IDEA-239121 diff: fix title and notifications header layout

* Update layout to correctly handle gaps for invisible components (ex: hidden notification).
* Fix invisible notifications:
  EditorNotificationPanel has minimum height of 0, which was used by previous MigLayout
  to give it zero height and force multiple panels to draw on top of each other.

GitOrigin-RevId: 15b8741815b3ab6acc408289a4961d9ee778a1e7

platform/diff-impl/intellij.platform.diff.impl.iml

@@ -16,7 +16,6 @@
     <orderEntry type="module" module-name="intellij.platform.ide.impl" />
     <orderEntry type="module" module-name="intellij.platform.lang" />
     <orderEntry type="library" name="Guava" level="project" />
-    <orderEntry type="library" name="miglayout-swing" level="project" />
     <orderEntry type="module" module-name="intellij.platform.statistics" />
     <orderEntry type="module" module-name="intellij.platform.boot" />
     <orderEntry type="module" module-name="intellij.platform.core.ui" />

platform/diff-impl/src/com/intellij/diff/tools/util/side/DiffContentPanel.java

@@ -21,13 +21,13 @@ import com.intellij.diff.util.DiffUtil;
 import com.intellij.diff.util.InvisibleWrapper;
 import com.intellij.ui.components.panels.Wrapper;
 import com.intellij.util.containers.ContainerUtil;
-import net.miginfocom.layout.CC;
-import net.miginfocom.layout.LC;
-import net.miginfocom.swing.MigLayout;
+import com.intellij.util.ui.AbstractLayoutManager;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
+import java.awt.*;
+import java.util.Arrays;
 import java.util.List;
 
 class DiffContentPanel extends JPanel {
@@ -71,15 +71,11 @@ class DiffContentPanel extends JPanel {
                                  @NotNull JComponent content,
                                  @NotNull JComponent bottomBreadcrumbs) {
     contentPanel.removeAll();
-
-    MigLayout mgr = new MigLayout(new LC().flowY().fill().hideMode(3)
-                                    .insets("0").gridGapY("0"));
-    contentPanel.setLayout(mgr);
-
-    contentPanel.add(title, new CC().growX().minWidth("0").gapY("0", String.valueOf(DiffUtil.TITLE_GAP)));
-    contentPanel.add(topBreadcrumbs, new CC().growX().minWidth("0"));
-    contentPanel.add(content, new CC().grow().push());
-    contentPanel.add(bottomBreadcrumbs, new CC().growX().minWidth("0"));
+    contentPanel.setLayout(new DiffContentLayout(title, topBreadcrumbs, content, bottomBreadcrumbs));
+    contentPanel.add(title);
+    contentPanel.add(topBreadcrumbs);
+    contentPanel.add(content);
+    contentPanel.add(bottomBreadcrumbs);
   }
 
   public static void syncTitleHeights(@NotNull List<DiffContentPanel> panels) {
@@ -96,4 +92,69 @@ class DiffContentPanel extends JPanel {
       initLayout(contentPanel, title, topBreadcrumb, contentPanel.myContent, contentPanel.myBottomBreadcrumbs);
     }
   }
+
+  private static class DiffContentLayout extends AbstractLayoutManager {
+    @NotNull private final JComponent myTitle;
+    @NotNull private final JComponent myTopBreadcrumbs;
+    @NotNull private final JComponent myContent;
+    @NotNull private final JComponent myBottomBreadcrumbs;
+
+    DiffContentLayout(@NotNull JComponent title,
+                      @NotNull JComponent topBreadcrumbs,
+                      @NotNull JComponent content,
+                      @NotNull JComponent bottomBreadcrumbs) {
+      myTitle = title;
+      myTopBreadcrumbs = topBreadcrumbs;
+      myContent = content;
+      myBottomBreadcrumbs = bottomBreadcrumbs;
+    }
+
+    @Override
+    public Dimension preferredLayoutSize(Container parent) {
+      int totalWidth = 0;
+      int totalHeight = 0;
+
+      for (JComponent component : Arrays.asList(myTitle, myTopBreadcrumbs, myContent, myBottomBreadcrumbs)) {
+        Dimension size = getPreferredSize(component);
+
+        totalWidth = Math.max(size.width, totalWidth);
+        totalHeight += size.height;
+
+        if (component == myTitle && size.height != 0) {
+          totalHeight += DiffUtil.TITLE_GAP;
+        }
+      }
+
+      return new Dimension(totalWidth, totalHeight);
+    }
+
+    @Override
+    public void layoutContainer(@NotNull Container parent) {
+      int y = 0;
+
+      int width = parent.getWidth();
+      int totalHeight = parent.getHeight();
+
+      Dimension titleSize = getPreferredSize(myTitle);
+      Dimension topSize = getPreferredSize(myTopBreadcrumbs);
+      Dimension bottomSize = getPreferredSize(myBottomBreadcrumbs);
+      int bottomY = totalHeight - bottomSize.height;
+
+      myTitle.setBounds(0, y, width, titleSize.height);
+      y += titleSize.height;
+      if (titleSize.height != 0) y += DiffUtil.TITLE_GAP;
+
+      myTopBreadcrumbs.setBounds(0, y, width, topSize.height);
+      y += topSize.height;
+
+      myContent.setBounds(0, y, width, Math.max(0, bottomY - y));
+
+      myBottomBreadcrumbs.setBounds(0, bottomY, width, bottomSize.height);
+    }
+
+    @NotNull
+    private static Dimension getPreferredSize(@NotNull JComponent component) {
+      return component.isVisible() ? component.getPreferredSize() : new Dimension();
+    }
+  }
 }

