CGShading

A definition for a smooth transition between colors, controlled by a custom function you provide, for drawing radial and axial gradient fills.

Overview

Shading means to fill using a smooth transition between colors across an area. You create a shading using a custom function with a CGFunctionRef object. To paint with a Core Graphics shading, you call CGContextDrawShading. This function fills the current clipping path using the specified color gradient, calling your parametric function repeatedly as it draws.

An alternative to using a CGShading object is to use the CGGradientRef type. For applications that run in macOS 10.5 and later, CGGradient objects are much simpler to use. (See CGGradient.)

Topics

Creating Shading Objects

CGShadingCreateAxial

Creates a shading object to use for axial shading.

CGShadingCreateRadial

Creates a shading object to use for radial shading.

Retaining and Releasing Shading Objects

CGShadingRetain

Increments the retain count of a shading object.

CGShadingRelease

Decrements the retain count of a shading object.

Getting the CFType ID

CGShadingGetTypeID

Returns the Core Foundation type identifier for Core Graphics shading objects.

Data Types

CGShadingRef

A definition for a smooth transition between colors, controlled by a custom function you provide, for drawing radial and axial gradient fills.

See Also

Opaque Types

CGBitmapContext

A type of CGContextRef that you can use for drawing bits to memory.

CGColor

A set of components that define a color, with a color space specifying how to interpret them.

CGColorConversionInfo

An object that describes how to convert between color spaces for use by other system services.

CGColorSpace

A profile that specifies how to interpret a color value for display.

CGContext

A Quartz 2D drawing destination.

CGDataConsumer

An abstraction for data-writing tasks that eliminates the need to manage a raw memory buffer.

CGDataProvider

An abstraction for data-reading tasks that eliminates the need to manage a raw memory buffer.

CGFont

A set of character glyphs and layout information for drawing text.

CGFunction

A general facility for defining and using callback functions.

CGGLContext

Deprecated. A type of CGContextRef for drawing OpenGL content.

CGGradient

A definition for a smooth transition between colors for drawing radial and axial gradient fills.

CGImage

A bitmap image or image mask.

CGLayer

An offscreen context for reusing content drawn with Core Graphics.

CGPath

Immutable and mutable types for graphics paths: mathematical descriptions of shapes or lines to be drawn in a graphics context.

CGPattern

A 2D pattern to be used for drawing graphics paths.

CGPDFArray

An array structure within a PDF document.

CGPDFContentStream

A representation of one or more content data streams in a PDF page.

CGPDFContext

A type of CGContextRef for drawing PDF content.

CGPDFDictionary

A dictionary structure within a PDF document.

CGPDFDocument

A document that contains PDF (Portable Document Format) drawing information.

CGPDFObject

An object representing content within a PDF document.

CGPDFOperatorTable

A set of callback functions for operators used when scanning content in a PDF document.

CGPDFPage

A page in a PDF document.

CGPDFScanner

A parser object for handling content and operators in a PDF content stream.

CGPDFStream

A stream or sequence of data bytes in a PDF document.

CGPDFString

A text string in a PDF document.

CGPSConverter

An object that converts PostScript data to PDF data.