refactor(colors): consolidate theme helpers

bec_widgets/utils/colors.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 import re
 from functools import lru_cache
-from typing import Literal
+from typing import Any, Literal
 
 import numpy as np
 import pyqtgraph as pg
@@ -21,8 +21,7 @@ logger = bec_logger.logger
 def get_theme_name():
     if QApplication.instance() is None or not hasattr(QApplication.instance(), "theme"):
         return "dark"
-    else:
-        return QApplication.instance().theme.theme
+    return QApplication.instance().theme.theme
 
 
 def get_theme_palette():
@@ -58,6 +57,26 @@ def apply_theme(theme: Literal["dark", "light"]):
     process_all_deferred_deletes(QApplication.instance())
 
 
+def theme_color(theme: Any | None, key: str, fallback: QColor | str) -> QColor:
+    """
+    Return a QColor from a BEC theme with a robust fallback.
+    """
+    fallback_color = fallback if isinstance(fallback, QColor) else QColor(str(fallback))
+    if theme is None or not hasattr(theme, "color"):
+        return fallback_color
+    color = theme.color(key, fallback_color.name())
+    return color if isinstance(color, QColor) else QColor(str(color))
+
+
+def rgba(color: QColor | str, alpha: int) -> str:
+    """
+    Return a QSS-compatible rgba string with alpha clamped to the 0-255 range.
+    """
+    qcolor = color if isinstance(color, QColor) else QColor(str(color))
+    alpha = max(0, min(255, alpha))
+    return f"rgba({qcolor.red()}, {qcolor.green()}, {qcolor.blue()}, {alpha})"
+
+
 class Colors:
     @staticmethod
     def list_available_colormaps() -> list[str]:
@@ -150,25 +169,6 @@ class Colors:
 
         return ge.colorMap()
 
-    @staticmethod
-    def golden_ratio(num: int) -> list:
-        """Calculate the golden ratio for a given number of angles.
-
-        Args:
-            num (int): Number of angles
-
-        Returns:
-            list: List of angles calculated using the golden ratio.
-        """
-        phi = 2 * np.pi * ((1 + np.sqrt(5)) / 2)
-        angles = []
-        for ii in range(num):
-            x = np.cos(ii * phi)
-            y = np.sin(ii * phi)
-            angle = np.arctan2(y, x)
-            angles.append(angle)
-        return angles
-
     @staticmethod
     def set_theme_offset(theme: Literal["light", "dark"] | None = None, offset=0.2) -> tuple:
         """
@@ -239,20 +239,7 @@ class Colors:
         else:
             positions = np.linspace(min_pos, max_pos, num)
 
-        # Sample colors from the colormap at the calculated positions
-        colors = cmap.map(positions, mode="float")
-        color_list = []
-
-        for color in colors:
-            if format.upper() == "HEX":
-                color_list.append(QColor.fromRgbF(*color).name())
-            elif format.upper() == "RGB":
-                color_list.append(tuple((np.array(color) * 255).astype(int)))
-            elif format.upper() == "QCOLOR":
-                color_list.append(QColor.fromRgbF(*color))
-            else:
-                raise ValueError("Unsupported format. Please choose 'RGB', 'HEX', or 'QColor'.")
-        return color_list
+        return Colors._format_mapped_colors(cmap.map(positions, mode="float"), format)
 
     @staticmethod
     def golden_angle_color(
@@ -288,20 +275,19 @@ class Colors:
         positions = np.mod(np.arange(num) * golden_angle_conjugate, 1)
         positions = min_pos + positions * (max_pos - min_pos)
 
-        # Sample colors from the colormap at the calculated positions
-        colors = cmap.map(positions, mode="float")
-        color_list = []
+        return Colors._format_mapped_colors(cmap.map(positions, mode="float"), format)
 
