Load a picture without a usable size at size 1, not 0

DiagramImageItem::fromXml() read the size attribute with a plain
toDouble(). A picture whose size was missing or not a number got size
0, so it was invisible on the folio, left out of the SVG export, and
a resave wrote size="0" back, which then stayed 0 on every load. "nan"
was kept and written back as such. The <transform> child, which newer
files carry, already defaults its scale to 1.

Read the size with an ok flag and use 1, the size a picture is added
with, when it is missing, not a number, not finite, or 0.

No file-format change for usable sizes. A picture that an earlier save
left at size="0" shows again, at size 1, after this change.

Tests: tst_imagemissingsize runs the binary's --resave and --export-svg
on a fixture with six small pictures: size missing, "0", "nan", "big",
"0.5" and "2". The first four fail on master (saved as 0, 0, nan, 0)
and the export draws only 3 of the 6 pictures there.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Beat Hangartner <beat@hangartners.ch>

sources/qetgraphicsitem/diagramimageitem.cpp

@@ -1686,7 +1686,12 @@ bool DiagramImageItem::fromXml(const QDomElement &e)
 	// pivot), the same two-tier fallback QetShapeItem's own fromXml()
 	// already uses for its identical <transform> element.
 	m_transform.rotation = e.attribute("rotation").toDouble();
-	m_transform.scaleX = e.attribute("size").toDouble();
+		//A missing, unreadable, non-finite or zero size would scale the
+		//picture to nothing (and a resave wrote size="0" back): use 1,
+		//the size a picture is added with, as the <transform> branch does
+	bool size_ok = false;
+	const qreal size = e.attribute("size").toDouble(&size_ok);
+	m_transform.scaleX = (size_ok && qIsFinite(size) && size != 0) ? size : 1;
 	m_transform.scaleY = m_transform.scaleX;
 	m_transform.pivot = imageRect().center();
 	m_pivotIsCustom = false;

tests/qttest/CMakeLists.txt

@@ -1024,6 +1024,19 @@ target_compile_definitions(tst_terminaluuids PRIVATE
   "QET_TEST_BINARY_PATH=\"$<TARGET_FILE:qelectrotech>\""
   "QET_EXAMPLES_DIR=\"${QET_DIR}/examples\"")
 
+# A picture whose size attribute is missing, unreadable, "nan" or 0 is
+# loaded at size 1, not 0: the real binary's --resave and --export-svg on
+# fixtures/image_missing_size.qet.
+add_executable(
+  tst_imagemissingsize
+  tst_imagemissingsize.cpp)
+add_test(NAME tst_imagemissingsize COMMAND tst_imagemissingsize)
+set_tests_properties(tst_imagemissingsize PROPERTIES ENVIRONMENT "QT_QPA_PLATFORM=offscreen")
+add_dependencies(tst_imagemissingsize qelectrotech)
+target_link_libraries(tst_imagemissingsize PRIVATE Qt::Test Qt::Xml)
+target_compile_definitions(tst_imagemissingsize PRIVATE
+  "QET_TEST_BINARY_PATH=\"$<TARGET_FILE:qelectrotech>\"")
+
 # Sequential numbers saved the old way, as sequ_1/.../seqhf_1 attributes,
 # are all read: the real binary's --resave on
 # fixtures/legacy_sequential_attributes.qet, whose element and conductor

