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<span style="font-family: "Iosevka Fixed SS16", Arial, Helvetica, sans-serif; font-size: 14px; color: rgb(31, 35, 40);">This is interesting, similar to
</span><span style="font-family: "Iosevka Fixed SS16", Arial, Helvetica, sans-serif; font-size: 11.9px; color: rgb(31, 35, 40); background-color: rgba(129, 139, 152, 0.12);"><code style="font-family: "Iosevka Fixed SS16", Arial, Helvetica, sans-serif;">BufferedImage.createGraphics()</code></span><span style="font-family: "Iosevka Fixed SS16", Arial, Helvetica, sans-serif; font-size: 14px; color: rgb(31, 35, 40);"> in
AWT.</span></p>
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<span style="font-family: "Iosevka Fixed SS16", Arial, Helvetica, sans-serif; font-size: 14px; color: rgb(31, 35, 40);">Questions:</span></p>
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so this will <span style="font-weight: 600;" role="presentation">aways</span> be slower than Canvas?</li><li style="font-family: "Iosevka Fixed SS16", Arial, Helvetica, sans-serif; font-size: 14px; color: rgb(31, 35, 40); margin-top: 0.25em; margin-left: 24px;">
<div role="presentation">are the results going to be exactly the same, or there will be platform-specific differences in anti-aliasing etc?</div>
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Thanks!</div>
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-andy</div>
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<b>From: </b>openjfx-dev <openjfx-dev-retn@openjdk.org> on behalf of John Hendrikx <john.hendrikx@gmail.com><br>
<b>Date: </b>Monday, November 10, 2025 at 06:29<br>
<b>To: </b>openjfx-dev@openjdk.org <openjfx-dev@openjdk.org><br>
<b>Subject: </b>Feedback requested: Proof of concept PR for extending WritableImage with its own "graphics context" to draw higher level primitives directly :)<br>
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<div class="PlainText" style="font-size: 11pt;">I've extended WritableImage with a new method `getDrawingContext`.<br>
<br>
This method gives you a similar interface as Canvas's<br>
`getGraphicsContext`, minus some methods that I didn't implement yet<br>
(save/restore, font rendering, path rendering, line dashes).<br>
<br>
The method signatures are compatible, and we could have Canvas's<br>
GraphicsContext extend the DrawingContext interface.<br>
<br>
Using it is trivial:<br>
<br>
WritableImage img = new WritableImage(400, 400);<br>
DrawingContext ctx = img.getDrawingContext();<br>
ctx.setFill(Color.RED);<br>
ctx.fillRect(50, 50, 100, 100);<br>
<br>
Internally, this leverages the software renderer Pisces which is part of<br>
JavaFX. This means that FX can still be fully GPU accelerated, while<br>
for drawing into a heap based WritableImage can be done with the CPU. A<br>
big advantage here is that this makes it possible to draw complex images<br>
without having to snapshot them later if you need them to be images or<br>
having to resort to drawing all primitives yourself with just a PixelWriter.<br>
<br>
See this PR <a href="https://github.com/openjdk/jfx/pull/1969" data-outlook-id="163b037b-eae0-45a3-a4ba-59cf1804974f">
https://github.com/openjdk/jfx/pull/1969</a><br>
<br>
A screenshot and demo program is included.<br>
<br>
Feedback on the implementation is much appreciated.<br>
<br>
--John<br>
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