diff --git a/src/pygui/backend/visualization/__init__.py b/src/pygui/backend/visualization/__init__.py
index b31b753..722f33d 100644
--- a/src/pygui/backend/visualization/__init__.py
+++ b/src/pygui/backend/visualization/__init__.py
@@ -2,9 +2,10 @@
 from pygui.backend.visualization.graph_quick_item import GraphQuickItem
 from pygui.backend.visualization.graph_view import GraphView
 from pygui.backend.visualization.rbf_heatmap import interpolate_field
+from pygui.backend.visualization.trend_chart_item import TrendChartItem
 from pygui.backend.visualization.wafer_map_item import WaferMapItem
 
 __all__ = [
-    "GraphQuickItem", "GraphView", "WaferMapItem",
+    "GraphQuickItem", "GraphView", "TrendChartItem", "WaferMapItem",
     "interpolate_field",
 ]
diff --git a/src/pygui/backend/visualization/trend_chart_item.py b/src/pygui/backend/visualization/trend_chart_item.py
new file mode 100644
index 0000000..8ce94bb
--- /dev/null
+++ b/src/pygui/backend/visualization/trend_chart_item.py
@@ -0,0 +1,262 @@
+"""QQuickPaintedItem trend chart — running-average temperature over time.
+
+Renders a single polyline series (per-frame average temperatures) using QPainter.
+Mirrors the @QmlElement registration pattern used by `WaferMapItem` so it can
+be embedded directly in QML via `import ISC.Wafer` and used as `TrendChartItem { }`.
+
+The series is driven by the existing `streamController.trendData` signal, which
+emits a JSON-encoded list of floats from both review-mode replay and live-mode
+streaming.
+"""
+from __future__ import annotations
+
+import json
+import logging
+from typing import Optional
+
+from PySide6.QtCore import Property, QPoint, QRectF, Qt, Signal, Slot
+from PySide6.QtGui import QColor, QFont, QPainter, QPen, QPolygon
+from PySide6.QtQml import QmlElement
+from PySide6.QtQuick import QQuickPaintedItem
+
+log = logging.getLogger(__name__)
+
+QML_IMPORT_NAME = "ISC.Wafer"
+QML_IMPORT_MAJOR_VERSION = 1
+
+
+@QmlElement
+class TrendChartItem(QQuickPaintedItem):
+    """Painted trend chart; driven by a list of floats via the `data` property."""
+
+    dataChanged = Signal()
+    hasDataChanged = Signal()
+    lineColorChanged = Signal()
+    gridColorChanged = Signal()
+    textColorChanged = Signal()
+    paddingChanged = Signal()
+
+    def __init__(self, parent: Optional[QQuickPaintedItem] = None) -> None:
+        super().__init__(parent)
+        self.setRenderTarget(QQuickPaintedItem.RenderTarget.FramebufferObject)
+        self.setAntialiasing(True)
+        self.setFillColor(QColor("transparent"))
+
+        self._data: list[float] = []
+        self._padding: int = 8
+        self._line_color = QColor("#5B9DF5")
+        self._grid_color = QColor("#2A3441")
+        self._text_color = QColor("#CBD5E1")
+
+    # ── Qt properties ─────────────────────────────────────────────────────
+
+    @Property("QVariantList", notify=dataChanged)
+    def data(self) -> list[float]:
+        return self._data
+
+    @data.setter
+    def data(self, val) -> None:
+        coerced = self._coerce_floats(val)
+        if coerced == self._data:
+            return
+        self._data = coerced
+        self.dataChanged.emit()
+        self.hasDataChanged.emit()
+        self.update()
+
+    @Property(bool, notify=hasDataChanged)
+    def hasData(self) -> bool:
+        """True when the data list has at least one point.
+
+        QML can bind to this safely (QVariantList `.length` is not bindable).
+        """
+        return len(self._data) > 0
+
+    @Property(QColor, notify=lineColorChanged)
+    def lineColor(self) -> QColor:
+        return self._line_color
+
+    @lineColor.setter
+    def lineColor(self, c: QColor) -> None:
+        if c == self._line_color:
+            return
+        self._line_color = QColor(c)
+        self.lineColorChanged.emit()
+        self.update()
+
+    @Property(QColor, notify=gridColorChanged)
+    def gridColor(self) -> QColor:
+        return self._grid_color
+
+    @gridColor.setter
+    def gridColor(self, c: QColor) -> None:
+        if c == self._grid_color:
+            return
+        self._grid_color = QColor(c)
+        self.gridColorChanged.emit()
+        self.update()
+
+    @Property(QColor, notify=textColorChanged)
+    def textColor(self) -> QColor:
+        return self._text_color
+
+    @textColor.setter
+    def textColor(self, c: QColor) -> None:
+        if c == self._text_color:
+            return
+        self._text_color = QColor(c)
+        self.textColorChanged.emit()
+        self.update()
+
+    @Property(int, notify=paddingChanged)
+    def padding(self) -> int:
+        return self._padding
+
+    @padding.setter
+    def padding(self, val: int) -> None:
+        v = max(0, int(val))
+        if v == self._padding:
+            return
+        self._padding = v
+        self.paddingChanged.emit()
+        self.update()
+
+    # ── Convenience slot for QML: accept a JSON string from a Signal(str) ──
+
+    @Slot(str)
+    def setDataFromJson(self, avgs_json: str) -> None:
+        """Slot for QML Connections handler: parse JSON array and update data.
+
+        Mirrors `streamController.trendData` (which emits JSON-encoded floats).
