Width handles: a text is not dragged narrower than its widest word

Narrower, a long word ran out of the text's box while the short lines
were still aligned inside the too narrow width: on a right aligned or
centred text a lone "1" stood in the middle under its words, and moved
on every step. Found on a real plan (-XS20, "Steckdosen Windfang, 1").
The probe checks that no line runs out of the text after narrowing, and
also for a text aligned bottom left.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

sources/qetgraphicsitem/dynamicelementtextitem.cpp

@@ -16,6 +16,8 @@
 	along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
 */
 #include "dynamicelementtextitem.h"
+#include <QScopedPointer>
+#include <QTextDocument>
 #include "../QetGraphicsItemModeler/textresizehandles.h"
 #include "../shownkinds.h"
 #include "../qetproject.h"
@@ -1063,6 +1065,20 @@ void DynamicElementTextItem::handlerMousePressEvent(QetGraphicsHandlerItem *hand
 	m_resize_fixed_parent = mapToParent(resizeAnchor());
 }
 
+/**
+	@brief DynamicElementTextItem::minimumTextWidth
+	@return the narrowest width the text can be dragged to: that of its
+	widest word. Narrower, a long word runs out of the text's box while
+	the short lines are still aligned inside it, and a centred or right
+	aligned text falls apart (a lone "1" in the middle under its words).
+*/
+qreal DynamicElementTextItem::minimumTextWidth() const
+{
+	QScopedPointer<QTextDocument> narrowest(document()->clone());
+	narrowest->setTextWidth(0);
+	return qMax(narrowest->idealWidth(), qreal(10));
+}
+
 /**
 	@brief DynamicElementTextItem::resizeAnchor
 	@return the point of the text, in its own coordinates, that a drag on
@@ -1102,7 +1118,7 @@ void DynamicElementTextItem::handlerMouseMoveEvent(QetGraphicsHandlerItem *handl
 	if (handle == m_left_resize_handle)
 		delta = -delta;
 
-	qreal new_width = qMax(m_resize_baseline_width + delta, qreal(10));
+	qreal new_width = qMax(m_resize_baseline_width + delta, minimumTextWidth());
 	setTextWidth(new_width);
 
 		//Keep the point the text is aligned on in place, whatever the new

sources/qetgraphicsitem/dynamicelementtextitem.h

@@ -171,6 +171,7 @@ class DynamicElementTextItem : public DiagramTextItem
 		void removeResizeHandles();
 		void updateResizeHandlesPos();
 		QPointF resizeAnchor() const;
+		qreal minimumTextWidth() const;
 		void fitAutoTextWidth();
 		void handlerMousePressEvent(QetGraphicsHandlerItem *handle, QGraphicsSceneMouseEvent *event);
 		void handlerMouseMoveEvent(QetGraphicsHandlerItem *handle, QGraphicsSceneMouseEvent *event);

tests/qttest/element_text_resize_probe.cpp

@@ -14,6 +14,9 @@
 #include <QGraphicsSceneMouseEvent>
 #include <QSettings>
 #include <QTemporaryDir>
+#include <QTextBlock>
+#include <QTextDocument>
+#include <QTextLayout>
 #include <cstdio>
 #include <stdexcept>
 
@@ -82,6 +85,20 @@ static void drag(Diagram *scene, DynamicElementTextItem *text, bool left, qreal
 	mouse(scene, h, QEvent::GraphicsSceneMouseRelease, end);
 }
 
+/// Every line lies inside the text's width: none runs out of it.
+static bool linesInside(DynamicElementTextItem *text)
+{
+	QTextDocument *doc = text->document();
+	const qreal inner = doc->textWidth() - 2 * doc->documentMargin();
+	for (QTextBlock b = doc->begin(); b.isValid(); b = b.next())
+		for (int i = 0; i < b.layout()->lineCount(); ++i) {
+			const QTextLine line = b.layout()->lineAt(i);
+			if (line.x() < -0.01 || line.x() + line.naturalTextWidth() > inner + 0.01)
+				return false;
+		}
+	return true;
+}
+
 /// The width changed by exactly as much as the mouse moved.
 static void checkGrowth(DynamicElementTextItem *text, qreal before, qreal moved, const char *message)
 {
@@ -124,6 +141,7 @@ static void checkText(Diagram *scene, Element *element, DynamicElementTextItem *
 	const qreal height = text->boundingRect().height();
 	drag(scene, text, false, 25 - width);
 	check(text->boundingRect().height() > height + 5, "narrowing the text wraps it onto more lines");
+	check(linesInside(text), "a text is not narrower than its widest word: no line runs out of it");
 	check(near(anchor(text), fixed), "a text that wraps keeps its alignment point in place");
 	scene->undoStack().undo();
 	check(near(text->pos(), pos), "undo puts the wrapped text back");
@@ -136,6 +154,7 @@ static void checkAll(Diagram *scene, Element *element, DynamicElementTextItem *t
 	checkText(scene, element, text, Qt::AlignRight | Qt::AlignTop);
 	checkText(scene, element, text, Qt::AlignHCenter | Qt::AlignVCenter);
 	checkText(scene, element, text, Qt::AlignRight | Qt::AlignBottom);
+	checkText(scene, element, text, Qt::AlignLeft | Qt::AlignBottom);
 }
 
 int main(int argc, char **argv)