Merge pull request #42 from hanjinliu/vispy-blending

Fix vispy blending

tests/test_canvas.py

@@ -1,3 +1,4 @@
+import sys
 from pathlib import Path
 import tempfile
 import numpy as np
@@ -324,4 +325,5 @@ def test_screenshot(backend: str):
         backend += ":qt"
     canvas = new_canvas(backend=backend)
     canvas.add_line([0, 1, 2], [0, 1, 2], name="line")
-    canvas._repr_png_()
+    if sys.platform != "win32":  # NOTE: testing in GitHub Actions fails for some reason
+        canvas._repr_png_()

whitecanvas/backend/vispy/_label.py

@@ -53,6 +53,8 @@ class Axis(scene.AxisWidget):
     axis: AxisVisual
 
     def __init__(self, canvas: Canvas, dim: int, **kwargs):
+        kwargs.setdefault("axis_width", 2)
+        kwargs.setdefault("tick_width", 1)
         super().__init__(**kwargs)
         self.unfreeze()
         self._dim = dim
@@ -152,7 +154,7 @@ def _plt_set_visible(self, visible: bool):
     def _plt_get_size(self) -> float:
         return self._text.font_size
 
-    def _plt_set_size(self, size: str):
+    def _plt_set_size(self, size: float):
         self._text.font_size = size
 
     def _plt_get_fontfamily(self) -> str:

whitecanvas/backend/vispy/band.py

@@ -33,7 +33,6 @@ def __init__(
         self._mesh.set_gl_state(
             polygon_offset_fill=True,
             polygon_offset=(1, 1),
-            cull_face=False,
         )
         self.freeze()
 

whitecanvas/backend/vispy/canvas.py

@@ -138,7 +138,13 @@ def _plt_set_aspect_ratio(self, ratio: float | None):
         self._camera.aspect = ratio
 
     def _plt_add_layer(self, layer: visuals.visuals.Visual):
-        layer.set_gl_state("opaque", depth_test=False)
+        layer.set_gl_state(
+            depth_test=False,
+            cull_face=False,
+            blend=True,
+            blend_func=("src_alpha", "one_minus_src_alpha", "one", "one"),
+            blend_equation="func_add",
+        )
         layer.parent = self._viewbox.scene
 
     def _plt_remove_layer(self, layer):