make it possible to change the interface font from the prefs

app/src/processing/app/platform/DefaultPlatform.java

@@ -29,6 +29,7 @@ import java.io.File;
 import java.net.URI;
 
 import javax.swing.UIManager;
+import javax.swing.plaf.FontUIResource;
 
 import com.sun.jna.Library;
 import com.sun.jna.Native;
@@ -110,6 +111,24 @@ public class DefaultPlatform {
     } else {
       UIManager.setLookAndFeel(laf);
     }
+
+    // If the default has been overridden in the preferences, set the font
+    String fontName = Preferences.get("ui.font.family");
+    int fontSize = Preferences.getInteger("ui.font.size");
+    if (!"Dialog".equals(fontName) || fontSize != 12) {
+      setUIFont(new FontUIResource(fontName, Font.PLAIN, fontSize));
+    }
+  }
+
+
+  // Rewritten from https://stackoverflow.com/a/7434935
+  static private void setUIFont(FontUIResource f) {
+    for (Object key : UIManager.getLookAndFeelDefaults().keySet()) {
+      Object value = UIManager.get(key);
+      if (value instanceof FontUIResource) {
+        UIManager.put(key, f);
+      }
+    }
   }
 
 
@@ -120,8 +139,11 @@ public class DefaultPlatform {
         scaleDefaultFont(widgetName);
       }
 
-      UIManager.put("Label.font", new Font("Dialog", Font.PLAIN, Toolkit.zoom(12)));
-      UIManager.put("TextField.font", new Font("Dialog", Font.PLAIN, Toolkit.zoom(12)));
+      String fontName = Preferences.get("ui.font.family");
+      int fontSize = Preferences.getInteger("ui.font.size");
+      FontUIResource uiFont = new FontUIResource(fontName, Font.PLAIN, Toolkit.zoom(fontSize));
+      UIManager.put("Label.font", uiFont);
+      UIManager.put("TextField.font", uiFont);
     }
   }
 

build/shared/lib/defaults.txt

@@ -95,6 +95,9 @@ platform.auto_file_type_associations = true
 
 # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
+# default font used for UI elements
+ui.font.family = Dialog
+ui.font.size = 12
 
 # default size for the main window
 editor.window.width.default = 700

todo.txt

@@ -1,6 +1,9 @@
 1275 (4.0a6)
 X remove java.class.path when launching code from inside the PDE
 X   should prevent conflicts, avoid papering over other bugs
+X add ui.font.family and ui.font.size as preferences
+
+readme
 _ was fixed in the source for 4.0a5, but may not have been included in the dist
 _   NoClassDefError: processing/core/PApplet when starting 4.0a2 on Windows 10
 _   https://github.com/processing/processing4/issues/154