fix matplotlib vectors 3d

whitecanvas/backend/matplotlib/components3d/vectors3d.py

@@ -27,11 +27,21 @@ def __init__(self, x0, dx, y0, dy, z0, dz):
         self._3d_w = dz
 
     def do_3d_projection(self, renderer=None):
-        x, y, z = proj3d.proj_transform(self._3d_x, self._3d_y, self._3d_z, self.axes.M)
-        u, v, w = proj3d.proj_transform(self._3d_u, self._3d_v, self._3d_w, self.axes.M)
-        self.set_UVC(u, v)
-        self.set_offsets(np.column_stack([x, y]))
-        return np.min(z)
+        x0, y0, z0 = proj3d.proj_transform(
+            self._3d_x,
+            self._3d_y,
+            self._3d_z,
+            self.axes.M,
+        )
+        x1, y1, z1 = proj3d.proj_transform(
+            self._3d_x + self._3d_u,
+            self._3d_y + self._3d_v,
+            self._3d_z + self._3d_w,
+            self.axes.M,
+        )
+        self.set_UVC(x1 - x0, y1 - y0)
+        self.set_offsets(np.column_stack([x0, y0]))
+        return np.min(z0)
 
     def post_add(self, canvas: Canvas3D):
         self.transform = canvas._axes.transData

whitecanvas/backend/mock/__init__.py

@@ -7,4 +7,5 @@
     MonoLine,
     MultiLine,
     Texts,
+    Vectors,
 )

whitecanvas/backend/mock/layers.py

@@ -2,6 +2,7 @@
 
 import numpy as np
 from cmap import Colormap
+from numpy.typing import NDArray
 
 from whitecanvas import protocols
 from whitecanvas.backend.mock._base import (
@@ -214,3 +215,27 @@ def _plt_get_text_fontfamily(self) -> str:
 
     def _plt_set_text_fontfamily(self, family: str):
         self._fontfamily = family
+
+
+@protocols.check_protocol(protocols.VectorsProtocol)
+class Vectors(MockHasData, MockHasEdges):
+    def __init__(self, x0, dx, y0, dy):
+        super().__init__((x0, dx, y0, dy))
+
+    def _plt_get_ndata(self) -> int:
+        return self._plt_get_data()[0].size
+
+    def _plt_get_edge_color(self) -> NDArray[np.float32]:
+        if not hasattr(self, "_edge_color"):
+            ndata = self._plt_get_ndata()
+            self._edge_color = np.zeros((ndata, 4), dtype=np.float32)
+        return self._edge_color
+
+    def _plt_set_edge_color(self, color: NDArray[np.float32]):
+        self._edge_color = as_color_array(color, self._plt_get_ndata())
+
+    def _plt_get_antialias(self) -> bool:
+        return self._antialias
+
+    def _plt_set_antialias(self, antialias: bool):
+        self._antialias = antialias

whitecanvas/canvas/canvas3d/_base.py

@@ -133,6 +133,7 @@ def native(self) -> Any:
 
     @property
     def aspect_locked(self) -> bool:
+        """Whether the aspect ratio is locked."""
         return self._canvas()._plt_get_aspect_locked()
 
     @aspect_locked.setter
@@ -440,6 +441,28 @@ def add_vectors(
         alpha: float = 1.0,
         antialias: bool = True,
     ) -> layer3d.Vectors3D:
+        """
+        Add a 3D vector field.
+
+        Parameters
+        ----------
+        x, y, z : array-like
+            Base points of the vectors.
+        vx, vy, vz : array-like
+            Components of the vectors.
+        name : str, optional
+            Name of the layer.
+        color : color-like, optional
+            Color of the vectors.
+        width : float, optional
+            Width of the vectors.
+        style : str or LineStyle, optional
+            Style of the vectors.
+        alpha : float, default 1.0
+            Alpha channel of the vectors.
+        antialias : bool, default True
+            Whether to use antialiasing.
+        """
         name = self._coerce_name(name)
         color = self._generate_colors(color)
         width = theme._default("line.width", width)

whitecanvas/plot/_methods.py

@@ -41,6 +41,7 @@ def _inner(*args, **kwargs):
     kde = _CANVAS.add_kde
     rug = _CANVAS.add_rug
     text = _CANVAS.add_text
+    vectors = _CANVAS.add_vectors
     # categorical methods
     cat = _CANVAS.cat
     cat_x = _CANVAS.cat_x
@@ -67,6 +68,7 @@ def _inner(*args, **kwargs):
     kde = _make_method("kde")
     rug = _make_method("rug")
     text = _make_method("text")
+    vectors = _make_method("vectors")
     cat = _make_method("cat", pref="")
     cat_x = _make_method("cat_x", pref="")
     cat_y = _make_method("cat_y", pref="")