adding a toolbar icon for adding a line

src/studio/ui/UserAction.java

@@ -32,6 +32,21 @@ public KeyStroke getKeyStroke() {
         return (KeyStroke)getValue(ACCELERATOR_KEY);
     }
 
+    public String getKeyString() {
+        StringBuilder builder = new StringBuilder(getText());
+        KeyStroke keyStroke = getKeyStroke();
+        if (keyStroke != null) builder.append(" - ").append(keyStroke);
+        return builder.toString();
+    }
+
+    public UserAction addActionToComponent(JComponent component) {
+        String key = getKeyString();
+        component.getActionMap().put(key, this);
+        component.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(getKeyStroke(), key);
+        return this;
+    }
+
+
     public static UserAction create(String text, Icon icon,
                                String desc, int mnemonic,
                                KeyStroke key, ActionListener listener) {

src/studio/ui/Util.java

@@ -62,6 +62,8 @@ public class Util {
     public final static ImageIcon SEARCH_CASE_SENSITIVE_ICON = getImage("/searchCaseSensitive.png");
     public final static ImageIcon SEARCH_CASE_SENSITIVE_SHADED_ICON = getImage("/searchCaseSensitive_shaded.png");
 
+    public final static ImageIcon LINE_ICON = getImage("/line.png");
+
     public static boolean MAC_OS_X = (System.getProperty("os.name").toLowerCase().startsWith("mac os x"));
     public static boolean WINDOWS = (System.getProperty("os.name").toLowerCase().contains("win"));
 

src/studio/ui/chart/Chart.java

@@ -108,19 +108,29 @@ private void initComponents() {
             return;
         }
 
-        int modifier = Util.MAC_OS_X ? KeyEvent.ALT_MASK : KeyEvent.CTRL_MASK;
-        JLabel lbl = new JLabel("  Use mouse wheel or select a rectangle to zoom. " +
-                "Hold " + KeyEvent.getKeyModifiersText(modifier) + " to move the chart. " +
-                "ESC - to restore scale");
+        int plotMoveModifier = Util.MAC_OS_X ? KeyEvent.ALT_MASK : KeyEvent.CTRL_MASK;
+        int lineDragModifier = Util.MAC_OS_X ? KeyEvent.META_MASK : KeyEvent.CTRL_MASK;
+
+        String defaultLabelText = "  Use mouse wheel or select a rectangle to zoom. " +
+                "Hold " + KeyEvent.getKeyModifiersText(plotMoveModifier) + " to move the chart. " +
+                "ESC - to restore scale";
+
+        String selectedLineText = "  Move the line wih mouse drag. " +
+                "Hold " + KeyEvent.getKeyModifiersText(lineDragModifier) + " to change the slope of the line. ";
+
+        JLabel lbl = new JLabel(defaultLabelText);
 
         chartPanel = createChartPanel();
         pnlConfig = new ChartConfigPanel(this, names, xIndex, yIndex);
 
         JToolBar toolbar = new Toolbar();
         toolbar.setLayout(new BoxLayout(toolbar, BoxLayout.X_AXIS));
         toolbar.setFloatable(false);
-        toolbar.add(chartPanel.getCopyAction());
-        toolbar.add(chartPanel.getSaveAction());
+        toolbar.add(chartPanel.getLineAction());
+        toolbar.add(chartPanel.getCopyAction()).setFocusable(false);
+        toolbar.add(chartPanel.getSaveAction()).setFocusable(false);
+        chartPanel.addNewLineListener(e -> chartPanel.getRootPane().requestFocusInWindow());
+        chartPanel.addLineSelectionListener(e -> lbl.setText(e.getLine() == null ? defaultLabelText : selectedLineText) );
 
         JPanel rightPanel = new JPanel(new BorderLayout());
         rightPanel.add(pnlConfig, BorderLayout.CENTER);

src/studio/ui/chart/ChartPanel.java

@@ -8,9 +8,14 @@
 import org.jfree.chart.ui.RectangleEdge;
 import studio.ui.UserAction;
 import studio.ui.Util;
+import studio.ui.chart.event.LineSelectionEvent;
+import studio.ui.chart.event.LineSelectionListener;
+import studio.ui.chart.event.NewLineEvent;
+import studio.ui.chart.event.NewLineListener;
 import studio.ui.chart.patched.CrosshairOverlay;
 
 import javax.swing.*;
+import javax.swing.event.EventListenerList;
 import java.awt.*;
 import java.awt.event.ActionEvent;
 import java.awt.event.KeyEvent;
@@ -24,13 +29,16 @@ public class ChartPanel extends studio.ui.chart.patched.ChartPanel {
     private final Crosshair xCrosshair;
     private final Crosshair yCrosshair;
 
