system/ui: add text scrolling support to InputBox for long text (#35310)

* add text scrolling support to InputBox for long text

* add 2 pixels buffer to the scissor region

system/ui/lib/inputbox.py

@@ -14,6 +14,8 @@ class InputBox:
     self._key_press_time = 0
     self._repeat_delay = 30
     self._repeat_rate = 4
+    self._text_offset = 0
+    self._visible_width = 0
 
   @property
   def text(self):
@@ -23,6 +25,7 @@ class InputBox:
   def text(self, value):
     self._input_text = value[: self._max_text_size]
     self._cursor_position = len(self._input_text)
+    self._update_text_offset()
 
   def set_password_mode(self, password_mode):
     self._password_mode = password_mode
@@ -30,6 +33,7 @@ class InputBox:
   def clear(self):
     self._input_text = ''
     self._cursor_position = 0
+    self._text_offset = 0
 
   def set_cursor_position(self, position):
     """Set the cursor position and reset the blink counter."""
@@ -37,6 +41,29 @@ class InputBox:
       self._cursor_position = position
       self._blink_counter = 0
       self._show_cursor = True
+      self._update_text_offset()
+
+  def _update_text_offset(self):
+    """Ensure the cursor is visible by adjusting text offset."""
+    if self._visible_width == 0:
+      return
+
+    font = gui_app.font()
+    display_text = "*" * len(self._input_text) if self._password_mode else self._input_text
+    padding = 10
+
+    if self._cursor_position > 0:
+      cursor_x = rl.measure_text_ex(font, display_text[: self._cursor_position], self._font_size, 0).x
+    else:
+      cursor_x = 0
+
+    visible_width = self._visible_width - (padding * 2)
+
+    # Adjust offset if cursor would be outside visible area
+    if cursor_x < self._text_offset:
+      self._text_offset = max(0, cursor_x - padding)
+    elif cursor_x > self._text_offset + visible_width:
+      self._text_offset = cursor_x - visible_width + padding
 
   def add_char_at_cursor(self, char):
     """Add a character at the current cursor position."""
@@ -63,6 +90,10 @@ class InputBox:
     return False
 
   def render(self, rect, color=rl.BLACK, border_color=rl.DARKGRAY, text_color=rl.WHITE, font_size=80):
+    # Store dimensions for text offset calculations
+    self._visible_width = rect.width
+    self._font_size = font_size
+
     # Handle mouse input
     self._handle_mouse_input(rect, font_size)
 
@@ -82,10 +113,14 @@ class InputBox:
     font = gui_app.font()
     display_text = "*" * len(self._input_text) if self._password_mode else self._input_text
     padding = 10
+
+    # Clip text within input box bounds
+    buffer = 2
+    rl.begin_scissor_mode(int(rect.x + padding - buffer), int(rect.y), int(rect.width - padding * 2 + buffer * 2), int(rect.height))
     rl.draw_text_ex(
       font,
       display_text,
-      rl.Vector2(int(rect.x + padding), int(rect.y + rect.height / 2 - font_size / 2)),
+      rl.Vector2(int(rect.x + padding - self._text_offset), int(rect.y + rect.height / 2 - font_size / 2)),
       font_size,
       0,
       text_color,
@@ -97,9 +132,14 @@ class InputBox:
       if len(display_text) > 0 and self._cursor_position > 0:
         cursor_x += rl.measure_text_ex(font, display_text[: self._cursor_position], font_size, 0).x
 
+      # Apply text offset to cursor position
+      cursor_x -= self._text_offset
+
       cursor_height = font_size + 4
       cursor_y = rect.y + rect.height / 2 - cursor_height / 2
-      rl.draw_line(int(cursor_x), int(cursor_y), int(cursor_x), int(cursor_y + cursor_height), rl.LIGHTGRAY)
+      rl.draw_line(int(cursor_x), int(cursor_y), int(cursor_x), int(cursor_y + cursor_height), rl.WHITE)
+
+    rl.end_scissor_mode()
 
   def _handle_mouse_input(self, rect, font_size):
     """Handle mouse clicks to position cursor."""
@@ -107,14 +147,22 @@ class InputBox:
     if rl.is_mouse_button_pressed(rl.MOUSE_LEFT_BUTTON) and rl.check_collision_point_rec(mouse_pos, rect):
       # Calculate cursor position from click
       if len(self._input_text) > 0:
-        text_width = rl.measure_text_ex(gui_app.font(), self._input_text, font_size, 0).x
-        text_pos_x = rect.x + 10
-
-        if mouse_pos.x - text_pos_x > text_width:
-          self.set_cursor_position(len(self._input_text))
-        else:
-          click_ratio = (mouse_pos.x - text_pos_x) / text_width
-          self.set_cursor_position(int(len(self._input_text) * click_ratio))
+        font = gui_app.font()
+        display_text = "*" * len(self._input_text) if self._password_mode else self._input_text
+
+        # Find the closest character position to the click
+        relative_x = mouse_pos.x - (rect.x + 10) + self._text_offset
+        best_pos = 0
+        min_distance = float('inf')
+
+        for i in range(len(self._input_text) + 1):
+          char_width = rl.measure_text_ex(font, display_text[:i], font_size, 0).x
+          distance = abs(relative_x - char_width)
+          if distance < min_distance:
+            min_distance = distance
+            best_pos = i
+
+        self.set_cursor_position(best_pos)
       else:
         self.set_cursor_position(0)