API reference¶

Pango Helpers¶

class pangocairohelpers.LayoutClusters(layout: pangocffi.layout.Layout)¶

A decomposed representation of pangocffi.Layout as clusters (in other words pangocffi.GlyphItem)

This class is useful in scenarios where one wants to iterate over each individual cluster (commonly a single glyph or character).

Warning: RTL directional text like Arabic or Hebrew is not supported for now.

get_layout() → pangocffi.layout.Layout¶

Returns:	the layout on which this instance is based on

get_clusters() → List[pangocffi.glyph_item.GlyphItem]¶

Returns:	a list of `GlyphItem` for each cluster in the layout

get_logical_extents() → List[pangocairohelpers.glyph_extent.GlyphExtent]¶

Returns:	a list of `GlyphExtent` for each cluster in the layout

get_max_logical_extent() → Optional[pangocairohelpers.extent.Extent]¶

Returns:	the extent of the layout itself

Shapely Helpers¶

Line Helper¶

Functions to help with a single line segments.

pangocairohelpers.line_helper.coords_length(coord_a: Tuple[float, float], coord_b: Tuple[float, float]) → float¶

Parameters:	coord_a – the first coordinate coord_b – the second coordinate
Returns:	the length between two coordinates

pangocairohelpers.line_helper.coords_are_left_to_right(coord_a: Tuple[float, float], coord_b: Tuple[float, float]) → Optional[bool]¶

Parameters:	coord_a – the first coordinate coord_b – the second coordinate
Returns:	`True` if the coordinates are going left to right, `False` if right to left. If the line is vertical, `None` is returned.

LineString Helper¶

Functions to help with Shapely’s LineString class.

pangocairohelpers.line_string_helper.left_to_right_length(line_string: shapely.geometry.linestring.LineString) → float¶

Parameters:	line_string – the `LineString` to measure
Returns:	the length of all the line segments in `line_string` that go left (-x) to right (+x)

pangocairohelpers.line_string_helper.right_to_left_length(line_string: shapely.geometry.linestring.LineString) → float¶

Parameters:	line_string – the `LineString` to measure
Returns:	the length of all the line segments in `line_string` that go right (+x) to left (-x)

pangocairohelpers.line_string_helper.interpolated_distance_of_point(line_string: shapely.geometry.linestring.LineString, point: shapely.geometry.point.Point) → float¶

Parameters:	line_string – the `LineString` to find the distance on point – the point to find on the line
Returns:	the interpolation distance to calculate the position of the point on the line string

pangocairohelpers.line_string_helper.points_at_distance_from_point_on_line_string(line_string: shapely.geometry.linestring.LineString, point: shapely.geometry.point.Point, distance: float) → List[shapely.geometry.point.Point]¶

Parameters:	line_string – the `LineString` to find points on point – the circle’s center point to find intersections on the line distance – the circle’s radius to find intersections on the line
Returns:	a list of points that exist in the `line_string` and intersect the circle at `point` with the radius `distance`

pangocairohelpers.line_string_helper.next_offset_from_offset_in_line_string(line_string: shapely.geometry.linestring.LineString, current_offset: float, distance: float) → Optional[float]¶

Used to find the next point on a line_string that is at a certain distance away from the current point on the line.

Parameters:	line_string – the `LineString` to find the offset on current_offset – the offset to start at distance – the distance the next offset should be
Returns:	the next offset that is `distance` units away from the current offset on the `line_string`

pangocairohelpers.line_string_helper.angles_at_offsets(line_string: shapely.geometry.linestring.LineString) → List[Tuple[float, float]]¶

Parameters:	line_string – the `LineString` to read values from
Returns:	a list of angle values, indexed by the offset within the `line_string`

pangocairohelpers.line_string_helper.angle_at_offset(angles_at_offsets_list: List[Tuple[float, float]], offset: float) → float¶

Parameters:	angles_at_offsets_list – a list of angle values, indexed by the offset offset – the offset value to look for
Returns:	the angle at a specific offset in the `angles_at_offsets`

pangocairohelpers.line_string_helper.reverse(line_string: shapely.geometry.linestring.LineString) → shapely.geometry.linestring.LineString¶: Todo :param line_string: :return:

pangocairohelpers.line_string_helper.substring(line_string: shapely.geometry.linestring.LineString, start: float, end: Optional[float] = None) → Optional[shapely.geometry.linestring.LineString]¶: Todo :param line_string: :param start: :param end: :return:

TextPath¶

class pangocairohelpers.text_path.TextPath(line_string: shapely.geometry.linestring.LineString, layout: pangocffi.layout.Layout)¶

Renders text similar to the behaviour found in SVG’s <textPath>.

line_string behaves as the baseline for the text in the layout.

Multi-line layouts are not supported and will throw an error.

Left-to-right text is assumed.

text_fits() → bool¶

Todo

Returns:	Todo

compute_baseline() → Optional[shapely.geometry.linestring.LineString]¶

Computes the baseline that the text covers

Returns:	a linestring representing the baseline of the text

compute_boundaries() → Optional[shapely.geometry.multipolygon.MultiPolygon]¶

Computes the combined glyph extents for the text path

Returns:	a union of glyph extents

draw(context: cairocffi.context.Context)¶

Todo

Returns:	Todo