Had a bit of fun adding support for diagonal highlighting (works with run.sh as well)

You can now pass "enhanced" as an argument when lauching the program to use the custom EnhancedCrosswordGUI class.
The class is the same as CrosswordGUI but functions were edited to support diagonal highlighting.

tp2/run.sh

-java -classpath out/ Main
+java -classpath out/ Main "$@"

tp2/src/Crossword.java

@@ -7,6 +7,9 @@ import java.nio.file.Files;
 
 public class Crossword
 {
+   private boolean USE_ENHANCED_GUI = false;
+   public void useEnhancedGUI(boolean b) { USE_ENHANCED_GUI = b; }
+
    public final static String DEFAULT_FILE_PATH = "WORDS.txt";
 
    private char array[][]; 	// Tableaux 2D contenant les caractères
@@ -155,7 +158,9 @@ public class Crossword
 			System.out.println("Error: Incorrect y-coordinates for Word");
 			return;		
       }
+      if (USE_ENHANCED_GUI)
          EnhancedCrosswordGUI.display(array, PositionY, PositionX, EndY, EndX);  
+      else CrosswordGUI.display(array, PositionY, PositionX, EndY, EndX);
    }
    
 }

tp2/src/EnhancedCrosswordGUI.java

+import java.awt.Color;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+
+import javax.swing.JTextField;
+
+/**
+ * This class is behaves exactly like CrosswordGUI 
+ * except that it supports diagonal highlighting.
+ * 
+ * It was created because CrosswordGUI was asked not to be modified.
+ */
+class EnhancedCrosswordGUI extends CrosswordGUI {
+    public enum Directions {
+        HORIZONTAL, VERTICAL, DIAGONAL_TOP, DIAGONAL_BOTTOM
+    };
+
+    public static void display(char array[][], int y1, int x1, int y2, int x2) {
+        final EnhancedCrosswordPanel panel = new EnhancedCrosswordPanel(array);
+        if (y1 == y2 && x1 <= x2)
+            panel.highlight(y1, x1, 1 + x2 - x1, Directions.HORIZONTAL);
+        else if (x1 == x2 && y1 <= y2)
+            panel.highlight(y1, x1, 1 + y2 - y1, Directions.VERTICAL);
+        else if (x1 <= x2 && y1 <= y2)
+            panel.highlight(y1, x1, 1 + x2 - x1, Directions.DIAGONAL_BOTTOM);
+        else if (x1 <= x2 && y1 >= y2)
+            panel.highlight(y1, x1, 1 + x2 - x1, Directions.DIAGONAL_TOP);
+
+        // We call the private method displayPanel(panel) via reflection
+        Method displayPanelMethod;
+        try {
+            displayPanelMethod = CrosswordGUI.class.getDeclaredMethod("displayPanel", CrosswordPanel.class);
+            displayPanelMethod.setAccessible(true);
+            displayPanelMethod.invoke(null, panel);
+        } catch (Exception e) {
+            System.err.println("Couldn't reflect method displayPanel :(");
+            e.printStackTrace();
+            return;
+        }
+    }
+
+    static public class EnhancedCrosswordPanel extends CrosswordPanel {
+        public EnhancedCrosswordPanel(char[][] array) {
+            super(array);
+        }
+
+        public void highlight(int startY, int startX, int length, Directions dir) {
+            // We get around accessing private member textFields using reflection
+            JTextField textFields[][];
+            {
+                try {
+                    Field f = CrosswordPanel.class.getDeclaredField("textFields");
+                    f.setAccessible(true);
+                    textFields = (JTextField[][]) f.get(this);
+
+                } catch (Exception e) {
+                    System.err.println("Couldn't reflect member textFields[][] :(");
+                    e.printStackTrace();
+                    return;
+                }
+            }
+
+            int incrementX = 0, incrementY = 0;
+            if (dir.equals(Directions.HORIZONTAL)) incrementX = 1;
+            else if (dir.equals(Directions.VERTICAL)) incrementY = 1;
+            else if (dir.equals(Directions.DIAGONAL_TOP)) { incrementX = 1; incrementY = -1; }
+            else if (dir.equals(Directions.DIAGONAL_BOTTOM)) { incrementX = 1; incrementY = 1; }
+
+            for (int i = 0; i < length; i++)
+                textFields[startY + (incrementY * i)][startX + (incrementX * i)]
+                    .setBackground(Color.green);
+                    
+            repaint();
+        }
+    }
+}
\ No newline at end of file

tp2/src/Main.java

 import java.io.*;
+import java.util.Arrays;
 import java.util.Scanner;
 
 /*** Methode Main : Lire le fichier donné et créer un tableau 2D qui contint le characters du fichier. 
@@ -10,12 +11,16 @@ public class Main {
 
     public static void main(String args[]) throws IOException {
 		Main mainInstance = new Main();
+		boolean useEnhancedGUI = mainInstance.checkEnhancedGUIArgs(args);
 		File crosswordFile = new File(mainInstance.promptFilePath());
+
 		if (!crosswordFile.exists()) {
 			System.err.printf("Error: The file %s doesn't exist\n", crosswordFile.getName());
 			return;
 		}
 		Crossword crossword = new Crossword(crosswordFile);
+		crossword.useEnhancedGUI(useEnhancedGUI);
+
 		crossword.display();
 
 		String wordInput;
@@ -44,4 +49,11 @@ public class Main {
 		String input = consoleScanner.nextLine();
 		return input;
 	}
+	private boolean checkEnhancedGUIArgs(String args[]) {
+		if (Arrays.asList(args).contains("enhanced")) return true;
+		else {
+			System.out.println("Pro Tip: you can pass \"enhanced\" as an argument to support diagonal highlighting");
+			return false;
+		}
+	}
 }
\ No newline at end of file