tests/qttest/fixtures/image_missing_size.qet

@@ -0,0 +1,45 @@
+<project title="Pictures without a usable size" uuid="{7b2e1d4f-3c55-4e2f-9a1b-4d6e8f0c2b00}" version="0.200.1">
+    <properties>
+        <property name="saveddate" show="1">10/2/26</property>
+        <property name="saveddate-eu" show="1">02-10-2026</property>
+        <property name="saveddate-us" show="1">2026-10-02</property>
+        <property name="savedfilename" show="1">image_missing_size</property>
+        <property name="savedtime" show="1">18:39</property>
+    </properties>
+    <usage enabled="true" time_spent="0"/>
+    <newdiagrams>
+        <border cols="17" colsize="60" displaycols="true" displayrows="true" rows="8" rowsize="80"/>
+        <inset author="" auto_page_num="" date="null" displayAt="bottom" filename="" folio="" indexrev="" locmach="" plant="" title="" version=""/>
+        <conductors bicolor="false" bus="" cable="" color2="#000000" condsize="1" conductor_color="" conductor_section="" dash-size="1" displaytext="1" formula="" function="" horizontal-alignment="AlignBottom" horizrotatetext="0" num="_" numsize="7" onetextperfolio="0" tension_protocol="" text_color="#000000" type="multi" vertical-alignment="AlignRight" vertirotatetext="270"/>
+        <report label="%f-%l%c"/>
+        <xrefs>
+            <xref delayprefix="" displayhas="cross" master_label="%f-%l%c" offset="0" powerprefix="" showallconfiguredslaves="false" showpowerctc="true" showterminalname="true" slave_label="(%f-%l%c)" slave_offset="0" snapto="label" switchprefix="" type="coil" xrefpos="AlignBottom"/>
+            <xref delayprefix="" displayhas="cross" master_label="%f-%l%c" offset="0" powerprefix="" showallconfiguredslaves="false" showpowerctc="true" showterminalname="true" slave_label="(%f-%l%c)" slave_offset="0" snapto="label" switchprefix="" type="commutator" xrefpos="AlignBottom"/>
+            <xref delayprefix="" displayhas="cross" master_label="%f-%l%c" offset="0" powerprefix="" showallconfiguredslaves="false" showpowerctc="true" showterminalname="true" slave_label="(%f-%l%c)" slave_offset="0" snapto="label" switchprefix="" type="plc" xrefpos="AlignBottom"/>
+            <xref delayprefix="" displayhas="cross" master_label="%f-%l%c" offset="0" powerprefix="" showallconfiguredslaves="false" showpowerctc="true" showterminalname="true" slave_label="(%f-%l%c)" slave_offset="0" snapto="label" switchprefix="" type="protection" xrefpos="AlignBottom"/>
+        </xrefs>
+        <conductors_autonums auto_break_conductors="false" current_autonum="" freeze_new_conductors="false"/>
+        <folio_autonums/>
+        <element_autonums current_autonum="" freeze_new_elements="false"/>
+        <guides/>
+    </newdiagrams>
+    <diagram author="" auto_page_num="" cols="17" colsize="60" date="null" displayAt="bottom" displaycols="true" displayrows="true" filename="" folio="" freezeNewConductor="false" freezeNewElement="false" height="660" indexrev="" locmach="" order="1" plant="" rows="8" rowsize="80" title="" uuid="{7b2e1d4f-3c55-4e2f-9a1b-4d6e8f0c2b10}" version="0.200.1-dev">
+        <defaultconductor bicolor="false" bus="" cable="" color2="#000000" condsize="1" conductor_color="" conductor_section="" dash-size="1" displaytext="1" formula="" function="" horizontal-alignment="AlignBottom" horizrotatetext="0" num="_" numsize="7" onetextperfolio="0" tension_protocol="" text_color="#000000" type="multi" vertical-alignment="AlignRight" vertirotatetext="270"/>
+        <inputs/>
+        <images>
+            <image z="0" rotation="0" y="100" x="100" is_movable="1">iVBORw0KGgoAAAANSUhEUgAAABQAAAAKCAIAAAA7N+mxAAAAFUlEQVR4nGM4ISdHNmIY1TyqmRACAJaAyyGTMvplAAAAAElFTkSuQmCC</image>
+            <image z="0" rotation="0" y="160" x="100" size="0" is_movable="1">iVBORw0KGgoAAAANSUhEUgAAABQAAAAKCAIAAAA7N+mxAAAAFUlEQVR4nGM4ISdHNmIY1TyqmRACAJaAyyGTMvplAAAAAElFTkSuQmCC</image>
+            <image z="0" rotation="0" y="220" x="100" size="nan" is_movable="1">iVBORw0KGgoAAAANSUhEUgAAABQAAAAKCAIAAAA7N+mxAAAAFUlEQVR4nGM4ISdHNmIY1TyqmRACAJaAyyGTMvplAAAAAElFTkSuQmCC</image>
+            <image z="0" rotation="0" y="280" x="100" size="big" is_movable="1">iVBORw0KGgoAAAANSUhEUgAAABQAAAAKCAIAAAA7N+mxAAAAFUlEQVR4nGM4ISdHNmIY1TyqmRACAJaAyyGTMvplAAAAAElFTkSuQmCC</image>
+            <image z="0" rotation="0" y="340" x="100" size="0.5" is_movable="1">iVBORw0KGgoAAAANSUhEUgAAABQAAAAKCAIAAAA7N+mxAAAAFUlEQVR4nGM4ISdHNmIY1TyqmRACAJaAyyGTMvplAAAAAElFTkSuQmCC</image>
+            <image z="0" rotation="0" y="400" x="100" size="2" is_movable="1">iVBORw0KGgoAAAANSUhEUgAAABQAAAAKCAIAAAA7N+mxAAAAFUlEQVR4nGM4ISdHNmIY1TyqmRACAJaAyyGTMvplAAAAAElFTkSuQmCC</image>
+        </images>
+    </diagram>
+    <collection>
+        <category name="import">
+            <names>
+                <name lang="en">Imported elements</name>
+            </names>
+        </category>
+    </collection>
+</project>

