CGColor Reference

Overview

The CGColorRef opaque type contains a set of components (such as red, green, and blue) that uniquely define a color, and a color space that specifies how those components should be interpreted. Quartz color objects provide a fast and convenient way to manage and set colors, especially colors that are used repeatedly. Quartz drawing operations use color objects for setting fill and stroke colors, managing alpha, and setting color with a pattern.

See also these related references: CGContext Reference, CGColorSpace Reference, and CGPattern Reference.

Functions by Task

Getting a Constant Color

• CGColorGetConstantColor

Retaining and Releasing Color Objects

• CGColorRelease
• CGColorRetain

Creating Quartz Colors

• CGColorCreate
• CGColorCreateCopy
• CGColorCreateGenericGray
• CGColorCreateGenericRGB
• CGColorCreateGenericCMYK
• CGColorCreateCopyWithAlpha
• CGColorCreateWithPattern

Getting Information about Quartz Colors

• CGColorEqualToColor
• CGColorGetAlpha
• CGColorGetColorSpace
• CGColorGetComponents
• CGColorGetNumberOfComponents
• CGColorGetPattern
• CGColorGetTypeID

Functions

CGColorCreate

Creates a Quartz color using a list of intensity values (including alpha) and an associated color space.

CGColorRef CGColorCreate (
   CGColorSpaceRef colorspace,
   const CGFloat components[]
);

CGColorCreateCopy

Creates a copy of an existing Quartz color.

CGColorRef CGColorCreateCopy (
   CGColorRef color
);

CGColorCreateCopyWithAlpha

Creates a copy of an existing Quartz color, substituting a new alpha value.

CGColorRef CGColorCreateCopyWithAlpha (
   CGColorRef color,
   CGFloat alpha
);

CGColorCreateGenericCMYK

Creates a color in the Generic CMYK color space.

CGColorRef CGColorCreateGenericCMYK(
   CGFloat cyan,
   CGFloat magenta,
   CGFloat yellow,
   CGFloat black,
   CGFloat alpha
);

CGColorCreateGenericGray

Creates a color in the Generic gray color space.

CGColorRef CGColorCreateGenericGray(
   CGFloat gray,
   CGFloat alpha
);

CGColorCreateGenericRGB

Creates a color in the Generic RGB color space.

CGColorRef CGColorCreateGenericRGB(
   CGFloat red,
   CGFloat green,
   CGFloat blue,
   CGFloat alpha
);

CGColorCreateWithPattern

Creates a Quartz color using a list of intensity values (including alpha), a pattern color space, and a pattern.

CGColorRef CGColorCreateWithPattern (
   CGColorSpaceRef colorspace,
   CGPatternRef pattern,
   const CGFloat components[]
);

CGColorEqualToColor

Indicates whether two colors are equal.

bool CGColorEqualToColor (
   CGColorRef color1,
   CGColorRef color2
);

CGColorGetAlpha

Returns the value of the alpha component associated with a Quartz color.

CGFloat CGColorGetAlpha (
   CGColorRef color
);

CGColorGetColorSpace

Returns the color space associated with a Quartz color.

CGColorSpaceRef CGColorGetColorSpace (
   CGColorRef color
);

CGColorGetComponents

Returns the values of the color components (including alpha) associated with a Quartz color.

const CGFloat * CGColorGetComponents (
   CGColorRef color
);

CGColorGetConstantColor

Returns a color object that represents a constant color.

CGColorRef CGColorGetConstantColor(
   CFStringRef colorName
);

CGColorGetNumberOfComponents

Returns the number of color components (including alpha) associated with a Quartz color.

size_t CGColorGetNumberOfComponents (
   CGColorRef color
);

CGColorGetPattern

Returns the pattern associated with a Quartz color in a pattern color space.

CGPatternRef CGColorGetPattern (
   CGColorRef color
);

CGColorGetTypeID

Returns the Core Foundation type identifier for a Quartz color data type.

CFTypeID CGColorGetTypeID (
   void
);

CGColorRelease

Decrements the retain count of a Quartz color.

void CGColorRelease (
   CGColorRef color
);

CGColorRetain

Increments the retain count of a Quartz color.

CGColorRef CGColorRetain (
   CGColorRef color
);

Data Types

CGColorRef

An opaque type that represents a color used in Quartz 2D drawing.

typedef struct CGColor *CGColorRef;

Constants

Constant Colors

Commonly used colors.

const CFStringRef kCGColorWhite;
const CFStringRef kCGColorBlack;
const CFStringRef kCGColorClear;

Constants

kCGColorWhite

The white color in the Generic gray color space.

Available in OS X v10.5 and later.

Declared in CGColor.h.

kCGColorBlack

The black color in the Generic gray color space.

Available in OS X v10.5 and later.

Declared in CGColor.h.

kCGColorClear

The clear color in the Generic gray color space.

Available in OS X v10.5 and later.

Declared in CGColor.h.