1 files changed, 120 insertions, 0 deletions
diff --git a/src/main/java/dev/isxander/yacl3/gui/tab/ScrollableNavigationBar.java b/src/main/java/dev/isxander/yacl3/gui/tab/ScrollableNavigationBar.java
new file mode 100644
index 0000000..5829202
--- /dev/null
+++ b/src/main/java/dev/isxander/yacl3/gui/tab/ScrollableNavigationBar.java
@@ -0,0 +1,120 @@
+package dev.isxander.yacl3.gui.tab;
+
+import com.google.common.collect.ImmutableList;
+import dev.isxander.yacl3.mixin.TabNavigationBarAccessor;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.gui.Font;
+import net.minecraft.client.gui.GuiGraphics;
+import net.minecraft.client.gui.components.AbstractWidget;
+import net.minecraft.client.gui.components.TabButton;
+import net.minecraft.client.gui.components.events.GuiEventListener;
+import net.minecraft.client.gui.components.tabs.Tab;
+import net.minecraft.client.gui.components.tabs.TabManager;
+import net.minecraft.client.gui.components.tabs.TabNavigationBar;
+import net.minecraft.client.gui.layouts.Layout;
+import net.minecraft.util.Mth;
+import org.jetbrains.annotations.Nullable;
+
+public class ScrollableNavigationBar extends TabNavigationBar {
+    private static final int NAVBAR_MARGIN = 28;
+
+    private static final Font font = Minecraft.getInstance().font;
+
+    private int scrollOffset;
+    private int maxScrollOffset;
+
+    public ScrollableNavigationBar(int width, TabManager tabManager, Iterable<? extends Tab> tabs) {
+        super(width, tabManager, ImmutableList.copyOf(tabs));
+
+        // add tab tooltips to the tab buttons
+        for (TabButton tabButton : this.tabButtons) {
+            if (tabButton.tab() instanceof TabExt tab) {
+                tabButton.setTooltip(tab.getTooltip());
+            }
+        }
+    }
+
+    @Override
+    public void arrangeElements() {
+        int noScrollWidth = this.width - NAVBAR_MARGIN*2;
+
+        int allTabsWidth = 0;
+        // first pass: set the width of each tab button
+        for (TabButton tabButton : this.tabButtons) {
+            int buttonWidth = font.width(tabButton.getMessage()) + 20;
+            allTabsWidth += buttonWidth;
+            tabButton.setWidth(buttonWidth);
+        }
+
+        if (allTabsWidth < noScrollWidth) {
+            int equalWidth = noScrollWidth / this.tabButtons.size();
+            var smallTabs = this.tabButtons.stream().filter(btn -> btn.getWidth() < equalWidth).toList();
+            var bigTabs = this.tabButtons.stream().filter(btn -> btn.getWidth() >= equalWidth).toList();
+            int leftoverWidth = noScrollWidth - bigTabs.stream().mapToInt(AbstractWidget::getWidth).sum();
+            int equalWidthForSmallTabs = leftoverWidth / smallTabs.size();
+            for (TabButton tabButton : smallTabs) {
+                tabButton.setWidth(equalWidthForSmallTabs);
+            }
+
+            allTabsWidth = noScrollWidth;
+        }
+
+        Layout layout = ((TabNavigationBarAccessor) this).getLayout();
+        layout.arrangeElements();
+        layout.setY(0);
+        scrollOffset = 0;
+
+        layout.setX(Math.max((this.width - allTabsWidth) / 2, NAVBAR_MARGIN));
+        this.maxScrollOffset = Math.max(0, allTabsWidth - noScrollWidth);
+    }
+
+    @Override
+    public void render(GuiGraphics graphics, int mouseX, int mouseY, float delta) {
+        graphics.pose().pushPose();
+        // render option list BELOW the navbar without need to scissor
+        graphics.pose().translate(0, 0, 10);
+
+        super.render(graphics, mouseX, mouseY, delta);
+
+        graphics.pose().popPose();
+    }
+
+    @Override
+    public boolean mouseScrolled(double mouseX, double mouseY, /*? if >1.20.2 {*/ double horizontal, /*?}*/ double vertical) {
+        this.setScrollOffset(this.scrollOffset - (int)(vertical*15));
+        return true;
+    }
+
+    @Override
+    public boolean isMouseOver(double mouseX, double mouseY) {
+        return mouseY <= 24;
+    }
+
+    public void setScrollOffset(int scrollOffset) {
+        Layout layout = ((TabNavigationBarAccessor) this).getLayout();
+
+        layout.setX(layout.getX() + this.scrollOffset);
+        this.scrollOffset = Mth.clamp(scrollOffset, 0, maxScrollOffset);
+        layout.setX(layout.getX() - this.scrollOffset);
+    }
+
+    public int getScrollOffset() {
+        return scrollOffset;
+    }
+
+    @Override
+    public void setFocused(@Nullable GuiEventListener child) {
+        super.setFocused(child);
+        if (child instanceof TabButton tabButton) {
+            this.ensureVisible(tabButton);
+        }
+    }
+
+    protected void ensureVisible(TabButton tabButton) {
+        if (tabButton.getX() < NAVBAR_MARGIN) {
+            this.setScrollOffset(this.scrollOffset - (NAVBAR_MARGIN - tabButton.getX()));
+        } else if (tabButton.getX() + tabButton.getWidth() > this.width - NAVBAR_MARGIN) {
+            this.setScrollOffset(this.scrollOffset + (tabButton.getX() + tabButton.getWidth() - (this.width - NAVBAR_MARGIN)));
+        }
+    }
+}