platform/diff-impl/src/com/intellij/diff/util/DiffUtil.java

@@ -565,21 +565,20 @@ public final class DiffUtil {
   private static JComponent createTitleWithNotifications(@Nullable DiffViewer viewer,
                                                          @Nullable JComponent title,
                                                          @NotNull DiffContent content) {
-    List<JComponent> notifications = new ArrayList<>(createCustomNotifications(viewer, content));
+    List<JComponent> components = new ArrayList<>();
+    if (title != null) components.add(title);
+
+    components.addAll(createCustomNotifications(viewer, content));
 
     if (content instanceof DocumentContent) {
       Document document = ((DocumentContent)content).getDocument();
       if (FileDocumentManager.getInstance().isPartialPreviewOfALargeFile(document)) {
-        notifications.add(DiffNotifications.createNotification(DiffBundle.message("error.file.is.too.large.only.preview.is.loaded")));
+        components.add(DiffNotifications.createNotification(DiffBundle.message("error.file.is.too.large.only.preview.is.loaded")));
       }
     }
 
-    if (notifications.isEmpty()) return title;
-
-    JPanel panel = new JPanel(new BorderLayout(0, TITLE_GAP));
-    if (title != null) panel.add(title, BorderLayout.NORTH);
-    panel.add(createStackedComponents(notifications, TITLE_GAP), BorderLayout.SOUTH);
-    return panel;
+    if (components.isEmpty()) return null;
+    return createStackedComponents(components, TITLE_GAP);
   }
 
   @Nullable
@@ -689,21 +688,18 @@ public final class DiffUtil {
     if (!ContainerUtil.exists(components, Conditions.notNull())) return components;
     List<JComponent> result = new ArrayList<>();
     for (int i = 0; i < components.size(); i++) {
-      result.add(new SyncHeightComponent(components, i));
+      JComponent component = components.get(i);
+      result.add(new SyncHeightComponent(components, component));
     }
     return result;
   }
 
   @NotNull
-  public static JComponent createStackedComponents(@NotNull List<? extends JComponent> components, int gap) {
-    JPanel panel = new JPanel();
-    panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
-
-    for (int i = 0; i < components.size(); i++) {
-      if (i != 0) panel.add(Box.createVerticalStrut(JBUIScale.scale(gap)));
-      panel.add(components.get(i));
+  public static JComponent createStackedComponents(@NotNull List<? extends JComponent> components, int vGap) {
+    JPanel panel = new JPanel(new VerticalStackLayout(vGap));
+    for (JComponent component : components) {
+      panel.add(component);
     }
-
     return panel;
   }
 

platform/diff-impl/src/com/intellij/diff/util/SyncHeightComponent.java

@@ -1,8 +1,9 @@
 // Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.diff.util;
 
-import com.intellij.util.Function;
+import com.intellij.util.ui.AbstractLayoutManager;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
 import java.awt.*;
@@ -11,35 +12,11 @@ import java.util.List;
 public class SyncHeightComponent extends JPanel {
   @NotNull private final List<? extends JComponent> myComponents;
 
