Fleshed out a lot of the Path interfac

experimental/SkV8Example/Path.cpp

+/*
+ * Copyright 2014 Google Inc.
+ *
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ */
+
+#include "Path.h"
+#include "Global.h"
+
+#define SkRadiansToDegrees(radians) ((radians) * (180 / SK_ScalarPI))
+
+Global* Path::gGlobal = NULL;
+
+void Path::ConstructPath(const v8::FunctionCallbackInfo<Value>& args) {
+    HandleScope handleScope(gGlobal->getIsolate());
+    Path* path = new Path();
+    args.This()->SetInternalField(0, External::New(path));
+}
+
+#define ADD_METHOD(name, fn) \
+    constructor->InstanceTemplate()->Set( \
+            String::NewFromUtf8( \
+                    global->getIsolate(), name, \
+                    String::kInternalizedString), \
+            FunctionTemplate::New(fn))
+
+// Install the constructor in the global scope so Paths can be constructed
+// in JS.
+void Path::AddToGlobal(Global* global) {
+    gGlobal = global;
+
+    // Create a stack-allocated handle scope.
+    HandleScope handleScope(gGlobal->getIsolate());
+
+    Handle<Context> context = gGlobal->getContext();
+
+    // Enter the scope so all operations take place in the scope.
+    Context::Scope contextScope(context);
+
+    Local<FunctionTemplate> constructor = FunctionTemplate::New(
+            Path::ConstructPath);
+    constructor->InstanceTemplate()->SetInternalFieldCount(1);
+
+    ADD_METHOD("close", ClosePath);
+    ADD_METHOD("moveTo", MoveTo);
+    ADD_METHOD("lineTo", LineTo);
+    ADD_METHOD("quadraticCurveTo", QuadraticCurveTo);
+    ADD_METHOD("bezierCurveTo", BezierCurveTo);
+    ADD_METHOD("arc", Arc);
+    ADD_METHOD("rect", Rect);
+
+    context->Global()->Set(String::New("Path"), constructor->GetFunction());
+}
+
+Path* Path::Unwrap(const v8::FunctionCallbackInfo<Value>& args) {
+    Handle<External> field = Handle<External>::Cast(
+            args.This()->GetInternalField(0));
+    void* ptr = field->Value();
+    return static_cast<Path*>(ptr);
+}
+
+void Path::ClosePath(const v8::FunctionCallbackInfo<Value>& args) {
+    Path* path = Unwrap(args);
+    path->fSkPath.close();
+}
+
+void Path::MoveTo(const v8::FunctionCallbackInfo<Value>& args) {
+    if (args.Length() != 2) {
+        args.GetIsolate()->ThrowException(
+                v8::String::NewFromUtf8(
+                        args.GetIsolate(), "Error: 2 arguments required."));
+        return;
+    }
+    double x = args[0]->NumberValue();
+    double y = args[1]->NumberValue();
+    Path* path = Unwrap(args);
+    path->fSkPath.moveTo(SkDoubleToScalar(x), SkDoubleToScalar(y));
+}
+
+void Path::LineTo(const v8::FunctionCallbackInfo<Value>& args) {
+    if (args.Length() != 2) {
+        args.GetIsolate()->ThrowException(
+                v8::String::NewFromUtf8(
+                        args.GetIsolate(), "Error: 2 arguments required."));
+        return;
+    }
+    double x = args[0]->NumberValue();
+    double y = args[1]->NumberValue();
+    Path* path = Unwrap(args);
+    path->fSkPath.lineTo(SkDoubleToScalar(x), SkDoubleToScalar(y));
+}
+
+void Path::QuadraticCurveTo(const v8::FunctionCallbackInfo<Value>& args) {
+    if (args.Length() != 4) {
+        args.GetIsolate()->ThrowException(
+                v8::String::NewFromUtf8(
+                        args.GetIsolate(), "Error: 4 arguments required."));
+        return;
+    }
+    double cpx = args[0]->NumberValue();
+    double cpy = args[1]->NumberValue();
+    double x = args[2]->NumberValue();
+    double y = args[3]->NumberValue();
+    Path* path = Unwrap(args);
+    // TODO(jcgregorio) Doesn't handle the empty last path case correctly per
+    // the HTML 5 spec.
+    path->fSkPath.quadTo(
+            SkDoubleToScalar(cpx), SkDoubleToScalar(cpy),
+            SkDoubleToScalar(x), SkDoubleToScalar(y));
+}
+
+void Path::BezierCurveTo(const v8::FunctionCallbackInfo<Value>& args) {
+    if (args.Length() != 6) {
+        args.GetIsolate()->ThrowException(
+                v8::String::NewFromUtf8(
+                        args.GetIsolate(), "Error: 6 arguments required."));
+        return;
+    }
+    double cp1x = args[0]->NumberValue();
+    double cp1y = args[1]->NumberValue();
+    double cp2x = args[2]->NumberValue();
+    double cp2y = args[3]->NumberValue();
+    double x = args[4]->NumberValue();
+    double y = args[5]->NumberValue();
+    Path* path = Unwrap(args);
+    // TODO(jcgregorio) Doesn't handle the empty last path case correctly per
+    // the HTML 5 spec.
+    path->fSkPath.cubicTo(
+            SkDoubleToScalar(cp1x), SkDoubleToScalar(cp1y),
+            SkDoubleToScalar(cp2x), SkDoubleToScalar(cp2y),
+            SkDoubleToScalar(x), SkDoubleToScalar(y));
+}
+
+void Path::Arc(const v8::FunctionCallbackInfo<Value>& args) {
+    if (args.Length() != 5 && args.Length() != 6) {
+        args.GetIsolate()->ThrowException(
+                v8::String::NewFromUtf8(
+                        args.GetIsolate(), "Error: 5 or 6 args required."));
+        return;
+    }
+    double x          = args[0]->NumberValue();
+    double y          = args[1]->NumberValue();
+    double radius     = args[2]->NumberValue();
+    double startAngle = args[3]->NumberValue();
+    double endAngle   = args[4]->NumberValue();
+    bool antiClockwise = false;
+    if (args.Length() == 6) {
+       antiClockwise = args[5]->BooleanValue();
+    }
+    double sweepAngle;
+    if (!antiClockwise) {
+      sweepAngle = endAngle - startAngle;
+    } else {
+      sweepAngle = startAngle - endAngle;
+      startAngle = endAngle;
+    }
+
+    Path* path = Unwrap(args);
+    SkRect rect = {
+        SkDoubleToScalar(x-radius),
+        SkDoubleToScalar(y-radius),
+        SkDoubleToScalar(x+radius),
+        SkDoubleToScalar(y+radius)
+    };
+
+    path->fSkPath.addArc(rect, SkRadiansToDegrees(startAngle),
+                         SkRadiansToDegrees(sweepAngle));
+}
+
+void Path::Rect(const v8::FunctionCallbackInfo<Value>& args) {
+    if (args.Length() != 4) {
+        args.GetIsolate()->ThrowException(
+                v8::String::NewFromUtf8(
+                        args.GetIsolate(), "Error: 4 arguments required."));
+        return;
+    }
+    double x = args[0]->NumberValue();
+    double y = args[1]->NumberValue();
+    double w = args[2]->NumberValue();
+    double h = args[3]->NumberValue();
+
+    SkRect rect = {
+        SkDoubleToScalar(x),
+        SkDoubleToScalar(y),
+        SkDoubleToScalar(x) + SkDoubleToScalar(w),
+        SkDoubleToScalar(y) + SkDoubleToScalar(h)
+    };
+    Path* path = Unwrap(args);
+    path->fSkPath.addRect(rect);
+}
+