Using plotstyles with drawing addon

[akantifirst]

I was able to find in the docs the corresponding section, but not sure how to implement it. When exporting .dxf file to .pdf with matplotlib backend, I get square line endings. It is not much of an issue, but may be somebody could give me an idea on how to implement CTB plotstyles to make line endings round. The picture illustrates what I mean:

[mbway]

if the lines are joined in the dxf file then they should be drawn as a single path

ezdxf/src/ezdxf/addons/drawing/matplotlib.py

Line 128 in 3fdba53

def draw_path(self, path, properties: Properties):

but from the screenshot it looks like they are rendered as separate line segments.

If you want to give all line segments rounded caps you could try passing solid_capstyle='round', dash_capstyle='round' here

ezdxf/src/ezdxf/addons/drawing/matplotlib.py

Lines 492 to 507 in 3fdba53

	def draw_line(
	self, start: Vec3, end: Vec3, properties: Properties, z: float
	):
	self.ax.add_line(
	Line2D(
	(start.x, end.x),
	(start.y, end.y),
	linewidth=self.lineweight(properties),
	linestyle="solid"
	if self._solid_only
	else self.linetype(properties),
	color=properties.color,
	zorder=z,
	)
	)

https://matplotlib.org/stable/api/_as_gen/matplotlib.lines.Line2D.html

[akantifirst]

Hello Matt, thank you for the advice. I'm struggling to implement it like this, but the generated pdf still looks same as with default MatplotlibLineRenderer.

class CustomBackend(MatplotlibBackend):
        ...
        self._line_renderer: CustomLineRenderer


class CustomLineRenderer(MatplotlibLineRenderer):

    def __init__(self, config: Configuration, ax: plt.Axes, solid_only: bool):
        super().__init__(config, ax)
        self._solid_only = solid_only

    def draw_line(
            self,
            start: Vec3,
            end: Vec3,
            properties: Properties,
            z: float
    ):
        self.ax.add_line(
            Line2D(
                (start.x, end.x),
                (start.y, end.y),
                linewidth=self.lineweight(properties),
                linestyle="solid"
                if self._solid_only
                else self.linetype(properties),
                color=properties.color,
                zorder=z,
                solid_capstyle='round',
                dash_capstyle='round'
            )
        )

Can you please show me how to implement it correctly?

[mbway]

I double checked and setting solid_capstyle should definitely create rounded edges. For example:

from matplotlib import pyplot as plt
from matplotlib.lines import Line2D


fig, ax = plt.subplots()
ax.add_line(Line2D((0, 1), (0, 1), linewidth=5, solid_capstyle='round'))
ax.autoscale(True)
plt.show()

perhaps your lines are actually paths which would have a different code path and not go through draw_line()?

you could try creating a custom backend which uses the default draw_path implementation which breaks them up into line segments then calls draw_line()

ezdxf/src/ezdxf/addons/drawing/backend.py

Lines 139 to 156 in 3fdba53

	def draw_path(self, path: Path, properties: Properties) -> None:
	"""Draw an outline path (connected string of line segments and Bezier
	curves).
	The :meth:`draw_path` implementation is a fall-back implementation
	which approximates Bezier curves by flattening as line segments.
	Backends can override this method if better path drawing functionality
	is available for that backend.
	"""
	if len(path):
	vertices = iter(
	path.flattening(distance=self.config.max_flattening_distance)
	)
	prev = next(vertices)
	for vertex in vertices:
	self.draw_line(prev, vertex, properties)
	prev = vertex