feat: update lr_gradient to use config.ACTIVE_THEME

- Remove hardcoded GRAD_COLS and MSG_GRAD_COLS module constants
- Add _default_green_gradient() and _default_magenta_gradient() fallback functions
- Add _color_codes_to_ansi() to convert integer color codes from themes to ANSI escape strings
- Update lr_gradient() signature: cols parameter (was grad_cols)
- lr_gradient() now pulls colors from config.ACTIVE_THEME when available
- Falls back to default green gradient when no theme is active
- Existing calls with explicit cols parameter continue to work
- Add comprehensive tests for new functionality

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

engine/render.py

@@ -16,37 +16,69 @@ from engine.terminal import RST
 from engine.translate import detect_location_language, translate_headline
 
 # ─── GRADIENT ─────────────────────────────────────────────
-# Left → right: white-hot leading edge fades to near-black
+def _color_codes_to_ansi(color_codes):
-GRAD_COLS = [
+    """Convert a list of 256-color codes to ANSI escape code strings.
-    "\033[1;38;5;231m",  # white
-    "\033[1;38;5;195m",  # pale cyan-white
-    "\033[38;5;123m",  # bright cyan
-    "\033[38;5;118m",  # bright lime
-    "\033[38;5;82m",  # lime
-    "\033[38;5;46m",  # bright green
-    "\033[38;5;40m",  # green
-    "\033[38;5;34m",  # medium green
-    "\033[38;5;28m",  # dark green
-    "\033[38;5;22m",  # deep green
-    "\033[2;38;5;22m",  # dim deep green
-    "\033[2;38;5;235m",  # near black
-]
 
-# Complementary sweep for queue messages (opposite hue family from ticker greens)
+    Pattern: first 2 are bold, middle 8 are normal, last 2 are dim.
-MSG_GRAD_COLS = [
+
-    "\033[1;38;5;231m",  # white
+    Args:
-    "\033[1;38;5;225m",  # pale pink-white
+        color_codes: List of 12 integers (256-color palette codes)
-    "\033[38;5;219m",  # bright pink
+
-    "\033[38;5;213m",  # hot pink
+    Returns:
-    "\033[38;5;207m",  # magenta
+        List of ANSI escape code strings
-    "\033[38;5;201m",  # bright magenta
+    """
-    "\033[38;5;165m",  # orchid-red
+    if not color_codes or len(color_codes) != 12:
-    "\033[38;5;161m",  # ruby-magenta
+        # Fallback to default green if invalid
-    "\033[38;5;125m",  # dark magenta
+        return _default_green_gradient()
-    "\033[38;5;89m",  # deep maroon-magenta
+
-    "\033[2;38;5;89m",  # dim deep maroon-magenta
+    result = []
-    "\033[2;38;5;235m",  # near black
+    for i, code in enumerate(color_codes):
-]
+        if i < 2:
+            # Bold for first 2 (bright leading edge)
+            result.append(f"\033[1;38;5;{code}m")
+        elif i < 10:
+            # Normal for middle 8
+            result.append(f"\033[38;5;{code}m")
+        else:
+            # Dim for last 2 (dark trailing edge)
+            result.append(f"\033[2;38;5;{code}m")
+    return result
+
+
+def _default_green_gradient():
+    """Return the default 12-color green gradient for fallback when no theme is active."""
+    return [
+        "\033[1;38;5;231m",  # white
+        "\033[1;38;5;195m",  # pale cyan-white
+        "\033[38;5;123m",  # bright cyan
+        "\033[38;5;118m",  # bright lime
+        "\033[38;5;82m",  # lime
+        "\033[38;5;46m",  # bright green
+        "\033[38;5;40m",  # green
+        "\033[38;5;34m",  # medium green
+        "\033[38;5;28m",  # dark green
+        "\033[38;5;22m",  # deep green
+        "\033[2;38;5;22m",  # dim deep green
+        "\033[2;38;5;235m",  # near black
+    ]
+
+
+def _default_magenta_gradient():
+    """Return the default 12-color magenta gradient for fallback when no theme is active."""
+    return [
+        "\033[1;38;5;231m",  # white
+        "\033[1;38;5;225m",  # pale pink-white
+        "\033[38;5;219m",  # bright pink
+        "\033[38;5;213m",  # hot pink
+        "\033[38;5;207m",  # magenta
+        "\033[38;5;201m",  # bright magenta
+        "\033[38;5;165m",  # orchid-red
+        "\033[38;5;161m",  # ruby-magenta
+        "\033[38;5;125m",  # dark magenta
+        "\033[38;5;89m",  # deep maroon-magenta
+        "\033[2;38;5;89m",  # dim deep maroon-magenta
+        "\033[2;38;5;235m",  # near black
+    ]
 
