Add chat font size controls

src/main/java/ee/carlrobert/codegpt/settings/GeneralSettingsState.java

@@ -7,6 +7,7 @@ public class GeneralSettingsState {
   private String displayName = "";
   private String avatarBase64 = "";
   private ServiceType selectedService = null;
+  private int chatFontSizeOffset = 0;
 
   public String getDisplayName() {
     if (displayName == null || displayName.isEmpty()) {
@@ -38,4 +39,12 @@ public class GeneralSettingsState {
   public void setSelectedService(ServiceType selectedService) {
     this.selectedService = selectedService;
   }
+
+  public int getChatFontSizeOffset() {
+    return chatFontSizeOffset;
+  }
+
+  public void setChatFontSizeOffset(int chatFontSizeOffset) {
+    this.chatFontSizeOffset = chatFontSizeOffset;
+  }
 }

src/main/java/ee/carlrobert/codegpt/toolwindow/chat/ChatFontSize.java

@@ -0,0 +1,40 @@
+package ee.carlrobert.codegpt.toolwindow.chat;
+
+import com.intellij.util.ui.JBUI;
+import ee.carlrobert.codegpt.settings.GeneralSettings;
+import javax.swing.JTextPane;
+
+public final class ChatFontSize {
+
+  private static final int MIN_OFFSET = -4;
+  private static final int MAX_OFFSET = 8;
+
+  private ChatFontSize() {
+  }
+
+  public static boolean canAdjust(int delta) {
+    int offset = getOffset();
+    return delta < 0 ? offset > MIN_OFFSET : offset < MAX_OFFSET;
+  }
+
+  public static void adjust(int delta) {
+    var state = GeneralSettings.getCurrentState();
+    state.setChatFontSizeOffset(clampOffset(state.getChatFontSizeOffset() + delta));
+  }
+
+  public static void apply(JTextPane textPane) {
+    textPane.setFont(JBUI.Fonts.label().deriveFont((float) getFontSize()));
+  }
+
+  private static int getFontSize() {
+    return Math.max(8, JBUI.Fonts.label().getSize() + getOffset());
+  }
+
+  private static int getOffset() {
+    return clampOffset(GeneralSettings.getCurrentState().getChatFontSizeOffset());
+  }
+
+  private static int clampOffset(int offset) {
+    return Math.max(MIN_OFFSET, Math.min(MAX_OFFSET, offset));
+  }
+}

src/main/java/ee/carlrobert/codegpt/toolwindow/chat/ChatToolWindowPanel.java

@@ -1,8 +1,10 @@
 package ee.carlrobert.codegpt.toolwindow.chat;
 
+import com.intellij.icons.AllIcons;
 import com.intellij.ide.BrowserUtil;
 import com.intellij.openapi.Disposable;
 import com.intellij.openapi.actionSystem.ActionManager;
+import com.intellij.openapi.actionSystem.ActionUpdateThread;
 import com.intellij.openapi.actionSystem.ActionToolbar;
 import com.intellij.openapi.actionSystem.AnActionEvent;
 import com.intellij.openapi.actionSystem.DefaultCompactActionGroup;
@@ -39,6 +41,7 @@ import ee.carlrobert.codegpt.toolwindow.chat.ui.textarea.AttachImageNotifier;
 import java.awt.CardLayout;
 import java.nio.file.Path;
 import java.util.Set;
+import javax.swing.Icon;
 import javax.swing.JComponent;
 import javax.swing.JPanel;
 import org.jetbrains.annotations.NotNull;
@@ -199,6 +202,19 @@ public class ChatToolWindowPanel extends SimpleToolWindowPanel {
     actionGroup.addSeparator();
     actionGroup.add(new OpenInEditorAction());
     actionGroup.addSeparator();
+    actionGroup.add(new AdjustChatFontSizeAction(
+        "Decrease chat font size",
+        "Decrease the chat message font size",
+        AllIcons.General.Remove,
+        -1,
+        tabbedPane));
+    actionGroup.add(new AdjustChatFontSizeAction(
+        "Increase chat font size",
+        "Increase the chat message font size",
+        AllIcons.General.Add,
+        1,
+        tabbedPane));
+    actionGroup.addSeparator();
     actionGroup.add(new SelectedPersonaActionLink(project));
 
     var toolbar = ActionManager.getInstance()
@@ -207,6 +223,39 @@ public class ChatToolWindowPanel extends SimpleToolWindowPanel {
     return toolbar;
   }
 
+  private static class AdjustChatFontSizeAction extends DumbAwareAction {
+
+    private final int delta;
+    private final ChatToolWindowTabbedPane tabbedPane;
+
+    AdjustChatFontSizeAction(
+        String text,
+        String description,
+        Icon icon,
+        int delta,
+        ChatToolWindowTabbedPane tabbedPane) {
+      super(text, description, icon);
+      this.delta = delta;
+      this.tabbedPane = tabbedPane;
+    }
+
+    @Override
+    public @NotNull ActionUpdateThread getActionUpdateThread() {
+      return ActionUpdateThread.EDT;
+    }
+
+    @Override
+    public void actionPerformed(@NotNull AnActionEvent e) {
+      ChatFontSize.adjust(delta);
+      tabbedPane.refreshChatFontSize();
+    }
+
+    @Override
+    public void update(@NotNull AnActionEvent e) {
+      e.getPresentation().setEnabled(ChatFontSize.canAdjust(delta));
+    }
+  }
+
   private static class SelectedPersonaActionLink extends DumbAwareAction implements
       CustomComponentAction {
 

src/main/java/ee/carlrobert/codegpt/toolwindow/chat/ChatToolWindowTabPanel.java

@@ -202,6 +202,12 @@ public class ChatToolWindowTabPanel implements Disposable {
     userInputPanel.requestFocus();
   }
 
