editor: Add a basic text editor

CMakeLists.txt

@@ -53,3 +53,4 @@ add_subdirectory(tests)
 add_subdirectory(shell)
 add_subdirectory(wind)
 add_subdirectory(terminal)
+add_subdirectory(editor)

editor/CMakeLists.txt

@@ -0,0 +1,12 @@
+set(SOURCES
+    main.cpp
+    EditorWidget.h
+    EditorWidget.cpp
+)
+
+add_executable(editor ${SOURCES})
+target_compile_options(editor PRIVATE -Os ${COMMON_FLAGS} -Wno-write-strings)
+add_dependencies(editor libc)
+target_include_directories(editor PRIVATE ${LUNA_BASE}/usr/include ${CMAKE_CURRENT_LIST_DIR})
+target_link_libraries(editor PRIVATE os ui)
+install(TARGETS editor DESTINATION ${LUNA_BASE}/usr/bin)

editor/EditorWidget.cpp

@@ -0,0 +1,236 @@
+/**
+ * @file EditorWidget.cpp
+ * @author apio (cloudapio.eu)
+ * @brief Multiline text editing widget.
+ *
+ * @copyright Copyright (c) 2024, the Luna authors.
+ *
+ */
+
+#include "EditorWidget.h"
+#include <ctype.h>
+#include <luna/Utf8.h>
+#include <os/File.h>
+#include <ui/App.h>
+
+EditorWidget::EditorWidget(SharedPtr<ui::Font> font) : ui::Widget(), m_font(font)
+{
+    m_cursor_timer = os::Timer::create_repeating(500, [this]() { this->tick_cursor(); }).release_value();
+    recalculate_lines();
+}
+
+Result<void> EditorWidget::load_file(const os::Path& path)
+{
+    os::eprintln("Loading file: %s", path.name().chars());
+
+    auto file = TRY(os::File::open_or_create(path, os::File::ReadOnly));
+
+    m_data = TRY(file->read_all());
+
+    os::eprintln("Read %zu bytes.", m_data.size());
+
+    m_cursor = m_data.size();
+
+    TRY(recalculate_lines());
+
+    return {};
+}
+
+Result<ui::EventResult> EditorWidget::handle_key_event(const ui::KeyEventRequest& request)
+{
+    // Avoid handling "key released" events
+    if (!request.pressed) return ui::EventResult::DidNotHandle;
+
+    if (m_insert)
+    {
+        if (request.code == moon::K_Esc)
+        {
+            m_insert = false;
+            ui::App::the().main_window()->set_title("Text Editor");
+        }
+
+        if (request.code == moon::K_Backspace)
+        {
+            if (m_cursor == 0) return ui::EventResult::DidNotHandle;
+            m_cursor--;
+
+            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));
+
+            TRY(recalculate_lines());
+
+            m_cursor_timer->restart();
+            m_cursor_activated = true;
+
+            return ui::EventResult::DidHandle;
+        }
+
+        if (request.letter != '\n' && iscntrl(request.letter)) return ui::EventResult::DidNotHandle;
+
+        if (m_cursor == m_data.size()) TRY(m_data.append_data((const u8*)&request.letter, 1));
+        else
+        {
+            usize size = m_data.size() - m_cursor;
+            u8* slice = TRY(m_data.slice(m_cursor, size + 1));
+            memmove(slice + 1, slice, size);
+            *slice = request.letter;
+        }
+
+        m_cursor++;
+        TRY(recalculate_lines());
+
+        m_cursor_timer->restart();
+        m_cursor_activated = true;
+
+        return ui::EventResult::DidHandle;
+    }
+
+    switch (request.letter)
+    {
+    case 'w': {
+        if (m_cursor_position.y > 0) m_cursor_position.y--;
+        else
+            return ui::EventResult::DidNotHandle;
+        recalculate_cursor_index();
+        m_cursor_timer->restart();
+        m_cursor_activated = true;
+        return ui::EventResult::DidHandle;
+    }
+    case 's': {
+        if (m_cursor_position.y + 1 < (int)m_lines.size()) m_cursor_position.y++;
+        else
+            return ui::EventResult::DidNotHandle;
+        recalculate_cursor_index();
+        m_cursor_timer->restart();
+        m_cursor_activated = true;
+        return ui::EventResult::DidHandle;
+    }
+    case 'a': {
+        if (m_cursor > 0) m_cursor--;
+        else
+            return ui::EventResult::DidNotHandle;
+        recalculate_cursor_position();
+        m_cursor_timer->restart();
+        m_cursor_activated = true;
+        return ui::EventResult::DidHandle;
+    }
+    case 'd': {
+        if (m_cursor < m_data.size()) m_cursor++;
+        else
+            return ui::EventResult::DidNotHandle;
+        recalculate_cursor_position();
+        m_cursor_timer->restart();
+        m_cursor_activated = true;
+        return ui::EventResult::DidHandle;
+    }
+    case 'i': {
+        m_insert = true;
+        ui::App::the().main_window()->set_title("Text Editor (insert)");
+        return ui::EventResult::DidHandle;
+    }
+    default: return ui::EventResult::DidNotHandle;
+    }
+}
+
+Result<void> EditorWidget::draw(ui::Canvas& canvas)
+{
+    int visible_lines = canvas.height / m_font->height();
+    int visible_columns = canvas.width / m_font->width();
+
+    if ((usize)visible_lines > m_lines.size()) visible_lines = static_cast<int>(m_lines.size());
+
+    for (int i = 0; i < visible_lines; i++)
+    {
+        auto line = m_lines[i];
+        if (line.begin == line.end) continue;
+
+        auto slice = TRY(m_data.slice(line.begin, line.end - line.begin));
+        auto string = TRY(
+            String::from_string_view(StringView::from_fixed_size_cstring((const char*)slice, line.end - line.begin)));
+
+        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_columns && j < characters_to_render; j++)
+        {
+            auto subcanvas =
+                canvas.subcanvas({ j * m_font->width(), i * m_font->height(), m_font->width(), m_font->height() });
+            m_font->render(buf[j], ui::WHITE, subcanvas);
+        }
+    }
+
+    // Draw the cursor
+    if (m_cursor_position.x < visible_columns && m_cursor_position.y < visible_lines && m_cursor_activated)
+    {
+        canvas
+            .subcanvas(
+                { m_cursor_position.x * m_font->width(), m_cursor_position.y * m_font->height(), 1, m_font->height() })
+            .fill(ui::WHITE);
+    }
+
+    return {};
+}
+
+Result<void> EditorWidget::recalculate_lines()
+{
+    m_lines.clear();
+
+    Line l;
+    l.begin = 0;
+    for (usize i = 0; i < m_data.size(); i++)
+    {
+        if (m_data.data()[i] == '\n')
+        {
+            l.end = i;
+            TRY(m_lines.try_append(l));
+            l.begin = i + 1;
+        }
+    }
+
+    l.end = m_data.size();
+    TRY(m_lines.try_append(l));
+
+    recalculate_cursor_position();
+
+    return {};
+}
+
+void EditorWidget::tick_cursor()
+{
+    m_cursor_activated = !m_cursor_activated;
+
+    ui::App::the().main_window()->draw();
+}
+
+void EditorWidget::recalculate_cursor_position()
+{
+    if (m_cursor == 0) m_cursor_position = { 0, 0 };
+
+    for (int i = 0; i < (int)m_lines.size(); i++)
+    {
+        auto line = m_lines[i];
+        if (m_cursor >= line.begin && m_cursor <= line.end)
+        {
+            m_cursor_position.x = (int)(m_cursor - line.begin);
+            m_cursor_position.y = i;
+            return;
+        }
+    }
+
+    unreachable();
+}
+
+void EditorWidget::recalculate_cursor_index()
+{
+    m_cursor = m_lines[m_cursor_position.y].begin + m_cursor_position.x;
+    if (m_cursor > m_lines[m_cursor_position.y].end)
+    {
+        m_cursor = m_lines[m_cursor_position.y].end;
+        recalculate_cursor_position();
+    }
+}

