fix: input

lib/nocterm.dart

@@ -26,6 +26,7 @@ export 'src/components/builder.dart';
 export 'src/components/focusable.dart';
 export 'src/components/focus_scope.dart';
 export 'src/components/block_focus.dart';
+export 'src/components/input_listener.dart';
 export 'src/components/scroll_controller.dart';
 export 'src/components/auto_scroll_controller.dart';
 export 'src/components/single_child_scroll_view.dart';

lib/src/binding/terminal_binding.dart

@@ -3,9 +3,9 @@ import 'dart:convert';
 
 import 'package:nocterm/nocterm.dart';
 import 'package:nocterm/src/framework/terminal_canvas.dart';
+import 'package:nocterm/src/image/image_cleanup.dart';
 import 'package:nocterm/src/navigation/render_theater.dart';
 import 'package:nocterm/src/rendering/scrollable_render_object.dart';
-import 'package:nocterm/src/image/image_cleanup.dart';
 
 import '../backend/terminal.dart' as term;
 import '../buffer.dart' as buf;
@@ -230,6 +230,15 @@ class TerminalBinding extends NoctermBinding
       }
       _lastInputTime = now;
 
+      // Check for raw input listeners before parsing. If an
+      // InputListener consumes the bytes, skip the parser.
+      if (_dispatchRawInput(bytes)) {
+        if (buildOwner.hasDirtyElements) {
+          scheduleFrame();
+        }
+        return;
+      }
+
       // Parse the bytes and process ALL events in the buffer
       _inputParser.addBytes(bytes);
 
@@ -656,6 +665,31 @@ class TerminalBinding extends NoctermBinding
     return result;
   }
 
+  /// Dispatch raw stdin bytes to [InputListenerElement]s in the tree.
+  /// Returns true if any listener consumed the bytes.
+  bool _dispatchRawInput(List<int> bytes) {
+    if (rootElement == null) return false;
+    return _findAndCallInputListener(rootElement!, bytes);
+  }
+
+  bool _findAndCallInputListener(Element element, List<int> bytes) {
+    // Respect BlockFocus — same as _dispatchKeyToElement.
+    if (element is BlockFocusElement && element.isBlocking) {
+      return true;
+    }
+
+    bool handled = false;
+    element.visitChildren((child) {
+      if (!handled) {
+        handled = _findAndCallInputListener(child, bytes);
+      }
+    });
+    if (!handled && element is InputListenerElement) {
+      handled = element.handleRawInput(bytes);
+    }
+    return handled;
+  }
+
   /// Dispatch a keyboard event to an element and its children
   bool _dispatchKeyToElement(Element element, KeyboardEvent event) {
     // Check if this element is a BlockFocus that's blocking

lib/src/components/input_listener.dart

@@ -0,0 +1,69 @@
+import '../framework/framework.dart';
+
+/// A callback that receives raw stdin bytes before nocterm's input
+/// parser processes them.
+///
+/// Return `true` to consume the bytes (nocterm skips parsing for
+/// this batch). Return `false` to let nocterm handle them normally.
+typedef RawInputHandler = bool Function(List<int> bytes);
+
+/// A component that intercepts raw stdin bytes before they reach
+/// nocterm's [InputParser].
+///
+/// Unlike [Focusable], which receives parsed keyboard events,
+/// [InputListener] operates on the raw byte stream. The two
+/// widgets serve different purposes:
+/// - Use [Focusable] when you need semantic key events (arrow up,
+///   Ctrl+C, printable characters).
+/// - Use [InputListener] when you need byte-for-byte passthrough.
+///
+/// Example:
+/// ```dart
+/// InputListener(
+///   onInput: (bytes) {
+///     return true; // return true to consume (don't parse), false for
+///                  // normal processing with nocterm's input parser.
+///   },
+///   child: Text('This widget can intercept raw input bytes.'),
+/// )
+/// ```
+class InputListener extends StatelessComponent {
+  const InputListener({
+    super.key,
+    required this.onInput,
+    required this.child,
+  });
+
+  /// Callback invoked with raw stdin bytes.
+  ///
+  /// Return `true` to consume the bytes (nocterm will not parse
+  /// them into keyboard/mouse events). Return `false` to let
+  /// nocterm process them normally.
+  final RawInputHandler onInput;
+
+  /// The child component to wrap.
+  final Component child;
+
+  @override
+  InputListenerElement createElement() => InputListenerElement(this);
+
+  @override
+  Component build(BuildContext context) => child;
+}
+
+/// Element for [InputListener].
+///
+/// The binding recognises this element type during raw input
+/// dispatch, just as it recognises [FocusableElement] during
+/// keyboard event dispatch.
+class InputListenerElement extends StatelessElement {
+  InputListenerElement(InputListener super.component);
+
+  @override
+  InputListener get component => super.component as InputListener;
+
+  /// Forward raw bytes to the widget's callback.
+  bool handleRawInput(List<int> bytes) {
+    return component.onInput(bytes);
+  }
+}

