Start working on a simple TextBox widget.

Widgets/Event.h

@@ -98,6 +98,15 @@ enum class MouseButton : byte {
     Right,
 };
 
+enum KeyboardKey {
+    Invalid,
+    LeftArrow,
+    RightArrow,
+    UpArrow,
+    DownArrow,
+    Backspace,
+};
+
 class KeyEvent final : public Event {
 public:
     KeyEvent(Type type, int key)

Widgets/EventLoopSDL.cpp

@@ -32,6 +32,16 @@ static inline MouseButton toMouseButton(byte sdlButton)
 void EventLoopSDL::handleKeyEvent(Event::Type type, const SDL_KeyboardEvent& sdlKey)
 {
     auto keyEvent = make<KeyEvent>(type, 0);
+    int key = 0;
+
+    switch (sdlKey.keysym.sym) {
+    case SDLK_LEFT: key = KeyboardKey::LeftArrow; break;
+    case SDLK_RIGHT: key = KeyboardKey::RightArrow; break;
+    case SDLK_UP: key = KeyboardKey::UpArrow; break;
+    case SDLK_DOWN: key = KeyboardKey::DownArrow; break;
+    case SDLK_BACKSPACE: key = KeyboardKey::Backspace; break;
+    }
+    keyEvent->m_key = key;
 
     if (sdlKey.keysym.sym > SDLK_UNKNOWN && sdlKey.keysym.sym <= 'z') {
         char buf[] = { 0, 0 };
@@ -62,6 +72,7 @@ void EventLoopSDL::handleKeyEvent(Event::Type type, const SDL_KeyboardEvent& sdl
                 case ']': ch = '}'; break;
                 case '\\': ch = '|'; break;
                 case '\'': ch = '"'; break;
+                case ';': ch = ':'; break;
                 }
             }
         }

Widgets/Makefile

@@ -26,6 +26,7 @@ VFS_OBJS = \
     CBitmap.o \
     CheckBox.o \
     ListBox.o \
+    TextBox.o \
     test.o
 
 OBJS = $(AK_OBJS) $(VFS_OBJS)

Widgets/Rect.h

@@ -40,6 +40,14 @@ public:
         setHeight(height() + h);
     }
 
+    void shrink(int w, int h)
+    {
+        setX(x() + w / 2);
+        setWidth(width() - w);
+        setY(y() + h / 2);
+        setHeight(height() - h);
+    }
+
     bool contains(int x, int y) const
     {
         return x >= m_location.x() && x < right() && y >= m_location.y() && y < bottom();

