fix: SVG rendering issue with filters attribute

From: lxqt/libqtxdg#247
Use QImageReader instead of QSvgRender for XdgIconLoader
QSvgRender itself only support SVG 1.2 Tiny for rendering so SVGs
that more complex might not able to rendered properly. Thus, some
DE like KDE and DDE provides their own Qt icon engine and registered
them as for SVG icons, and seems that causes libqtxdg have issues, so
lxqt/libqtxdg/pull/246 was there.

But user or DE might still want to install or provide Qt image formats
plugins for better SVG files/icons rendering, using QSvgRender will
stop the Qt image formats plugin from being used.

Using QImageReader will still allow us avoiding the usage of Qt icon
engines, but kepts the ability to make Qt image formats plugin to
work properly.

This patch originally provided by @zccrs

Issue: linuxdeepin/developer-center#6480

debian/changelog

@@ -1,3 +1,10 @@
+libqtxdg (3.12.0-1deepin1) unstable; urgency=medium
+
+  * release 3.12.0-1deepin1
+  * Add Patch to fix #6480
+
+ -- Mike Chen <[email protected]>  Tue, 19 Dec 2023 13:49:08 +0800
+
 libqtxdg (3.12.0-1) unstable; urgency=medium
 
   * New upstream release.

debian/patches/Fix_6480_svg_with_filters.patch

@@ -0,0 +1,48 @@
+diff --git a/src/xdgiconloader/xdgiconloader.cpp b/src/xdgiconloader/xdgiconloader.cpp
+index 217eca1..95aecc8 100644
+--- a/src/xdgiconloader/xdgiconloader.cpp
++++ b/src/xdgiconloader/xdgiconloader.cpp
+@@ -53,7 +53,7 @@
+ #include <QImageReader>
+ #include <QXmlStreamReader>
+ #include <QFileSystemWatcher>
+-#include <QSvgRenderer>
++#include <QBuffer>
+
+ #include <private/qhexstring_p.h>
+
+@@ -829,12 +829,12 @@ QPixmap ScalableEntry::pixmap(const QSize &size, QIcon::Mode mode, QIcon::State
+         pm = QPixmap(icnSize, icnSize);
+         pm.fill(Qt::transparent);
+
+-        QSvgRenderer renderer;
+-        if (renderer.load(filename))
+-        {
++        QImageReader imageReader(filename);
++        if (imageReader.canRead()) {
++            imageReader.setScaledSize(QSize(icnSize, icnSize));
+             QPainter p;
+             p.begin(&pm);
+-            renderer.render(&p, QRect(0, 0, icnSize, icnSize));
++            p.drawImage(0, 0, imageReader.read());
+             p.end();
+         }
+
+@@ -928,11 +928,14 @@ QPixmap ScalableFollowsColorEntry::pixmap(const QSize &size, QIcon::Mode mode, Q
+
+             if (!svgBuffer.isEmpty())
+             {
+-                QSvgRenderer renderer;
+-                renderer.load(svgBuffer);
++                QBuffer buffer;
++                buffer.setData(svgBuffer);
++                buffer.open(QIODevice::ReadOnly);
++                QImageReader imageReader(&buffer);
++                imageReader.setScaledSize(QSize(icnSize, icnSize));
+                 QPainter p;
+                 p.begin(&pm);
+-                renderer.render(&p, QRect(0, 0, icnSize, icnSize));
++                p.drawImage(0, 0, imageReader.read());
+                 p.end();
+             }
+         }

debian/patches/series

@@ -0,0 +1 @@
+Fix_6480_svg_with_filters.patch