ui: cleanup setMainWindow (#28768)

* cleanup

* revert that

---------

Co-authored-by: Adeeb Shihadeh <adeebshihadeh@gmail.com>
old-commit-hash: 289fd32699

selfdrive/ui/qt/qt_window.cc

@@ -1,15 +1,15 @@
 #include "selfdrive/ui/qt/qt_window.h"
 
 void setMainWindow(QWidget *w) {
+  const float scale = util::getenv("SCALE", 1.0f);
   const QSize sz = QGuiApplication::primaryScreen()->size();
-  if (Hardware::PC() && sz.width() <= 1920 && sz.height() <= 1080 && getenv("SCALE") == nullptr) {
+
+  if (Hardware::PC() && scale == 1.0 && !(sz - DEVICE_SCREEN_SIZE).isValid()) {
     w->setMinimumSize(QSize(640, 480)); // allow resize smaller than fullscreen
-    w->setMaximumSize(QSize(2160, 1080));
+    w->setMaximumSize(DEVICE_SCREEN_SIZE);
     w->resize(sz);
   } else {
-    const float scale = util::getenv("SCALE", 1.0f);
-    const bool wide = (sz.width() >= WIDE_WIDTH) ^ (getenv("INVERT_WIDTH") != NULL);
-    w->setFixedSize(QSize(wide ? WIDE_WIDTH : 1920, 1080) * scale);
+    w->setFixedSize(DEVICE_SCREEN_SIZE * scale);
   }
   w->show();
 

selfdrive/ui/qt/qt_window.h

@@ -15,7 +15,6 @@
 #include "system/hardware/hw.h"
 
 const QString ASSET_PATH = ":/";
-
-const int WIDE_WIDTH = 2160;
+const QSize DEVICE_SCREEN_SIZE = {2160, 1080};
 
 void setMainWindow(QWidget *w);