lib/src/components/render_paragraph.dart

@@ -229,15 +229,16 @@ class RenderParagraph extends RenderObject with Selectable {
             canvas, Offset(xOffset, offset.dy + i), lineSegments, lineText, i);
       } else {
         // Paint each segment with its style
-        double currentX = xOffset;
+        // Snap to integer cell boundary — fractional offsets from
+        // alignment calculations (e.g. center: (width - text) / 2)
+        // cause rounding drift across styled segments.
+        int currentX = xOffset.round();
         for (final segment in lineSegments) {
           canvas.drawText(
-            Offset(currentX, offset.dy + i),
+            Offset(currentX.toDouble(), offset.dy + i),
             segment.text,
             style: segment.style,
           );
-          // Move x position by the actual display width of the segment text
-          // This accounts for wide characters like emojis and CJK characters
           currentX += UnicodeWidth.stringWidth(segment.text);
         }
       }
@@ -277,7 +278,7 @@ class RenderParagraph extends RenderObject with Selectable {
     final hasLineSelection =
         selRangeEnd > lineStartOffset && selRangeStart < lineEndOffset;
 
-    double currentX = offset.dx;
+    double currentX = offset.dx.roundToDouble();
     int charOffset = lineStartOffset;
 
     for (final segment in segments) {

lib/src/framework/terminal_canvas.dart

@@ -1,6 +1,7 @@
 library;
 
 import 'dart:math' as math;
+
 import 'package:characters/characters.dart';
 import 'package:nocterm/src/rectangle.dart';
 
@@ -16,6 +17,21 @@ class TerminalCanvas {
   final Buffer _buffer;
   final Rect area;
 
+  /// Set a cell directly at the given position without any text
+  /// layout, width measurement, or style blending.
+  ///
+  /// Use this when you already have a pre-laid-out cell grid
+  /// and want cell-perfect placement without nocterm re-interpreting
+  /// character widths.
+  ///
+  /// [x] and [y] are in local coordinates (relative to this
+  /// canvas's area). Out-of-bounds writes are silently ignored.
+  void setRaw(int x, int y, Cell cell) {
+    final cellX = area.left.round() + x;
+    final cellY = area.top.round() + y;
+    _buffer.setCell(cellX, cellY, cell);
+  }
+
   /// Blends a style with the background color from the existing cell if needed.
   ///
   /// This handles alpha blending for semi-transparent colors:

lib/src/keyboard/input_parser.dart

@@ -353,8 +353,10 @@ class InputParser {
       if (result != null) return result;
     }
 
-    // Arrow keys: ESC [ A/B/C/D (3 bytes)
-    if (_buffer.length == 3) {
+    // Arrow keys and other 3-byte CSI finals: ESC [ A/B/C/D/H/F/Z
+    // Check byte[2] directly — buffer may contain trailing bytes from
+    // the next keystroke, so we can't require length == 3.
+    {
       switch (_buffer[2]) {
         case 0x41:
           return (
@@ -690,7 +692,8 @@ class InputParser {
   }
 
