Merge pull request #373 from caldwell/linedash

Add support for the lineDash API

src/CanvasRenderingContext2d.cc

@@ -117,6 +117,8 @@ Context2d::Initialize(Handle<Object> target) {
   NODE_SET_PROTOTYPE_METHOD(ctor, "closePath", ClosePath);
   NODE_SET_PROTOTYPE_METHOD(ctor, "arc", Arc);
   NODE_SET_PROTOTYPE_METHOD(ctor, "arcTo", ArcTo);
+  NODE_SET_PROTOTYPE_METHOD(ctor, "setLineDash", SetLineDash);
+  NODE_SET_PROTOTYPE_METHOD(ctor, "getLineDash", GetLineDash);
   NODE_SET_PROTOTYPE_METHOD(ctor, "_setFont", SetFont);
 #ifdef HAVE_FREETYPE
   NODE_SET_PROTOTYPE_METHOD(ctor, "_setFontFace", SetFontFace);
@@ -137,6 +139,7 @@ Context2d::Initialize(Handle<Object> target) {
   proto->SetAccessor(NanSymbol("lineWidth"), GetLineWidth, SetLineWidth);
   proto->SetAccessor(NanSymbol("lineCap"), GetLineCap, SetLineCap);
   proto->SetAccessor(NanSymbol("lineJoin"), GetLineJoin, SetLineJoin);
+  proto->SetAccessor(NanSymbol("lineDashOffset"), GetLineDashOffset, SetLineDashOffset);
   proto->SetAccessor(NanSymbol("shadowOffsetX"), GetShadowOffsetX, SetShadowOffsetX);
   proto->SetAccessor(NanSymbol("shadowOffsetY"), GetShadowOffsetY, SetShadowOffsetY);
   proto->SetAccessor(NanSymbol("shadowBlur"), GetShadowBlur, SetShadowBlur);
@@ -2018,6 +2021,87 @@ NAN_METHOD(Context2d::SetTextAlignment) {
   NanReturnUndefined();
 }
 
+/*
+ * Set line dash
+ * ref: http://www.w3.org/TR/2dcontext/#dom-context-2d-setlinedash
+ */
+NAN_METHOD(Context2d::SetLineDash) {
+  NanScope();
+
+  if (!args[0]->IsArray()) NanReturnUndefined();
+  Handle<Array> dash = Handle<Array>::Cast(args[0]);
+  uint32_t dashes = dash->Length() & 1 ? dash->Length() * 2 : dash->Length();
+
+  double a[dashes];
+  for (uint32_t i=0; i<dashes; i++) {
+    Local<Value> d = dash->Get(i % dash->Length());
+    if (!d->IsNumber()) NanReturnUndefined();
+    a[i] = d->NumberValue();
+    if (a[i] < 0 || isnan(a[i]) || isinf(a[i])) NanReturnUndefined();
+  }
+
+  Context2d *context = ObjectWrap::Unwrap<Context2d>(args.This());
+  cairo_t *ctx = context->context();
+  double offset;
+  cairo_get_dash(ctx, NULL, &offset);
+  cairo_set_dash(ctx, a, dashes, offset);
+  NanReturnUndefined();
+}
+
+/*
+ * Get line dash
+ * ref: http://www.w3.org/TR/2dcontext/#dom-context-2d-setlinedash
+ */
+NAN_METHOD(Context2d::GetLineDash) {
+  NanScope();
+
+  Context2d *context = ObjectWrap::Unwrap<Context2d>(args.This());
+  cairo_t *ctx = context->context();
+  int dashes = cairo_get_dash_count(ctx);
+  double a[dashes];
+  cairo_get_dash(ctx, a, NULL);
+
+  Local<Array> dash = NanNew<Array>(dashes);
+  for (int i=0; i<dashes; i++)
+      dash->Set(NanNew<Number>(i), NanNew<Number>(a[i]));
+
+  NanReturnValue(dash);
+}
+
+/*
+ * Set line dash offset
+ * ref: http://www.w3.org/TR/2dcontext/#dom-context-2d-setlinedash
+ */
+NAN_SETTER(Context2d::SetLineDashOffset) {
+  NanScope();
+
+  double offset = value->NumberValue();
+  if (isnan(offset) || isinf(offset)) return;
+
+  Context2d *context = ObjectWrap::Unwrap<Context2d>(args.This());
+  cairo_t *ctx = context->context();
+
+  int dashes = cairo_get_dash_count(ctx);
+  double a[dashes];
+  cairo_get_dash(ctx, a, NULL);
+  cairo_set_dash(ctx, a, dashes, offset);
+}
+
+/*
+ * Get line dash offset
+ * ref: http://www.w3.org/TR/2dcontext/#dom-context-2d-setlinedash
+ */
+NAN_GETTER(Context2d::GetLineDashOffset) {
+  NanScope();
+
+  Context2d *context = ObjectWrap::Unwrap<Context2d>(args.This());
+  cairo_t *ctx = context->context();
+  double offset;
+  cairo_get_dash(ctx, NULL, &offset);
+
+  NanReturnValue(NanNew<Number>(offset));
+}
+
 /*
  * Fill the rectangle defined by x, y, width and height.
  */

