utils.py

# -*- coding: utf-8 -*-
"""
/***************************************************************************
 Gisquick plugin
 Publish your projects into Gisquick application
 ***************************************************************************/
"""
from decimal import Decimal
from qgis.PyQt.QtWidgets import QTreeWidgetItem

def to_decimal_array(value):
    """Converts array of numbers or comma-separated string to array of Decimal values.

    Args:
        value (List[float], str): 

    Returns:
        List[Decimal]: array with Decimal numbers
    """
    if isinstance(value, str):
        return [Decimal(res_string.strip())for res_string in value.split(',')]
    else:
        return [Decimal(res) for res in value]

def scales_to_resolutions(scales, units, dpi=96):
    """Converts array of map scales to tile resolutions.

    Args:
        scales (List[int]): array of map scales
        units (str): map units name ('feet', 'meters', 'miles', 'degrees')
        dpi (int): optional DPI value

    Returns:
        List[Decimal]: array of computed tile resolutions
    """

    dpi = Decimal(dpi)
    factor = {
        'feet': Decimal('12.0'), 'meters': Decimal('39.37'),
        'miles': Decimal('63360.0'), 'degrees': Decimal('4374754.0')
    }
    return [int(scale)/(dpi*factor[units]) for scale in scales]

def resolutions_to_scales(resolutions, units, dpi=96):
    """Converts array of tile resolutions to map scales.

    Args:
        resolutions (List[Decimal]): array of tile resolutions
        units (str): map units name ('feet', 'meters', 'miles', 'degrees')
        dpi (int): optional DPI value

    Returns:
        List[int]: array of computed map scales
    """
    dpi = Decimal(dpi)
    factor = {
        'feet': Decimal('12.0'), 'meters': Decimal('39.37'),
        'miles': Decimal('63360.0'), 'degrees': Decimal('4374754.0')
    }
    return [int(round(resolution * dpi * factor[units])) for resolution in resolutions]

def opt_value(data, param_name, default_value=''):
    """Helper function for accessing optional nested values in dictionary.

    >>> data = {'meta': {'data': {'value': 'foo'}}}
    >>> opt_value(data, 'meta.data.value', 'default')

    Args:
        data (Dict[str, Any]): data dictionary
        param_name (str): sequence of keys separated with dot '.'
        default_value (Any): default value returned when a given data do not contain
            lookup parameter

    Returns:
        Any: value of given parameter(s) from data dict or default value
    """
    obj = data
    value = default_value
    for param in param_name.split('.'):
        if obj and param in obj:
            value = obj[param]
            obj = value
        else:
            return default_value
    return value

def create_formatted_tree(root, data, template_data=None):
    """Helper function to add items to QTreeWidget

    Args:
        root: tree root item
        data: text item to be added (list/dict for multiple items or string for single item)
        format_format_data: function to format data
        format_data: data dictionary for formatting
    """
    def format_template_data(data):
        iterator = iter(list(data.items())) if type(data) == dict else enumerate(data)
        for key, value in iterator:
            if type(value) in (list, tuple):
                if value and isinstance(value[0], Decimal):
                    value = ['{0:.5f}'.format(v) for v in value]
                data[key] = ', '.join(map(str, value))
        return data

    def add_item(root, text, template_data):
        item = QTreeWidgetItem(root)
        if template_data:
            if type(template_data) == dict:
                item.setText(0, str(text).format(**template_data))
            else:
                item.setText(0, str(text).format(*template_data))
        else:
            item.setText(0, str(text))

        return item

    item = root

    formatted_data = None
    if template_data:
        formatted_data = format_template_data(template_data)

    if isinstance(data, list) or isinstance(data, set):
        for data_item in data:
            if isinstance(data_item, list):
                create_formatted_tree(item, data_item, formatted_data)
            else:
                item = add_item(root, data_item, formatted_data)
    elif isinstance(data, dict):
        for key, key_data in list(data.items()):
            item = add_item(root, key, formatted_data)
            create_formatted_tree(item, key_data, formatted_data)
    else:
        item = add_item(item, data, formatted_data)

    return item