libui: Add a TextInput base class to handle most input fields and add an InputField class for single-line inputs

libui/CMakeLists.txt

@@ -17,6 +17,8 @@ set(SOURCES
     src/Container.cpp
     src/Button.cpp
     src/Label.cpp
+    src/InputField.cpp
+    src/TextInput.cpp
 )
 
 add_library(ui ${SOURCES})

libui/include/ui/InputField.h

@@ -0,0 +1,40 @@
+/**
+ * @file InputField.h
+ * @author apio (cloudapio.eu)
+ * @brief Single line text input widget.
+ *
+ * @copyright Copyright (c) 2024, the Luna authors.
+ *
+ */
+
+#pragma once
+#include <os/Action.h>
+#include <ui/Font.h>
+#include <ui/TextInput.h>
+
+namespace ui
+{
+    class InputField : public ui::TextInput
+    {
+      public:
+        InputField(SharedPtr<ui::Font> font);
+
+        Result<ui::EventResult> handle_key_event(const ui::KeyEventRequest& request) override;
+
+        Result<void> draw(ui::Canvas& canvas) override;
+
+        StringView data();
+
+        void on_submit(os::Function<StringView>&& action)
+        {
+            m_on_submit_action = move(action);
+            m_has_on_submit_action = true;
+        }
+
+      private:
+        SharedPtr<ui::Font> m_font;
+
+        os::Function<StringView> m_on_submit_action;
+        bool m_has_on_submit_action { false };
+    };
+}

libui/include/ui/TextInput.h

@@ -0,0 +1,41 @@
+/**
+ * @file TextInput.h
+ * @author apio (cloudapio.eu)
+ * @brief Base class for text inputs.
+ *
+ * @copyright Copyright (c) 2024, the Luna authors.
+ *
+ */
+
+#pragma once
+#include <luna/Buffer.h>
+#include <os/Timer.h>
+#include <ui/Widget.h>
+
+namespace ui
+{
+    class TextInput : public Widget
+    {
+      public:
+        TextInput();
+
+        virtual Result<ui::EventResult> handle_key_event(const ui::KeyEventRequest& request) = 0;
+
+        virtual Result<void> draw(ui::Canvas& canvas) = 0;
+
+      protected:
+        Buffer m_data;
+
+        usize m_cursor { 0 };
+        ui::Point m_cursor_position { 0, 0 };
+
+        OwnedPtr<os::Timer> m_cursor_timer;
+        bool m_cursor_activated = true;
+
+        void tick_cursor();
+        void update_cursor();
+
+        Result<void> delete_current_character();
+        Result<void> insert_character(char c);
+    };
+}

libui/src/InputField.cpp

@@ -0,0 +1,112 @@
+/**
+ * @file InputField.cpp
+ * @author apio (cloudapio.eu)
+ * @brief Single line text input widget.
+ *
+ * @copyright Copyright (c) 2024, the Luna authors.
+ *
+ */
+
+#include <ctype.h>
+#include <luna/String.h>
+#include <luna/StringView.h>
+#include <luna/Utf8.h>
+#include <ui/InputField.h>
+
+namespace ui
+{
+    InputField::InputField(SharedPtr<ui::Font> font) : ui::TextInput(), m_font(font)
+    {
+    }
+
+    Result<ui::EventResult> InputField::handle_key_event(const ui::KeyEventRequest& request)
+    {
+        // Avoid handling "key released" events
+        if (!request.pressed) return ui::EventResult::DidNotHandle;
+
+        if (request.code == moon::K_LeftArrow)
+        {
+            if (m_cursor > 0) m_cursor--;
+            else
+                return ui::EventResult::DidNotHandle;
+            update_cursor();
+            return ui::EventResult::DidHandle;
+        }
+
+        if (request.code == moon::K_RightArrow)
+        {
+            if (m_cursor < m_data.size()) m_cursor++;
+            else
+                return ui::EventResult::DidNotHandle;
+            update_cursor();
+            return ui::EventResult::DidHandle;
+        }
+
+        if (request.code == moon::K_Backspace)
+        {
+            if (m_cursor == 0) return ui::EventResult::DidNotHandle;
+            m_cursor--;
+
+            delete_current_character();
+
+            update_cursor();
+
+            return ui::EventResult::DidHandle;
+        }
+
+        if (request.letter == '\n')
+        {
+            if (m_has_on_submit_action)
+            {
+                m_on_submit_action(data());
+                return ui::EventResult::DidHandle;
+            }
+
+            return ui::EventResult::DidNotHandle;
+        }
+
+        if (iscntrl(request.letter)) return ui::EventResult::DidNotHandle;
+
+        if (m_cursor == m_data.size()) TRY(m_data.append_data((const u8*)&request.letter, 1));
+        else
+            TRY(insert_character(request.letter));
+
+        m_cursor++;
+
+        update_cursor();
+
+        return ui::EventResult::DidHandle;
+    }
+
+    Result<void> InputField::draw(ui::Canvas& canvas)
+    {
+        int visible_characters = canvas.width / m_font->width();
+
+        auto string = data();
+
+        Utf8StringDecoder decoder(string.chars());
+        wchar_t buf[4096];
+        decoder.decode(buf, sizeof(buf)).release_value();
+
+        int characters_to_render = (int)wcslen(buf);
+
+        for (int j = 0; j < visible_characters && j < characters_to_render; j++)
+        {
+            auto subcanvas = canvas.subcanvas({ j * m_font->width(), 0, m_font->width(), m_font->height() });
+            m_font->render(buf[j], ui::WHITE, subcanvas);
+        }
+
+        // Draw the cursor
+        if ((int)m_cursor < visible_characters && m_cursor_activated)
+        {
+            canvas.subcanvas({ (int)m_cursor * m_font->width(), 0, 1, m_font->height() }).fill(ui::WHITE);
+        }
+
+        return {};
+    }
+
+    StringView InputField::data()
+    {
+        return StringView { (const char*)m_data.data(), m_data.size() };
+    }
+}

libui/src/TextInput.cpp

@@ -0,0 +1,52 @@
+/**
+ * @file TextInput.cpp
+ * @author apio (cloudapio.eu)
+ * @brief Base class for text inputs.
+ *
+ * @copyright Copyright (c) 2024, the Luna authors.
+ *
+ */
+
+#include <ui/App.h>
+#include <ui/TextInput.h>
+
+namespace ui
+{
+    TextInput::TextInput() : Widget()
+    {
+        m_cursor_timer = os::Timer::create_repeating(500, [this]() { this->tick_cursor(); }).release_value();
+    }
+
+    void TextInput::update_cursor()
+    {
+        m_cursor_timer->restart();
+        m_cursor_activated = true;
+    }
+
+    Result<void> TextInput::delete_current_character()
+    {
+        usize size = m_data.size() - m_cursor;
+        u8* slice = TRY(m_data.slice(m_cursor, size));
+        memmove(slice, slice + 1, size - 1);
+        TRY(m_data.try_resize(m_data.size() - 1));
+
+        return {};
+    }
+
+    Result<void> TextInput::insert_character(char c)
+    {
+        usize size = m_data.size() - m_cursor;
+        u8* slice = TRY(m_data.slice(m_cursor, size + 1));
+        memmove(slice + 1, slice, size);
+        *slice = (u8)c;
+
+        return {};
+    }
+
+    void TextInput::tick_cursor()
+    {
+        m_cursor_activated = !m_cursor_activated;
+
+        window()->draw();
+    }
+}