USVString <span data-x="dom-canvas-toDataURL">toDataURL</span>(optional DOMString type, any... arguments);

void <span data-x="dom-canvas-toBlob">toBlob</span>(<span>BlobCallback</span> _callback, optional DOMString type, any... arguments);

<dt><var>url</var> = <var>canvas</var> . <code subdfn data-x="dom-canvas-toDataURL">toDataURL</code>( [ <var>type</var>, ... ] )</dt>

JPEG). The default is <code data-x="">image/png</code>; that type is also used if the given type

isn't supported. The other arguments are specific to the type, and control the way that the

image is generated, as given <a href="#canvas-serialisation-arguments">in the table

below</a>.</p>

<dt><var>canvas</var> . <code subdfn data-x="dom-canvas-toBlob">toBlob</code>(<var>callback</var> [, <var>type</var>, ... ] )</dt>

JPEG). The default is <code data-x="">image/png</code>; that type is also used if the given type

isn't supported. The other arguments are specific to the type, and control the way that the

image is generated, as given <a href="#canvas-serialisation-arguments">in the table

below</a>.</p>

<p>The <dfn><code data-x="dom-canvas-toDataURL">toDataURL()</code></dfn> method must run the

following steps:</p>

<li><p>If the <code>canvas</code> element's bitmap's <span

<li><p>If the <code>canvas</code> element's bitmap has no pixels (i.e. either its horizontal

serialisation of the <code>canvas</code> element's bitmap as a file</span>, using the method's

arguments (if any) as the <var>arguments</var>.</p></li>

<p>The <dfn><code data-x="dom-canvas-toBlob">toBlob()</code></dfn> method must run the following

steps:</p>

<li><p>Let <var>callback</var> be the first argument.</p></li>

<li><p>Let <var>arguments</var> be the second and subsequent arguments to the method, if

any.</p></li>

bitmap as a file</span>, using <var>arguments</var>. <ref spec=FILEAPI> </p>

<li><p><span>Queue a task</span> to invoke the <code>BlobCallback</code> <var>callback</var> with

<var>result</var> as its argument. The <span>task source</span> for this task is the <dfn>canvas

blob serialisation task source</dfn>.</p></li>

<p>When a user agent is to create <dfn>a serialisation of the bitmap as a file</dfn>, optionally

with some given <var>arguments</var>, and optionally with a <var>native</var> flag set, it must

create an image file in the format given by the first value of <var>arguments</var>, or, if there

are no <var>arguments</var>, in the PNG format. <ref spec=PNG></p>

<p>If the <var>native</var> flag is set, or if the bitmap has one pixel per coordinate space unit,

then the image file must have the same pixel data (before compression, if applicable) as the

bitmap, and if the file format used supports encoding resolution metadata, the resolution of that

bitmap (device pixels per coordinate space units being interpreted as image pixels per <span

data-x="'px'">CSS pixel</span>) must be given as well.</p>

<p>Otherwise, the image file's pixel data must be the bitmap's pixel data scaled to one image

pixel per coordinate space unit, and if the file format used supports encoding resolution

metadata, the resolution must be given as 96dpi (one image pixel per <span data-x="'px'">CSS

pixel</span>).</p>

<p>If <var>arguments</var> is not empty, the first value must be interpreted as a <span

data-x="MIME type">MIME type</span> giving the format to use. If the type has any parameters, it

must be treated as not supported.</p>

<p>If the first argument in <var>arguments</var> gives a type corresponding to one of the

types given in the first column of the following table, and the user agent supports that type,

then the subsequent arguments, if any, must be treated as described in the second cell of that

row.</p>

</div>

<table id="canvas-serialisation-arguments">

<caption>Arguments for serialisation methods</caption>

<thead>

<tr> <th> Type <th> Other arguments <th> Reference

<tbody>

<tr>

<td> <code>image/jpeg</code>

<td> The second argument<span w-nodev>, if it</span> is a number in the range 0.0 to 1.0

inclusive<span w-nodev>, must be</span> treated as the desired quality level. <span

w-nodev>If it is not a number or is outside that range, the user agent must use its

default value, as if the argument had been omitted.</span>

<td> <ref spec=JPEG>

</table>

<div w-nodev>

<p>For the purposes of these rules, an argument is considered to be a number if it is converted to

an IDL double value by the rules for handling arguments of type <code data-x="">any</code> in the

Web IDL specification. <ref spec=WEBIDL></p>

<p>Other arguments must be ignored and must not cause the user agent to throw an exception. A

future version of this specification will probably define other parameters to be passed to these

methods to allow authors to more carefully control compression settings, image metadata, etc.</p>