LibGUI: Add a basic BreadcrumbBar widget! :^)

This can be used to implement segmented path bars in FileManager and
wherever else wanted.

Libraries/LibGUI/BreadcrumbBar.cpp

@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <LibGUI/BoxLayout.h>
+#include <LibGUI/BreadcrumbBar.h>
+#include <LibGUI/Button.h>
+#include <LibGfx/Font.h>
+
+namespace GUI {
+
+// FIXME: Move this somewhere else
+class UnuncheckableButton : public GUI::Button {
+    C_OBJECT(UnuncheckableButton);
+
+public:
+    virtual ~UnuncheckableButton() override { }
+
+    virtual bool is_uncheckable() const override { return false; }
+
+private:
+    UnuncheckableButton() { }
+};
+
+BreadcrumbBar::BreadcrumbBar()
+{
+    auto& layout = set_layout<HorizontalBoxLayout>();
+    layout.set_spacing(0);
+}
+
+BreadcrumbBar::~BreadcrumbBar()
+{
+}
+
+void BreadcrumbBar::clear_segments()
+{
+    m_segments.clear();
+
+    // FIXME: Should Core::Object have something like "remove_all_children()" perhaps?
+    auto children = this->children();
+    for (auto& child : children)
+        child.remove_from_parent();
+}
+
+void BreadcrumbBar::append_segment(const String& text, const Gfx::Bitmap* icon, const String& data)
+{
+    auto& button = add<UnuncheckableButton>();
+    button.set_button_style(Gfx::ButtonStyle::CoolBar);
+    button.set_text(text);
+    button.set_icon(icon);
+    button.set_checkable(true);
+    button.set_exclusive(true);
+    button.on_click = [this, index = m_segments.size()](auto) {
+        if (on_segment_click)
+            on_segment_click(index);
+    };
+
+    button.set_size_policy(SizePolicy::Fixed, SizePolicy::Fixed);
+
+    auto button_text_width = button.font().width(text);
+    auto icon_width = icon ? icon->width() : 0;
+    auto icon_padding = icon ? 4 : 0;
+    button.set_preferred_size(button_text_width + icon_width + icon_padding + 16, 16 + 8);
+
+    Segment segment { icon, text, data, button.make_weak_ptr<GUI::Button>() };
+
+    m_segments.append(move(segment));
+}
+
+void BreadcrumbBar::set_selected_segment(Optional<size_t> index)
+{
+    if (!index.has_value()) {
+        for_each_child_of_type<GUI::AbstractButton>([&](auto& button) {
+            button.set_checked(false);
+            return IterationDecision::Continue;
+        });
+        return;
+    }
+
+    auto& segment = m_segments[index.value()];
+    ASSERT(segment.button);
+    segment.button->set_checked(true);
+}
+
+}

Libraries/LibGUI/BreadcrumbBar.h

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <LibGUI/Widget.h>
+
+namespace GUI {
+
+class BreadcrumbBar : public GUI::Widget {
+    C_OBJECT(BreadcrumbBar);
+
+public:
+    virtual ~BreadcrumbBar() override;
+
+    void clear_segments();
+    void append_segment(const String& text, const Gfx::Bitmap* icon = nullptr, const String& data = {});
+
+    size_t segment_count() const { return m_segments.size(); }
+    String segment_data(size_t index) const { return m_segments[index].data; }
+
+    void set_selected_segment(Optional<size_t> index);
+    Optional<size_t> selected_segment() const { return m_selected_segment; }
+
+    Function<void(size_t index)> on_segment_click;
+
+private:
+    BreadcrumbBar();
+
+    struct Segment {
+        RefPtr<const Gfx::Bitmap> icon;
+        String text;
+        String data;
+        WeakPtr<GUI::Button> button;
+    };
+
+    Vector<Segment> m_segments;
+    Optional<size_t> m_selected_segment;
+};
+
+}

Libraries/LibGUI/CMakeLists.txt

@@ -8,6 +8,7 @@ set(SOURCES
     Application.cpp
     BoxLayout.cpp
     Button.cpp
+    BreadcrumbBar.cpp
     Calendar.cpp
     CheckBox.cpp
     Clipboard.cpp