Core Graphics

利用Quartz技术的力量执行具有高保真输出的轻量级2D渲染。处理基于路径的绘图，抗锯齿渲染，渐变，图像，颜色管理，PDF文档等。

概述

Core Graphics框架基于Quartz高级绘图引擎。它提供了低级的轻量级的2D渲染，具有无与伦比的输出保真度。你使用此框架来处理基于路径的绘图，转换，颜色管理，屏幕外渲染，图案，渐变和阴影，图像数据管理，图像创建和图像蒙版，以及PDF文档的创建，显示和解析。

在macOS中，Core Graphics还包括用于处理显示硬件，低级用户输入事件和窗口系统的服务。

struct CGFloat The basic type for floating-point scalar values in Core Graphics and related frameworks.

struct CGPoint A structure that contains a point in a two-dimensional coordinate system.

struct CGSize A structure that contains width and height values.

struct CGRect A structure that contains the location and dimensions of a rectangle.

struct CGVector A structure that contains a two-dimensional vector.

struct CGAffineTransform An affine transformation matrix for use in drawing 2D graphics.

class CGContext

Quartz 2D绘图环境。
class CGImage A bitmap image or image mask.
class CGPath An immutable graphics path: a mathematical description of shapes or lines to be drawn in a graphics context.
class CGMutablePath A mutable graphics path: a mathematical description of shapes or lines to be drawn in a graphics context.
class CGLayer An offscreen context for reusing content drawn with Core Graphics.