<?xml version="1.0" encoding="UTF-8"?><rss xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:atom="http://www.w3.org/2005/Atom" version="2.0"><channel><title><![CDATA[odd error Parenting and QGraphicsScene coordinate transforms]]></title><description><![CDATA[<p dir="auto">I am writing a graphical node-edge editor, and am implementing hyperedges - single edges but with more than two ends. These are drawn between nodes, as can be seen in the image below, of 2 starting nodes and one ending node.</p>
<p dir="auto"><img src="https://ddgobkiprc33d.cloudfront.net/cf62e33d-f7fa-404a-a4f1-bf7da97eddd1.png" alt="6b42218f-4aba-4a6d-b5cb-64fdd2df0050-image.png" class=" img-fluid img-markdown" /></p>
<p dir="auto">The following has 2 ending nodes:<br />
<img src="https://ddgobkiprc33d.cloudfront.net/5bd1d9af-a3db-4642-8bd3-f1cfc0cb26cd.png" alt="7096ed91-ccf1-4941-a62c-3590e9b95c33-image.png" class=" img-fluid img-markdown" /></p>
<p dir="auto">The objects and code for creating these is nearly identical, with only the commands and lists for which end changing between the two. The 2-starts version can be dragged around perfectly, but the 2-ends version does this, with the end positions being updated 'twice' - by the same code that works for the 2-starts version.<br />
<img src="https://ddgobkiprc33d.cloudfront.net/bfe95016-0450-4bf0-aac9-b18bd1ddafea.png" alt="19675174-5e88-4f73-90d9-5fb6b5539bc1-image.png" class=" img-fluid img-markdown" /><br />
If I add another 'end' to the working one, it starts giving the error too.</p>
<p dir="auto">This looks like a <code>scenePos</code> vs <code>pos</code> issue, but it only occurs when the parent edge is split on an <em>outgoing</em> edge, not an <em>incoming</em> one. Could a <code>transform</code> of some sort help?</p>
<p dir="auto">I have checked the calls for both moves, and they are identical. The structure of the data connecting the items is correct - I have carefully checked it, and again, it works for 2-starts.</p>
<p dir="auto">Any ideas where to look would be welcomed!<br />
Grant</p>
]]></description><link>https://forum.qt.io/topic/164549/odd-error-parenting-and-qgraphicsscene-coordinate-transforms</link><generator>RSS for Node</generator><lastBuildDate>Wed, 06 May 2026 01:01:54 GMT</lastBuildDate><atom:link href="https://forum.qt.io/topic/164549.rss" rel="self" type="application/rss+xml"/><pubDate>Fri, 10 Apr 2026 19:05:31 GMT</pubDate><ttl>60</ttl></channel></rss>