Fix filename validity check

mainwindow.hpp

@@ -28,8 +28,8 @@ private slots:
     void on_actionSettings_triggered();
     void on_actionColor_Picker_triggered();
     void on_actionAbout_triggered();
-
     void on_actionActive_window_triggered();
+    void on_actionAbort_triggered();
 
 public:
     static MainWindow *inst();

mainwindow.ui

@@ -84,6 +84,7 @@
     </property>
     <addaction name="actionStart"/>
     <addaction name="actionStop"/>
+    <addaction name="actionAbort"/>
    </widget>
    <addaction name="menuFile"/>
    <addaction name="menuScreenshot"/>
@@ -136,6 +137,11 @@
     <string>Active window</string>
    </property>
   </action>
+  <action name="actionAbort">
+   <property name="text">
+    <string>Abort</string>
+   </property>
+  </action>
  </widget>
  <layoutdefault spacing="6" margin="11"/>
  <resources/>

platformspecifics/u32/u32backend.cpp

@@ -29,6 +29,17 @@ WId PlatformBackend::getActiveWID() {
     return (WId)GetForegroundWindow();
 }
 
+QString illegal(QStringLiteral("<>:\"/\|?*"));
+QStringList illegalNames({ "CON",  "PRN",  "AUX",  "NUL",  "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7",
+                           "COM8", "COM9", "LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9" });
+
 bool PlatformBackend::filenamValid(QString name) {
-    return IsValidFileName(name.toLocal8Bit().constData()) == 0;
+    unsigned int periods = 0;
+    for (QChar c : name) {
+        if (c == '.') periods++;
+        if (illegal.contains(c)) return false;
+        if (c < 32) return false;
+    }
+    if (periods == name.length()) return false;
+    return !illegalNames.contains(name);
 }