0042_volume_tin_representation.py

# -*- coding: utf-8 -*-
# Generated by Django 1.11.13 on 2018-07-17 15:45
from __future__ import unicode_literals

import django.core.validators
from django.db import migrations, models
import django.db.models.deletion


# Construct a PostGIS TIN representation of a bounding box
bb_vertices = """
    (({0}, {2}, {1}, {0})),
    (({1}, {2}, {3}, {1})),

    (({0}, {1}, {5}, {0})),
    (({0}, {5}, {4}, {0})),

    (({2}, {6}, {7}, {2})),
    (({2}, {7}, {3}, {2})),

    (({4}, {7}, {6}, {4})),
    (({4}, {5}, {7}, {4})),

    (({0}, {6}, {2}, {0})),
    (({0}, {4}, {6}, {0})),

    (({1}, {3}, {5}, {1})),
    (({3}, {7}, {5}, {3}))
""".format(*[
    '%{a}$s %{b}$s %{c}$s'.format(**{
        'a': 1 if i & 0b001 else 2,
        'b': 3 if i & 0b010 else 4,
        'c': 5 if i & 0b100 else 6,
    })
    for i in range(8)
])

forward = """
    DO $$
    BEGIN
        -- Make sure we only deal with polyhedeal surfaces and TINs
        IF (SELECT COUNT(*) FROM catmaid_volume
            WHERE ST_GeometryType(geometry) NOT IN ('ST_PolyhedralSurface', 'ST_Tin')
            LIMIT 1) <> 0
        THEN
            RAISE EXCEPTION 'Only geometries of type ST_PolyhedralSurface and '
                'ST_Tin are supported by CATMAID. Please fix volumes manually.';
        END IF;

        -- Make sure that all polyhedral surfaces have 30 vertices and six faces,
        -- in which case we assume it is a simple box.
        IF (SELECT COUNT(*) FROM catmaid_volume
            WHERE ST_GeometryType(geometry) = 'ST_PolyhedralSurface'
            AND (ST_NPoints(geometry) <> 30 OR ST_NumGeometries(geometry) <> 6)
            LIMIT 1) <> 0
        THEN
            RAISE EXCEPTION 'All polyhedral surfaces need to be boxes, i.e. '
                'have 30 vertices and 6 faces. Please fix volumes manually.';
        END IF;
    END
    $$;

    SELECT disable_history_tracking_for_table('catmaid_volume'::regclass,
            get_history_table_name('catmaid_volume'::regclass));
    SELECT drop_history_view_for_table('catmaid_volume'::regclass);

    -- Convert polyhedral surfaces to TINs, assuming that we only deal with
    -- boxes.
    UPDATE catmaid_volume
    SET geometry = ST_GeomFromEWKT(FORMAT('TINZ ({bb_vertices})',
        ST_XMax(geometry),
        ST_XMin(geometry),
        ST_YMax(geometry),
        ST_YMin(geometry),
        ST_ZMax(geometry),
        ST_ZMin(geometry)))
    WHERE ST_GeometryType(geometry) = 'ST_PolyhedralSurface';

    UPDATE catmaid_volume__history
    SET geometry = ST_GeomFromEWKT(FORMAT('TINZ ({bb_vertices})',
        ST_XMax(geometry),
        ST_XMin(geometry),
        ST_YMax(geometry),
        ST_YMin(geometry),
        ST_ZMax(geometry),
        ST_ZMin(geometry)))
    WHERE ST_GeometryType(geometry) = 'ST_PolyhedralSurface';

    ALTER TABLE catmaid_volume
    ALTER COLUMN geometry TYPE Geometry(TINZ);

    ALTER TABLE catmaid_volume__history
    ALTER COLUMN geometry TYPE Geometry(TINZ);

    SELECT create_history_view_for_table('catmaid_volume'::regclass);
    SELECT enable_history_tracking_for_table('catmaid_volume'::regclass,
            get_history_table_name('catmaid_volume'::regclass), FALSE);
""".format(bb_vertices=bb_vertices)

backward = """
    SELECT disable_history_tracking_for_table('catmaid_volume'::regclass,
            get_history_table_name('catmaid_volume'::regclass));
    SELECT drop_history_view_for_table('catmaid_volume'::regclass);

    ALTER TABLE catmaid_volume
    ALTER COLUMN geometry TYPE Geometry(GeometryZ);

    ALTER TABLE catmaid_volume__history
    ALTER COLUMN geometry TYPE Geometry(GeometryZ);

    SELECT create_history_view_for_table('catmaid_volume'::regclass);
    SELECT enable_history_tracking_for_table('catmaid_volume'::regclass,
            get_history_table_name('catmaid_volume'::regclass), FALSE);
"""

class Migration(migrations.Migration):

    dependencies = [
        ('catmaid', '0041_add_sampler_column_leaf_handling'),
    ]

    operations = [
        migrations.RunSQL(forward, backward)
    ]