Fix 3D mark drawing

src/drawable.typ

@@ -160,6 +160,11 @@
   })
   let norm-dir = (-dir.at(1), dir.at(0), dir.at(2))
 
+  // Marks in 3D are rotated on the z axis depending on the style
+  if dir.at(2) != 0 {
+    norm-dir = vector.cross(dir, style.z-up)
+  }
+
   // Generic positions
   //
   //    t      t - tip

src/matrix.typ

@@ -74,7 +74,6 @@
 
 // Return 4x4 rotate z matrix
 #let transform-rotate-z(angle) = {
-  // let (cos, sin) = (calc.cos, calc.sin)
   ((cos(angle), -sin(angle), 0, 0),
    (sin(angle), cos(angle), 0, 0),
    (0, 0, 1, 0),
@@ -83,26 +82,27 @@
 
 // Return 4x4 rotate xz matrix
 #let transform-rotate-xz(x, z) = {
-  // let (pi, cos, sin) = (calc.pi, calc.cos, calc.sin)
   ((cos(z), sin(z), 0, 0),
    (-cos(x)*sin(z), cos(x)*cos(z), -sin(x), 0),
    (sin(x)*sin(z), -sin(x)*cos(z), cos(x), 1),
    (0, 0, 0, 1))
 }
 
-// Return 4x4 rotate xyz matrix
+
+/// Return 4x4 rotation matrix
+///
+/// Calculates the product of the three rotation matrices
+/// R = Rz(z) Ry(y) Rx(x)
+///
+/// - x (angle): Rotation about x
+/// - y (angle): Rotation about y
+/// - z (angle): Rotation about z
+/// -> matrix
 #let transform-rotate-xyz(x, y, z) = {
-  // let (pi, cos, sin) = (calc.pi, calc.cos, calc.sin)
-  ((cos(x)*cos(y)*cos(z)-sin(x)*sin(z),
-    -cos(x)*cos(y)*sin(z)-sin(x)*cos(z),
-    cos(x)*sin(y), 0),
-   (sin(x)*cos(y)*cos(z)+cos(x)*sin(z),
-    -sin(x)*cos(y)*sin(z)+cos(x)*cos(z),
-    sin(x)*sin(y), 0),
-   (-sin(y)*cos(z),
-    sin(y)*sin(z),
-    cos(y), 0),
-    (0, 0, 0, 1))
+  ((cos(y)*cos(z), sin(x)*sin(y)*cos(z) - cos(x)*sin(z), cos(x)*sin(y)*cos(z) + sin(x)*sin(z), 0),
+   (cos(y)*sin(z), sin(x)*sin(y)*sin(z) + cos(x)*cos(z), cos(x)*sin(y)*sin(z) - sin(x)*cos(z), 0),
+   (-sin(y), sin(x)*cos(y), cos(x)*cos(y), 0),
+   (0,0,0,1))
 }
 
 // Multiply matrix with matrix

src/styles.typ

@@ -8,12 +8,17 @@
 //   - inset  Sets the inner length of triangular shaped marks
 //   - scale  A factor that is applied to all of the three attributes above
 //   - sep    Is the distance between multiple marks along their path
+//
+// If a mark is pointing to positive or negative z, the mark will be drawn
+// with width on the axis perpendicular to its direction and the styles `z-up`
+// vector.
 #let _default-mark = (
   scale: 1,     // Scaling factor
   length: .2,   // Length
   width: 0.15,  // Width
   inset: .05,   // Arrow mark base inset
   sep: .1,      // Extra distance between marks
+  z-up: (0,1,0),// Z-Axis upwards vector
   start: none,  // Mark start symbol(s)
   end: none,    // Mark end symbol(s)
   stroke: auto,

src/vector.typ

@@ -81,9 +81,9 @@
 /// Calculate cross product of two vectors of dim 3
 #let cross(v1, v2) = {
   assert(dim(v1) == 3 and dim(v2) == 3)
-  let x = v1.at(1) * v2.at(2) - v1.at(2) * v1.at(1)
-  let y = v1.at(2) * v2.at(0) - v1.at(0) * v1.at(2)
-  let z = v1.at(0) * v2.at(1) - v1.at(1) * v1.at(0)
+  let x = v1.at(1) * v2.at(2) - v1.at(2) * v2.at(1)
+  let y = v1.at(2) * v2.at(0) - v1.at(0) * v2.at(2)
+  let z = v1.at(0) * v2.at(1) - v1.at(1) * v2.at(0)
   return (x, y, z)
 }
 

tests/mark/multiple/test.typ

@@ -18,7 +18,7 @@
   bezier((-1,-.5), (1,1), (0,-.5), (0,1),
     mark: (start: l, end: l, fill: red, stroke: blue, flex: false))
   bezier((-1,-1.5), (1,0), (0,-1.5), (0,0),
-    mark: (start: l, end: l, fill: red, stroke: blue, flex: false, scale: .05))
+    mark: (start: l, end: l, fill: red, stroke: blue, flex: false, scale: .5))
 }))
 
 #box(stroke: 2pt + red, canvas({
@@ -28,7 +28,7 @@
   bezier((-1,-.5), (1,1), (0,-.5), (0,1),
     mark: (start: l, end: l, fill: red, stroke: blue, flex: true))
   bezier((-1,-1.5), (1,0), (0,-1.5), (0,0),
-    mark: (start: l, end: l, fill: red, stroke: blue, flex: true, scale: .05))
+    mark: (start: l, end: l, fill: red, stroke: blue, flex: true, scale: .5))
 }))
 
 #box(stroke: 2pt + red, canvas({

tests/mark/z-axis/test.typ

@@ -0,0 +1,11 @@
+#set page(width: auto, height: auto)
+#import "/src/lib.typ": *
+
+#box(stroke: 2pt + red, canvas({
+  import draw: *
+
+  line((-1,0), (1,0), mark: (start: ">", end: ">"))
+  line((0,-1), (0,1), mark: (start: ">", end: ">"))
+  line((0,0,-1), (0,0,1), mark: (start: ">", end: ">",
+    scale: 1))
+}))