仕様書

canvas 要素の内容

[18] canvas 要素の内容は透過内容ですが、 子孫に制約があります。対話的内容は子孫にできませんが、 次の場合は認められています >>17。

[28] addHitRegion メソッドで指定できる要素は対応対話的canvasフォールバック要素supported interactive canvas fallback elementとされており、 次の要素です >>27。

canvas フォールバック内容

[1] ある要素が canvas 要素を祖先として持ち、直近のそれがレンダリングされているものであって、 埋め込み内容を表現している時、 これを関係する canvas のフォールバック内容として使われているbeing used as relevant canvas fallback contentといいます。 >>2

[5] そのような要素は直接はレンダリングされているわけではありませんが、フォーカスの処理においてはほぼレンダリングされている要素と同じように扱われています。

歴史

[4] >>1 の定義は >>3 で追加されました。

[6] Web Applications 1.0 r8485 Fix the condition for the <option> in the previous checkin, and reword this into a list so it's clearer ( (2014-02-21 07:39:00 +09:00 版)) http://html5.org/tools/web-apps-tracker?from=8484&to=8485

[7] Web Applications 1.0 r8544 More work on event rerouting for hit regions ( (2014-03-15 08:05:00 +09:00 版)) http://html5.org/tools/web-apps-tracker?from=8543&to=8544

[8] Web Applications 1.0 r8545 Exclude <input type=image> buttons from canvas fallback, to avoid having to define pixel-level retargetting in hit regions ( (2014-03-15 08:10:00 +09:00 版)) http://html5.org/tools/web-apps-tracker?from=8544&to=8545

[9] Web Applications 1.0 r8546 Also update the Touch object for hit regions ( (2014-03-15 08:56:00 +09:00 版)) http://html5.org/tools/web-apps-tracker?from=8545&to=8546

[10] Web Applications 1.0 r8548 Allow <img>-based and <input>-based image maps as canvas fallback (hit regions excludes those separately) ( (2014-03-18 05:08:00 +09:00 版)) http://html5.org/tools/web-apps-tracker?from=8547&to=8548

[11] Web Applications 1.0 r8564 Make addHitRegion() honour clip regions. ( (2014-04-03 12:44:00 +09:00 版)) http://html5.org/tools/web-apps-tracker?from=8563&to=8564

[12] Web Applications 1.0 r8484 Allow <select multiple> and <select size=4> to be used as canvas fallback ( (2014-02-21 07:34:00 +09:00 版)) http://html5.org/tools/web-apps-tracker?from=8483&to=8484

[13] Web Applications 1.0 r8491 Allow addHitRegion() to be used with elements that are only focusable because of tabindex= or sortable= (since they're basically just buttons at that point) ( (2014-02-21 08:33:00 +09:00 版)) http://html5.org/tools/web-apps-tracker?from=8490&to=8491

[14] Web Applications 1.0 r8494 Allow addHitRegion() to refer to non-interactive table-related elements, so that we can expose grids in canvases (e.g. crosswords) ( (2014-02-21 08:38:00 +09:00 版)) http://html5.org/tools/web-apps-tracker?from=8493&to=8494

[15] Web Applications 1.0 r8545 Exclude <input type=image> buttons from canvas fallback, to avoid having to define pixel-level retargetting in hit regions ( (2014-03-15 08:10:00 +09:00 版)) http://html5.org/tools/web-apps-tracker?from=8544&to=8545

[16] Web Applications 1.0 r8548 Allow <img>-based and <input>-based image maps as canvas fallback (hit regions excludes those separately) ( (2014-03-18 05:08:00 +09:00 版)) http://html5.org/tools/web-apps-tracker?from=8547&to=8548

[41] Web Applications 1.0 r8586 Remove the logic that prevents multiple regions from mapping to the same control, since there are use cases for that. ( (2014-04-30 04:39:00 +09:00 版)) http://html5.org/tools/web-apps-tracker?from=8585&to=8586

[48] Web Applications 1.0 r8747 Define an API to clear all the hit regions, for authors who don't need to use clearRect() since everything they paint is opaque. ( (2014-09-05 07:46:00 +09:00 版)) http://html5.org/r/8747

[42] IRC logs: freenode / #whatwg / 20140905 ( (2014-09-06 01:59:14 +09:00 版)) http://krijnhoetmer.nl/irc-logs/whatwg/20140905

[43] Fix #345: Remove table sorting model · whatwg/html@59b7e24 (2016-01-29 23:30:27 +09:00 版) https://github.com/whatwg/html/commit/59b7e2466c2b7c5c408a4963b05b13fd808aa07a

[44] CanvasRenderingContext2D.addHitRegion() - Web API インターフェイス | MDN ( (2015-02-25 03:24:33 +09:00)) https://developer.mozilla.org/ja/docs/Web/API/CanvasRenderingContext2D/addHitRegion

[45] Hit Regions - WebGL · Issue #1030 · whatwg/html ( (2016-05-13 15:33:44 +09:00)) https://github.com/whatwg/html/issues/1030

[46] Remove canvas element's hit region feature (for now) (annevk著, 2016-10-21 18:01:07 +09:00) https://github.com/whatwg/html/commit/9d493a37ed7e49c58522a3fed05d14bde1a8913c

[47] Remove CanvasProxy along with related concepts and complexities · whatwg/html@740634d (2016-03-08 18:45:30 +09:00 版) https://github.com/whatwg/html/commit/740634d0f30a3b76e9da166ac2fa8835fcc073ab

[49] Remove requirement left behind by hit-region removal (sideshowbarker著, 2016-11-25 23:16:56 +09:00) https://github.com/whatwg/html/commit/a26f9481d63b050d41ea9ea423128928ac8b47c9