+    private final Action lineAction;
     private final Action copyAction;
     private final Action saveAction;
     private final Action propertiesAction;
     private final Action resetZoomAction;
     private final Action zoomInAction;
     private final Action zoomOutAction;
 
+    private final EventListenerList listenerList = new EventListenerList();
+    private boolean addingLine = false;
     private Line newLine = null;
     private Line selectedLine = null;
 
@@ -54,22 +62,25 @@ public ChartPanel(JFreeChart chart) {
         setMouseWheelEnabled(true);
         setMouseZoomable(true, true);
 
-        int meta = java.awt.Toolkit.getDefaultToolkit().getMenuShortcutKeyMask();
-        copyAction = addAccelerator(copyItem, KeyStroke.getKeyStroke(KeyEvent.VK_C, meta));
+        copyAction = addAccelerator(copyItem, KeyStroke.getKeyStroke(KeyEvent.VK_C, DRAG_LINE_MASK));
         copyAction.putValue(Action.SMALL_ICON, Util.COPY_ICON);
         copyAction.putValue(Action.SHORT_DESCRIPTION, "Copy the chart");
 
-        saveAction = addAccelerator(pngItem, KeyStroke.getKeyStroke(KeyEvent.VK_S, meta));
+        saveAction = addAccelerator(pngItem, KeyStroke.getKeyStroke(KeyEvent.VK_S, DRAG_LINE_MASK));
         saveAction.putValue(Action.SMALL_ICON, Util.DISKS_ICON);
         saveAction.putValue(Action.SHORT_DESCRIPTION, "Save the chart");
 
         propertiesAction = addAccelerator(propertiesItem, KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, KeyEvent.ALT_MASK));
-        zoomInAction = addAccelerator(zoomInBothMenuItem, KeyStroke.getKeyStroke(KeyEvent.VK_PLUS, meta),
-                                                          KeyStroke.getKeyStroke(KeyEvent.VK_EQUALS, meta),
-                                                          KeyStroke.getKeyStroke(KeyEvent.VK_ADD, meta));
-        zoomOutAction = addAccelerator(zoomOutBothMenuItem, KeyStroke.getKeyStroke(KeyEvent.VK_MINUS, meta),
-                                                            KeyStroke.getKeyStroke(KeyEvent.VK_SUBTRACT, meta));
+        zoomInAction = addAccelerator(zoomInBothMenuItem, KeyStroke.getKeyStroke(KeyEvent.VK_PLUS, DRAG_LINE_MASK),
+                                                          KeyStroke.getKeyStroke(KeyEvent.VK_EQUALS, DRAG_LINE_MASK),
+                                                          KeyStroke.getKeyStroke(KeyEvent.VK_ADD, DRAG_LINE_MASK));
+        zoomOutAction = addAccelerator(zoomOutBothMenuItem, KeyStroke.getKeyStroke(KeyEvent.VK_MINUS, DRAG_LINE_MASK),
+                                                            KeyStroke.getKeyStroke(KeyEvent.VK_SUBTRACT, DRAG_LINE_MASK));
         resetZoomAction = addAccelerator(zoomResetBothMenuItem, KeyStroke.getKeyStroke(KeyEvent.VK_ESCAPE, 0));
+
+        lineAction = UserAction.create("Add line", Util.LINE_ICON, "Add a line", KeyEvent.VK_L,null,
+                                        e -> addLineAction() );
+//                        .addActionToComponent(this); // didn't figure out why keyStroke doesn't trigger the action
     }
 
     private Action addAccelerator(JMenuItem menuItem, KeyStroke... keyStrokes) {
@@ -85,6 +96,10 @@ private Action addAccelerator(JMenuItem menuItem, KeyStroke... keyStrokes) {
         return action;
     }
 
