Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Add a lang IDL Attribute to CanvasTextDrawingStyles, and clarify "direction" on same #10873

Merged
merged 24 commits into from
Mar 4, 2025
Merged

Add a lang IDL Attribute to CanvasTextDrawingStyles, and clarify "direction" on same #10873

Changes from 9 commits
Commits
Show all changes
24 commits
Select commit Hold shift + click to select a range
eba506c
Add the lang IDL attribute to CanvasTextDrawingStyles
schenney-chromium Dec 18, 2024
caa22ca
Merge branch 'whatwg:main' into main
schenney-chromium Dec 18, 2024
488b95b
Fix Developer info
schenney-chromium Dec 18, 2024
01e6185
Merge branch 'whatwg:main' into main
schenney-chromium Jan 10, 2025
b6df5ee
Merge branch 'whatwg:main' into main
schenney-chromium Jan 22, 2025
1b5a1df
Post review revisions
schenney-chromium Jan 22, 2025
152e3a4
Clean up offscreen snapshot behavior
schenney-chromium Jan 23, 2025
60a5971
Fix the setter/getter for lang.
schenney-chromium Jan 23, 2025
720ff90
Next round of edits.
schenney-chromium Jan 23, 2025
c131fd6
Merge branch 'whatwg:main' into main
schenney-chromium Feb 3, 2025
119a4c5
Update the offscreen transfer steps, and clarify lang rules.
schenney-chromium Feb 3, 2025
25efd43
Text cleanup
schenney-chromium Feb 4, 2025
369688c
Post-review update
schenney-chromium Feb 5, 2025
7e5c880
Update link to content language
schenney-chromium Feb 5, 2025
37d7233
Minor cleanup
schenney-chromium Feb 14, 2025
e999e9e
Merge branch 'whatwg:main' into main
schenney-chromium Feb 21, 2025
f129f9b
Next iteration
schenney-chromium Feb 22, 2025
bf760d7
Update with latest review fixes.
schenney-chromium Feb 24, 2025
12d6c1f
Extract OffscreenCanvas constructor steps.
schenney-chromium Feb 25, 2025
779363e
Next round of edits.
schenney-chromium Feb 26, 2025
cdd56da
Fix annotaton of direction inherit.
schenney-chromium Feb 26, 2025
2e79feb
More formatting cleanup and text improvements.
schenney-chromium Feb 26, 2025
c19feba
More cleanup.
schenney-chromium Feb 27, 2025
ef5c3bd
Final edit.
schenney-chromium Feb 27, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
173 changes: 131 additions & 42 deletions source
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -65332,13 +65332,21 @@ callback <dfn callback>BlobCallback</dfn> = undefined (<span>Blob</span>? blob);
and <code data-x="attr-canvas-height">height</code> content attributes of this
<code>canvas</code> element.</p></li>

<li><p>Set the <span data-x="offscreencanvas-placeholder">placeholder <code>canvas</code>
element</span> of <var>offscreenCanvas</var> to a weak reference to this <code>canvas</code>
element.</p></li>
<li><p>Set the <var>offscreenCanvas</var>'s <span
data-x="offscreencanvas-placeholder">placeholder <code>canvas</code> element</span> of <var>
offscreenCanvas</var> to a weak reference to this <code>canvas</code> element.</p></li>

<li><p>Set this <code>canvas</code> element's <span data-x="concept-canvas-context-mode">context
mode</span> to <span data-x="concept-canvas-placeholder">placeholder</span>.</p></li>

<li><p>Set the <var>offscreenCanvas</var>'s <span
data-x="offscreencanvas-inherited-lang">inherited language</span> to the <span
data-x="language">language</span> of this <code>canvas</code> element.</p></li>

<li><p>Set the <var>offscreenCanvas</var>'s <span
data-x="offscreencanvas-inherited-direction">inherited direction</span> to the <span
data-x="the directionality">directionality</span> of this <code>canvas</code> element.</p></li>