-        for color in colors:
-            if format.upper() == "HEX":
-                color_list.append(QColor.fromRgbF(*color).name())
-            elif format.upper() == "RGB":
-                color_list.append(tuple((np.array(color) * 255).astype(int)))
-            elif format.upper() == "QCOLOR":
-                color_list.append(QColor.fromRgbF(*color))
-            else:
-                raise ValueError("Unsupported format. Please choose 'RGB', 'HEX', or 'QColor'.")
-        return color_list
+    @staticmethod
+    def _format_mapped_colors(colors: np.ndarray, format: Literal["QColor", "HEX", "RGB"]) -> list:
+        color_format = format.upper()
+        if color_format not in {"QCOLOR", "HEX", "RGB"}:
+            raise ValueError("Unsupported format. Please choose 'RGB', 'HEX', or 'QColor'.")
+
+        if color_format == "QCOLOR":
+            return [QColor.fromRgbF(*color) for color in colors]
+        if color_format == "HEX":
+            return [QColor.fromRgbF(*color).name() for color in colors]
+        return [tuple((np.array(color) * 255).astype(int)) for color in colors]
 
     @staticmethod
     def hex_to_rgba(hex_color: str, alpha=255) -> tuple:
@@ -325,22 +311,6 @@ class Colors:
             raise ValueError("HEX color must be 6 or 8 characters long.")
         return (r, g, b, alpha)
 
-    @staticmethod
-    def rgba_to_hex(r: int, g: int, b: int, a: int = 255) -> str:
-        """
-        Convert RGBA color to HEX.
-
-        Args:
-            r(int): Red value (0-255).
-            g(int): Green value (0-255).
-            b(int): Blue value (0-255).
-            a(int): Alpha value (0-255). Default is 255 (opaque).
-
-        Returns:
-            hec_color(str): HEX color string.
-        """
-        return "#{:02X}{:02X}{:02X}{:02X}".format(r, g, b, a)
-
     @staticmethod
     def validate_color(color: tuple | str) -> tuple | str:
         """

tests/unit_tests/test_color_utils.py

@@ -2,11 +2,11 @@ import pyqtgraph as pg
 import pytest
 from pydantic import ValidationError
 from qtpy.QtGui import QColor
-from qtpy.QtWidgets import QVBoxLayout, QWidget
+from qtpy.QtWidgets import QApplication, QVBoxLayout, QWidget
 
 from bec_widgets.utils.bec_connector import ConnectionConfig
 from bec_widgets.utils.bec_widget import BECWidget
-from bec_widgets.utils.colors import Colors, apply_theme
+from bec_widgets.utils.colors import Colors, apply_theme, get_theme_name, rgba, theme_color
 from bec_widgets.widgets.plots.waveform.curve import CurveConfig
 from tests.unit_tests.client_mocks import mocked_client
 from tests.unit_tests.conftest import create_widget
@@ -76,10 +76,27 @@ def test_hex_to_rgba():
         Colors.hex_to_rgba("#FF573")
 
 
-def test_rgba_to_hex():
-    assert Colors.rgba_to_hex(255, 87, 51, 255) == "#FF5733FF"
-    assert Colors.rgba_to_hex(255, 87, 51, 128) == "#FF573380"
-    assert Colors.rgba_to_hex(255, 87, 51) == "#FF5733FF"
+def test_get_theme_name_uses_application_theme():
+    app = QApplication.instance()
+    assert app.theme.theme == "light"
+    assert get_theme_name() == "light"
+
+
+def test_theme_color_uses_theme_color_method():
+    app = QApplication.instance()
+    fallback = QColor("#ffffff")
+    expected = app.theme.color("FG", fallback.name())
+    expected = expected if isinstance(expected, QColor) else QColor(str(expected))
+
+    assert theme_color(app.theme, "FG", fallback).name() == expected.name()
+
+
+def test_theme_color_returns_fallback_without_theme_color_method():
+    assert theme_color("light", "FG", QColor("#ffffff")).name() == "#ffffff"
+
+
+def test_qss_rgba_and_blend_helpers():
+    assert rgba(QColor("#010203"), 300) == "rgba(1, 2, 3, 255)"
 
 
 def test_canonical_colormap_name_case_insensitive():