一.相关的类(个人感觉必须要熟悉的)
CGPathRef,CGImageRef,CGLayerRef,CGPatternRef,CGShadingRef,CGGradientRef
其它
CGFunctionRef, used to define callback functions that take an arbitrary number of floating-point arguments. You use this data type when you create gradients for a shading. See “Gradients.”
CGColorRef and CGColorSpaceRef, used to inform Quartz how to interpret color. See “Color and Color Spaces.”
CGImageSourceRef and CGImageDestinationRef, which you use to move data into and out of Quartz. See “Data Management in Quartz 2D” and Image I/O Programming Guide.
CGFontRef, used to draw text. See “Text.”
CGPDFDictionaryRef, CGPDFObjectRef, CGPDFPageRef, CGPDFStream, CGPDFStringRef, and CGPDFArrayRef, which provide access to PDF metadata. See “PDF Document Creation, Viewing, and Transforming.”
CGPDFScannerRef and CGPDFContentStreamRef, which parse PDF metadata. See “PDF Document Parsing.”
CGPSConverterRef, used to convert PostScript to PDF. It is not available in iOS. See “PostScript Conversion.”
二.Graphics State
CGContextSaveGState
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