moz-opaque
属性[1] HTMLCanvasElement.mozOpaque - Web API Interfaces | MDN ( 版) <https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement.mozOpaque>
[2] 430906 – Add moz-opaque attribute on canvas ( 版) <https://bugzilla.mozilla.org/show_bug.cgi?id=430906>
alpha
オプション[3] CanvasOpaque - WHATWG Wiki ( 版) <https://wiki.whatwg.org/wiki/CanvasOpaque>
[4] Re: [whatwg] Enabling LCD Text and antialiasing in canvas (Stephen White 著, 版) <https://lists.w3.org/Archives/Public/public-whatwg-archive/2013Mar/0109.html>
[5] [webkit-dev] New web-facing canvas feature: "opaque" attribute ( 版) <https://lists.webkit.org/pipermail/webkit-dev/2013-March/024141.html>
[92] Web Applications 1.0 r8755 Define getContext('2d', {alpha:false}). ( ( 版)) <http://html5.org/r/8755>