Use Win10 API SetThreadDpiAwarenessContext to force DPI Awareness

This commit contains debug messages used for testing purposes.

Author: cmaglie

arduino-core/src/processing/app/windows/Platform.java

@@ -36,6 +36,7 @@
 import java.util.List;
 
 import com.sun.jna.Native;
+import com.sun.jna.Pointer;
 import com.sun.jna.win32.StdCallLibrary;
 import com.sun.jna.win32.W32APIOptions;
 
@@ -250,15 +251,54 @@ interface ExtUser32 extends StdCallLibrary, com.sun.jna.platform.win32.User32 {
     ExtUser32 INSTANCE = (ExtUser32) Native.loadLibrary("user32", ExtUser32.class, W32APIOptions.DEFAULT_OPTIONS);
 
     public int GetDpiForSystem();
+
+    public int SetProcessDpiAwareness(int value);
+
+    public final int DPI_AWARENESS_INVALID = -1;
+    public final int DPI_AWARENESS_UNAWARE = 0;
+    public final int DPI_AWARENESS_SYSTEM_AWARE = 1;
+    public final int DPI_AWARENESS_PER_MONITOR_AWARE = 2;
+
+    public Pointer SetThreadDpiAwarenessContext(Pointer dpiContext);
+
+    public final Pointer DPI_AWARENESS_CONTEXT_UNAWARE = new Pointer(-1);
+    public final Pointer DPI_AWARENESS_CONTEXT_SYSTEM_AWARE = new Pointer(-2);
+    public final Pointer DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE = new Pointer(-3);
   }
 
+  private static int detected = detectSystemDPI();
+
   @Override
   public int getSystemDPI() {
+    if (detected == -1)
+      return super.getSystemDPI();
+    return detected;
+  }
+
+  public static int detectSystemDPI() {
+    try {
+      int res = ExtUser32.INSTANCE.SetProcessDpiAwareness(ExtUser32.DPI_AWARENESS_SYSTEM_AWARE);
+      System.out.println("SetProcessDpiAwareness returned " + res);
+    } catch (Throwable e) {
+      System.out.println("SetProcessDpiAwareness failed!");
+      // Ignore error
+    }
+    try {
+      System.out.println("before any SetThreadDpiAwarenessContext(...) -> dpi " + ExtUser32.INSTANCE.GetDpiForSystem());
+      ExtUser32.INSTANCE.SetThreadDpiAwarenessContext(ExtUser32.DPI_AWARENESS_CONTEXT_UNAWARE);
+      System.out.println("SetThreadDpiAwarenessContext(UNAWARE) -> dpi " + ExtUser32.INSTANCE.GetDpiForSystem());
+      ExtUser32.INSTANCE.SetThreadDpiAwarenessContext(ExtUser32.DPI_AWARENESS_CONTEXT_SYSTEM_AWARE);
+      System.out.println("SetThreadDpiAwarenessContext(SYSTEM) -> dpi " + ExtUser32.INSTANCE.GetDpiForSystem());
+    } catch (Throwable e) {
+      System.out.println("SetThreadDpiAwarenessContext failed!");
+      // Ignore error (call valid only on Windows 10)
+    }
     try {
       return ExtUser32.INSTANCE.GetDpiForSystem();
     } catch (Throwable e) {
       // DPI detection failed, fall back with default
-      return super.getSystemDPI();
+      System.out.println("DPI detection failed, fallback to 96 dpi");
+      return -1;
     }
   }
 }