feat: add widget for a text browser with image support

Signed-off-by: flow <flowlnlnln@gmail.com>

launcher/ui/widgets/VariableSizedImageObject.h

@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (c) 2022 flowln <flowlnlnln@gmail.com>
+ *
+ *  This program 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, version 3.
+ *
+ *  This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <QObject>
+#include <QString>
+#include <QTextObjectInterface>
+#include <QUrl>
+
+/** Custom image text object to be used instead of the normal one in ProjectDescriptionPage.
+ *
+ *  Why? Because we want to re-scale images dynamically based on the document's size, in order to
+ *  not have images being weirdly cropped out in different resolutions.
+ */
+class VariableSizedImageObject : public QObject, public QTextObjectInterface {
+    Q_OBJECT
+    Q_INTERFACES(QTextObjectInterface)
+
+   public:
+    QSizeF intrinsicSize(QTextDocument* doc, int posInDocument, const QTextFormat& format) override;
+    void drawObject(QPainter* painter, const QRectF& rect, QTextDocument* doc, int posInDocument, const QTextFormat& format) override;
+
+    void setMetaEntry(QString meta_entry) { m_meta_entry = meta_entry; }
+
+   protected:
+    /** Adds the image to the document, in the given position.
+     */
+    void parseImage(QTextDocument* doc, QImage image, int posInDocument);
+
+    /** Loads an image from an external source, and adds it to the document.
+     *
+     *  This uses m_meta_entry to cache the image.
+     */
+    void loadImage(QTextDocument* doc, const QUrl& source, int posInDocument);
+
+    QString m_meta_entry;
+
+    QList<QUrl> m_fetching_images;
+};