+        """
+        try:
+            parsed = json.loads(avgs_json) if avgs_json else []
+        except (json.JSONDecodeError, TypeError) as exc:
+            log.error("TrendChartItem: failed to parse trend JSON: %s", exc)
+            return
+        coerced = self._coerce_floats(parsed)
+        if coerced == self._data:
+            return
+        self._data = coerced
+        self.dataChanged.emit()
+        self.hasDataChanged.emit()
+        self.update()
+
+    # ── paint ─────────────────────────────────────────────────────────────
+
+    def paint(self, painter: QPainter) -> None:  # type: ignore[override]
+        painter.setRenderHint(QPainter.RenderHint.Antialiasing, True)
+        painter.setRenderHint(QPainter.RenderHint.TextAntialiasing, True)
+
+        w = self.width()
+        h = self.height()
+        if w <= 0 or h <= 0:
+            return
+
+        plot_rect = QRectF(self._padding, self._padding,
+                           max(1, w - 2 * self._padding),
+                           max(1, h - 2 * self._padding))
+
+        self._draw_grid(painter, plot_rect)
+
+        if len(self._data) < 2:
+            return
+
+        y_min, y_max = self._y_range()
+        self._draw_axes_labels(painter, plot_rect, y_min, y_max)
+        self._draw_line(painter, plot_rect, y_min, y_max)
+
+    # ── internals ─────────────────────────────────────────────────────────
+
+    def _coerce_floats(self, val) -> list[float]:
+        if not val:
+            return []
+        out: list[float] = []
+        for v in val:
+            try:
+                out.append(float(v))
+            except (TypeError, ValueError):
+                continue
+        return out
+
+    def _y_range(self) -> tuple[float, float]:
+        lo = min(self._data)
+        hi = max(self._data)
+        if hi - lo < 1e-9:
+            return lo - 5.0, hi + 5.0
+        buf = (hi - lo) * 0.1
+        return lo - buf, hi + buf
+
+    def _x_to_px(self, i: int, n: int, plot_rect: QRectF) -> float:
+        if n <= 1:
+            return plot_rect.left()
+        return plot_rect.left() + (i / (n - 1)) * plot_rect.width()
+
+    def _y_to_px(self, v: float, y_min: float, y_max: float, plot_rect: QRectF) -> float:
+        if y_max - y_min < 1e-9:
+            return plot_rect.center().y()
+        t = (v - y_min) / (y_max - y_min)
+        return plot_rect.bottom() - t * plot_rect.height()
+
+    def _draw_grid(self, painter: QPainter, plot_rect: QRectF) -> None:
+        pen = QPen(self._grid_color)
+        pen.setWidthF(1.0)
+        pen.setCosmetic(True)
+        painter.setPen(pen)
+        rows = 4
+        for i in range(rows + 1):
+            y = plot_rect.top() + (i / rows) * plot_rect.height()
+            painter.drawLine(int(plot_rect.left()), int(y),
+                             int(plot_rect.right()), int(y))
+
+    def _draw_axes_labels(
+        self,
+        painter: QPainter,
+        plot_rect: QRectF,
+        y_min: float,
+        y_max: float,
+    ) -> None:
+        painter.setPen(self._text_color)
+        font = QFont(painter.font())
+        font.setPointSizeF(max(7.0, font.pointSizeF() * 0.85))
+        painter.setFont(font)
+        rows = 4
+        for i in range(rows + 1):
+            t = i / rows
+            y_val = y_max - t * (y_max - y_min)
+            y_px = plot_rect.top() + t * plot_rect.height()
+            label = f"{y_val:.1f}"
+            painter.drawText(QRectF(0, y_px - 7, self._padding, 14),
+                             Qt.AlignmentFlag.AlignRight | Qt.AlignmentFlag.AlignVCenter,
+                             label)
+
+    def _draw_line(
+        self,
+        painter: QPainter,
+        plot_rect: QRectF,
+        y_min: float,
+        y_max: float,
+    ) -> None:
+        n = len(self._data)
+        pen = QPen(self._line_color)
+        pen.setWidthF(2.0)
+        pen.setCosmetic(True)
+        pen.setCapStyle(Qt.PenCapStyle.RoundCap)
+        pen.setJoinStyle(Qt.PenJoinStyle.RoundJoin)
+        painter.setPen(pen)
+
+        poly = QPolygon()
+        for i, v in enumerate(self._data):
+            px = self._x_to_px(i, n, plot_rect)
+            py = self._y_to_px(v, y_min, y_max, plot_rect)
+            poly.append(QPoint(int(px), int(py)))
+        painter.drawPolyline(poly)
+
+        # Trailing dot at the last data point
+        last_x = int(self._x_to_px(n - 1, n, plot_rect))
+        last_y = int(self._y_to_px(self._data[-1], y_min, y_max, plot_rect))
+        painter.setBrush(self._line_color)
+        painter.setPen(Qt.PenStyle.NoPen)
+        radius = 3
+        painter.drawEllipse(last_x - radius, last_y - radius,
+                            radius * 2, radius * 2)
diff --git a/src/pygui/backend/visualization/wafer_map_item.py b/src/pygui/backend/visualization/wafer_map_item.py
index 68cddbc..96310cc 100644
--- a/src/pygui/backend/visualization/wafer_map_item.py
+++ b/src/pygui/backend/visualization/wafer_map_item.py
@@ -10,6 +10,7 @@ All sensor coordinates are center-origin mm (from wafer_layouts or a loaded CSV)
 """
 from __future__ import annotations
 
