TabHeader: selecting items works

You can modify the active tab by clicing it.

src/main.cxx

@@ -127,7 +127,7 @@ int main() {
 
     auto list_names = std::vector<std::string_view>{
         "Tab 1",
-        "Tab 2",
+        "Tab with very long name",
         "Tab 3",
         "‎Tab‎ 4",
     };
@@ -145,7 +145,10 @@ int main() {
     stack->add_new<Label>(Position{}, Size{}, "Widget 4")->content.background_color =
         MakeColor(0x33, 0x22, 0xaa);
 
-    list->on_item_selected = [&stack](auto list, auto index /*, auto reason*/) {
+    list->on_item_selected = [&stack](auto &combo, auto index /*, auto reason*/) {
+        stack->set_current_page(index);
+    };
+    tab_header->on_item_selected = [&stack](auto &tab_header, auto index /*, auto reason*/) {
         stack->set_current_page(index);
     };
 

src/tabheader.cpp

@@ -7,6 +7,7 @@
 
 #include "tabheader.h"
 #include "theme.h"
+#include <spdlog/spdlog.h>
 
 TabHeader::TabHeader() : Widget() {
     //
@@ -45,6 +46,9 @@ auto TabHeader::draw() -> void {
     theme->draw_widget_background(content, has_focus);
 
     this->content.fill(0);
+    this->tab_offset.clear();
+    this->tab_offset.resize(names.size());
+
     auto i = 0;
     for (auto s : names) {
         auto is_active_tab = i == this->active_tab;
@@ -59,12 +63,31 @@ auto TabHeader::draw() -> void {
                                 tab_size.height + padding_y * 2, bg_color);
 
         font.write(this->content, {offset + padding_x, padding_y}, s, 0x00);
+        this->tab_offset[i] = {offset, tab_size.width + padding_x};
         offset += tab_size.width;
         offset += padding_x + padding_x;
         i++;
     }
 }
 
+auto TabHeader::on_mouse_click(const EventMouse &event) -> EventPropagation {
+    if (event.pressed) {
+        auto index = 0;
+        for (const auto &offset : tab_offset) {
+            if (event.x > offset.offset && event.x < offset.offset + offset.width) {
+                this->needs_redraw = true;
+                this->active_tab = index;
+                if (this->on_item_selected) {
+                    on_item_selected(*this, index);
+                }
+                return EventPropagation::handled;
+            }
+            index++;
+        }
+    }
+    return Widget::on_mouse_click(event);
+}
+
 auto TabHeader::size_hint() const -> Size {
     auto hint = this->get_theme()->font.text_size("X");
     hint.width = 0;

src/tabheader.h

@@ -7,10 +7,12 @@
 
 #pragma once
 
+#include <vector>
 #include <widget.h>
 
 struct TabHeader : Widget {
     std::vector<std::string_view> names;
+    std::function<void(TabHeader &, int)> on_item_selected = {};
 
     TabHeader();
 
@@ -21,8 +23,15 @@ struct TabHeader : Widget {
     auto get_active_tab() const -> int { return active_tab; }
 
     virtual auto draw() -> void override;
+    virtual auto on_mouse_click(const EventMouse &event) -> EventPropagation override;
     virtual auto size_hint() const -> Size override;
 
   private:
+    struct TabOffsets {
+        int offset;
+        int width;
+    };
+    std::vector<TabOffsets> tab_offset;
+
     int active_tab = 0;
 };