Add other views to Camera.tight (#3391)

* refactor view_xyz, allow reuse of calculating view_vectors

* add multiple views to tight

* Typo fix

Co-authored-by: Andras Deak <adeak@users.noreply.github.com>

* fix naming to fix high variance image regression filtering

* Apply suggestions from code review

Co-authored-by: Andras Deak <adeak@users.noreply.github.com>

* fix return types

* better description of view planes

* fix negative issue for view_*

* move view_vectors in helpers and fix circular import

* use objects center as focal point, and offset by 1

* simplify absolute and dot products

* move test_tight_direction to be near other tight_* tests

* test for multiple objects when using tight

* Apply suggestions from code review: Comment clarifications

Co-authored-by: Andras Deak <adeak@users.noreply.github.com>

* Use parallel projection in docstring in tight

* add tests specifically for view_vectors

* don't use names in returns section

* Update pyvista/plotting/helpers.py

Co-authored-by: Andras Deak <adeak@users.noreply.github.com>
Co-authored-by: Alex Kaszynski <akascap@gmail.com>

pyvista/plotting/camera.py

@@ -8,6 +8,8 @@
 from pyvista import _vtk
 from pyvista.utilities.misc import PyVistaDeprecationWarning
 
+from .helpers import view_vectors
+
 
 class Camera(_vtk.vtkCamera):
     """PyVista wrapper for the VTK Camera class.
@@ -645,9 +647,18 @@ def copy(self):
 
         return new_camera
 
-    def tight(self, padding=0.0, adjust_render_window=True):
+    def tight(self, padding=0.0, adjust_render_window=True, view='xy', negative=False):
         """Adjust the camera position so that the actors fill the entire renderer.
 
+        The camera view direction is reoriented to be normal to the ``view``
+        plane. When ``negative=False``, The first letter of ``view`` refers
+        to the axis that points to the right. The second letter of ``view``
+        refers to axis that points up.  When ``negative=True``, the first
+        letter refers to the axis that points left.  The up direction is
+        unchanged.
+
+        Parallel projection is enabled when using this function.
+
         Parameters
         ----------
         padding : float, optional
@@ -658,9 +669,15 @@ def tight(self, padding=0.0, adjust_render_window=True):
             Adjust the size of the render window as to match the dimensions of
             the visible actors.
 
+        view : {'xy', 'yx', 'xz', 'zx', 'yz', 'zy'}
+            Plane to which the view is oriented. Default 'xy'.
+
+        negative : bool
+            Whether to view in opposite direction. Default ``False``.
+
         Notes
         -----
-        This resets the view direction to look at the XY plane.
+        This resets the view direction to look at a plane with parallel projection.
 
         Examples
         --------
@@ -690,23 +707,37 @@ def tight(self, padding=0.0, adjust_render_window=True):
 
         self._renderer.ComputeAspect()
         aspect = self._renderer.GetAspect()
-        angle = np.pi * self.view_angle / 180.0
-        dx, dy = (x1 - x0), (y1 - y0)
-        dist = max(dx / aspect[0], dy) / np.sin(angle / 2) / 2
 
-        self.SetViewUp(0, 1, 0)
-        self.SetPosition(x0 + dx / 2, y0 + dy / 2, dist * (1 + padding))
-        self.SetFocalPoint(x0 + dx / 2, y0 + dy / 2, 0)
+        position0 = np.array([x0, y0, z0])
+        position1 = np.array([x1, y1, z1])
+        objects_size = position1 - position0
+        position = position0 + objects_size / 2
+
+        direction, viewup = view_vectors(view, negative)
+        horizontal = np.cross(direction, viewup)
+
+        vert_dist = abs(objects_size @ viewup)
+        horiz_dist = abs(objects_size @ horizontal)
+
+        # set focal point to objects' center
+        # offset camera position from objects center by dist in opposite of viewing direction
+        # (actual distance doesn't matter due to parallel projection)
+        dist = 1
+        camera_position = position + dist * direction
+
+        self.SetViewUp(*viewup)
+        self.SetPosition(*camera_position)
+        self.SetFocalPoint(*position)
 