-  SyncHeightComponent(@NotNull List<? extends JComponent> components, int index) {
-    super(new BorderLayout());
-    myComponents = components;
-    JComponent delegate = components.get(index);
-    if (delegate != null) add(delegate, BorderLayout.CENTER);
-  }
+  SyncHeightComponent(@NotNull List<? extends JComponent> syncComponents, @Nullable JComponent component) {
+    super(new SyncHeightLayout(syncComponents, component));
+    myComponents = syncComponents;
 
-  @Override
-  public Dimension getMinimumSize() {
-    Dimension size = super.getMinimumSize();
-    size.height = getMaximumHeight(JComponent::getPreferredSize);
-    return size;
-  }
-
-  @Override
-  public Dimension getPreferredSize() {
-    Dimension size = super.getPreferredSize();
-    size.height = getMaximumHeight(JComponent::getPreferredSize);
-    return size;
-  }
-
-  private int getMaximumHeight(@NotNull Function<? super JComponent, ? extends Dimension> getter) {
-    int height = 0;
-    for (JComponent component : myComponents) {
-      if (component != null) {
-        height = Math.max(height, getter.fun(component).height);
-      }
-    }
-    return height;
+    if (component != null) add(component);
   }
 
   public void revalidateAll() {
@@ -47,4 +24,44 @@ public class SyncHeightComponent extends JPanel {
       if (component != null) component.revalidate();
     }
   }
+
+  private static class SyncHeightLayout extends AbstractLayoutManager {
+    @NotNull private final List<? extends JComponent> mySyncComponents;
+    @Nullable private final JComponent myComponent;
+
+    SyncHeightLayout(@NotNull List<? extends JComponent> syncComponents, @Nullable JComponent component) {
+      mySyncComponents = syncComponents;
+      myComponent = component;
+    }
+
+    @Override
+    public Dimension preferredLayoutSize(Container parent) {
+      int totalHeight = 0;
+
+      for (JComponent component : mySyncComponents) {
+        Dimension size = getPreferredSize(component);
+        totalHeight = Math.max(size.height, totalHeight);
+      }
+
+      int width = getPreferredSize(myComponent).width;
+
+      return new Dimension(width, totalHeight);
+    }
+
+    @Override
+    public void layoutContainer(@NotNull Container parent) {
+      int width = parent.getWidth();
+      int height = parent.getHeight();
+
+      if (myComponent == null) return;
+
+      Dimension size = getPreferredSize(myComponent);
+      myComponent.setBounds(0, 0, width, Math.min(height, size.height));
+    }
+
+    @NotNull
+    private static Dimension getPreferredSize(@Nullable Component component) {
+      return component != null && component.isVisible() ? component.getPreferredSize() : new Dimension();
+    }
+  }
 }

platform/diff-impl/src/com/intellij/diff/util/VerticalStackLayout.java

@@ -0,0 +1,52 @@
+// Copyright 2000-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.diff.util;
+
+import com.intellij.util.ui.AbstractLayoutManager;
+import com.intellij.util.ui.JBUI;
+import org.jetbrains.annotations.NotNull;
+
+import javax.swing.*;
+import java.awt.*;
+
+class VerticalStackLayout extends AbstractLayoutManager {
+  private final int myVGap;
+
+  VerticalStackLayout(int vGap) {
+    myVGap = vGap;
+  }
+
+  @Override
+  public Dimension preferredLayoutSize(Container parent) {
+    int totalWidth = 0;
+    int totalHeight = 0;
+
+    for (Component component : parent.getComponents()) {
+      Dimension size = getPreferredSize(component);
+
+      totalWidth = Math.max(size.width, totalWidth);
+      if (size.height != 0 && totalHeight != 0) totalHeight += myVGap;
+      totalHeight += size.height;
+    }
+
+    return new Dimension(totalWidth, totalHeight);
+  }
+
+  @Override
+  public void layoutContainer(@NotNull Container parent) {
+    int width = parent.getWidth();
+
+    int y = 0;
+    for (Component component : parent.getComponents()) {
+      Dimension size = getPreferredSize(component);
+
+      component.setBounds(0, y, width, size.height);
+      if (size.height != 0) y += myVGap;
+      y += size.height;
+    }
+  }
+
+  @NotNull
+  private static Dimension getPreferredSize(@NotNull Component component) {
+    return component.isVisible() ? component.getPreferredSize() : new Dimension();
+  }
+}