src/CanvasRenderingContext2d.h

@@ -100,6 +100,8 @@ class Context2d: public node::ObjectWrap {
     static NAN_METHOD(SetStrokePattern);
     static NAN_METHOD(SetTextBaseline);
     static NAN_METHOD(SetTextAlignment);
+    static NAN_METHOD(SetLineDash);
+    static NAN_METHOD(GetLineDash);
     static NAN_METHOD(MeasureText);
     static NAN_METHOD(BezierCurveTo);
     static NAN_METHOD(QuadraticCurveTo);
@@ -121,6 +123,7 @@ class Context2d: public node::ObjectWrap {
     static NAN_GETTER(GetLineCap);
     static NAN_GETTER(GetLineJoin);
     static NAN_GETTER(GetLineWidth);
+    static NAN_GETTER(GetLineDashOffset);
     static NAN_GETTER(GetShadowOffsetX);
     static NAN_GETTER(GetShadowOffsetY);
     static NAN_GETTER(GetShadowBlur);
@@ -135,6 +138,7 @@ class Context2d: public node::ObjectWrap {
     static NAN_SETTER(SetLineCap);
     static NAN_SETTER(SetLineJoin);
     static NAN_SETTER(SetLineWidth);
+    static NAN_SETTER(SetLineDashOffset);
     static NAN_SETTER(SetShadowOffsetX);
     static NAN_SETTER(SetShadowOffsetY);
     static NAN_SETTER(SetShadowBlur);

test/public/tests.js

@@ -1850,4 +1850,69 @@ tests['putImageData() png data 3'] = function(ctx, done){
   };
   img.onerror = function(){}
   img.src = 'state.png';
-};
+};
+
+tests['setLineDash']  = function(ctx, done){
+  ctx.setLineDash([10, 5, 25, 15]);
+  ctx.lineWidth = 17;
+
+  var y=5;
+  var line = function(lineDash, color){
+    ctx.setLineDash(lineDash);
+    if (color) ctx.strokeStyle = color;
+    ctx.beginPath();
+    ctx.moveTo(0,   y);
+    ctx.lineTo(200, y);
+    ctx.stroke();
+    y += ctx.lineWidth + 4;
+  };
+
+  line([15, 30], "blue");
+  line([], "black");
+  line([5,10,15,20,25,30,35,40,45,50], "purple");
+  line([8], "green");
+  line([3, 3, -30], "red");
+  line([4, Infinity, 4]);
+  line([10, 10, NaN]);
+  line((function(){
+    ctx.setLineDash([8]);
+    var a = ctx.getLineDash();
+    a[0] -= 3;
+    a.push(20);
+    return a;
+  })(), "orange");
+};
+
+tests['lineDashOffset']  = function(ctx, done){
+  ctx.setLineDash([10, 5, 25, 15]);
+  ctx.lineWidth = 4;
+
+  var y=5;
+  var line = function(lineDashOffset, color){
+    ctx.lineDashOffset = lineDashOffset;
+    if (color) ctx.strokeStyle = color;
+    ctx.beginPath();
+    ctx.moveTo(0,   y);
+    ctx.lineTo(200, y);
+    ctx.stroke();
+    y += ctx.lineWidth + 4;
+  };
+
+  line(-10, "black");
+  line(0);
+  line(10);
+  line(20);
+  line(30);
+  line(40, "blue");
+  line(NaN)
+  line(50, "green");
+  line(Infinity)
+  line(60, "orange");
+  line(-Infinity)
+  line(70, "purple");
+  line(void 0)
+  line(80, "black");
+  line(ctx.lineDashOffset + 10);
+  for (var i=0; i<10; i++)
+    line(90 + i/5, "red");
+}