[ui] ability to add a second line to the status text

When a component is empty, it's nice to have an action displayed that can make it not empty.
This action can be displayed as a link in the second line after the normal status text.

platform/platform-api/src/com/intellij/util/ui/StatusText.java

@@ -35,17 +35,20 @@ public abstract class StatusText {
   public static final SimpleTextAttributes DEFAULT_ATTRIBUTES = SimpleTextAttributes.GRAYED_ATTRIBUTES;
   public static final String DEFAULT_EMPTY_TEXT = UIBundle.message("message.nothingToShow");
 
-  @Nullable
-  private Component myOwner;
+  private static final int Y_GAP = JBUI.scale(2);
+
+  @Nullable private Component myOwner;
   private Component myMouseTarget;
-  private final MouseMotionListener myMouseMotionListener;
-  private final ClickListener myClickListener;
+  @NotNull private final MouseMotionListener myMouseMotionListener;
+  @NotNull private final ClickListener myClickListener;
 
   private boolean myIsDefaultText;
 
   private String myText = "";
-  protected final SimpleColoredComponent myComponent = new SimpleColoredComponent();
+  @NotNull protected final SimpleColoredComponent myComponent = new SimpleColoredComponent();
+  @NotNull private final SimpleColoredComponent mySecondaryComponent = new SimpleColoredComponent();
   private final List<ActionListener> myClickListeners = new ArrayList<>();
+  private final List<ActionListener> mySecondaryListeners = new ArrayList<>();
   private boolean myHasActiveClickListeners; // calculated field for performance optimization
   private boolean myShowAboveCenter = true;
 
@@ -70,7 +73,6 @@ public abstract class StatusText {
     };
 
     myMouseMotionListener = new MouseAdapter() {
-
       private Cursor myOriginalCursor;
 
       @Override
@@ -94,6 +96,9 @@ public abstract class StatusText {
     myComponent.setFont(UIUtil.getLabelFont());
     setText(DEFAULT_EMPTY_TEXT, DEFAULT_ATTRIBUTES);
     myIsDefaultText = true;
+
+    mySecondaryComponent.setOpaque(false);
+    mySecondaryComponent.setFont(UIUtil.getLabelFont());
   }
 
   public void attachTo(@Nullable Component owner) {
@@ -117,6 +122,25 @@ public abstract class StatusText {
 
   protected abstract boolean isStatusVisible();
 
+  @Nullable
+  private ActionListener findActionListenerAt(int xCoord, int yCoord) {
+    if (myComponent.getPreferredSize().height >= yCoord) {
+      return findListener(myComponent, myClickListeners, xCoord);
+    }
+    return findListener(mySecondaryComponent, mySecondaryListeners, xCoord);
+  }
+
+  @Nullable
+  private static ActionListener findListener(@NotNull SimpleColoredComponent component,
+                                             @NotNull List<ActionListener> listeners,
+                                             int xCoord) {
+    int index = component.findFragmentAt(xCoord);
+    if (index >= 0 && index < listeners.size()) {
+      return listeners.get(index);
+    }
+    return null;
+  }
+
   @Nullable
   private ActionListener findActionListenerAt(Point point) {
     if (!myHasActiveClickListeners || !isStatusVisible()) return null;
@@ -125,10 +149,7 @@ public abstract class StatusText {
 
     Rectangle b = getTextComponentBound();
     if (b.contains(point)) {
-      int index = myComponent.findFragmentAt(point.x - b.x);
-      if (index >= 0 && index < myClickListeners.size()) {
-        return myClickListeners.get(index);
-      }
+      return findActionListenerAt(point.x - b.x, point.y - b.y);
     }
     return null;
   }
@@ -136,9 +157,9 @@ public abstract class StatusText {
   protected Rectangle getTextComponentBound() {
     Rectangle ownerRec = myOwner == null ? new Rectangle(0, 0, 0, 0) : myOwner.getBounds();
 
-    Dimension size = myComponent.getPreferredSize();
+    Dimension size = getPreferredSize();
     int x = (ownerRec.width - size.width) / 2;
-    int y = (ownerRec.height - size.height) / (isShowAboveCenter() ? 3 : 2);
+    int y = (ownerRec.height - size.height) / (myShowAboveCenter ? 3 : 2);
     return new Rectangle(x, y, size.width, size.height);
   }
 