-        ps = max(dx / aspect[0], dy) / 2
+        ps = max(horiz_dist / aspect[0], vert_dist) / 2
         self.parallel_scale = ps * (1 + padding)
         self._renderer.ResetCameraClippingRange(x0, x1, y0, y1, z0, z1)
 
         if adjust_render_window:
             ren_win = self._renderer.GetRenderWindow()
             size = list(ren_win.GetSize())
             size_ratio = size[0] / size[1]
-            tight_ratio = dx / dy
+            tight_ratio = horiz_dist / vert_dist
             resize_ratio = tight_ratio / size_ratio
             if resize_ratio < 1:
                 size[0] = round(size[0] * resize_ratio)
@@ -717,4 +748,4 @@ def tight(self, padding=0.0, adjust_render_window=True):
 
             # simply call tight again to reset the parallel scale due to the
             # resized window
-            self.tight(padding=padding, adjust_render_window=False)
+            self.tight(padding=padding, adjust_render_window=False, view=view, negative=negative)

pyvista/plotting/helpers.py

@@ -1,12 +1,12 @@
 """This module contains some convenience helper functions."""
 
+from typing import Tuple
+
 import numpy as np
 
 import pyvista
 from pyvista.utilities import is_pyvista_dataset
 
-from .plotting import Plotter
-
 
 def plot(
     var_item,
@@ -227,7 +227,7 @@ def plot(
     show_grid = kwargs.pop('show_grid', False)
     auto_close = kwargs.get('auto_close')
 
-    pl = Plotter(
+    pl = pyvista.Plotter(
         window_size=window_size,
         off_screen=off_screen,
         notebook=notebook,
@@ -462,3 +462,52 @@ def plot_itk(mesh, color=None, scalars=None, opacity=1.0, smooth_shading=False):
     else:
         pl.add_mesh(mesh, color, scalars, opacity, smooth_shading)
     return pl.show()
+
+
+def view_vectors(view: str, negative: bool = False) -> Tuple[np.ndarray, np.ndarray]:
+    """Given a plane to view, return vectors for setting up camera.
+
+    Parameters
+    ----------
+    view : {'xy', 'yx', 'xz', 'zx', 'yz', 'zy'}
+        Plane to return vectors for.
+
+    negative : bool
+        Whether to view from opposite direction.  Default ``False``.
+
+    Returns
+    -------
+    vec : numpy.ndarray
+        ``[x, y, z]`` vector that points in the viewing direction
+
+    viewup : numpy.ndarray
+        ``[x, y, z]`` vector that points to the viewup direction
+
+    """
+    if view == 'xy':
+        vec = np.array([0, 0, 1])
+        viewup = np.array([0, 1, 0])
+    elif view == 'yx':
+        vec = np.array([0, 0, -1])
+        viewup = np.array([1, 0, 0])
+    elif view == 'xz':
+        vec = np.array([0, -1, 0])
+        viewup = np.array([0, 0, 1])
+    elif view == 'zx':
+        vec = np.array([0, 1, 0])
+        viewup = np.array([1, 0, 0])
+    elif view == 'yz':
+        vec = np.array([1, 0, 0])
+        viewup = np.array([0, 0, 1])
+    elif view == 'zy':
+        vec = np.array([-1, 0, 0])
+        viewup = np.array([0, 1, 0])
+    else:
+        raise ValueError(
+            f"Unexpected value for direction {view}\n"
+            "    Expected: 'xy', 'yx', 'xz', 'zx', 'yz', 'zy'"
+        )
+
+    if negative:
+        vec *= -1
+    return vec, viewup

pyvista/plotting/renderer.py

@@ -17,6 +17,7 @@
 from .camera import Camera
 from .charts import Charts
 from .colors import Color
+from .helpers import view_vectors
 from .render_passes import RenderPasses
 from .tools import create_axes_marker, create_axes_orientation_box, parse_font_family
 
