColorSpace.sRGB to convert between color spaces.

// Convert between sRGB and CMYK using the editor API. Conversions are not
// perfectly reversible because the color gamuts differ.
let rgbBlue = Color.rgba(r: 0.2, g: 0.4, b: 0.9, a: 1.0)
let convertedCmyk = try engine.editor.convertColorToColorSpace(color: rgbBlue, colorSpace: .cmyk)
print("RGB to CMYK conversion: \(convertedCmyk)")

let cmykGreen = Color.cmyk(c: 0.7, m: 0.0, y: 1.0, k: 0.2, tint: 1.0)
let convertedRgb = try engine.editor.convertColorToColorSpace(color: cmykGreen, colorSpace: .sRGB)
print("CMYK to RGB conversion: \(convertedRgb)")

Conversions may not be perfectly reversible because RGB and CMYK have different color gamuts. Some sRGB colors cannot be represented exactly in CMYK and vice versa.

Using CMYK in Gradients#

CMYK colors work in gradient color stops. Create a linear gradient fill and pass GradientColorStop values whose color is a Color.cmyk case.

// CMYK colors can be used in any gradient color stop.
let gradientBlock = try engine.block.create(.graphic)
try engine.block.setShape(gradientBlock, shape: engine.block.createShape(.rect))
try engine.block.setWidth(gradientBlock, value: 320)
try engine.block.setHeight(gradientBlock, value: 150)
try engine.block.appendChild(to: page, child: gradientBlock)

let gradientFill = try engine.block.createFill(.linearGradient)
try engine.block.setFill(gradientBlock, fill: gradientFill)

try engine.block.setGradientColorStops(
  gradientFill,
  property: "fill/gradient/colors",
  colors: [
    GradientColorStop(color: .cmyk(c: 1.0, m: 0.0, y: 0.0, k: 0.0, tint: 1.0), stop: 0.0),
    GradientColorStop(color: .cmyk(c: 0.0, m: 1.0, y: 0.0, k: 0.0, tint: 1.0), stop: 0.5),
    GradientColorStop(color: .cmyk(c: 0.0, m: 0.0, y: 1.0, k: 0.0, tint: 1.0), stop: 1.0),
  ],
)

Troubleshooting#

Colors Look Different on Screen vs. Print#

Screen previews convert CMYK to RGB using a standard conversion. For accurate color proofing, use calibrated monitors and print proofs from your production workflow.

Tint Not Having the Expected Effect#

The tint value must be between 0.0 and 1.0. On screen, it is rendered as transparency, so values below 1.0 make the color appear more translucent rather than lighter.

API Reference#

Method	Description
`engine.block.setColor(_:property:color:)`	Set a color property on a block. Accepts any `Color` case.
`engine.block.getColor(_:property:)`	Get the current color value from a property. Returns a `Color` enum.
`engine.editor.convertColorToColorSpace(color:colorSpace:)`	Convert a color between `ColorSpace.sRGB` and `ColorSpace.cmyk`.
`engine.block.createFill(_:)`	Create a fill. Use `.color` for solid fills or `.linearGradient` for gradients.
`engine.block.setFill(_:fill:)`	Assign a fill to a block.
`engine.block.setGradientColorStops(_:property:colors:)`	Set color stops on a gradient fill.

Type	Description
`Color.cmyk(c:m:y:k:tint:)`	CMYK color for print. Components and tint range 0.0–1.0.
`ColorSpace.cmyk` / `ColorSpace.sRGB`	Target color space for `convertColorToColorSpace`.
`GradientColorStop`	Gradient stop with a `color: Color` and a `stop: Float` position.

Next Steps#

Spot Colors — Work with named spot colors for brand consistency and specialized printing
Color Conversion — Convert colors between sRGB, CMYK, and spot color spaces
Apply Colors — Apply colors to design elements programmatically