Files
018-turtle/src/turtle_challenges/dashed_line.py
T
Tirsvad a34bf6bbc2 Add draw_square and draw_dashed_line with tests
Challenge 1 draws four sides and turns right 90 degrees after each. Challenge 2 puts
the pen down for a dash and up for a gap and leaves it down at the end. Lengths and
counts come from constants.py; invalid values raise ValueError.

Task: MIL-002#3
Task: MIL-002#4
Task: MIL-002#5
2026-10-07 23:58:52 +08:00

41 lines
1.2 KiB
Python

"""!
@file dashed_line.py
@brief Turtle Challenge 2: draw a dashed line.
"""
from turtle_challenges.constants import DASH_COUNT, DASH_LENGTH, GAP_LENGTH
from turtle_challenges.pen import Pen
def draw_dashed_line(
pen: Pen,
dash_count: int = DASH_COUNT,
dash_length: float = DASH_LENGTH,
gap_length: float = GAP_LENGTH,
) -> None:
"""!
@brief Draw a line of dashes: pen down for a dash, pen up for a gap.
The pen is down again when the function returns, so that the caller can
keep drawing.
@param pen The turtle that draws.
@param dash_count How many dashes to draw.
@param dash_length Length of one dash, in turtle units.
@param gap_length Length of the gap after each dash, in turtle units.
@exception ValueError If @p dash_count is negative, or a length is not
positive.
"""
if dash_count < 0:
raise ValueError(f"dash_count must not be negative, got {dash_count}")
if dash_length <= 0 or gap_length <= 0:
raise ValueError(
f"lengths must be positive, got dash {dash_length} and gap {gap_length}"
)
for _ in range(dash_count):
pen.pendown()
pen.forward(dash_length)
pen.penup()
pen.forward(gap_length)
pen.pendown()