inkstitch/lib/svg/rendering.py

255 wiersze
8.8 KiB
Python

# Authors: see git history
#
# Copyright (c) 2010 Authors
# Licensed under the GNU GPL version 3.0 or later. See the file LICENSE for details.
import math
from math import pi
import inkex
from ..i18n import _
from ..utils import Point, cache
from .tags import INKSCAPE_GROUPMODE, INKSCAPE_LABEL, INKSTITCH_ATTRIBS
from .units import PIXELS_PER_MM, get_viewbox_transform
# The stitch vector path looks like this:
# _______
# (_______)
#
# It's 0.32mm high, which is the approximate thickness of common machine
# embroidery threads.
# 1.398 pixels = 0.37mm
stitch_height = 1.398
# This vector path starts at the upper right corner of the stitch shape and
# proceeds counter-clockwise and contains a placeholder (%s) for the stitch
# length.
#
# It contains four invisible "whiskers" of zero width that go outwards
# to ensure that the SVG renderer allocates a large enough canvas area when
# computing the gaussian blur steps:
# \_____/
# (_____) (whiskers not to scale)
# / \
# This is necessary to avoid artifacting near the edges and corners that seems to be due to
# edge conditions for the feGaussianBlur, which is used to build the heightmap for
# the feDiffuseLighting node. So we need some extra buffer room around the shape.
# The whiskers let us specify a "fixed" amount of spacing around the stitch.
# Otherwise, we'd have to expand the width and height attributes of the <filter>
# tag to add more buffer space. The filter's width and height are specified in multiples of
# the bounding box size, It's the bounding box aligned with the global SVG canvas's axes,
# not the axes of the stitch itself. That means that having a big enough value
# to add enough padding on the long sides of the stitch would waste a ton
# of space on the short sides and significantly slow down rendering.
# The specific extent of the whiskers (0.55 parallel to the stitch, 0.1 perpendicular)
# was found by experimentation. It seems to work with almost no artifacting.
stitch_path = (
"M0,0" # Start point
"l0.55,-0.1,-0.55,0.1" # Bottom-right whisker
"c0.613,0,0.613,1.4,0,1.4" # Right endcap
"l0.55,0.1,-0.55,-0.1" # Top-right whisker
"h-%s" # Stitch length
"l-0.55,0.1,0.55,-0.1" # Top-left whisker
"c-0.613,0,-0.613,-1.4,0,-1.4" # Left endcap
"l-0.55,-0.1,0.55,0.1" # Bottom-left whisker
"z") # return to start
def generate_realistic_filter() -> inkex.BaseElement:
"""
Return a copy of the realistic stitch filter, ready to add to svg defs.
"""
filter = inkex.Filter(attrib={
"style": "color-interpolation-filters:sRGB",
"id": "realistic-stitch-filter",
"x": "0",
"width": "1",
"y": "0",
"height": "1",
inkex.addNS('auto-region', 'inkscape'): "false",
})
filter.add(
inkex.Filter.GaussianBlur(attrib={
"edgeMode": "none",
"stdDeviation": "0.9",
"in": "SourceAlpha",
}),
inkex.Filter.SpecularLighting(
inkex.Filter.DistantLight(attrib={
"azimuth": "154",
"elevation": "112",
}), attrib={
"result": "result2",
"surfaceScale": "4.29",
"specularConstant": "0.65",
"specularExponent": "1.6",
}
),
inkex.Filter.Composite(attrib={
"in2": "SourceAlpha",
"operator": "atop",
}),
inkex.Filter.Composite(attrib={
"in2": "SourceGraphic",
"operator": "arithmetic",
"result": "result3",
"k1": "0",
"k2": "0.8",
"k3": "1.2",
"k4": "0",
})
)
return filter
def realistic_stitch(start, end):
"""Generate a stitch vector path given a start and end point."""
