Mirror: terminal names, reload drawings, turned text groups, a leak

Found by review of #1354:
- Terminal names (shown on the folio) read backwards on a mirrored
  symbol: Terminal::paint() now mirrors them back about the centre of
  their box, in the frame they are drawn in.
- "Reload the drawings of the symbols" left mirrored symbols with the old
  drawing: reloadPicture() refreshes the mirrored pictures too.
- Turning a group of texts on a mirrored symbol left the group's
  readable mirror about the centre of its old box until the next layout:
  ElementTextItemGroup::setRotation() reapplies it, as texts already do.
- The mirrored build of a symbol's drawing leaked the texts of its
  primitives, which only the drawing without mirror keeps.

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

sources/factory/elementpicturefactory.cpp

@@ -379,6 +379,9 @@ bool ElementPictureFactory::build(const ElementsLocation &location,
 
 	const auto uuid_ = cacheKey(location);
 	if (!mirror.isIdentity()) {
+			//The primitives are those of the drawing without mirror,
+			//already kept by the build of that one
+		qDeleteAll(primitives_.m_texts);
 		const QPair<QUuid, int> key(uuid_, (mirror.m11() < 0 ? 1 : 0)
 											| (mirror.m22() < 0 ? 2 : 0));
 		if (!picture) {

sources/qetgraphicsitem/element.cpp

@@ -2186,6 +2186,13 @@ Element::ReloadPictureResult Element::reloadPicture()
 
 	m_picture = picture;
 	m_low_zoom_picture = low_zoom_picture;
+	if (isMirrored())
+		ElementPictureFactory::instance()->getMirroredPictures(
+					m_location,
+					m_horizontal_mirror,
+					m_vertical_mirror,
+					m_mirrored_picture,
+					m_mirrored_low_zoom_picture);
 	update();
 	return ReloadPictureResult::Reloaded;
 }

sources/qetgraphicsitem/elementtextitemgroup.cpp

@@ -648,6 +648,10 @@ QRectF ElementTextItemGroup::boundingRect() const
 void ElementTextItemGroup::setRotation(qreal angle)
 {	
 	QGraphicsItemGroup::setRotation(angle);
+		//On a mirrored element, the mirror that keeps this group readable
+		//is about the centre of its turned box
+	if (m_parent_element)
+		m_parent_element->keepReadable(this);
 	emit rotationChanged(angle);
 }
 

sources/qetgraphicsitem/terminal.cpp

@@ -306,6 +306,23 @@ void Terminal::paint(
 		QFontMetrics fm(d->m_label_font);
 		QSizeF text_size = fm.size(Qt::TextSingleLine, display_name);
 
+			// On a mirrored element, mirror the name a second time about
+			// the centre of its box, in the frame it is drawn in (turned
+			// by label_rotation): its box stays where the element's mirror
+			// puts it, but it reads normally (Element::keepReadable())
+		const Element *mirrored = qgraphicsitem_cast<Element *>(parentItem());
+		if (mirrored && !mirrored->isMirrored()) mirrored = nullptr;
+		auto keep_readable = [painter, mirrored](const QRectF &rect, qreal label_rotation) {
+			if (!mirrored) return;
+			const QTransform mirror = QTransform().rotate(label_rotation)
+									  * mirrored->mirrorTransform()
+									  * QTransform().rotate(-label_rotation);
+			const QPointF c = rect.center();
+			painter->setTransform(QTransform::fromTranslate(-c.x(), -c.y())
+								  * mirror
+								  * QTransform::fromTranslate(c.x(), c.y()), true);
+		};
+
 		if (!qFuzzyIsNull(d->m_label_rotation)) {
 			painter->save();
 			painter->translate(label_pos);
@@ -321,6 +338,7 @@ void Terminal::paint(
 			else if (d->m_label_valignment & Qt::AlignBottom) ry = -text_size.height();
 
 			QRectF text_rect(QPointF(rx, ry), text_size);
+			keep_readable(text_rect, d->m_label_rotation);
 			painter->drawText(text_rect, static_cast<int>(d->m_label_halignment | d->m_label_valignment), display_name);
 			painter->restore();
 		} else {
@@ -334,6 +352,7 @@ void Terminal::paint(
 			else if (d->m_label_valignment & Qt::AlignBottom) dy = -text_size.height();
 
 			QRectF text_rect(label_pos + QPointF(dx, dy), text_size);
+			keep_readable(text_rect, 0);
 			if (d->m_label_frame) {
 				painter->drawRect(text_rect.adjusted(-1, -1, 1, 1));
 			}