<li><p>Return <var>offscreenCanvas</var>.</p></li>
</ol>

Expand Down Expand Up @@ -65549,6 +65557,7 @@ interface mixin <dfn interface>CanvasPathDrawingStyles</dfn> {

interface mixin <dfn interface>CanvasTextDrawingStyles</dfn> {
// text
attribute DOMString <span data-x="dom-context-2d-lang">lang</span>; // (default: "inherit")
attribute DOMString <span data-x="dom-context-2d-font">font</span>; // (default 10px sans-serif)
attribute <span>CanvasTextAlign</span> <span data-x="dom-context-2d-textAlign">textAlign</span>; // (default: "start")
attribute <span>CanvasTextBaseline</span> <span data-x="dom-context-2d-textBaseline">textBaseline</span>; // (default: "alphabetic")
Expand Down Expand Up @@ -66022,6 +66031,7 @@ context.fillRect(100,0,50,50); // only this square remains</code></pre>
data-x="dom-context-2d-shadowOffsetX">shadowOffsetX</code>, <code
data-x="dom-context-2d-shadowOffsetY">shadowOffsetY</code>, <code
data-x="dom-context-2d-shadowBlur">shadowBlur</code>, <code
data-x="dom-context-2d-lang">lang</code>, <code
data-x="dom-context-2d-font">font</code>, <code
data-x="dom-context-2d-textAlign">textAlign</code>, <code
data-x="dom-context-2d-textBaseline">textBaseline</code>, <code
Expand Down Expand Up @@ -66516,13 +66526,27 @@ transform. ack Shaun Morris. -->
<h6>Text styles</h6>

<dl class="domintro">
<dt><code data-x=""><var>context</var>.<span subdfn data-x="dom-context-2d-lang">lang</span> [ = <var>value</var> ]</code></dt>
<dt><code data-x=""><var>styles</var>.<span data-x="dom-context-2d-lang">lang</span> [ = <var>value</var> ]</code></dt>
<dd>
<p>Returns the current language setting.</p>

<p>Can be set, to change the language used when resolving fonts. The syntax and valid values
are the same as those for the <span data-x="attr-lang">lang</span> element attribute, or the
value "<code data-x="dom-context-2d-direction-inherit">inherit</code>" which is described
below.</p>

<p>The default is "<code data-x="dom-context-2d-direction-inherit">inherit</code>".</p>
</dd>

<dt><code data-x=""><var>context</var>.<span subdfn data-x="dom-context-2d-font">font</span> [ = <var>value</var> ]</code></dt>
<dt><code data-x=""><var>styles</var>.<span data-x="dom-context-2d-font">font</span> [ = <var>value</var> ]</code></dt>
<dd>
<p>Returns the current font settings.</p>

<p>Can be set, to change the font. The syntax is the same as for the CSS <span>'font'</span>
property; values that cannot be parsed as CSS font values are ignored.</p>
property; values that cannot be parsed as CSS font values are ignored. The default is "10px
sans-serif".</p>

<p>Relative keywords and lengths are computed relative to the font of the <code>canvas</code>
element.</p>
Expand Down Expand Up @@ -66694,15 +66718,53 @@ worker.postMessage(offscreenCanvas, [offscreenCanvas]);</code></pre>
Notice that the font is only loaded inside the worker, and not in the document context.</p>
</div>

<p>Objects that implement the <code>CanvasTextDrawingStyles</code> interface have a <dfn attribute
for="CanvasTextDrawingStyles"><code data-x="dom-context-2d-lang">lang</code></dfn> attribute
that controls localization of the font. It is used to set the internal <dfn
data-x="concept-CanvasTextDrawingStyles-font-language">font language</dfn> used when setting the
<code data-x="dom-context-2d-font">font</code> attribute.</p>

<p>The <code data-x="dom-context-2d-lang">lang</code> getter steps are to return the current
value.</p>

<p>The <code data-x="dom-context-2d-lang">lang</code> setter steps are:</p>

<ol>
<li><p>Change the current value to the new value.</p></li>
<li><p>If the value is "<code data-x="dom-context-2d-direction-inherit">inherit</code>", then</p>
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This should probably perform the same checks as in https://whatpr.org/html/10873/dom.html#the-lang-and-xml:lang-attributes so that it's limited to BCP 47 allowed values and the special inherit value (, and maybe ""?)

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yeah, it says it must be valid, but then it says:
If the resulting value is not a recognized language tag, then it must be treated as an unknown language having the given language tag, distinct from all other languages. For the purposes of round-tripping or communicating with other services that expect language tags, user agents should pass unknown language tags through unmodified, and tagged as being BCP 47 language tags, so that subsequent services do not interpret the data as another type of language description. [[BCP47]](https://whatpr.org/html/10873/references.html#refsBCP47)

So maybe say it must be valid but the UA must still pass invalid values through unmodified?

