create_style.py¶

Overview¶

This file contains 15 documented elements.

Classes¶

ThesaurusStyler¶

No description available. Manages the loading and application of QML-based fill styles to QGIS vector layers using a thesaurus mapping. It initialises with a default QML style file path, from which it extracts a QgsFillSymbol to serve as the base style, falling back to a simple grey fill symbol if the file is unavailable or invalid. The class applies categorized rendering to a target layer by mapping field values through a provided thesaurus dictionary and assigning each category a randomly coloured, semi-transparent symbol derived from the default style.

Methods¶

init(self, default_style_path)¶

Inizializza la classe con il percorso dello stile QML predefinito.

:param default_style_path: Percorso del file QML di default

load_default_style(self)¶

Carica lo stile predefinito dal file QML.

get_style(self, sigla)¶

Restituisce lo stile per una data sigla. In questo caso, restituisce sempre lo stile predefinito.

:param sigla: La sigla per cui si vuole lo stile (non utilizzata in questa implementazione) :return: QgsFillSymbol predefinito

apply_style_to_layer(self, layer, d_stratigrafica_field, thesaurus_mapping)¶

Applica gli stili al layer basandosi sul mapping del thesaurus.

:param layer: Il layer QGIS a cui applicare gli stili :param d_stratigrafica_field: Il nome del campo contenente i valori d_stratigrafica :param thesaurus_mapping: Il mapping tra d_stratigrafica e sigla_estesa

USViewStyler¶

No description available. Manages the creation and application of QGIS vector layer styles for stratigraphic unit (US) data loaded from a database connection. The class queries the us_table to retrieve stratigraphic records, generates rule-based fill symbols differentiated by stratigraphic phase, unit type, and stratigraphic index, and provides interactive workflows for applying, saving, or loading named styles to a target layer. It also enforces feature rendering order based on order_layer and stratigraph_index_us fields to ensure correct stratigraphic drawing sequence.

Methods¶

init(self, connection, sito)¶

No description available. Initializes a USViewStyler instance by storing the provided connection object and optional sito parameter as instance attributes. A SQLAlchemy engine is created from the connection string, and the database server type is determined as either "sqlite" or "postgres" based on the connection string prefix. Upon initialization, stratigraphic unit data is immediately loaded via _load_us_data() and the corresponding styles are generated via _create_styles_for_us(), storing the results in self.us_data and self.us_styles respectively.

ask_user_style_preference(self)¶

Displays a locale-aware modal dialog prompting the user to choose how to manage a layer's style. The dialog presents four options — save a new style, load an existing style, use a temporary style, or apply a single-symbol outline-only style — with labels rendered in Italian or English based on the QGIS user locale setting. Returns one of the string values "save", "load", "null_fill", or "temp" corresponding to the button clicked by the user.

ask_user_categorization_field(self, layer)¶

Ask user which field to use for rule-based categorization. Only shows fields that are available in the layer. Uses localized labels based on QGIS language settings.

Args: layer: Optional QgsVectorLayer to check for available fields

Returns the selected field name or default if cancelled.

load_style_from_db(self, layer)¶

No description available. Retrieves and returns a style XML string from the database for the given layer by calling layer.listStylesInDatabase(). If exactly one style is found, it is loaded automatically; if multiple styles exist, the user is prompted via a QInputDialog to select one by name. Returns None if the styles data is invalid, no styles are found, the selection is cancelled, or an exception occurs during the process.

load_style_from_db_new(self, layer)¶

No description available. Retrieves a style definition in XML format from the database associated with the given layer by calling layer.listStylesInDatabase(). If exactly one style is found, it is loaded automatically; if multiple styles are present, a QInputDialog prompt is displayed to allow the user to select the desired style by name. Returns the style XML string on success, or None if no styles are found, the selection is cancelled, or an error occurs.

apply_style_to_layer(self, layer)¶

No description available. Applies a visual style to the given QGIS vector layer based on user preference and field availability. The method first validates the layer and checks for required fields (stratigraph_index_us, tipo_us_s) and at least one categorization field (d_stratigrafica, tipo_us_s, d_interpretativa), then prompts the user to choose between loading a saved style from the database, applying a null-fill (transparent fill with dark grey outline) style, or generating and optionally saving a temporary categorized style. After applying the chosen style, the method triggers a layer repaint, emits a legend change signal, and invokes _apply_feature_ordering to ensure correct stratigraphic rendering order.

show_message(self, message)¶

Mostra un messaggio all'utente.

save_style_to_db(self, layer)¶

Prompts the user via a QInputDialog to enter a name for the style, then reads the current style from the provided layer using QgsMapLayerStyle and attempts to save it to the database by calling layer.saveStyleToDatabase. If the save operation raises an exception or returns None, diagnostic information is printed or displayed via show_message; if the user cancels the dialog or leaves the name empty, a cancellation message is shown. Any outer exception during the process is also caught and reported through show_message.

get_all_styles(self)¶

No description available. Returns the us_styles collection held by the instance. This method provides direct access to all styles currently stored in the object without applying any filtering or transformation.