Merge pull request #1477 from ispyisail/perf/parallel-picture-decode

Speed up opening folios with photos: decode pictures in parallel

tests/qttest/CMakeLists.txt

@@ -271,6 +271,10 @@ qet_add_app_test(tst_rotateselectionimage tst_rotateselectionimage.cpp)
 # it selected and records no undo step (#1414); the key goes to the view.
 qet_add_app_test(tst_imagehandleescape tst_imagehandleescape.cpp)
 
+# A folio's pictures, decoded in parallel, each come back with its own
+# pixels and position; an <image> with no picture does not stop the others.
+qet_add_app_test(tst_folioimageload tst_folioimageload.cpp)
+
 # SVG export with smaller pictures (--svg-small-pictures, the export dialog's
 # option): a picture drawn at a tenth of its size is stored at four times
 # that, a small one whole; without the option every picture is whole.

tests/qttest/tst_folioimageload.cpp

@@ -0,0 +1,132 @@
+/*
+	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 "qetapptest.h"
+#include "diagramcontent.h"
+#include "qetgraphicsitem/diagramimageitem.h"
+
+#include <QDomDocument>
+#include <QRandomGenerator>
+
+/**
+	Diagram::fromXml() decodes a folio's pictures in parallel, then builds
+	the items in file order. Every picture must come back with its own
+	pixels and position, whatever thread decoded it.
+*/
+class tst_folioimageload : public QObject
+{
+	Q_OBJECT
+
+	Diagram *m_diagram = nullptr;
+
+	/// A picture no other one equals: its own size and noise.
+	static QImage distinctImage(int n)
+	{
+		QImage image(40 + 7 * n, 30 + 3 * n, QImage::Format_ARGB32);
+		QRandomGenerator random(quint32(n + 1));
+		for (int y = 0 ; y < image.height() ; ++y)
+			for (int x = 0 ; x < image.width() ; ++x)
+				image.setPixel(x, y, random.generate() | 0xFF000000);
+		return image;
+	}
+
+	static QImage pixelsOf(const DiagramImageItem *item)
+	{
+		return item->pixmap().toImage()
+				.convertToFormat(QImage::Format_ARGB32);
+	}
+
+	void removePictures()
+	{
+			// A selected picture's handles are its children, in items()
+			// too: deleting the picture first would leave them dangling.
+		m_diagram->clearSelection();
+		for (QGraphicsItem *item : m_diagram->items())
+			if (item->type() == DiagramImageItem::Type)
+				delete item;
+	}
+
+private slots:
+	void initTestCase()
+	{
+		QVERIFY(QetAppTest::editor());
+		m_diagram = QetAppTest::diagram();
+		QVERIFY(m_diagram);
+	}
+
+	void cleanup()
+	{
+		m_diagram->clearSelection();
+		removePictures();
+		m_diagram->undoStack().clear();
+	}
+
+	void everyPictureComesBackWithItsPixels()
+	{
+		QHash<int, QImage> expected;	// by x position, each its own
+		for (int n = 0 ; n < 6 ; ++n) {
+			const QImage image = distinctImage(n);
+			auto *picture = new DiagramImageItem(QPixmap::fromImage(image));
+			m_diagram->addItem(picture);
+			picture->setPos(100 + 150 * n, 200);
+			picture->setSelected(true);
+			expected.insert(qRound(picture->pos().x()), image);
+		}
+		QDomDocument document = m_diagram->toXml(false);
+		removePictures();
+
+		DiagramContent content;
+		QVERIFY(m_diagram->fromXml(document, QPointF(), false, &content));
+
+		QCOMPARE(content.m_images.size(), expected.size());
+		for (const DiagramImageItem *picture : std::as_const(content.m_images)) {
+			const int x = qRound(picture->pos().x());
+			QVERIFY2(expected.contains(x), "picture moved");
+			QCOMPARE(picture->pos().y(), 200.0);
+			QCOMPARE(pixelsOf(picture), expected.value(x));
+		}
+	}
+
+	void anImageWithoutPictureDoesNotStopTheOthers()
+	{
+		for (int n = 0 ; n < 3 ; ++n) {
+			auto *picture = new DiagramImageItem(
+						QPixmap::fromImage(distinctImage(n)));
+			m_diagram->addItem(picture);
+			picture->setSelected(true);
+		}
+		QDomDocument document = m_diagram->toXml(false);
+		removePictures();
+		QDomElement images = document.documentElement()
+				.firstChildElement(QStringLiteral("images"));
+		QVERIFY(!images.isNull());
+		QDomElement empty = document.createElement(QStringLiteral("image"));
+		images.insertBefore(empty, images.firstChild());
+
+		DiagramContent content;
+		QVERIFY(m_diagram->fromXml(document, QPointF(), false, &content));
+
+		int with_pixels = 0;
+		for (const DiagramImageItem *picture : std::as_const(content.m_images))
+			if (!picture->pixmap().isNull())
+				++with_pixels;
+		QCOMPARE(with_pixels, 3);
+	}
+};
+
+QET_APP_TEST_MAIN(tst_folioimageload)
+#include "tst_folioimageload.moc"