Qt: Fix HiDPI icon scaling

Source/Core/DolphinQt2/Main.cpp

@@ -19,6 +19,9 @@
 
 int main(int argc, char* argv[])
 {
+  QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
+  QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
+
   QApplication app(argc, argv);
 
   UICommon::SetUserDirectory("");

Source/Core/DolphinQt2/Resources.cpp

@@ -2,46 +2,92 @@
 // Licensed under GPLv2+
 // Refer to the license.txt file included.
 
+#include <QGuiApplication>
+#include <QIcon>
+#include <QPixmap>
+#include <QScreen>
 #include <QStringList>
 
 #include "Common/CommonPaths.h"
 #include "Common/FileUtil.h"
 #include "DolphinQt2/Resources.h"
+#include "DolphinQt2/Settings.h"
 
 QList<QPixmap> Resources::m_platforms;
 QList<QPixmap> Resources::m_countries;
 QList<QPixmap> Resources::m_ratings;
 QList<QPixmap> Resources::m_misc;
 
+QIcon Resources::GetIcon(const QString& name, const QString& dir)
+{
+  QString base_path = dir + name;
+
+  const auto dpr = QGuiApplication::primaryScreen()->devicePixelRatio();
+
+  QIcon icon(base_path.append(QStringLiteral(".png")));
+
+  if (dpr > 2)
+  {
+    QPixmap pixmap(base_path.append(QStringLiteral("@4x.png")));
+    if (!pixmap.isNull())
+    {
+      pixmap.setDevicePixelRatio(4.0);
+      icon.addPixmap(pixmap);
+    }
+  }
+
+  return icon;
+}
+
+QPixmap Resources::GetPixmap(const QString& name, const QString& dir)
+{
+  const auto icon = GetIcon(name, dir);
+  return icon.pixmap(icon.availableSizes()[0]);
+}
+
+QIcon Resources::GetScaledIcon(const std::string& name)
+{
+  return GetIcon(QString::fromStdString(name), Settings().GetResourcesDir());
+}
+
+QIcon Resources::GetScaledThemeIcon(const std::string& name)
+{
+  return GetIcon(QString::fromStdString(name), Settings().GetThemeDir());
+}
+
+QPixmap Resources::GetScaledPixmap(const std::string& name)
+{
+  return GetPixmap(QString::fromStdString(name), Settings().GetResourcesDir());
+}
+
+QPixmap Resources::GetScaledThemePixmap(const std::string& name)
+{
+  return GetPixmap(QString::fromStdString(name), Settings().GetThemeDir());
+}
+
 void Resources::Init()
 {
   QString sys_dir = QString::fromStdString(File::GetSysDirectory() + RESOURCES_DIR + DIR_SEP);
 
-  QStringList platforms{QStringLiteral("Platform_Gamecube.png"), QStringLiteral("Platform_Wii.png"),
-                        QStringLiteral("Platform_Wad.png"), QStringLiteral("Platform_File.png")};
-  for (QString platform : platforms)
-    m_platforms.append(QPixmap(platform.prepend(sys_dir)));
+  for (const std::string& platform :
+       {"Platform_Gamecube", "Platform_Wii", "Platform_Wad", "Platform_File"})
+  {
+    m_platforms.append(GetScaledPixmap(platform));
+  }
 
-  QStringList countries{
-      QStringLiteral("Flag_Europe.png"),        QStringLiteral("Flag_Japan.png"),
-      QStringLiteral("Flag_USA.png"),           QStringLiteral("Flag_Australia.png"),
-      QStringLiteral("Flag_France.png"),        QStringLiteral("Flag_Germany.png"),
-      QStringLiteral("Flag_Italy.png"),         QStringLiteral("Flag_Korea.png"),
-      QStringLiteral("Flag_Netherlands.png"),   QStringLiteral("Flag_Russia.png"),
-      QStringLiteral("Flag_Spain.png"),         QStringLiteral("Flag_Taiwan.png"),
-      QStringLiteral("Flag_International.png"), QStringLiteral("Flag_Unknown.png")};
-  for (QString country : countries)
-    m_countries.append(QPixmap(country.prepend(sys_dir)));
+  for (const std::string& country :
+       {"Flag_Europe", "Flag_Japan", "Flag_USA", "Flag_Australia", "Flag_France", "Flag_Germany",
+        "Flag_Italy", "Flag_Korea", "Flag_Netherlands", "Flag_Russia", "Flag_Spain", "Flag_Taiwan",
+        "Flag_International", "Flag_Unknown"})
+  {
+    m_countries.append(GetScaledPixmap(country));
+  }
+  for (int stars = 0; stars <= 5; stars++)
+    m_ratings.append(GetScaledPixmap("rating" + std::to_string(stars)));
 
