1 /* 2 * Copyright 2013 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkDocument_DEFINED 9 #define SkDocument_DEFINED 10 11 #include "SkRefCnt.h" 12 #include "SkScalar.h" 13 14 class SkCanvas; 15 class SkWStream; 16 struct SkRect; 17 18 /** SK_ScalarDefaultDPI is 72 dots per inch. */ 19 static constexpr SkScalar SK_ScalarDefaultRasterDPI = 72.0f; 20 21 /** 22 * High-level API for creating a document-based canvas. To use.. 23 * 24 * 1. Create a document, specifying a stream to store the output. 25 * 2. For each "page" of content: 26 * a. canvas = doc->beginPage(...) 27 * b. draw_my_content(canvas); 28 * c. doc->endPage(); 29 * 3. Close the document with doc->close(). 30 */ 31 class SK_API SkDocument : public SkRefCnt { 32 public: 33 34 /** 35 * Begin a new page for the document, returning the canvas that will draw 36 * into the page. The document owns this canvas, and it will go out of 37 * scope when endPage() or close() is called, or the document is deleted. 38 */ 39 SkCanvas* beginPage(SkScalar width, SkScalar height, const SkRect* content = nullptr); 40 41 /** 42 * Call endPage() when the content for the current page has been drawn 43 * (into the canvas returned by beginPage()). After this call the canvas 44 * returned by beginPage() will be out-of-scope. 45 */ 46 void endPage(); 47 48 /** 49 * Call close() when all pages have been drawn. This will close the file 50 * or stream holding the document's contents. After close() the document 51 * can no longer add new pages. Deleting the document will automatically 52 * call close() if need be. 53 */ 54 void close(); 55 56 /** 57 * Call abort() to stop producing the document immediately. 58 * The stream output must be ignored, and should not be trusted. 59 */ 60 void abort(); 61 62 protected: 63 SkDocument(SkWStream*); 64 65 // note: subclasses must call close() in their destructor, as the base class 66 // cannot do this for them. 67 virtual ~SkDocument(); 68 69 virtual SkCanvas* onBeginPage(SkScalar width, SkScalar height) = 0; 70 virtual void onEndPage() = 0; 71 virtual void onClose(SkWStream*) = 0; 72 virtual void onAbort() = 0; 73 74 // Allows subclasses to write to the stream as pages are written. getStream()75 SkWStream* getStream() { return fStream; } 76 77 enum State { 78 kBetweenPages_State, 79 kInPage_State, 80 kClosed_State 81 }; getState()82 State getState() const { return fState; } 83 84 private: 85 SkWStream* fStream; 86 State fState; 87 88 typedef SkRefCnt INHERITED; 89 }; 90 91 #endif 92