Widgets/TextBox.cpp

@@ -0,0 +1,137 @@
+#include "TextBox.h"
+#include "Painter.h"
+#include "Font.h"
+#include "CBitmap.h"
+#include <AK/StdLib.h>
+
+TextBox::TextBox(Widget* parent)
+    : Widget(parent)
+{
+    startTimer(500);
+}
+
+TextBox::~TextBox()
+{
+}
+
+void TextBox::setText(String&& text)
+{
+    m_text = std::move(text);
+    m_cursorPosition = m_text.length();
+    update();
+}
+
+void TextBox::onPaint(PaintEvent&)
+{
+    Painter painter(*this);
+
+    // FIXME: Reduce overdraw.
+    painter.fillRect(rect(), backgroundColor());
+    painter.drawRect(rect(), foregroundColor());
+
+    if (isFocused())
+        painter.drawFocusRect(rect());
+
+    Rect innerRect = rect();
+    innerRect.shrink(6, 6);
+
+    auto& font = Font::defaultFont();
+
+    unsigned maxCharsToPaint = innerRect.width() / font.glyphWidth();
+
+    int firstVisibleChar = max((int)m_cursorPosition - (int)maxCharsToPaint, 0);
+    unsigned charsToPaint = min(m_text.length() - firstVisibleChar, maxCharsToPaint);
+
+    for (unsigned i = 0; i < charsToPaint; ++i) {
+        char ch = m_text[firstVisibleChar + i];
+        if (ch == ' ')
+            continue;
+        int x = innerRect.x() + (i * font.glyphWidth());
+        int y = innerRect.y();
+        auto* bitmap = font.glyphBitmap(ch);
+        if (!bitmap) {
+            printf("TextBox: glyph missing: %02x\n", ch);
+            ASSERT_NOT_REACHED();
+        }
+        painter.drawBitmap({x, y}, *bitmap, Color::Black);
+    }
+
+    if (m_cursorBlinkState) {
+        unsigned visibleCursorPosition = m_cursorPosition - firstVisibleChar;
+        Rect cursorRect(innerRect.x() + visibleCursorPosition * font.glyphWidth(), innerRect.y(), 1, innerRect.height());
+        painter.fillRect(cursorRect, foregroundColor());
+    }
+}
+
+void TextBox::onMouseDown(MouseEvent&)
+{
+}
+
+void TextBox::handleBackspace()
+{
+    if (m_cursorPosition == 0)
+        return;
+
+    if (m_text.length() == 1) {
+        m_text = String::empty();
+        m_cursorPosition = 0;
+        update();
+        return;
+    }
+
+    char* buffer;
+    auto newText = StringImpl::createUninitialized(m_text.length() - 1, buffer);
+
+    memcpy(buffer, m_text.characters(), m_cursorPosition - 1);
+    memcpy(buffer + m_cursorPosition - 1, m_text.characters() + m_cursorPosition, m_text.length() - (m_cursorPosition - 1));
+
+    m_text = std::move(newText);
+    --m_cursorPosition;
+    update();
+}
+
+void TextBox::onKeyDown(KeyEvent& event)
+{
+    switch (event.key()) {
+    case KeyboardKey::LeftArrow:
+        if (m_cursorPosition)
+            --m_cursorPosition;
+        m_cursorBlinkState = true;
+        update();
+        return;
+    case KeyboardKey::RightArrow:
+        if (m_cursorPosition < m_text.length())
+            ++m_cursorPosition;
+        m_cursorBlinkState = true;
+        update();
+        return;
+    case KeyboardKey::Backspace:
+        return handleBackspace();
+    }
+
+    if (!event.text().isEmpty()) {
+        ASSERT(event.text().length() == 1);
+
+        char* buffer;
+        auto newText = StringImpl::createUninitialized(m_text.length() + 1, buffer);
+
+        memcpy(buffer, m_text.characters(), m_cursorPosition);
+        buffer[m_cursorPosition] = event.text()[0];
+        memcpy(buffer + m_cursorPosition + 1, m_text.characters() + m_cursorPosition, m_text.length() - m_cursorPosition);
+
+        m_text = std::move(newText);
+        ++m_cursorPosition;
+        update();
+        return;
+    }
+}
+
+void TextBox::onTimer(TimerEvent&)
+{
+    // FIXME: Disable the timer when not focused.
+    if (!isFocused())
+        return;
+
+    m_cursorBlinkState = !m_cursorBlinkState;
+    update();
+}

Widgets/TextBox.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include "Widget.h"
+
+class TextBox final : public Widget {
+public:
+    explicit TextBox(Widget* parent = nullptr);
+    virtual ~TextBox() override;
+
+    String text() const { return m_text; }
+    void setText(String&&);
+
+private:
+    virtual void onPaint(PaintEvent&) override;
+    virtual void onMouseDown(MouseEvent&) override;
+    virtual void onKeyDown(KeyEvent&) override;
+    virtual void onTimer(TimerEvent&) override;
+
+    void handleBackspace();
+
+    String m_text;
+    unsigned m_cursorPosition { 0 };
+    bool m_cursorBlinkState { false };
+};
+

Widgets/test.cpp

@@ -9,6 +9,7 @@
 #include "ClockWidget.h"
 #include "CheckBox.h"
 #include "ListBox.h"
+#include "TextBox.h"
 #include <cstdio>
 
 int main(int argc, char** argv)
@@ -48,7 +49,7 @@ int main(int argc, char** argv)
     {
         auto* widgetTestWindow = new Window;
         widgetTestWindow->setTitle("Widget test");
-        widgetTestWindow->setRect({ 20, 40, 100, 160 });
+        widgetTestWindow->setRect({ 20, 40, 100, 180 });
 
         auto* widgetTestWindowWidget = new Widget;
         widgetTestWindowWidget->setWindowRelativeRect({ 0, 0, 100, 100 });
@@ -67,11 +68,18 @@ int main(int argc, char** argv)
         c->setCaption("CheckBox");
 
         auto *lb = new ListBox(widgetTestWindowWidget);
-        lb->setWindowRelativeRect({0, 60, 100, 100 });
+        lb->setWindowRelativeRect({ 0, 60, 100, 100 });
         lb->addItem("This");
         lb->addItem("is");
         lb->addItem("a");
         lb->addItem("ListBox");
+
+        auto *tb = new TextBox(widgetTestWindowWidget);
+        tb->setWindowRelativeRect({ 0, 160, 100, 20 });
+        tb->setText("Hello!");
+        tb->setFocus(true);
+
+        WindowManager::the().setActiveWindow(widgetTestWindow);
     }
 
     auto* win = new Window;