-  QStringList ratings{QStringLiteral("rating0.png"), QStringLiteral("rating1.png"),
-                      QStringLiteral("rating2.png"), QStringLiteral("rating3.png"),
-                      QStringLiteral("rating4.png"), QStringLiteral("rating5.png")};
-  for (QString rating : ratings)
-    m_ratings.append(QPixmap(rating.prepend(sys_dir)));
-
-  m_misc.append(QPixmap(QStringLiteral("nobanner.png").prepend(sys_dir)));
-  m_misc.append(QPixmap(QStringLiteral("dolphin_logo.png").prepend(sys_dir)));
-  m_misc.append(QPixmap(QStringLiteral("Dolphin.png").prepend(sys_dir)));
+  m_misc.append(GetScaledPixmap("nobanner"));
+  m_misc.append(GetScaledPixmap("dolphin_logo"));
+  m_misc.append(GetScaledPixmap("Dolphin"));
 }
 
 QPixmap Resources::GetPlatform(int platform)

Source/Core/DolphinQt2/Resources.h

@@ -5,7 +5,6 @@
 #pragma once
 
 #include <QList>
-#include <QPixmap>
 
 // Store for various QPixmaps that will be used repeatedly.
 class Resources final
@@ -26,8 +25,17 @@ public:
     LOGO_SMALL
   };
 
+  static QIcon GetScaledIcon(const std::string& name);
+  static QIcon GetScaledThemeIcon(const std::string& name);
+
+  static QPixmap GetScaledPixmap(const std::string& name);
+  static QPixmap GetScaledThemePixmap(const std::string& name);
+
 private:
   Resources() {}
+  static QIcon GetIcon(const QString& name, const QString& dir);
+  static QPixmap GetPixmap(const QString& name, const QString& dir);
+
   static QList<QPixmap> m_platforms;
   static QList<QPixmap> m_countries;
   static QList<QPixmap> m_ratings;

Source/Core/DolphinQt2/ToolBar.cpp

@@ -4,6 +4,7 @@
 
 #include <QIcon>
 
+#include "DolphinQt2/Resources.h"
 #include "DolphinQt2/Settings.h"
 #include "DolphinQt2/ToolBar.h"
 
@@ -91,15 +92,13 @@ void ToolBar::MakeActions()
 
 void ToolBar::UpdateIcons()
 {
-  QString dir = Settings().GetThemeDir();
-
-  m_open_action->setIcon(QIcon(QStringLiteral("open.png").prepend(dir)));
-  m_paths_action->setIcon(QIcon(QStringLiteral("browse.png").prepend(dir)));
-  m_play_action->setIcon(QIcon(QStringLiteral("play.png").prepend(dir)));
-  m_pause_action->setIcon(QIcon(QStringLiteral("pause.png").prepend(dir)));
-  m_stop_action->setIcon(QIcon(QStringLiteral("stop.png").prepend(dir)));
-  m_fullscreen_action->setIcon(QIcon(QStringLiteral("fullscreen.png").prepend(dir)));
-  m_screenshot_action->setIcon(QIcon(QStringLiteral("screenshot.png").prepend(dir)));
-  m_config_action->setIcon(QIcon(QStringLiteral("config.png").prepend(dir)));
-  m_controllers_action->setIcon(QIcon(QStringLiteral("classic.png").prepend(dir)));
+  m_open_action->setIcon(Resources::GetScaledThemeIcon("open"));
+  m_paths_action->setIcon(Resources::GetScaledThemeIcon("browse"));
+  m_play_action->setIcon(Resources::GetScaledThemeIcon("play"));
+  m_pause_action->setIcon(Resources::GetScaledThemeIcon("pause"));
+  m_stop_action->setIcon(Resources::GetScaledThemeIcon("stop"));
+  m_fullscreen_action->setIcon(Resources::GetScaledThemeIcon("fullscreen"));
+  m_screenshot_action->setIcon(Resources::GetScaledThemeIcon("screenshot"));
+  m_config_action->setIcon(Resources::GetScaledThemeIcon("config"));
+  m_controllers_action->setIcon(Resources::GetScaledThemeIcon("classic"));
 }