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Add safePrintableInset parameter for printing. #1950

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Add safePrintableInset parameter for printing. #1950

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Add safePrintableInset parameter for printing.
mstensho Feb 25, 2026
75e3e5a
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mstensho Feb 27, 2026
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Expand Up @@ -11313,6 +11313,13 @@ <h3><dfn>Print Page</dfn></h3>
<li><p>If <var>shrinkToFit</var> is not a <a>Boolean</a>
return <a>error</a> with <a>error code</a> <a>invalid argument</a>.

<li><p>Let <var>safePrintableInset</var> be the result of <a>getting a
property with default</a> named "<code>safePrintableInset</code>" and with
default <code>0</code> from <var>parameters</var>.
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@whimboo whimboo Feb 26, 2026

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This only defines the extraction of the safePrintableInset parameter but I do not see how it actually affects printing. So how can WebDriver actually control the right printing behavior of the browser?

I can see in the feature spec that page-margin-safety has the states none | clamp | add, while here a number is used. Will it be added as a paper setting similar to margin?

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@mstensho mstensho Feb 27, 2026

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This value is used to implement page-margin-safety. I added some spec text now.

For real printers in a real browser, try printing with Margins: Minimum. This is what this value is about. With page-margin-safety, this becomes web-exposed.


<li><p>If <var>safePrintableInset</var> is not a <a>Number</a>, or is less than 0,
return <a>error</a> with <a>error code</a> <a>invalid argument</a>.

<li><p>Let <var>pageRanges</var> be the result of <a>getting a
property with default</a> named "<code>pageRanges</code>" from
<var>parameters</var> with default of an
Expand Down Expand Up @@ -11364,6 +11371,13 @@ <h3><dfn>Print Page</dfn></h3>
page width specified in the content
</dl>

<p>The value of <var>safePrintableInset</var> defines the minimum inset along
each page edge needed to steer clear of the area that the printer is potentially
incapable of marking reliably. Most printers have a small region along each
edge of the page sheet which is unprintable, typically due to the printer's
paper handling mechanism. The document that is being printed may have CSS rules
to adjust page margins based on this. TODO: Link to spec, when it has landed?

<li><p>If <var>pageRanges</var> is not an empty <a>Array</a>,
Let <var>pages</var> be the result of <a>trying</a> to <a>parse a
page range</a> with arguments <var>pageRanges</var> and the number of
Expand Down