end = Point(*end)
start = Point(*start)
stitch_length = (end - start).length()
stitch_center = Point((end.x+start.x)/2.0, (end[1]+start[1])/2.0)
stitch_direction = (end - start)
stitch_angle = math.atan2(stitch_direction.y, stitch_direction.x) * (180 / pi)
stitch_length = max(0, stitch_length - 0.2 * PIXELS_PER_MM)
# rotate the path to match the stitch
rotation_center_x = -stitch_length / 2.0
rotation_center_y = stitch_height / 2.0
transform = (
inkex.Transform()
.add_translate(stitch_center.x - rotation_center_x, stitch_center.y - rotation_center_y)
.add_rotate(stitch_angle, (rotation_center_x, rotation_center_y))
)
# create the path by filling in the length in the template, and transforming it as above
path = inkex.Path(stitch_path % stitch_length).transform(transform, True)
return str(path)
def color_block_to_point_lists(color_block, render_jumps=True):
point_lists = [[]]
for stitch in color_block:
if stitch.trim:
if point_lists[-1]:
point_lists.append([])
continue
if stitch.jump and not render_jumps and point_lists[-1]:
point_lists.append([])
continue
if not stitch.jump and not stitch.color_change and not stitch.stop:
point_lists[-1].append(stitch.as_tuple())
# filter out empty point lists
point_lists = [p for p in point_lists if len(p) > 1]
return point_lists
@cache
def get_correction_transform(svg):
transform = get_viewbox_transform(svg)
# we need to correct for the viewbox
transform = -inkex.transforms.Transform(transform)
return str(transform)
def color_block_to_realistic_stitches(color_block, svg, destination, render_jumps=True):
for point_list in color_block_to_point_lists(color_block, render_jumps):
color = color_block.color.visible_on_white.darker.to_hex_str()
start = point_list[0]
for point in point_list[1:]:
destination.append(inkex.PathElement(attrib={
'style': "fill: %s; stroke: none; filter: url(#realistic-stitch-filter);" % color,
'd': realistic_stitch(start, point),
'transform': get_correction_transform(svg)
}))
start = point
def color_block_to_paths(color_block, svg, destination, visual_commands, line_width, render_jumps=True):
# If we try to import these above, we get into a mess of circular
# imports.
from ..commands import add_commands
from ..elements.stroke import Stroke
# We could emit just a single path with one subpath per point list, but
# emitting multiple paths makes it easier for the user to manipulate them.
first = True
path = None
for point_list in color_block_to_point_lists(color_block, render_jumps):
if first:
first = False
elif visual_commands:
add_commands(Stroke(destination[-1]), ["trim"])
else:
path.set(INKSTITCH_ATTRIBS['trim_after'], 'true')
color = color_block.color.visible_on_white.to_hex_str()
path = inkex.PathElement(attrib={
'id': svg.get_unique_id("object"),
'style': f"stroke: {color}; stroke-width: {line_width}; fill: none;stroke-linejoin: round;stroke-linecap: round;",
'd': "M" + " ".join(" ".join(str(coord) for coord in point) for point in point_list),
'transform': get_correction_transform(svg),
INKSTITCH_ATTRIBS['stroke_method']: 'manual_stitch'
})
destination.append(path)
if path is not None and color_block.trim_after:
if visual_commands:
add_commands(Stroke(path), ["trim"])
else:
path.set(INKSTITCH_ATTRIBS['trim_after'], 'true')
if path is not None and color_block.stop_after:
if visual_commands:
add_commands(Stroke(path), ["stop"])
else:
path.set(INKSTITCH_ATTRIBS['stop_after'], 'true')
def render_stitch_plan(svg, stitch_plan, realistic=False, visual_commands=True, render_jumps=True, line_width=0.4) -> inkex.Group:
layer_or_image = svg.findone(".//*[@id='__inkstitch_stitch_plan__']")
if layer_or_image is not None:
layer_or_image.delete()
layer = inkex.Group(attrib={
'id': '__inkstitch_stitch_plan__',
INKSCAPE_LABEL: _('Stitch Plan'),
INKSCAPE_GROUPMODE: 'layer'
})
svg.append(layer)
for i, color_block in enumerate(stitch_plan):
group = inkex.Group(attrib={
'id': f'__color_block_{i}__',
INKSCAPE_LABEL: f"color block {(i + 1)}"
})
layer.append(group)
if realistic:
color_block_to_realistic_stitches(color_block, svg, group, render_jumps)
else:
color_block_to_paths(color_block, svg, group, visual_commands, line_width, render_jumps)
if realistic:
# Remove filter from defs, if any
filter: inkex.BaseElement = svg.defs.findone("//*[@id='realistic-stitch-filter']")
if filter is not None:
filter.delete()
svg.defs.append(generate_realistic_filter())
return layer