Passing Canvas' 2D Context in Dart

Question

I have a function that accepts CanvasRenderingContext2D as a parameter and does the drawing. Whenever I try to pass it, I get this:

CanvasRenderingContext2D is not assignable to CanvasRenderingContext2D

That function looks like this:

  void draw(CanvasRenderingContext2D context) {
  ...
  }

I thought everything is passed as a reference in Dart (just like JS), which shouldn't cause such problems. Is there a way to say I want a reference to the object and not the object it self? Or is there something else I should know?

EDIT:

The problem was that in one file I imported dart:html and in another I had dart:dom. The names for corresponding interfaces are the same but they are different.

You are right. That was my problem. This error appeared before I realized that dart:dom and dart:html are not compatible with each other ;) — Pijusn, Apr 23 '12 at 15:50

score 1 · Accepted Answer · edited May 23 '17 at 12:22

1

This is likely because you are using dart:dom and dart:html in the same application. To avoid such errors you should import one of them with a namespace

#import('dart:html');
#import('dart:dom', prefix: 'dom');

then you can access code defined in both of them as

window     // dart:html window
dom.window // dart:dom window

for more information see this answer

edited May 23 '17 at 12:22

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answered Apr 23 '12 at 16:44

Lars Tackmann

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Passing Canvas' 2D Context in Dart

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