tests/qttest/tst_imagemissingsize.cpp

@@ -0,0 +1,108 @@
+/*
+	Copyright 2006-2026 The QElectroTech Team
+	This file is part of QElectroTech.
+
+	QElectroTech is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 2 of the License, or
+	(at your option) any later version.
+
+	QElectroTech is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include <QtTest>
+#include <QDir>
+#include <QDomDocument>
+#include <QProcess>
+#include <QTemporaryDir>
+
+/**
+	A picture on a folio (<image>, without a <transform> child) whose size
+	attribute is missing, unreadable, "nan" or 0 is loaded at size 1. It
+	used to be loaded at size 0, so it was invisible, not exported, and a
+	resave wrote size="0" back. Runs the real binary's --resave and
+	--export-svg on fixtures/image_missing_size.qet: six 20x10 pictures,
+	one per size value, told apart by their y position.
+*/
+class tst_imagemissingsize : public QObject
+{
+	Q_OBJECT
+
+	QTemporaryDir m_dir;
+	QString m_fixture;
+	QDomDocument m_resaved;
+
+	static bool runQet(const QStringList &arguments)
+	{
+		QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
+		env.insert(QStringLiteral("QT_QPA_PLATFORM"), QStringLiteral("offscreen"));
+		QProcess proc;
+		proc.setProcessEnvironment(env);
+		proc.start(QStringLiteral(QET_TEST_BINARY_PATH), arguments);
+		return proc.waitForFinished(60000)
+				&& proc.exitStatus() == QProcess::NormalExit
+				&& proc.exitCode() == 0;
+	}
+
+private slots:
+	void initTestCase()
+	{
+		QVERIFY2(QFile::exists(QStringLiteral(QET_TEST_BINARY_PATH)), "qelectrotech binary not found");
+		QVERIFY(m_dir.isValid());
+		m_fixture = QFINDTESTDATA("fixtures/image_missing_size.qet");
+		QVERIFY2(!m_fixture.isEmpty(), "fixture project not found");
+		const QString out = m_dir.filePath(QStringLiteral("resaved.qet"));
+		QVERIFY2(runQet({QStringLiteral("--resave"), m_fixture, out}), "--resave failed");
+		QFile file(out);
+		QVERIFY(file.open(QIODevice::ReadOnly));
+		QVERIFY(m_resaved.setContent(&file));
+	}
+
+	void savedSize_data()
+	{
+		QTest::addColumn<QString>("y");
+		QTest::addColumn<QString>("size");
+		QTest::newRow("missing")       << "100" << "1";
+		QTest::newRow("0")             << "160" << "1";
+		QTest::newRow("nan")           << "220" << "1";
+		QTest::newRow("not a number")  << "280" << "1";
+		// Usable sizes are kept, below and above 1.
+		QTest::newRow("0.5")           << "340" << "0.5";
+		QTest::newRow("2")             << "400" << "2";
+	}
+
+	void savedSize()
+	{
+		QFETCH(QString, y);
+		QFETCH(QString, size);
+		const QDomNodeList list = m_resaved.elementsByTagName(QStringLiteral("image"));
+		QDomElement found;
+		for (int i = 0; i < list.size(); ++i) {
+			const QDomElement e = list.at(i).toElement();
+			if (e.attribute(QStringLiteral("y")) == y) found = e;
+		}
+		QVERIFY2(!found.isNull(), "picture not found in the resaved project");
+		QCOMPARE(found.attribute(QStringLiteral("size")), size);
+	}
+
+	// All six pictures are drawn in the export.
+	void allPicturesAreExported()
+	{
+		const QString dir = m_dir.filePath(QStringLiteral("svg"));
+		QVERIFY(QDir().mkpath(dir));
+		QVERIFY2(runQet({QStringLiteral("--export-svg"), m_fixture, dir}), "--export-svg failed");
+		const QStringList files = QDir(dir).entryList({QStringLiteral("*.svg")}, QDir::Files);
+		QCOMPARE(files.size(), 1);
+		QFile svg(QDir(dir).filePath(files.first()));
+		QVERIFY(svg.open(QIODevice::ReadOnly));
+		QCOMPARE(QString::fromUtf8(svg.readAll()).count(QStringLiteral("<image")), 6);
+	}
+};
+
+QTEST_MAIN(tst_imagemissingsize)
+#include "tst_imagemissingsize.moc"