gws.lib.svg.draw

Build SVG fragments from shapes and drawing soups.

Source code: gws.lib.svg.draw

Module Contents

gws.lib.svg.draw.DEFAULT_FONT_SIZE = 10
gws.lib.svg.draw.DEFAULT_MARKER_SIZE = 10
gws.lib.svg.draw.DEFAULT_POINT_SIZE = 10
gws.lib.svg.draw.MAX_SOUP_POINTS = 5000
gws.lib.svg.draw.MAX_SOUP_TAGS = 5000
gws.lib.svg.draw.shape_to_fragment(shape: gws.Shape, view: gws.MapView, label: str = None, style: gws.Style = None) → list[gws.XmlElement]

Convert a shape to an SVG fragment.

The shape is transformed to pixel coordinates using the view. Without a style, only the geometry is drawn. With a style, the fragment can contain a marker definition, the geometry, an icon and a label, depending on the style values and the view scale.

Parameters:

  • shape – Shape to draw.

  • view – Map view, which defines the pixel transformation, scale and dpi.

  • label – Label text, can contain newlines.

  • style – Style to apply.

Returns:

A list of SVG elements, empty if the shape is missing or empty.

Raises:

gws.Error – If the geometry type is not supported.

gws.lib.svg.draw.soup_to_fragment(view: gws.MapView, points: list[gws.Point], tags: list) → list[gws.XmlElement]

Convert an SVG “soup” to an SVG fragment.

A soup represents client-side SVG drawings (e.g. dimensions) in a resolution-independent way. It has two components:

  • a list of points, in the map coordinate system,

  • a list of tuples (tag-name, {atts}, child1, child2, ...), where children are tuples of the same form or strings.

First, points are converted to pixels using the view’s transform. Then, the attributes of each tag are evaluated. If an attribute value is a list, it is a function call: the first element is a function name, the rest are arguments. The functions are:

  • ['x', n]: returns the x pixel coordinate of points[n],

  • ['y', n]: returns the y pixel coordinate of points[n],

  • ['r', p1, p2, r]: computes the slope between points[p1] and points[p2] and returns rotate(slope, x, y) with the coordinates of points[r].

The result is normalized, so unsafe tags and attributes are removed.

Parameters:

  • view – Map view, which defines the pixel transformation.

  • points – Points in map coordinates.

  • tags – Tag tuples.

Returns:

A list of SVG elements.

Raises:

gws.Error – If the soup is too large or invalid, or uses an unknown function.