+  public void refreshChatFontSize() {
+    toolWindowScrollablePanel.refreshChatFontSize();
+    rootPanel.revalidate();
+    rootPanel.repaint();
+  }
+
   public void displayLandingView() {
     toolWindowScrollablePanel.displayLandingView(getLandingView());
     totalTokensPanel.updateConversationTokens(conversation);

src/main/java/ee/carlrobert/codegpt/toolwindow/chat/ChatToolWindowTabbedPane.java

@@ -64,6 +64,12 @@ public class ChatToolWindowTabbedPane extends JBTabbedPane {
     return activeTabMapping;
   }
 
+  public void refreshChatFontSize() {
+    activeTabMapping.values().forEach(ChatToolWindowTabPanel::refreshChatFontSize);
+    repaint();
+    revalidate();
+  }
+
   public void setTabLifecycleCallbacks(Runnable onTabsOpened, Runnable onAllTabsClosed) {
     this.onTabsOpened = onTabsOpened;
     this.onAllTabsClosed = onAllTabsClosed;

src/main/java/ee/carlrobert/codegpt/toolwindow/chat/ui/ChatMessageResponseBody.java

@@ -38,6 +38,7 @@ import ee.carlrobert.codegpt.settings.service.FeatureType;
 import ee.carlrobert.codegpt.settings.models.ModelSettings;
 import ee.carlrobert.codegpt.settings.service.ServiceType;
 import ee.carlrobert.codegpt.telemetry.TelemetryAction;
+import ee.carlrobert.codegpt.toolwindow.chat.ChatFontSize;
 import ee.carlrobert.codegpt.toolwindow.chat.editor.ResponseEditorPanel;
 import ee.carlrobert.codegpt.toolwindow.chat.editor.actions.CopyAction;
 import ee.carlrobert.codegpt.toolwindow.chat.editor.header.DefaultHeaderPanel;
@@ -59,6 +60,8 @@ import ee.carlrobert.codegpt.ui.UIUtil;
 import ee.carlrobert.codegpt.ui.hover.PsiLinkHoverPreview;
 import ee.carlrobert.codegpt.util.EditorUtil;
 import java.awt.BorderLayout;
+import java.awt.Component;
+import java.awt.Container;
 import java.util.Locale;
 import java.util.Objects;
 import javax.swing.DefaultListModel;
@@ -276,6 +279,23 @@ public class ChatMessageResponseBody extends JPanel {
     revalidate();
   }
 
+  public void refreshFontSize() {
+    refreshFontSize(contentPanel);
+    revalidate();
+    repaint();
+  }
+
+  private static void refreshFontSize(Component component) {
+    if (component instanceof JTextPane textPane) {
+      ChatFontSize.apply(textPane);
+    }
+    if (component instanceof Container container) {
+      for (var child : container.getComponents()) {
+        refreshFontSize(child);
+      }
+    }
+  }
+
   private void displayErrorMessage(String message, HyperlinkListener hyperlinkListener) {
     ApplicationManager.getApplication().invokeLater(() -> {
       if (webpageListPanel != null) {
@@ -526,6 +546,7 @@ public class ChatMessageResponseBody extends JPanel {
 
       UIUtil.handleHyperlinkClicked(event);
     });
+    ChatFontSize.apply(textPane);
     if (caretVisible) {
       textPane.getCaret().setVisible(true);
       textPane.setCaretPosition(textPane.getDocument().getLength());

src/main/java/ee/carlrobert/codegpt/toolwindow/chat/ui/ChatToolWindowScrollablePanel.java

@@ -3,6 +3,8 @@ package ee.carlrobert.codegpt.toolwindow.chat.ui;
 import com.intellij.openapi.roots.ui.componentsList.components.ScrollablePanel;
 import com.intellij.openapi.roots.ui.componentsList.layout.VerticalStackLayout;
 import ee.carlrobert.codegpt.toolwindow.ui.ResponseMessagePanel;
+import java.awt.Component;
+import java.awt.Container;
 import java.awt.Rectangle;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -72,6 +74,24 @@ public class ChatToolWindowScrollablePanel extends ScrollablePanel {
     revalidate();
   }
 
+  public void refreshChatFontSize() {
+    for (var component : getComponents()) {
+      refreshChatFontSize(component);
+    }
+    update();
+  }
+
+  private static void refreshChatFontSize(Component component) {
+    if (component instanceof ChatMessageResponseBody responseBody) {
+      responseBody.refreshFontSize();
+    }
+    if (component instanceof Container container) {
+      for (var child : container.getComponents()) {
+        refreshChatFontSize(child);
+      }
+    }
+  }
+
   public JPanel getLastComponent() {
     var comp = getComponents()[getComponentCount() - 1];
     if (comp instanceof JPanel panel) {