Adding a 'magic_font_scale'

https://community.osarch.org/discussion/2202/blenderbim-edit-text-preview-size

src/blenderbim/blenderbim/bim/module/drawing/decoration.py

@@ -415,12 +415,14 @@ class BaseDecorator:
         factor = self.camera_zoom_to_factor(context.space_data.region_3d.view_camera_zoom)
         camera_width_px = factor * context.region.width
         mm_to_px = camera_width_px / self.get_camera_width_mm()
-        # 0.004118616 is a magic constant number I visually discovered to get the right number.
+        # magic_font_scale's default of (0.004118616) is a magic constant number I visually discovered to get the right number.
         # In particular it works only for the OpenGOST font and produces a 2.5mm font size.
         # It probably should be dynamically calculated using system.dpi or something.
         # font_size = 16 <-- this is a good default
         # TODO: need to synchronize it better with svg
-        font_size_px = int(0.004118616 * mm_to_px) * font_size_mm / 2.5
+
+        magic_font_scale = bpy.context.scene.DocProperties.magic_font_scale
+        font_size_px = int(magic_font_scale * mm_to_px) * font_size_mm / 2.5
         pos = pos - line_no * font_size_px * rotation_matrix[1]
 
         blf.size(font_id, font_size_px)

src/blenderbim/blenderbim/bim/module/drawing/prop.py

@@ -370,6 +370,7 @@ class DocProperties(PropertyGroup):
     )
     shadingstyle_default: StringProperty(default="Blender Default", name="Default Shading Style")
     drawing_font: StringProperty(default="OpenGost Type B TT.ttf", name="Drawing Font")
+    magic_font_scale: bpy.props.FloatProperty(default=0.004118616, name="Font Scale Factor")
 
 
 class BIMCameraProperties(PropertyGroup):

src/blenderbim/blenderbim/bim/ui.py

@@ -341,6 +341,8 @@ class BIM_ADDON_preferences(bpy.types.AddonPreferences):
         row.prop(context.scene.DocProperties, "shadingstyle_default")
         row = self.layout.row()
         row.prop(context.scene.DocProperties, "drawing_font")
+        row = self.layout.row()
+        row.prop(context.scene.DocProperties, "magic_font_scale")
 
 
 # Scene panel groups