editor/EditorWidget.h

@@ -0,0 +1,51 @@
+/**
+ * @file EditorWidget.h
+ * @author apio (cloudapio.eu)
+ * @brief Multiline text editing widget.
+ *
+ * @copyright Copyright (c) 2024, the Luna authors.
+ *
+ */
+
+#include <luna/String.h>
+#include <os/Timer.h>
+#include <ui/Font.h>
+#include <ui/Widget.h>
+
+class EditorWidget : public ui::Widget
+{
+  public:
+    EditorWidget(SharedPtr<ui::Font> font);
+
+    Result<void> load_file(const os::Path& path);
+
+    Result<ui::EventResult> handle_key_event(const ui::KeyEventRequest& request) override;
+
+    Result<void> draw(ui::Canvas& canvas) override;
+
+  private:
+    SharedPtr<ui::Font> m_font;
+
+    Buffer m_data;
+
+    struct Line
+    {
+        usize begin;
+        usize end;
+    };
+    Vector<Line> m_lines;
+
+    usize m_cursor { 0 };
+    ui::Point m_cursor_position { 0, 0 };
+
+    OwnedPtr<os::Timer> m_cursor_timer;
+    bool m_cursor_activated = true;
+
+    bool m_insert = false;
+
+    void tick_cursor();
+
+    Result<void> recalculate_lines();
+    void recalculate_cursor_position();
+    void recalculate_cursor_index();
+};

editor/main.cpp

@@ -0,0 +1,30 @@
+/**
+ * @file main.cpp
+ * @author apio (cloudapio.eu)
+ * @brief Graphical text editor.
+ *
+ * @copyright Copyright (c) 2024, the Luna authors.
+ *
+ */
+
+#include "EditorWidget.h"
+#include <ui/App.h>
+
+Result<int> luna_main(int, char**)
+{
+    ui::App app;
+    TRY(app.init());
+
+    auto* window = TRY(ui::Window::create(ui::Rect { 200, 300, 600, 600 }));
+    window->set_background(ui::Color::from_rgb(40, 40, 40));
+    window->set_title("Text Editor");
+    app.set_main_window(window);
+
+    auto* editor = TRY(make<EditorWidget>(ui::Font::default_font()));
+    // TRY(editor->load_file("/etc/skel/welcome"));
+    window->set_main_widget(*editor);
+
+    window->draw();
+
+    return app.run();
+}