Set the url to have the AtNx filename if one is found

There’s no need to convert the file name/path to QUrl,
and then back again to QString before calling qt_findAtNxFile().

Call qt_findAtNxFile first, and then convert to QUrl.
This makes sure the url-name and string-name stays
in sync.

Change-Id: I8b8939eabbdaff473945ebe31faafd408e9c4295
Pick-to: 5.15
Fixes: QTBUG-60793
Reviewed-by: Andy Shaw <andy.shaw@qt.io>

src/gui/text/qtextimagehandler.cpp

@@ -53,40 +53,21 @@ QT_BEGIN_NAMESPACE
 
 extern QString qt_findAtNxFile(const QString &baseFileName, qreal targetDevicePixelRatio,
                                qreal *sourceDevicePixelRatio);
-static QString resolveFileName(QString fileName, QUrl *url, qreal targetDevicePixelRatio,
-                               qreal *sourceDevicePixelRatio)
+
+static inline QUrl fromLocalfileOrResources(QString path)
 {
-    // We might use the fileName for loading if url loading fails
-    // try to make sure it is a valid file path.
-    // Also, QFile{Info}::exists works only on filepaths (not urls)
-
-    if (url->isValid()) {
-      if (url->scheme() == QLatin1String("qrc")) {
-        fileName = fileName.right(fileName.length() - 3);
-      }
-      else if (url->scheme() == QLatin1String("file")) {
-        fileName = url->toLocalFile();
-      }
-    }
-
-    if (targetDevicePixelRatio <= 1.0)
-        return fileName;
-
-    // try to find a Nx version
-    return qt_findAtNxFile(fileName, targetDevicePixelRatio, sourceDevicePixelRatio);
+    if (path.startsWith(QLatin1String(":/"))) // auto-detect resources and convert them to url
+        path.prepend(QLatin1String("qrc"));
+    return QUrl(path);
 }
 
-
 static QPixmap getPixmap(QTextDocument *doc, const QTextImageFormat &format, const qreal devicePixelRatio = 1.0)
 {
-    QPixmap pm;
-
-    QString name = format.name();
-    if (name.startsWith(QLatin1String(":/"))) // auto-detect resources and convert them to url
-        name.prepend(QLatin1String("qrc"));
-    QUrl url = QUrl(name);
     qreal sourcePixelRatio = 1.0;
-    name = resolveFileName(name, &url, devicePixelRatio, &sourcePixelRatio);
+    const QString name = qt_findAtNxFile(format.name(), devicePixelRatio, &sourcePixelRatio);
+    const QUrl url = fromLocalfileOrResources(name);
+
+    QPixmap pm;
     const QVariant data = doc->resource(QTextDocument::ImageResource, url);
     if (data.userType() == QMetaType::QPixmap || data.userType() == QMetaType::QImage) {
         pm = qvariant_cast<QPixmap>(data);
@@ -153,14 +134,11 @@ static QSize getPixmapSize(QTextDocument *doc, const QTextImageFormat &format)
 
 static QImage getImage(QTextDocument *doc, const QTextImageFormat &format, const qreal devicePixelRatio = 1.0)
 {
-    QImage image;
-
-    QString name = format.name();
-    if (name.startsWith(QLatin1String(":/"))) // auto-detect resources
-        name.prepend(QLatin1String("qrc"));
-    QUrl url = QUrl(name);
     qreal sourcePixelRatio = 1.0;
-    name = resolveFileName(name, &url, devicePixelRatio, &sourcePixelRatio);
+    const QString name = qt_findAtNxFile(format.name(), devicePixelRatio, &sourcePixelRatio);
+    const QUrl url = fromLocalfileOrResources(name);
+
+    QImage image;
     const QVariant data = doc->resource(QTextDocument::ImageResource, url);
     if (data.userType() == QMetaType::QImage) {
         image = qvariant_cast<QImage>(data);

tests/auto/gui/text/qtextimagehandler/qtextimagehandler.pro

@@ -0,0 +1,4 @@
+CONFIG += testcase
+TARGET = tst_qtextimagehandler
+QT += core-private gui gui-private testlib
+SOURCES += tst_qtextimagehandler.cpp

tests/auto/gui/text/qtextimagehandler/tst_qtextimagehandler.cpp

@@ -0,0 +1,87 @@
+/****************************************************************************
+ **
+ ** Copyright (C) 2020 The Qt Company Ltd.
+ ** Contact: https://www.qt.io/licensing/
+ **
+ ** This file is part of the test suite of the Qt Toolkit.
+ **
+ ** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+ ** Commercial License Usage
+ ** Licensees holding valid commercial Qt licenses may use this file in
+ ** accordance with the commercial license agreement provided with the
+ ** Software or, alternatively, in accordance with the terms contained in
+ ** a written agreement between you and The Qt Company. For licensing terms
+ ** and conditions see https://www.qt.io/terms-conditions. For further
+ ** information use the contact form at https://www.qt.io/contact-us.
+ **
+ ** GNU General Public License Usage
+ ** Alternatively, this file may be used under the terms of the GNU
+ ** General Public License version 3 as published by the Free Software
+ ** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+ ** included in the packaging of this file. Please review the following
+ ** information to ensure the GNU General Public License requirements will
+ ** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+ **
+ ** $QT_END_LICENSE$
+ **
+ ****************************************************************************/
+
+#include <QtTest/QtTest>
+
+#include <QPainter>
+#include <private/qtextimagehandler_p.h>
+
+class tst_QTextImageHandler : public QObject
+{
+    Q_OBJECT
+
+public:
+    tst_QTextImageHandler();
+
+private slots:
+    void init();
+    void cleanup();
+    void cleanupTestCase();
+    void loadAtNImages();
+};
+
+tst_QTextImageHandler::tst_QTextImageHandler()
+{
+}
+
+void tst_QTextImageHandler::init()
+{
+}
+
+void tst_QTextImageHandler::cleanup()
+{
+}
+
+void tst_QTextImageHandler::cleanupTestCase()
+{
+}
+
+void tst_QTextImageHandler::loadAtNImages()
+{
+    QTextDocument doc;
+    QTextCursor c(&doc);
+    c.insertHtml("<img src=\"data/image.png\">");
+    QTextImageHandler handler;
+    QTextImageFormat fmt;
+    fmt.setName("data/image.png");
+
+    for (int i = 1; i < 3; ++i) {
+        QImage img(20, 20, QImage::Format_ARGB32_Premultiplied);
+        img.fill(Qt::white);
+        img.setDevicePixelRatio(i);
+        QPainter p(&img);
+        handler.drawObject(&p, QRect(0, 0, 20, 20), &doc, 0, fmt);
+        p.end();
+        QVERIFY(!img.isNull());
+        const auto expectedColor = i == 1 ? Qt::red : Qt::green;
+        QCOMPARE(img.pixelColor(0, 0), expectedColor);
+    }
+}
+
+QTEST_MAIN(tst_QTextImageHandler)
+#include "tst_qtextimagehandler.moc"