@@ -168,11 +189,17 @@ public abstract class StatusText {
     myText = "";
     myComponent.clear();
     myClickListeners.clear();
+    mySecondaryComponent.clear();
+    mySecondaryListeners.clear();
     myHasActiveClickListeners = false;
-    if (myOwner != null && isStatusVisible()) myOwner.repaint();
+    repaintOwner();
     return this;
   }
 
+  private void repaintOwner() {
+    if (myOwner != null && isStatusVisible()) myOwner.repaint();
+  }
+
   public StatusText appendText(String text) {
     return appendText(text, DEFAULT_ATTRIBUTES);
   }
@@ -193,7 +220,17 @@ public abstract class StatusText {
     if (listener != null) {
       myHasActiveClickListeners = true;
     }
-    if (myOwner != null && isStatusVisible()) myOwner.repaint();
+    repaintOwner();
+    return this;
+  }
+
+  public StatusText appendSecondaryText(String text, SimpleTextAttributes attrs, ActionListener listener) {
+    mySecondaryComponent.append(text, attrs);
+    mySecondaryListeners.add(listener);
+    if (listener != null) {
+      myHasActiveClickListeners = true;
+    }
+    repaintOwner();
     return this;
   }
 
@@ -226,10 +263,23 @@ public abstract class StatusText {
     viewport.repaint(textBoundsInViewport);
   }
 
-  private void doPaintStatusText(Graphics g, Rectangle textComponentBounds) {
-    myComponent.setBounds(0, 0, textComponentBounds.width, textComponentBounds.height);
-    Graphics2D g2 = (Graphics2D)g.create(textComponentBounds.x, textComponentBounds.y, textComponentBounds.width, textComponentBounds.height);
-    myComponent.paint(g2);
+  private void doPaintStatusText(@NotNull Graphics g, @NotNull Rectangle bounds) {
+    paintComponentAtY(myComponent, g, bounds, 0);
+    if (hasSecondaryText()) paintComponentAtY(mySecondaryComponent, g, bounds, bounds.height / 2 + Y_GAP);
+  }
+
+  private boolean hasSecondaryText() {
+    return mySecondaryComponent.getCharSequence(false).length() > 0;
+  }
+
+  private static void paintComponentAtY(@NotNull SimpleColoredComponent component, @NotNull Graphics g,
+                                        @NotNull Rectangle bounds, int yCoord) {
+    Dimension size = component.getPreferredSize();
+    Graphics2D g2 = (Graphics2D)g.create(bounds.x + (bounds.width - size.width) / 2,
+                                         bounds.y + yCoord,
+                                         size.width, size.height);
+    component.setBounds(0, 0, size.width, size.height);
+    component.paint(g2);
     g2.dispose();
   }
 
@@ -239,6 +289,10 @@ public abstract class StatusText {
   }
 
   public Dimension getPreferredSize() {
-    return myComponent.getPreferredSize();
+    Dimension componentSize = myComponent.getPreferredSize();
+    if (!hasSecondaryText()) return componentSize;
+    Dimension secondaryComponentSize = mySecondaryComponent.getPreferredSize();
+    return new Dimension(Math.max(componentSize.width, secondaryComponentSize.width),
+                         componentSize.height + secondaryComponentSize.height + Y_GAP);
   }
 }

platform/vcs-log/impl/src/com/intellij/vcs/log/ui/frame/VcsLogChangesBrowser.java

@@ -142,8 +142,8 @@ class VcsLogChangesBrowser extends ChangesBrowserBase implements Disposable {
       }
 
       if (myChanges.isEmpty() && details.getParents().size() > 1) {
-        myViewer.getEmptyText().setText("No merged conflicts. ").
-          appendText("Show changes to parents", getLinkAttributes(),
+        myViewer.getEmptyText().setText("No merged conflicts.").
+          appendSecondaryText("Show changes to parents", getLinkAttributes(),
                      e -> myUiProperties.set(SHOW_CHANGES_FROM_PARENTS, true));
       }
       else {