<ol>
<li><p>If <var>object</var>'s <span>font style source object</span> is a <code>canvas</code>
element, then set the <span data-x="concept-CanvasTextDrawingStyles-font-language">font
language</span> to the element's <span data-x="language">language</span>.</p></li>

<li><p>Otherwise, <var>object</var>'s <span>font style source object</span> is an
<code>OffscreenCanvas</code> object. Set the <span
data-x="concept-CanvasTextDrawingStyles-font-language">
font language</span> to the <code>OffscreenCanvas</code>'s internal
<span data-x="offscreencanvas-inherited-lang">inherited language</span>.</p></li>
</ol>
</li>
<li><p>Otherwise, the <span data-x="concept-CanvasTextDrawingStyles-font-language">font
language</span> is the value.</p></li>
</ol>

<p>When the object implementing the <code>CanvasTextDrawingStyles</code> interface is created,
the <code data-x="dom-context-2d-lang">lang</code> attribute must initially have the value
"<code data-x="dom-context-2d-direction-inherit">inherit</code>" and the
<span data-x="concept-CanvasTextDrawingStyles-font-language">font language</span> must be set as
above.</p>

<p>The <dfn attribute for="CanvasTextDrawingStyles"><code
data-x="dom-context-2d-font">font</code></dfn> IDL attribute, on setting, must be <span
data-x="parse something according to a CSS grammar">parsed as a CSS &lt;'font'> value</span> (but
without supporting property-independent style sheet syntax like 'inherit'), and the resulting font
must be assigned to the context, with the <span>'line-height'</span> component forced to 'normal',
with the <span>'font-size'</span> component converted to <span data-x="'px'">CSS pixels</span>,
and with system fonts being computed to explicit values. If the new value is syntactically
incorrect (including using property-independent style sheet syntax like 'inherit' or 'initial'),
then it must be ignored, without assigning a new font value. <ref>CSS</ref></p>
must be assigned to the context, with the <span
data-x="concept-CanvasTextDrawingStyles-font-language">font language</span> as determined above,
with the <span>'line-height'</span> component forced to 'normal', with the
<span>'font-size'</span> component converted to <span data-x="'px'">CSS pixels</span>, and with
system fonts being computed to explicit values. If the new value is syntactically incorrect
(including using property-independent style sheet syntax like 'inherit' or 'initial'), then it
must be ignored, without assigning a new font value.<ref>CSS</ref></p>

<p>Font family names must be interpreted in the context of the <span>font style source
object</span> when the font is to be used; any fonts embedded using <code
Expand Down Expand Up @@ -66900,16 +66962,30 @@ worker.postMessage(offscreenCanvas, [offscreenCanvas]);</code></pre>

<dd><p>Treat input to the <span>text preparation algorithm</span> as right-to-left text.</p></dd>

<!--
<dt><dfn><code data-x="dom-context-2d-direction-auto">auto</code></dfn>
<dt><dfn enum-value for="CanvasDirection"><code data-x="dom-context-2d-direction-inherit">inherit</code></dfn>

<dd><p>Determine the direction from the input to the <span>text preparation algorithm</span>.</p></dd>
-->
<dd><p>Use the following process to determine the value for the
<dfn for="CanvasDirection"><code data-x="dom-context-2d-inherited-direction">inherited direction</code></dfn> referred to in the <span>text preparation algorithm</span></p>

<dt><dfn enum-value for="CanvasDirection"><code data-x="dom-context-2d-direction-inherit">inherit</code></dfn>
<ol>
<li><p>If <var>object</var>'s <span>font style source object</span> is a <code>canvas</code>
element:</p>
<ol>
<li><p>If the element has a <span>computed value</span> for
<span>'direction'</span> use that as the <span data-x="dom-context-2d-inherited-direction">inherited direction</span>.</p></li>

<li><p>Otherwise, use the <span data-x="the directionality">directionality</span>
of the element as the <span data-x="dom-context-2d-inherited-direction">inherited direction</span>.</p></li>
</ol>

<dd><p>Default to the directionality of the <code>canvas</code> element or <code>Document</code>
as appropriate.</p></dd>
<li><p>Otherwise, <var>object</var>'s <span>font style source object</span> is an
<code>OffscreenCanvas</code> object. Set the <span
data-x="dom-context-2d-inherited-direction">inherited direction</span> to the
<code>OffscreenCanvas</code>'s internal <span
data-x="offscreencanvas-inherited-direction">inherited
direction</span>.</p></li>
</ol>
</dd>
</dl>

<p>The <code data-x="dom-context-2d-fontKerning">fontKerning</code> attribute's allowed keywords
Expand Down Expand Up @@ -67033,32 +67109,11 @@ worker.postMessage(offscreenCanvas, [offscreenCanvas]);</code></pre>
data-x="dom-context-2d-direction-rtl">rtl</code>"</dt>
<dd>Let <var>direction</var> be '<span data-x="concept-rtl">rtl</span>'.</dd>

