From 6cd4a2d78be00b23c9dc94e41432ec912799e8fe Mon Sep 17 00:00:00 2001
From: Dion Moult <dion@thinkmoult.com>
Date: Tue, 29 Mar 2022 20:30:10 +1100
Subject: [PATCH] #1153. Add support for elevation symbols in generated SVGs.

---
 .../blenderbim/bim/data/templates/symbols.svg |  9 +++++-
 .../blenderbim/bim/module/drawing/operator.py |  3 ++
 .../bim/module/drawing/svgwriter.py           | 30 ++++++++++++++++---
 3 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/src/blenderbim/blenderbim/bim/data/templates/symbols.svg b/src/blenderbim/blenderbim/bim/data/templates/symbols.svg
index b3209968e5..1dc3c36950 100644
--- a/src/blenderbim/blenderbim/bim/data/templates/symbols.svg
+++ b/src/blenderbim/blenderbim/bim/data/templates/symbols.svg
@@ -5,6 +5,13 @@
     </g>
     <g id="door-tag">
         <circle cy="1.75" r="5" fill="white" stroke="black" style="stroke-width: 0.25;" />
-        <line x1="-5" y1="1.75" x2="5" y2="1.75" style="stroke:black; stroke-width: 0.25;" />
+        <line x1="-5" y1="1.75" x2="5" y2="1.75" style="stroke: black; stroke-width: 0.25;" />
+    </g>
+    <g id="elevation-arrow">
+        <path style="fill: black;" d="M -7.07106 0 0 -7.07106 7.07106 0" />
+    </g>
+    <g id="elevation-tag">
+        <circle r="5" fill="white" stroke="black" style="stroke-width: 0.25;" />
+        <line x1="-5" y1="0" x2="5" y2="0" style="stroke: black; stroke-width: 0.25;" />
     </g>
 </svg>
diff --git a/src/blenderbim/blenderbim/bim/module/drawing/operator.py b/src/blenderbim/blenderbim/bim/module/drawing/operator.py
index b77e870b81..a519ccd9a2 100644
--- a/src/blenderbim/blenderbim/bim/module/drawing/operator.py
+++ b/src/blenderbim/blenderbim/bim/module/drawing/operator.py
@@ -457,6 +457,8 @@ class CreateDrawing(bpy.types.Operator):
                 svg_writer.annotations.setdefault("equal_objs", []).append(obj)
             elif element.ObjectType == "DIMENSION":
                 svg_writer.annotations.setdefault("dimension_objs", []).append(obj)
+            elif element.ObjectType == "ELEVATION":
+                svg_writer.annotations.setdefault("elevation_objs", []).append(obj)
             elif element.ObjectType == "BREAKLINE":
                 svg_writer.annotations["break_obj"] = obj
             elif element.ObjectType == "HIDDEN_LINE":
@@ -681,6 +683,7 @@ class ActivateView(bpy.types.Operator):
 
                     project_collection.children["Views"].children[camera.users_collection[0].name].hide_viewport = False
         bpy.data.collections.get(camera.users_collection[0].name).hide_render = False
+        bpy.context.scene.DocProperties.active_drawing_id = self.drawing
         bpy.ops.bim.activate_drawing_style()
         core.sync_references(tool.Ifc, tool.Collector, tool.Drawing, drawing=tool.Ifc.get().by_id(self.drawing))
         return {"FINISHED"}
diff --git a/src/blenderbim/blenderbim/bim/module/drawing/svgwriter.py b/src/blenderbim/blenderbim/bim/module/drawing/svgwriter.py
index baabc5cef0..4e81798518 100644
--- a/src/blenderbim/blenderbim/bim/module/drawing/svgwriter.py
+++ b/src/blenderbim/blenderbim/bim/module/drawing/svgwriter.py
@@ -286,7 +286,12 @@ class SvgWriter:
                         },
                     )
                 )
-        self.draw_text_annotations()
+
+        for obj in self.annotations.get("elevation_objs", []):
+            self.draw_elevation_annotation(obj)
+
+        for text_obj in self.annotations.get("text_objs", []):
+            self.draw_text_annotation(text_obj, text_obj.location)
 
     def draw_ifc_annotation(self):
         x_offset = self.raw_width / 2
@@ -425,9 +430,25 @@ class SvgWriter:
                 position = Vector((0, 0, 0))
             self.draw_text_annotation(obj, position)
 
-    def draw_text_annotations(self):
-        for text_obj in self.annotations.get("text_objs", []):
-            self.draw_text_annotation(text_obj, text_obj.location)
+    def draw_elevation_annotation(self, obj):
+        x_offset = self.raw_width / 2
+        y_offset = self.raw_height / 2
+        symbol_position = self.project_point_onto_camera(obj.location)
+        symbol_position = Vector(((x_offset + symbol_position.x), (y_offset - symbol_position.y)))
+
+        v1 = self.project_point_onto_camera(obj.matrix_world @ Vector((0, 0, 0)))
+        v2 = self.project_point_onto_camera(obj.matrix_world @ Vector((0, 0, -1)))
+        angle = -math.degrees((v2 - v1).xy.angle_signed(Vector((0, 1))))
+
+        transform = "rotate({}, {}, {})".format(
+            angle,
+            (symbol_position * self.scale)[0],
+            (symbol_position * self.scale)[1],
+        )
+
+        self.svg.add(self.svg.use("#elevation-arrow", insert=tuple(symbol_position * self.scale), transform=transform))
+        self.svg.add(self.svg.use("#elevation-tag", insert=tuple(symbol_position * self.scale)))
+
 
     def draw_text_annotation(self, text_obj, position):
         x_offset = self.raw_width / 2
@@ -646,6 +667,7 @@ class SvgWriter:
         )
 
     def project_point_onto_camera(self, point):
+        # TODO is this needlessly complex?
         return self.camera.matrix_world.inverted() @ geometry.intersect_line_plane(
             point.xyz,
             point.xyz - Vector(self.camera_projection),