Rework radar system

python_app/gui/controllers/renderers/common.py

@@ -0,0 +1,23 @@
+"""Plot construction and color tables shared by radar views."""
+
+import numpy as np
+import pyqtgraph as pg
+
+
+def create_plot(title: str = "") -> pg.PlotWidget:
+    plot = pg.PlotWidget(background="#0f141c", enableMenu=False, title=title)
+    plot.showGrid(x=True, y=True, alpha=0.2)
+    return plot
+
+
+def build_lut(stops: list[str], *, size: int = 256) -> np.ndarray:
+    """Interpolate hex color stops into 8-bit RGB LUT array."""
+    stop_positions = np.linspace(0.0, 1.0, num=len(stops), dtype=np.float32)
+    sample_positions = np.linspace(0.0, 1.0, num=size, dtype=np.float32)
+    stop_colors = np.asarray([pg.mkColor(value).getRgb()[:3] for value in stops], dtype=np.float32)
+
+    lut = np.empty((size, 3), dtype=np.uint8)
+    for channel in range(3):
+        lut[:, channel] = np.interp(sample_positions, stop_positions, stop_colors[:, channel]).astype(np.uint8)
+    return lut
+