 # ─── FONT LOADING ─────────────────────────────────────────
 _FONT_OBJ = None
@@ -189,9 +221,15 @@ def big_wrap(text, max_w, fnt=None):
     return out
 
 
-def lr_gradient(rows, offset=0.0, grad_cols=None):
+def lr_gradient(rows, offset=0.0, cols=None):
     """Color each non-space block character with a shifting left-to-right gradient."""
-    cols = grad_cols or GRAD_COLS
+    if cols is None:
+        from engine import config
+
+        if config.ACTIVE_THEME:
+            cols = _color_codes_to_ansi(config.ACTIVE_THEME.main_gradient)
+        else:
+            cols = _default_green_gradient()
     n = len(cols)
     max_x = max((len(r.rstrip()) for r in rows if r.strip()), default=1)
     out = []
@@ -213,7 +251,7 @@ def lr_gradient(rows, offset=0.0, grad_cols=None):
 
 def lr_gradient_opposite(rows, offset=0.0):
     """Complementary (opposite wheel) gradient used for queue message panels."""
-    return lr_gradient(rows, offset, MSG_GRAD_COLS)
+    return lr_gradient(rows, offset, _default_magenta_gradient())
 
 
 # ─── HEADLINE BLOCK ASSEMBLY ─────────────────────────────

tests/test_render.py

@@ -0,0 +1,174 @@
+"""
+Tests for engine.render module.
+"""
+
+import pytest
+
+from engine import config, render
+
+
+class TestDefaultGradients:
+    """Tests for default gradient fallback functions."""
+
+    def test_default_green_gradient_length(self):
+        """_default_green_gradient returns 12 colors."""
+        gradient = render._default_green_gradient()
+        assert len(gradient) == 12
+
+    def test_default_green_gradient_is_list(self):
+        """_default_green_gradient returns a list."""
+        gradient = render._default_green_gradient()
+        assert isinstance(gradient, list)
+
+    def test_default_green_gradient_all_strings(self):
+        """_default_green_gradient returns list of ANSI code strings."""
+        gradient = render._default_green_gradient()
+        assert all(isinstance(code, str) for code in gradient)
+
+    def test_default_magenta_gradient_length(self):
+        """_default_magenta_gradient returns 12 colors."""
+        gradient = render._default_magenta_gradient()
+        assert len(gradient) == 12
+
+    def test_default_magenta_gradient_is_list(self):
+        """_default_magenta_gradient returns a list."""
+        gradient = render._default_magenta_gradient()
+        assert isinstance(gradient, list)
+
+    def test_default_magenta_gradient_all_strings(self):
+        """_default_magenta_gradient returns list of ANSI code strings."""
+        gradient = render._default_magenta_gradient()
+        assert all(isinstance(code, str) for code in gradient)
+
+
+class TestLrGradientUsesActiveTheme:
+    """Tests for lr_gradient using active theme."""
+
+    def test_lr_gradient_uses_active_theme_when_cols_none(self):
+        """lr_gradient uses ACTIVE_THEME.main_gradient when cols=None."""
+        # Save original state
+        original_theme = config.ACTIVE_THEME
+
+        try:
+            # Set a theme
+            config.set_active_theme("green")
+
+            # Create simple test data
+            rows = ["text"]
+
+            # Call without cols parameter (cols=None)
+            result = render.lr_gradient(rows, offset=0.0)
+
+            # Should not raise and should return colored output
+            assert isinstance(result, list)
+            assert len(result) == 1
+            # Should have ANSI codes (no plain "text")
+            assert result[0] != "text"
+        finally:
+            # Restore original state
+            config.ACTIVE_THEME = original_theme
