Add password text input support

TextInputStyle gains a Password flag and optional PasswordChar (defaults
to '*'). When enabled, the widget measures and renders mask characters
while keeping the real text in the underlying buffer. Cursor positioning
and selection highlights use masked widths for correct alignment.

ClayUI.TextInput gets a convenience password parameter.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: andreakarasho

src/Clay.GameEditor/RaylibRenderer.cs

@@ -255,6 +255,18 @@ private void RenderCustom(BoundingBox box, CustomRenderData data)
             RenderTextInput(box, widget);
         else if (data.CustomData is HsvGradientData gradient)
             RenderHsvGradient(box, gradient);
+        else if (data.CustomData is ViewportTextureData viewport)
+            RenderViewportTexture(box, viewport);
+    }
+
+    public void RenderViewportTexture(BoundingBox box, ViewportTextureData viewport)
+    {
+        if (viewport.RenderTexture is not RenderTexture rt) return;
+        var texture = rt.texture;
+        // RenderTexture is flipped vertically, so we use negative height in source rect
+        var source = new Rectangle(0, 0, texture.width, -texture.height);
+        var dest = new Rectangle(box.X, box.Y, box.Width, box.Height);
+        Raylib.DrawTexturePro(texture, source, dest, new System.Numerics.Vector2(0, 0), 0, Raylib.WHITE);
     }
 
     private unsafe void RenderHsvGradient(BoundingBox box, HsvGradientData gradient)
@@ -349,7 +361,7 @@ private void RenderTextInput(BoundingBox box, TextInputWidget widget)
             int selEnd = Math.Max(widget.SelectionStart, widget.SelectionEnd);
             var selColor = ToRayColor(style.SelectionColor);
             int pos = 0, row = 0;
-            string text = widget.Text;
+            string text = widget.DisplayText;
             while (pos <= text.Length && pos < selEnd)
             {
                 int lineStart = pos;
@@ -375,7 +387,7 @@ private void RenderTextInput(BoundingBox box, TextInputWidget widget)
         {
             var font = _fonts[style.FontId];
             var textColor = ToRayColor(style.TextColor);
-            string text = widget.Text;
+            string text = widget.DisplayText;
             int lineStart = 0, row = 0;
             while (row < firstVisibleRow && lineStart <= text.Length)
             {

src/Clay/ClayUI.cs

@@ -1380,9 +1380,10 @@ public static void ProgressBar(float value, float min = 0f, float max = 1f, Prog
     /// <param name="text">Reference to the text string. Updated when the user edits it.</param>
     /// <param name="style">Visual style. Use <see cref="TextInputStyle.Default"/> or customize.</param>
     /// <param name="singleLine">Block newlines and make up/down act as left/right.</param>
-    public static bool TextInput(string label, ref string text, TextInputStyle? style = null, bool singleLine = true)
+    public static bool TextInput(string label, ref string text, TextInputStyle? style = null, bool singleLine = true, bool password = false)
     {
         var s = style ?? DefaultTextInputStyle;
+        if (password) s.Password = true;
         var id = StableId(label);
 
         if (IsDisabled)

src/Clay/Widgets/TextInputStyle.cs

@@ -54,6 +54,17 @@ public struct TextInputStyle
     /// </summary>
     public Func<char, bool>? CharFilter;
 
+    /// <summary>
+    /// When true, displays mask characters instead of the actual text (for password fields).
+    /// The underlying text value is unaffected.
+    /// </summary>
+    public bool Password;
+
+    /// <summary>
+    /// The character used to mask text when <see cref="Password"/> is true. Defaults to '*'.
+    /// </summary>
+    public char PasswordChar;
+
     /// <summary>
     /// When true, the text input ignores all pointer interaction (click-to-focus, drag selection).
     /// Set by ClayUI when inside a disabled region.

src/Clay/Widgets/TextInputWidget.cs

@@ -85,6 +85,11 @@ public string Text
     /// <summary>The style applied during the last <see cref="Element"/> call.</summary>
     public TextInputStyle CurrentStyle { get; private set; }
 
+    /// <summary>Returns the text to display — masked if in password mode, otherwise the real text.</summary>
+    public string DisplayText => CurrentStyle.Password
+        ? new string(CurrentStyle.PasswordChar == '\0' ? '*' : CurrentStyle.PasswordChar, _chars.Count)
+        : Text;
+
     /// <summary>Current vertical scroll offset in pixels (for multiline inputs).</summary>
     public float ScrollY => _scrollY;
 
@@ -171,7 +176,15 @@ public float MeasureSubstring(int from, int to)
     {
         if (from >= to || from >= _chars.Count) return 0;
         to = Math.Min(to, _chars.Count);
-        var span = CollectionsMarshal.AsSpan(_chars).Slice(from, to - from);
+        int len = to - from;
+        if (CurrentStyle.Password)
+        {
+            char mask = CurrentStyle.PasswordChar == '\0' ? '*' : CurrentStyle.PasswordChar;
+            Span<char> maskBuf = len <= 256 ? stackalloc char[len] : new char[len];
+            maskBuf.Fill(mask);
+            return _measurer.MeasureText(maskBuf, _fontId, _fontSize, _letterSpacing).Width;
+        }
+        var span = CollectionsMarshal.AsSpan(_chars).Slice(from, len);
         return _measurer.MeasureText(span, _fontId, _fontSize, _letterSpacing).Width;
     }
 
@@ -322,6 +335,12 @@ float ITextEditHandler.GetCharWidth(int lineStartIndex, int charIndex)
         if (idx >= _chars.Count) return 0;
         var span = CollectionsMarshal.AsSpan(_chars);
         if (span[idx] == '\n') return 0;
+        if (CurrentStyle.Password)
+        {
+            char mask = CurrentStyle.PasswordChar == '\0' ? '*' : CurrentStyle.PasswordChar;
+            ReadOnlySpan<char> maskSpan = stackalloc char[] { mask };
+            return _measurer.MeasureText(maskSpan, _fontId, _fontSize, _letterSpacing).Width;
+        }
         return _measurer.MeasureText(span.Slice(idx, 1), _fontId, _fontSize, _letterSpacing).Width;
     }
 
@@ -339,7 +358,19 @@ void ITextEditHandler.LayoutRow(out TextEditRow row, int lineStartIndex)
 
         float width = 0;
         if (textChars > 0)
-            width = _measurer.MeasureText(span.Slice(lineStartIndex, textChars), _fontId, _fontSize, _letterSpacing).Width;
+        {
+            if (CurrentStyle.Password)
+            {
+                char mask = CurrentStyle.PasswordChar == '\0' ? '*' : CurrentStyle.PasswordChar;
+                Span<char> maskBuf = textChars <= 256 ? stackalloc char[textChars] : new char[textChars];
+                maskBuf.Fill(mask);
+                width = _measurer.MeasureText(maskBuf, _fontId, _fontSize, _letterSpacing).Width;
+            }
+            else
+            {
+                width = _measurer.MeasureText(span.Slice(lineStartIndex, textChars), _fontId, _fontSize, _letterSpacing).Width;
+            }
+        }
 
         float lh = _cachedLineHeight;
         row = new TextEditRow