@@ -2385,11 +2386,7 @@ def view_xy(self, negative=False):
         >>> pl.show()
 
         """
-        vec = np.array([0, 0, 1])
-        viewup = np.array([0, 1, 0])
-        if negative:
-            vec *= -1
-        self.view_vector(vec, viewup)
+        self.view_vector(*view_vectors('xy', negative=negative))
 
     def view_yx(self, negative=False):
         """View the YX plane.
@@ -2412,11 +2409,7 @@ def view_yx(self, negative=False):
         >>> pl.show()
 
         """
-        vec = np.array([0, 0, -1])
-        viewup = np.array([1, 0, 0])
-        if negative:
-            vec *= -1
-        self.view_vector(vec, viewup)
+        self.view_vector(*view_vectors('yx', negative=negative))
 
     def view_xz(self, negative=False):
         """View the XZ plane.
@@ -2439,11 +2432,7 @@ def view_xz(self, negative=False):
         >>> pl.show()
 
         """
-        vec = np.array([0, -1, 0])
-        viewup = np.array([0, 0, 1])
-        if negative:
-            vec *= -1
-        self.view_vector(vec, viewup)
+        self.view_vector(*view_vectors('xz', negative=negative))
 
     def view_zx(self, negative=False):
         """View the ZX plane.
@@ -2466,11 +2455,7 @@ def view_zx(self, negative=False):
         >>> pl.show()
 
         """
-        vec = np.array([0, 1, 0])
-        viewup = np.array([1, 0, 0])
-        if negative:
-            vec *= -1
-        self.view_vector(vec, viewup)
+        self.view_vector(*view_vectors('zx', negative=negative))
 
     def view_yz(self, negative=False):
         """View the YZ plane.
@@ -2493,11 +2478,7 @@ def view_yz(self, negative=False):
         >>> pl.show()
 
         """
-        vec = np.array([1, 0, 0])
-        viewup = np.array([0, 0, 1])
-        if negative:
-            vec *= -1
-        self.view_vector(vec, viewup)
+        self.view_vector(*view_vectors('yz', negative=negative))
 
     def view_zy(self, negative=False):
         """View the ZY plane.
@@ -2520,11 +2501,7 @@ def view_zy(self, negative=False):
         >>> pl.show()
 
         """
-        vec = np.array([-1, 0, 0])
-        viewup = np.array([0, 1, 0])
-        if negative:
-            vec *= -1
-        self.view_vector(vec, viewup)
+        self.view_vector(*view_vectors('zy', negative=negative))
 
     def disable(self):
         """Disable this renderer's camera from being interactive."""

tests/plotting/conftest.py

@@ -41,3 +41,10 @@ def check_gc(request):
     assert len(after) == 0, 'Not all objects GCed:\n' + '\n'.join(
         sorted(o.__class__.__name__ for o in after)
     )
+
+
+@pytest.fixture()
+def colorful_tetrahedron():
+    mesh = pyvista.Tetrahedron()
+    mesh.cell_data["colors"] = [[255, 255, 255], [255, 0, 0], [0, 255, 0], [0, 0, 255]]
+    return mesh

tests/plotting/test_helpers.py

@@ -0,0 +1,20 @@
+"""Tests for plotting helpers."""
+
+import numpy as np
+import pytest
+
+from pyvista.plotting.helpers import view_vectors
+
+
+def test_view_vectors():
+    views = ('xy', 'yx', 'xz', 'zx', 'yz', 'zy')
+
+    for view in views:
+        vec, viewup = view_vectors(view)
+        assert isinstance(vec, np.ndarray)
+        assert np.array_equal(vec.shape, (3,))
+        assert isinstance(viewup, np.ndarray)
+        assert np.array_equal(viewup.shape, (3,))
+
+    with pytest.raises(ValueError, match="Unexpected value for direction"):
+        view_vectors('invalid')