1 /*
2  * Copyright 2014 Google Inc.
3  *
4  *
5  * Use of this source code is governed by a BSD-style license that can be
6  * found in the LICENSE file.
7  *
8  */
9 
10 #ifndef SkV8Example_JsContext_DEFINED
11 #define SkV8Example_JsContext_DEFINED
12 
13 #include <v8.h>
14 
15 #include "SkPaint.h"
16 #include "DrawingMethods.h"
17 
18 class SkCanvas;
19 class Global;
20 
21 // Provides the canvas context implementation in JS, and the OnDraw() method in
22 // C++ that's used to bridge from C++ to JS. Should be used in JS as:
23 //
24 //  function onDraw(context) {
25 //    context.fillStyle="#FF0000";
26 //    context.fillRect(x, y, w, h);
27 //  }
28 class JsContext : public DrawingMethods {
29 public:
JsContext(Global * global)30     JsContext(Global* global)
31             : INHERITED(global)
32             , fCanvas(NULL)
33     {
34     }
~JsContext()35     virtual ~JsContext() {}
36 
37     // Parse the script.
38     bool initialize();
39 
40     // Call this with the SkCanvas you want onDraw to draw on.
41     void onDraw(SkCanvas* canvas);
42 
getCanvas()43     virtual SkCanvas* getCanvas() { return fCanvas; };
44 
45 private:
46 
47     // Wrap the 'this' pointer into an Object. Can be retrieved via Unwrap.
48     v8::Handle<v8::Object> wrap();
49 
50     // A handle to the onDraw function defined in the script.
51     v8::Persistent<v8::Function> fOnDraw;
52 
53     // The template for what a canvas context object looks like. The canvas
54     // context object is what's passed into the JS onDraw() function.
55     static v8::Persistent<v8::ObjectTemplate> gContextTemplate;
56 
57     // Only valid when inside OnDraw().
58     SkCanvas* fCanvas;
59 
60     typedef DrawingMethods INHERITED;
61 };
62 
63 #endif
64