Markdown: Fix images with special chars in URLs not loaded

If an image URL contains a non-ASCII character (e.g. `kartöffelchen.jpg`), the html returned by the markdown parser contains the encoded path `kart%C3%B6ffelchen.jpg`. We must decode the path before checking if the image file exists.

(cherry picked from commit 8aa96484da)

autotests/data/imageUrlsWithSpecialChars.md

@@ -0,0 +1,3 @@
+# Test for having images with non-ASCII characters in their name
+
+![Kartöffelchen](kartöffelchen.jpg)

autotests/markdowntest.cpp

@@ -23,6 +23,7 @@ private slots:
     void testFancyPantsEnabled();
     void testFancyPantsDisabled();
     void testImageSizes();
+    void testSpecialCharsInImageFileName();
 
 private:
     void findImages(QTextFrame *parent, QVector<QTextImageFormat> &images);
@@ -121,5 +122,20 @@ void MarkdownTest::findImages(const QTextBlock &parent, QVector<QTextImageFormat
     }
 }
 
+void MarkdownTest::testSpecialCharsInImageFileName()
+{
+    Markdown::Converter converter;
+    QTextDocument *document = converter.convert(QStringLiteral(KDESRCDIR "data/imageUrlsWithSpecialChars.md"));
+
+    QTextFrame *parent = document->rootFrame();
+
+    QVector<QTextImageFormat> images;
+    findImages(parent, images);
+
+    QCOMPARE(images.size(), 1);
+    QVERIFY(images[0].name().endsWith(QStringLiteral("kartöffelchen.jpg")));
+    QVERIFY(!images[0].name().contains(QStringLiteral("kart%C3%B6ffelchen.jpg")));
+}
+
 QTEST_MAIN(MarkdownTest)
 #include "markdowntest.moc"

generators/markdown/converter.cpp

@@ -197,7 +197,8 @@ void Converter::convertImages(const QTextBlock &parent, const QDir &dir, QTextDo
                 cursor.setPosition(textFragment.position(), QTextCursor::MoveAnchor);
                 cursor.setPosition(textFragment.position() + textFragment.length(), QTextCursor::KeepAnchor);
 
-                const QString imageFilePath = QDir::cleanPath(dir.absoluteFilePath(textCharFormat.toImageFormat().name()));
+                const QString imageFilePath = QDir::cleanPath(dir.absoluteFilePath(QUrl::fromPercentEncoding(textCharFormat.toImageFormat().name().toUtf8())));
+
                 if (QFile::exists(imageFilePath)) {
                     cursor.removeSelectedText();
                     format.setName(imageFilePath);