   (KeyboardEvent, int)? _parseSS3Sequence() {
-    if (_buffer.length != 3) return null;
+    // Don't require exact length 3 — buffer may have trailing bytes.
+    if (_buffer.length < 3) return null;
 
     // F1-F4 use SS3 sequences (all are 3 bytes: ESC O X)
     switch (_buffer[2]) {

lib/src/test/nocterm_test_binding.dart

@@ -39,6 +39,9 @@ class NoctermTestBinding extends NoctermBinding with SchedulerBinding {
   /// Stream controller for simulating keyboard events
   final _testKeyboardController = StreamController<KeyboardEvent>.broadcast();
 
+  /// Queue of pending raw input byte batches to be dispatched.
+  final _pendingRawInputs = <List<int>>[];
+
   /// Queue of pending keyboard events to be processed
   final _pendingKeyboardEvents = <KeyboardEvent>[];
 
@@ -58,6 +61,12 @@ class NoctermTestBinding extends NoctermBinding with SchedulerBinding {
       await Future.delayed(duration);
     }
 
+    // Process any pending raw input batches.
+    while (_pendingRawInputs.isNotEmpty) {
+      final bytes = _pendingRawInputs.removeAt(0);
+      _dispatchRawInput(bytes);
+    }
+
     // Process any pending keyboard events
     while (_pendingKeyboardEvents.isNotEmpty) {
       final event = _pendingKeyboardEvents.removeAt(0);
@@ -103,6 +112,13 @@ class NoctermTestBinding extends NoctermBinding with SchedulerBinding {
     }
   }
 
+  /// Simulate raw stdin bytes. Dispatched to [InputListenerElement]s
+  /// during [pump]. Unconsumed bytes are dropped (use
+  /// [sendKeyboardEvent] for parsed event testing).
+  void sendRawInput(List<int> bytes) {
+    _pendingRawInputs.add(bytes);
+  }
+
   /// Simulate keyboard input
   void sendKeyboardEvent(KeyboardEvent event) {
     _pendingKeyboardEvents.add(event);
@@ -257,6 +273,28 @@ class NoctermTestBinding extends NoctermBinding with SchedulerBinding {
   }
 
   /// Dispatch a keyboard event to an element and its children
+  bool _dispatchRawInput(List<int> bytes) {
+    if (rootElement == null) return false;
+    return _findAndCallInputListener(rootElement!, bytes);
+  }
+
+  bool _findAndCallInputListener(Element element, List<int> bytes) {
+    if (element is BlockFocusElement && element.isBlocking) {
+      return true;
+    }
+
+    bool handled = false;
+    element.visitChildren((child) {
+      if (!handled) {
+        handled = _findAndCallInputListener(child, bytes);
+      }
+    });
+    if (!handled && element is InputListenerElement) {
+      handled = element.handleRawInput(bytes);
+    }
+    return handled;
+  }
+
   bool _dispatchKeyToElement(Element element, KeyboardEvent event) {
     // Check if this element is a BlockFocus that's blocking
     // Import BlockFocusElement dynamically to avoid circular dependencies

lib/src/test/nocterm_tester.dart

@@ -137,6 +137,12 @@ class NoctermTester {
   Future<void> sendArrowLeft() => sendKey(LogicalKey.arrowLeft);
   Future<void> sendArrowRight() => sendKey(LogicalKey.arrowRight);
 
+  /// Send raw stdin bytes, dispatched to [InputListener] widgets.
+  Future<void> sendRawBytes(List<int> bytes) async {
+    _binding.sendRawInput(bytes);
+    await pump();
+  }
+
   /// Send a mouse event
   Future<void> sendMouseEvent(MouseEvent event) async {
     _binding.sendMouseEvent(event);