<!--
<dt>If the <var>target</var> object's <code
data-x="dom-context-2d-direction">direction</code> attribute has the value "<code
data-x="dom-context-2d-direction-auto">auto</code>"</dt>
<dd>
Find the first character in <var>text</var> of bidirectional character type L, AL, or
R, if any. If such a character is found and it is of bidirectional character type AL or R,
then let <var>direction</var> be '<span data-x="concept-rtl">rtl</span>'; otherwise,
let <var>direction</var> be '<span data-x="concept-rtl">rtl</span>'. <ref>BIDI</ref>
</dd>
-->

<dt>If the <var>target</var> object's <span>font style source object</span> is an
element</dt>

<dd>Let <var>direction</var> be <span>the directionality</span> of the <var>target</var> object's <span>font style source object</span>.</dd>

<dt>If the <var>target</var> object's <span>font style source object</span> is a
<code>Document</code> with a non-null <span>document element</span></dt>

<dd>Let <var>direction</var> be <span>the directionality</span> of the <var>target</var>
object's <span>font style source object</span>'s <span>document element</span>.</dd>

<dt>Otherwise</dt>

<dd>Let <var>direction</var> be '<span data-x="concept-ltr">ltr</span>'.</dd>
data-x="dom-context-2d-direction-inherit">inherit</code>"</dt>
<dd>Let <var>direction</var> be the <var>target</var>'s <span
data-x="dom-context-2d-inherited-direction">inherited direction</span>.</dd>
</dl>
</li>

Expand Down Expand Up @@ -71268,6 +71323,11 @@ interface <dfn interface>OffscreenCanvas</dfn> : <span>EventTarget</span> {
data-x="dom-OffscreenCanvas-height">height</code> attributes of the <code>OffscreenCanvas</code>
object. Initially, all the bitmap's pixels are <span>transparent black</span>.</p>

<p>An <code>OffscreenCanvas</code> object has an internal <dfn
data-x="offscreencanvas-inherited-lang">inherited language</dfn> and <dfn
data-x="offscreencanvas-inherited-direction">inherited direction</dfn> set when
the <code>OffscreenCanvas</code> is created.</p>

<p>An <code>OffscreenCanvas</code> object can have a rendering context bound to it. Initially,
it does not have a bound rendering context. To keep track of whether it has a rendering context
or not, and what kind of rendering context it is, an <code>OffscreenCanvas</code> object also
Expand All @@ -71288,9 +71348,37 @@ interface <dfn interface>OffscreenCanvas</dfn> : <span>EventTarget</span> {
array of <span>transparent black</span> pixels of the dimensions specified by <var>width</var> and
<var>height</var>; and its <code data-x="dom-OffscreenCanvas-width">width</code> and <code
data-x="dom-OffscreenCanvas-height">height</code> attributes initialized to <var>width</var> and
<var>height</var> respectively.</p>
<var>height</var> respectively. The <span data-x="offscreencanvas-inherited-lang">inherited
language</span> and <span data-x="offscreencanvas-inherited-direction">inherited direction</span>
internal values must be set as follows:</p>

<hr>
<ol>
<li><p>Let <var>global</var> be the <code>OffscreenCanvas</code>'s <span>relevant global
object</span>.</p></li>
<li><p>If <var>global</var> is a <code>Window</code> object:</p>
<ol>
<li><p>Let <var>Document</var> be the <var>global</var>'s
<span data-x="concept-document-window">associated <code>Document</code></span>.</p></li>

<li><p>Set the <code>OffscreenCanvas</code>'s <span
data-x="offscreencanvas-inherited-lang">inherited language</span> to the
<var>Document</var>'s <span data-x="language">language</span>.</p></li>

<li><p>Set the <code>OffscreenCanvas</code>'s <span
data-x="offscreencanvas-inherited-direction">inherited direction</span>
to the <var>Document</var>'s <span data-x="the directionality">directionality</span>.</p></li>
</ol>
</li>
<li><p>Otherwise:</p>
<ol>
<li><p>Set the <span data-x="offscreencanvas-inherited-lang">inherited language</span>
to explicitly unknown.</p></li>

<li><p>Set the <span data-x="offscreencanvas-inherited-direction">inherited direction</span>
to "ltr".</p></li>
</ol>
</li>
</ol>

<p><code>OffscreenCanvas</code> objects are <span data-x="transferable
objects">transferable</span>. Their <span>transfer steps</span>, given <var>value</var> and
Expand Down Expand Up @@ -146999,6 +147087,7 @@ INSERT INTERFACES HERE
Ştefan Vargyas,
Stefan Weiss,
Steffen Meschkat,
Stephen Chenney,
Stephen Ma,
Stephen Stewart,
Stephen White,
Expand Down