Path#

Added in version 4.14.

class Path(*args, **kwargs)#

A GskPath describes lines and curves that are more complex than simple rectangles.

Paths can used for rendering (filling or stroking) and for animations (e.g. as trajectories).

GskPath is an immutable, opaque, reference-counted struct. After creation, you cannot change the types it represents. Instead, new GskPath objects have to be created. The PathBuilder structure is meant to help in this endeavor.

Conceptually, a path consists of zero or more contours (continuous, connected curves), each of which may or may not be closed. Contours are typically constructed from Bézier segments.

https://docs.gtk.org/gsk4/path-light.png

Methods#

class Path
foreach(flags: PathForeachFlags, func: Callable[[PathOperation, Point, int, float, Any], bool], user_data: Any = None) → bool#

Calls func for every operation of the path.

Note that this may only approximate self, because paths can contain optimizations for various specialized contours, and depending on the flags, the path may be decomposed into simpler curves than the ones that it contained originally.

This function serves two purposes:

  • When the flags allow everything, it provides access to the raw, unmodified data of the path.

  • When the flags disallow certain operations, it provides an approximation of the path using just the allowed operations.

Added in version 4.14.

Parameters:

  • flags – flags to pass to the foreach function. See PathForeachFlags for details about flags

  • func – the function to call for operations

  • user_data – user data passed to func

get_bounds() → tuple[bool, Rect]#

Computes the bounds of the given path.

The returned bounds may be larger than necessary, because this function aims to be fast, not accurate. The bounds are guaranteed to contain the path.

It is possible that the returned rectangle has 0 width and/or height. This can happen when the path only describes a point or an axis-aligned line.

If the path is empty, FALSE is returned and bounds are set to zero(). This is different from the case where the path is a single point at the origin, where the bounds will also be set to the zero rectangle but TRUE will be returned.

Added in version 4.14.

get_closest_point(point: Point, threshold: float) → tuple[bool, PathPoint, float]#

Computes the closest point on the path to the given point and sets the result to it.

If there is no point closer than the given threshold, FALSE is returned.

Added in version 4.14.

Parameters:

  • point – the point

  • threshold – maximum allowed distance

get_end_point() → tuple[bool, PathPoint]#

Gets the end point of the path.

An empty path has no points, so FALSE is returned in this case.

Added in version 4.14.

get_start_point() → tuple[bool, PathPoint]#

Gets the start point of the path.

An empty path has no points, so FALSE is returned in this case.

Added in version 4.14.

get_stroke_bounds(stroke: Stroke) → tuple[bool, Rect]#

Computes the bounds for stroking the given path with the parameters in stroke.

The returned bounds may be larger than necessary, because this function aims to be fast, not accurate. The bounds are guaranteed to contain the area affected by the stroke, including protrusions like miters.

Added in version 4.14.

Parameters:

stroke – stroke parameters

in_fill(point: Point, fill_rule: FillRule) → bool#

Returns whether the given point is inside the area that would be affected if the path was filled according to fill_rule.

Note that this function assumes that filling a contour implicitly closes it.

Added in version 4.14.

Parameters:

  • point – the point to test

  • fill_rule – the fill rule to follow

is_closed() → bool#

Returns if the path represents a single closed contour.

Added in version 4.14.

is_empty() → bool#

Checks if the path is empty, i.e. contains no lines or curves.

Added in version 4.14.

classmethod parse() → Path | None#

This is a convenience function that constructs a GskPath from a serialized form.

The string is expected to be in (a superset of) SVG path syntax, as e.g. produced by to_string.

A high-level summary of the syntax:

  • M x y Move to (x, y)

  • L x y Add a line from the current point to (x, y)

  • Q x1 y1 x2 y2 Add a quadratic Bézier from the current point to (x2, y2), with control point (x1, y1)

  • C x1 y1 x2 y2 x3 y3 Add a cubic Bézier from the current point to (x3, y3), with control points (x1, y1) and (x2, y2)

  • Z Close the contour by drawing a line back to the start point

  • H x Add a horizontal line from the current point to the given x value

  • V y Add a vertical line from the current point to the given y value

  • T x2 y2 Add a quadratic Bézier, using the reflection of the previous segments’ control point as control point

  • S x2 y2 x3 y3 Add a cubic Bézier, using the reflection of the previous segments’ second control point as first control point

  • A rx ry r l s x y Add an elliptical arc from the current point to (x, y) with radii rx and ry. See the SVG documentation for how the other parameters influence the arc.

  • O x1 y1 x2 y2 w Add a rational quadratic Bézier from the current point to (x2, y2) with control point (x1, y1) and weight w.

All the commands have lowercase variants that interpret coordinates relative to the current point.

The O command is an extension that is not supported in SVG.

Added in version 4.14.

print_(string: String) → None#
Parameters:

string

to_cairo(cr: Context) → None#

Appends the given path to the given cairo context for drawing with Cairo.

This may cause some suboptimal conversions to be performed as Cairo does not support all features of GskPath.

This function does not clear the existing Cairo path. Call cairo_new_path() if you want this.

Added in version 4.14.

Parameters:

cr – a cairo context

to_string() → str#

Converts the path into a string that is suitable for printing.

You can use this function in a debugger to get a quick overview of the path.

This is a wrapper around print, see that function for details.

Added in version 4.14.