1 files changed, 140 insertions, 0 deletions

diff --git a/src/main/java/Helper.java b/src/main/java/Helper.java
new file mode 100644
index 0000000..b7a139a
--- /dev/null
+++ b/src/main/java/Helper.java
@@ -0,0 +1,140 @@
+import javax.imageio.ImageIO;
+import javax.swing.*;
+import java.awt.*;
+import java.awt.event.WindowAdapter;
+import java.awt.event.WindowEvent;
+import java.awt.image.BufferedImage;
+import java.io.File;
+import java.io.IOException;
+
+/**
+ * Provide simple tools to read, write and show pictures.
+ */
+public final class Helper {
+
+    // Convert specified BufferedImage into an array
+    private static int[][] fromBufferedImage(BufferedImage image) {
+        int width = image.getWidth();
+        int height = image.getHeight();
+        int[][] array = new int[height][width];
+        for (int row = 0; row < height; ++row) {
+            for (int col = 0; col < width; ++col) {
+                array[row][col] = image.getRGB(col, row);
+            }
+        }
+        return array;
+    }
+
+    // Convert specified array int a BufferedImage
+    private static BufferedImage toBufferedImage(int[][] array) {
+        int width = array[0].length;
+        int height = array.length;
+        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
+        for (int row = 0; row < height; ++row) {
+            for (int col = 0; col < width; ++col) {
+                image.setRGB(col, row, array[row][col]);
+            }
+        }
+        return image;
+    }
+
+    /**
+     * Reads specified image from disk.
+     *
+     * @param path Input file path
+     * @return HxW array of packed RGB colors, or <code>null</code> on failure
+     * @see #write
+     */
+    public static int[][] read(String path) {
+        try {
+            BufferedImage image = ImageIO.read(new File(path));
+            return fromBufferedImage(image);
+        } catch (IOException e) {
+            return null;
+        }
+    }
+
+    /**
+     * Writes specified image to disk.
+     *
+     * @param path  Output file path
+     * @param array HxW array of packed RGB colors
+     * @return {@code true} if write operation was successful, {@code false} otherwise
+     * @see #read
+     */
+    public static boolean write(String path, int[][] array) {
+
+        // Convert array to Java image
+        BufferedImage image = toBufferedImage(array);
+
+        // Get desired file format
+        int index = path.lastIndexOf('.');
+        if (index < 0)
+            return false;
+        String extension = path.substring(index + 1);
+
+        // Export image
+        try {
+            return ImageIO.write(image, extension, new File(path));
+        } catch (IOException e) {
+            return false;
+        }
+
+    }
+
+    /**
+     * Shows specified image in a window.
+     *
+     * @param array HxW array of packed RGB colors
+     * @param title title to be displayed
+     */
+    public static void show(int[][] array, String title) {
+
+        // Convert array to Java image
+        final BufferedImage image = toBufferedImage(array);
+
+        // Create a panel to render this image
+        @SuppressWarnings("serial")
+        JPanel panel = new JPanel() {
+            @Override
+            protected void paintComponent(Graphics g) {
+                super.paintComponent(g);
+                g.drawImage(image, 0, 0, getWidth(), getHeight(), null, null);
+            }
+        };
+
+        // Create a frame to hold this panel
+        final JFrame frame = new JFrame(title);
+        frame.add(panel);
+        frame.pack();
+        frame.setSize(image.getWidth(), image.getHeight());
+
+        // Register closing event
+        frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
+        frame.addWindowListener(new WindowAdapter() {
+            @Override
+            public void windowClosing(WindowEvent e) {
+                frame.setVisible(false);
+                synchronized (frame) {
+                    frame.notifyAll();
+                }
+            }
+        });
+
+        // Show this frame
+        frame.setVisible(true);
+
+        // Wait for close operation
+        try {
+            synchronized (frame) {
+                while (frame.isVisible())
+                    frame.wait();
+            }
+        } catch (InterruptedException e) {
+            // Empty on purpose
+        }
+        frame.dispose();
+
+    }
+
+}