Merge pull request #88 from WIAS-PDELib/fix/rot2d

Fix coordinate transformation for 1D slice plots

Author: pjaap

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## [1.15.2] - 2025-06-24
+- fixed a corner case in `compute_2d_rotation_matrix` leading to wrong coordinate transformation in 1D slice plots
+
 ## [1.15.1] - 2025-06-22
 - Allow for Makie 0.24 and Triangulate 3.0
 

Project.toml

@@ -1,6 +1,6 @@
 name = "GridVisualize"
 uuid = "5eed8a63-0fb0-45eb-886d-8d5a387d12b8"
-version = "1.15.1"
+version = "1.15.2"
 authors = ["Juergen Fuhrmann <[email protected]>", "Patrick Jaap <[email protected]>"]
 
 [deps]

src/slice_plots.jl

@@ -173,6 +173,11 @@ function compute_2d_rotation_matrix(target_vector)
     # solve non-linear system for α
     α = asin(t[1])
 
+    # check second condition and rotate in the other direction if necessary
+    if !(cos(α) ≈ t[2])
+        α = π - α
+    end
+
     return R(α)
 end
 

test/test_slice_plots.jl

@@ -79,12 +79,18 @@ end
     t = [0, 1]
     @test GridVisualize.compute_2d_rotation_matrix(t) ≈ I
 
-    # random test
-    t = [0.3543579344795591, 0.21250427156069385]
-    R = GridVisualize.compute_2d_rotation_matrix(t)
-
-    # test rotation property
-    @test R't ≈ [0, 1]
+    # random tests
+    for t in [
+            [0.3543579344795591, 0.21250427156069385],
+            [1.0, 1.0],
+            [1.0, -1.0],
+            [-1.0, 1.0],
+            [-1.0, -1.0],
+        ]
+        R = GridVisualize.compute_2d_rotation_matrix(t)
+        # test rotation property
+        @test R't ≈ [0, 1]
+    end
 end