constraints.py

# -*- coding: utf-8 -*-


from const import (ANGLE_MAX, ANGLE_MIN, COLOR_MAX, COLOR_MIN, NUM_MAX,
                   NUM_MIN, SIZE_MAX, SIZE_MIN, TYPE_MAX, TYPE_MIN, UNI_MAX,
                   UNI_MIN)


def gen_layout_constraint(pos_type, pos_list,
                          num_min=NUM_MIN, num_max=NUM_MAX,
                          uni_min=UNI_MIN, uni_max=UNI_MAX):
    constraint = {"Number": [num_min, num_max],
                  "Position": [pos_type, pos_list[:]],
                  "Uni": [uni_min, uni_max]}
    return constraint


def gen_entity_constraint(type_min=TYPE_MIN, type_max=TYPE_MAX,
                          size_min=SIZE_MIN, size_max=SIZE_MAX,
                          color_min=COLOR_MIN, color_max=COLOR_MAX,
                          angle_min=ANGLE_MIN, angle_max=ANGLE_MAX):
    constraint = {"Type": [type_min, type_max],
                  "Size": [size_min, size_max],
                  "Color": [color_min, color_max],
                  "Angle": [angle_min, angle_max]}
    return constraint


def rule_constraint(rule_list, num_min: int, num_max: int,
                    uni_min: int, uni_max: int,
                    type_min: int, type_max: int,
                    size_min: int, size_max: int,
                    color_min: int, color_max: int):
    """Generate constraints given the rules and the original constraints 
    from layout and entity. Note that each attribute has at most one rule
    applied on it.
    Arguments:
        rule_list(ordered list of Rule): all rules applied to this layout
        others (int): boundary levels for each attribute in a layout; note that
            num_max + 1 == len(layout.position.values)
    Returns:
        layout_constraint(dict): a new layout constraint
        entity_constraint(dict): a new entity constraint
    """
    assert len(rule_list) > 0
    for rule in rule_list:
        if rule.name == "Progression":
            # rule.value: add/sub how many levels
            if rule.attr == "Number":
                if rule.value > 0:
                    num_max = num_max - rule.value * 2
                else:
                    num_min = num_min - rule.value * 2
            if rule.attr == "Position":
                # Progression here means moving in Layout slots in order
                abs_value = abs(rule.value)
                num_max = num_max - abs_value * 2
            if rule.attr == "Type":
                if rule.value > 0:
                    type_max = type_max - rule.value * 2
                else:
                    type_min = type_min - rule.value * 2
            if rule.attr == "Size":
                if rule.value > 0:
                    size_max = size_max - rule.value * 2
                else:
                    size_min = size_min - rule.value * 2
            if rule.attr == "Color":
                if rule.value > 0:
                    color_max = color_max - rule.value * 2
                else:
                    color_min = color_min - rule.value * 2
        if rule.name == "Arithmetic":
            # rule.value > 0 if add col_0 + col_1
            # rule.value < 0 if sub col_0 - col_1
            if rule.attr == "Number":
                if rule.value > 0:
                    num_max = num_max - num_min - 1
                else:
                    num_min = 2 * num_min + 1
            if rule.attr == "Position":
                # SET_UNION
                # at least two position configurations
                if rule.value > 0:
                    num_max = num_max - 1
                # num_min makes sure of overlap
                # at least two configurations
                # SET_DIFF
                else:
                    num_min = (num_max + 2) // 2 - 1
                    num_max = num_max - 1
            if rule.attr == "Size":
                if rule.value > 0:
                    size_max = size_max - size_min - 1
                else:
                    size_min = 2 * size_min + 1
            if rule.attr == "Color":
                # at least two different colors
                if color_max - color_min < 1:
                    color_max = color_min - 1
                else:
                    if rule.value > 0:
                        color_max = color_max - color_min
                    if rule.value < 0:
                        color_min = 2 * color_min
        if rule.name == "Distribute_Three":
            # if less than 3 values, invalidate it
            if rule.attr == "Number":
                if num_max - num_min + 1 < 3:
                    num_max = num_min - 1
            if rule.attr == "Position":
                # max number allowed in the layout should be >= 3
                if num_max + 1 < 3:
                    num_max = num_min - 1
                # num_max + 1 == len(layout.position.values)
                # C_{num_max + 1}^{num_value} >= 3
                # C_{num_max + 1} = num_max + 1 >= 3
                # hence only need to constrain num_max: num_max = num_max - 1
                # Check Yang Hui’s Triangle (Pascal's Triangle): https://www.varsitytutors.com/hotmath/hotmath_help/topics/yang-huis-triangle
                else:
                    num_max = num_max - 1
            if rule.attr == "Type":
                if type_max - type_min + 1 < 3:
                    type_max = type_min - 1
            if rule.attr == "Size":
                if size_max - size_min + 1 < 3:
                    size_max = size_min - 1
            if rule.attr == "Color":
                if color_max - color_min + 1 < 3:
                    color_max = color_min - 1

        assert isinstance(num_min, int)
        assert isinstance(num_max, int)
        assert isinstance(uni_min, int)
        assert isinstance(uni_max, int)
        assert isinstance(type_min, int)
        assert isinstance(type_max, int)
        assert isinstance(size_min, int)
        assert isinstance(size_max, int)
        assert isinstance(color_min, int)
        assert isinstance(color_max, int)
    return gen_layout_constraint(None, [],
                                 num_min, num_max,
                                 uni_min, uni_max), \
           gen_entity_constraint(type_min, type_max,
                                 size_min, size_max,
                                 color_min, color_max)