摘要： 【PDF Document Creation, Viewing, and Transforming】 Quartz provides the data type CGPDFDocumentRef to represent a PDF document. You create a CGPDFDocument object using either the function CGPDFDocumentCreateWithProvider or the function CGPDFDocumentCreateWithURL. After you create a CGPDFDocument obj. 阅读全文

摘要： 【Core Graphics Layer Drawing】CGLayer objects (CGLayerRef data type) allow your application to use layers for drawing.Layers are suited for the following:High-quality offscreen rendering of drawing that you plan to reuse.Repeated drawing.Buffering. Although you can use layers for this purpose, you sh 阅读全文