+
+    def test_lr_gradient_fallback_when_no_theme(self):
+        """lr_gradient uses fallback green when ACTIVE_THEME is None."""
+        # Save original state
+        original_theme = config.ACTIVE_THEME
+
+        try:
+            # Clear the theme
+            config.ACTIVE_THEME = None
+
+            # Create simple test data
+            rows = ["text"]
+
+            # Call without cols parameter (should use fallback)
+            result = render.lr_gradient(rows, offset=0.0)
+
+            # Should not raise and should return colored output
+            assert isinstance(result, list)
+            assert len(result) == 1
+            # Should have ANSI codes (no plain "text")
+            assert result[0] != "text"
+        finally:
+            # Restore original state
+            config.ACTIVE_THEME = original_theme
+
+    def test_lr_gradient_explicit_cols_parameter_still_works(self):
+        """lr_gradient with explicit cols parameter overrides theme."""
+        # Custom gradient
+        custom_cols = ["\033[38;5;1m", "\033[38;5;2m"] * 6
+
+        rows = ["xy"]
+        result = render.lr_gradient(rows, offset=0.0, cols=custom_cols)
+
+        # Should use the provided cols
+        assert isinstance(result, list)
+        assert len(result) == 1
+
+    def test_lr_gradient_respects_cols_parameter_name(self):
+        """lr_gradient accepts cols as keyword argument."""
+        custom_cols = ["\033[38;5;1m", "\033[38;5;2m"] * 6
+
+        rows = ["xy"]
+        # Call with cols as keyword
+        result = render.lr_gradient(rows, offset=0.0, cols=custom_cols)
+
+        assert isinstance(result, list)
+
+
+class TestLrGradientBasicFunctionality:
+    """Tests to ensure lr_gradient basic functionality still works."""
+
+    def test_lr_gradient_colors_non_space_chars(self):
+        """lr_gradient colors non-space characters."""
+        rows = ["hello"]
+
+        # Set a theme for the test
+        original_theme = config.ACTIVE_THEME
+        try:
+            config.set_active_theme("green")
+            result = render.lr_gradient(rows, offset=0.0)
+
+            # Result should have ANSI codes
+            assert any("\033[" in r for r in result), "Expected ANSI codes in result"
+        finally:
+            config.ACTIVE_THEME = original_theme
+
+    def test_lr_gradient_preserves_spaces(self):
+        """lr_gradient preserves spaces in output."""
+        rows = ["a b c"]
+
+        original_theme = config.ACTIVE_THEME
+        try:
+            config.set_active_theme("green")
+            result = render.lr_gradient(rows, offset=0.0)
+
+            # Spaces should be preserved (not colored)
+            assert " " in result[0]
+        finally:
+            config.ACTIVE_THEME = original_theme
+
+    def test_lr_gradient_empty_rows(self):
+        """lr_gradient handles empty rows correctly."""
+        rows = [""]
+
+        original_theme = config.ACTIVE_THEME
+        try:
+            config.set_active_theme("green")
+            result = render.lr_gradient(rows, offset=0.0)
+
+            assert result == [""]
+        finally:
+            config.ACTIVE_THEME = original_theme
+
+    def test_lr_gradient_multiple_rows(self):
+        """lr_gradient handles multiple rows."""
+        rows = ["row1", "row2", "row3"]
+
+        original_theme = config.ACTIVE_THEME
+        try:
+            config.set_active_theme("green")
+            result = render.lr_gradient(rows, offset=0.0)
+
+            assert len(result) == 3
+        finally:
+            config.ACTIVE_THEME = original_theme