PDF: Portable Document Format Renders like PostScript; lacks its general purpose programming language. (Uses the Adobe Imaging Model same as PostScript) A PDF Document is: a collection of objects describing one or more pages optional interactive elements annotations actions on mouse/key input interactive form fields, can import/export their values. optional higher level application data ("structure" and "id") Text graphics and images includeable. PDF Content Stream: a sequence of graphic objects to be painted on the page. Paint by elements: lines, glyphs, geometric shapes, sampled data. Colors: B&W, Grayscale, Color, RepeatingPattern and ColorTransition Clipping ok. <1.3, overrendering overwrites. 1.4ff can composit over. Objects are characterized by a sequence of operators and operands. A path object is a sequence of construction operators, then Stroke or Fill. P = C* S Text object: one or more glyph shapes (stroked or filled) T = G+ Image Object: a rectangular array of color samples. Graphics State: a set of implicit parameters such as current color, line width, etc. (also clipping path) Objects can refer to other objects in any link pattern. XRef table at the end tells you where to find each one.