+    public Action getLineAction() {
+        return lineAction;
+    }
+
     public Action getCopyAction() {
         return copyAction;
     }
@@ -93,6 +108,40 @@ public Action getSaveAction() {
         return saveAction;
     }
 
+    public void addNewLineListener(NewLineListener listener) {
+        listenerList.add(NewLineListener.class, listener);
+    }
+
+    public void removeNewLineListener(NewLineListener listener) {
+        listenerList.remove(NewLineListener.class, listener);
+    }
+
+    public void addLineSelectionListener(LineSelectionListener listener) {
+        listenerList.add(LineSelectionListener.class, listener);
+    }
+
+    public void removeLineSelectionListener(LineSelectionListener listener) {
+        listenerList.remove(LineSelectionListener.class, listener);
+    }
+
+    private void notifyListeners(NewLineEvent event) {
+        Object[] listeners = listenerList.getListenerList();
+        for (int i = listeners.length - 2; i >= 0; i -= 2) {
+            if (listeners[i] == NewLineListener.class) {
+                ((NewLineListener) listeners[i + 1]).lineAdded(event);
+            }
+        }
+    }
+
+    private void notifyListeners(LineSelectionEvent event) {
+        Object[] listeners = listenerList.getListenerList();
+        for (int i = listeners.length - 2; i >= 0; i -= 2) {
+            if (listeners[i] == LineSelectionListener.class) {
+                ((LineSelectionListener) listeners[i + 1]).lineSelected(event);
+            }
+        }
+    }
+
     @Override
     public void actionPerformed(ActionEvent event) {
         if (event.getActionCommand().equals(ZOOM_RESET_BOTH_COMMAND)) {
@@ -290,10 +339,14 @@ else if (e.isPopupTrigger()) {
 
     @Override
     public void mouseClicked(MouseEvent event) {
-        addLine(event);
+        if (addingLine) addLine(event);
         super.mouseClicked(event);
     }
 
+    private void addLineAction() {
+        addingLine = true;
+    }
+
     private boolean checkLineDrag(MouseEvent event) {
         if (selectedLine == null) return false;
 
@@ -338,6 +391,7 @@ private void checkLineSelection(Point p) {
         }
 
         if (selectedIndex != newSelectedIndex) {
+            notifyListeners(new LineSelectionEvent(this, selectedLine));
             chartChanged(new AnnotationChangeEvent(this, line));
         }
     }
@@ -351,7 +405,9 @@ private void addLine(MouseEvent e) {
         } else {
             newLine.addPoint(p);
             chartChanged(new AnnotationChangeEvent(this, newLine));
+            notifyListeners(new NewLineEvent(this, newLine));
             newLine = null;
+            addingLine = false;
         }
     }
 

src/studio/ui/chart/event/LineSelectionEvent.java

@@ -0,0 +1,19 @@
+package studio.ui.chart.event;
+
+import studio.ui.chart.Line;
+
+import java.util.EventObject;
+
+public class LineSelectionEvent extends EventObject {
+
+    private final Line line;
+
+    public LineSelectionEvent(Object source, Line line) {
+        super(source);
+        this.line = line;
+    }
+
+    public Line getLine() {
+        return line;
+    }
+}

src/studio/ui/chart/event/LineSelectionListener.java

@@ -0,0 +1,8 @@
+package studio.ui.chart.event;
+
+import java.util.EventListener;
+
+public interface LineSelectionListener extends EventListener {
+
+    void lineSelected(LineSelectionEvent event);
+}

src/studio/ui/chart/event/NewLineEvent.java

@@ -0,0 +1,19 @@
+package studio.ui.chart.event;
+
+import studio.ui.chart.Line;
+
+import java.util.EventObject;
+
+public class NewLineEvent extends EventObject {
+
+    private final Line line;
+
+    public NewLineEvent(Object source, Line line) {
+        super(source);
+        this.line = line;
+    }
+
+    public Line getLine() {
+        return line;
+    }
+}

src/studio/ui/chart/event/NewLineListener.java

@@ -0,0 +1,8 @@
+package studio.ui.chart.event;
+
+import java.util.EventListener;
+
+public interface NewLineListener extends EventListener {
+
+    void lineAdded(NewLineEvent event);
+}