added mesh surface arrows

examples/gui/transport_icons.py

@@ -0,0 +1,50 @@
+"""Monochrome play/pause icons for the dashboard toolbar (avoids Windows emoji glyphs)."""
+
+from __future__ import annotations
+
+from typing import Literal
+
+from PyQt5.QtCore import QPointF, QRectF, Qt
+from PyQt5.QtGui import QColor, QIcon, QPainter, QPixmap, QPolygonF
+
+TransportKind = Literal["play", "pause"]
+
+_DEFAULT_ICON_PX = 18
+
+
+def transport_icon(kind: TransportKind, color: str, *, size: int = _DEFAULT_ICON_PX) -> QIcon:
+    """Build a flat play triangle or pause bars in ``color`` (#rrggbb)."""
+    pixmap = QPixmap(size, size)
+    pixmap.fill(Qt.transparent)
+
+    painter = QPainter(pixmap)
+    painter.setRenderHint(QPainter.Antialiasing, True)
+    painter.setBrush(QColor(color))
+    painter.setPen(Qt.NoPen)
+
+    if kind == "play":
+        w = size * 0.52
+        h = size * 0.60
+        x0 = (size - w) * 0.58
+        y0 = (size - h) / 2.0
+        painter.drawPolygon(
+            QPolygonF(
+                [
+                    QPointF(x0, y0),
+                    QPointF(x0, y0 + h),
+                    QPointF(x0 + w, y0 + h / 2.0),
+                ]
+            )
+        )
+    else:
+        bar_w = size * 0.17
+        bar_h = size * 0.60
+        gap = size * 0.14
+        y0 = (size - bar_h) / 2.0
+        x0 = (size - (2.0 * bar_w + gap)) / 2.0
+        radius = max(1.0, size * 0.06)
+        painter.drawRoundedRect(QRectF(x0, y0, bar_w, bar_h), radius, radius)
+        painter.drawRoundedRect(QRectF(x0 + bar_w + gap, y0, bar_w, bar_h), radius, radius)
+
+    painter.end()
+    return QIcon(pixmap)