Remove Renderer.set_colors(), move into constructor

Makes it simpler to create an impl which constructs all canvases
within __init__, not on first frame.

ovgenpy/ovgenpy.py

@@ -140,8 +140,8 @@ class Ovgen:
                 yield
 
     def _load_renderer(self):
-        renderer = MatplotlibRenderer(self.cfg.render, self.cfg.layout, self.nchan)
+        renderer = MatplotlibRenderer(self.cfg.render, self.cfg.layout, self.nchan,
-        renderer.set_colors(self.cfg.channels)
+                                      self.cfg.channels)
         return renderer
 
     def play(self):

ovgenpy/renderer.py

@@ -41,13 +41,21 @@ class RendererConfig:
 
 
 class Renderer(ABC):
-    def __init__(self, cfg: RendererConfig, lcfg: 'LayoutConfig', nplots: int):
+    def __init__(self, cfg: RendererConfig, lcfg: 'LayoutConfig', nplots: int,
+                 channel_cfgs: Optional[List['ChannelConfig']]):
         self.cfg = cfg
         self.nplots = nplots
         self.layout = RendererLayout(lcfg, nplots)
 
-    @abstractmethod
+        # Load line colors.
-    def set_colors(self, channel_cfgs: List['ChannelConfig']) -> None: ...
+        if channel_cfgs is not None:
+            if len(channel_cfgs) != self.nplots:
+                raise ValueError(
+                    f"cannot assign {len(channel_cfgs)} colors to {self.nplots} plots"
+                )
+            self._line_colors = [cfg.line_color for cfg in channel_cfgs]
+        else:
+            self._line_colors = [None] * self.nplots
 
     @abstractmethod
     def render_frame(self, datas: List[np.ndarray]) -> None: ...
@@ -87,8 +95,6 @@ class MatplotlibRenderer(Renderer):
         self._axes: List['Axes'] = None        # set by set_layout()
         self._lines: List['Line2D'] = None     # set by render_frame() first call
 
-        self._line_colors: List = [None] * self.nplots
-
         self._set_layout()   # mutates self
 
     def _set_layout(self) -> None:
@@ -130,18 +136,6 @@ class MatplotlibRenderer(Renderer):
         if self.cfg.create_window:
             plt.show(block=False)
 
-    def set_colors(self, channel_cfgs: List['ChannelConfig']):
-        if len(channel_cfgs) != self.nplots:
-            raise ValueError(
-                f"cannot assign {len(channel_cfgs)} colors to {self.nplots} plots"
-            )
-
-        if self._lines is not None:
-            raise ValueError(
-                f'cannot set line colors after calling render_frame()'
-            )
-        self._line_colors = [cfg.line_color for cfg in channel_cfgs]
-
     def render_frame(self, datas: List[np.ndarray]) -> None:
         ndata = len(datas)
         if self.nplots != ndata:

tests/test_layout.py

@@ -70,7 +70,7 @@ def test_renderer_layout():
     lcfg = LayoutConfig(ncols=2)
     nplots = 15
 
-    r = MatplotlibRenderer(cfg, lcfg, nplots)
+    r = MatplotlibRenderer(cfg, lcfg, nplots, None)
 
     # 2 columns, 8 rows
     assert r.layout.ncols == 2

tests/test_output.py

@@ -19,7 +19,7 @@ NULL_CFG = FFmpegOutputConfig(None, '-f null')
 
 def test_render_output():
     """ Ensure rendering to output does not raise exceptions. """
-    renderer = MatplotlibRenderer(CFG.render, CFG.layout, nplots=1)
+    renderer = MatplotlibRenderer(CFG.render, CFG.layout, nplots=1, channel_cfgs=None)
     out: FFmpegOutput = NULL_CFG(CFG)
 
     renderer.render_frame([ALL_ZEROS])

tests/test_renderer.py

@@ -32,13 +32,13 @@ def test_default_colors(bg_str, fg_str):
     lcfg = LayoutConfig()
     nplots = 1
 
-    r = MatplotlibRenderer(cfg, lcfg, nplots)
+    r = MatplotlibRenderer(cfg, lcfg, nplots, None)
     verify(r, bg_str, fg_str)
 
     # Ensure default ChannelConfig(line_color=None) does not override line color
-    r = MatplotlibRenderer(cfg, lcfg, nplots)
     chan = ChannelConfig(wav_path='')
-    r.set_colors([chan] * nplots)
+    channels = [chan] * nplots
+    r = MatplotlibRenderer(cfg, lcfg, nplots, channels)
     verify(r, bg_str, fg_str)
 
 
@@ -54,9 +54,9 @@ def test_line_colors(bg_str, fg_str):
     lcfg = LayoutConfig()
     nplots = 1
 
-    r = MatplotlibRenderer(cfg, lcfg, nplots)
     chan = ChannelConfig(wav_path='', line_color=fg_str)
-    r.set_colors([chan] * nplots)
+    channels = [chan] * nplots
+    r = MatplotlibRenderer(cfg, lcfg, nplots, channels)
     verify(r, bg_str, fg_str)