+import logging
 import math
 
 import numpy as np
@@ -22,13 +23,15 @@ from PySide6.QtGui import (
     QPainter,
     QPen,
     QPolygon,
-)
+)  # fmt: skip
 from PySide6.QtQml import QmlElement
 from PySide6.QtQuick import QQuickPaintedItem
 
 from pygui.backend.visualization.rbf_heatmap import interpolate_field
 from pygui.backend.wafer.zwafer_models import Sensor
 
+log = logging.getLogger(__name__)
+
 QML_IMPORT_NAME = "ISC.Wafer"
 QML_IMPORT_MAJOR_VERSION = 1
 
@@ -197,10 +200,10 @@ class WaferMapItem(QQuickPaintedItem):
     def thicknessData(self, val:list) -> None:
         self._thickness_data = list(val or [])
         self._rebuild_thickness()
-        self._thicknessChanged.emit()
+        self.thicknessChanged.emit()
         self.update
 
-    @property(bool, notify=showThicknessChanged)
+    @Property(bool, notify=showThicknessChanged)
     def showThickness(self) -> bool:
         return self._show_thickness
 
@@ -265,14 +268,59 @@ class WaferMapItem(QQuickPaintedItem):
         if not file_path:
             return False
         try:
-            image = self.grabToImage()
-            image.save(file_path, "PNG")
+            result = self.grabToImage()
+            img = result.image()
+            img.save(file_path, "PNG")
             return True
         except Exception as e:
             log.error("Export failed: %s", e)
             return False
+
     # ── internal ─────────────────────────────────────────────────────────
 
+    def _rebuild_thickness(self) -> None:
+        """Interpolate thickness data into a gray/orange heatmap QImage."""
+        if not self._sensors or not self._thickness_data:
+            self._thickness_heatmap = None
+            return
+        ds = self._draw_size()
+        r_mm = self._wafer_radius_mm()
+        xs = np.array([s.x for s in self._sensors])
+        ys = np.array([s.y for s in self._sensors])
+        vs = np.array(self._thickness_data[:len(self._sensors)], dtype=float)
+        if len(vs) < len(self._sensors):
+            self._thickness_heatmap = None
+            return
+        try:
+            field = interpolate_field(
+                xs, ys, vs,
+                width=ds, height=ds,
+                extent=(-r_mm, r_mm, -r_mm, r_mm),
+                round_clip=(self._shape == "round"),
+            )
+        except Exception:
+            self._thickness_heatmap = None
+            return
+        # Gray/orange colormap: map field range 0→1 to gray→orange
+        vmin, vmax = np.nanmin(field), np.nanmax(field)
+        span = vmax - vmin or 1.0
+        t = np.clip((field - vmin) / span, 0.0, 1.0)
+
+        # Gray (0.5, 0.5, 0.5) → orange (1.0, 0.65, 0.0)
+        rgb = np.zeros((ds, ds, 3), dtype=np.float32)
+        rgb[:, :, 0] = 0.5 + 0.5 * t
+        rgb[:, :, 1] = 0.5 + 0.15 * t
+        rgb[:, :, 2] = 0.5 - 0.5 * t
+
+        rgb = np.nan_to_num(rgb, nan=0.0)
+        rgba = np.zeros((ds, ds, 4), dtype=np.uint8)
+        rgba[:, :, :3] = (rgb * 255).astype(np.uint8)
+        rgba[:, :, 3] = np.where(np.isfinite(field), 180, 0).astype(np.uint8)
+
+        self._thickness_heatmap = (
+            QImage(rgba.tobytes(), ds, ds, QImage.Format.Format_RGBA8888).copy()
+        )
+
     def _on_resize(self) -> None:
         self._rebuild()