Make setLineDash able to handle full zeroed dashes (Automattic#1060)

* added fix and test Fixes Automattic#1055
zbjornson · Dec 21, 2017 · 727cb2c · 727cb2c
1 parent 7c9ec58
commit 727cb2c
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Showing 2 changed files with 12 additions and 3 deletions.
diff --git a/src/CanvasRenderingContext2d.cc b/src/CanvasRenderingContext2d.cc
@@ -2193,20 +2193,26 @@ NAN_METHOD(Context2d::SetLineDash) {
   if (!info[0]->IsArray()) return;
   Local<Array> dash = Local<Array>::Cast(info[0]);
   uint32_t dashes = dash->Length() & 1 ? dash->Length() * 2 : dash->Length();
-
+  uint32_t zero_dashes = 0;
   std::vector<double> a(dashes);
   for (uint32_t i=0; i<dashes; i++) {
     Local<Value> d = dash->Get(i % dash->Length());
     if (!d->IsNumber()) return;
     a[i] = d->NumberValue();
+    if (a[i] == 0) zero_dashes++;
     if (a[i] < 0 || isnan(a[i]) || isinf(a[i])) return;
   }
 
   Context2d *context = Nan::ObjectWrap::Unwrap<Context2d>(info.This());
   cairo_t *ctx = context->context();
   double offset;
   cairo_get_dash(ctx, NULL, &offset);
-  cairo_set_dash(ctx, a.data(), dashes, offset);
+  if (zero_dashes == dashes) {
+    std::vector<double> b(0);
+    cairo_set_dash(ctx, b.data(), 0, offset);
+  } else {
+    cairo_set_dash(ctx, a.data(), dashes, offset);
+  }
 }
 
 /*

diff --git a/test/public/tests.js b/test/public/tests.js
@@ -2069,7 +2069,7 @@ tests['putImageData() png data 3'] = function (ctx, done) {
 
 tests['setLineDash'] = function (ctx) {
   ctx.setLineDash([10, 5, 25, 15])
-  ctx.lineWidth = 17
+  ctx.lineWidth = 14
 
   var y = 5
   var line = function (lineDash, color) {
@@ -2096,6 +2096,9 @@ tests['setLineDash'] = function (ctx) {
     a.push(20)
     return a
   })(), 'orange')
+  line([0, 0], 'purple') // should be full
+  line([0, 0, 3, 0], 'orange') // should be full
+  line([0, 3, 0, 0], 'green') // should be empty
 }
 
 tests['lineDashOffset'] = function (ctx) {