inkstitch/lib/svg/rendering.py

254 wiersze
8.1 KiB
Python

import math
import inkex
import simplepath
import simplestyle
import simpletransform
from ..i18n import _
from ..utils import Point
from ..utils import cache
from .tags import SVG_GROUP_TAG, INKSCAPE_LABEL, INKSCAPE_GROUPMODE, SVG_PATH_TAG, SVG_DEFS_TAG
from .units import PIXELS_PER_MM
from .units import 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.
# 1.216 pixels = 0.32mm
stitch_height = 1.216
# 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 two invisible "whiskers" of zero width that go above and below
# to ensure that the SVG renderer allocates a large enough canvas area when
# computing the gaussian blur steps. Otherwise, we'd have to expand the
# width and height attributes of the <filter> tag to add more buffer space.
# The 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.
stitch_path = "M0,0c0.4,0,0.4,0.3,0.4,0.6c0,0.3,-0.1,0.6,-0.4,0.6v0.2,-0.2h-%sc-0.4,0,-0.4,-0.3,-0.4,-0.6c0,-0.3,0.1,-0.6,0.4,-0.6v-0.2,0.2z"
# This filter makes the above stitch path look like a real stitch with lighting.
realistic_filter = """
<filter
style="color-interpolation-filters:sRGB"
id="realistic-stitch-filter"
x="-0.1"
width="1.2"
y="-0.1"
height="1.2">
<feGaussianBlur
stdDeviation="1.5"
id="feGaussianBlur1542-6"
in="SourceAlpha" />
<feComponentTransfer
id="feComponentTransfer1544-7"
result="result1">
<feFuncR
id="feFuncR1546-5"
type="identity" />
<feFuncG
id="feFuncG1548-3"
type="identity" />
<feFuncB
id="feFuncB1550-5"
type="identity"
slope="4.5300000000000002" />
<feFuncA
id="feFuncA1552-6"
type="gamma"
slope="0.14999999999999999"
intercept="0"
amplitude="3.1299999999999999"
offset="-0.33000000000000002" />
</feComponentTransfer>
<feComposite
in2="SourceAlpha"
id="feComposite1558-2"
operator="in" />
<feGaussianBlur
stdDeviation="0.089999999999999997"
id="feGaussianBlur1969" />
<feMorphology
id="feMorphology1971"
operator="dilate"
radius="0.10000000000000001" />
<feSpecularLighting
id="feSpecularLighting1973"
result="result2"
specularConstant="0.70899999"
surfaceScale="30">
<fePointLight
id="fePointLight1975"
z="10" />
</feSpecularLighting>
<feGaussianBlur
stdDeviation="0.040000000000000001"
id="feGaussianBlur1979" />
<feComposite
in2="SourceGraphic"
id="feComposite1977"
operator="arithmetic"
k2="1"
k3="1"
result="result3"
k1="0"
k4="0" />
<feComposite
in2="SourceAlpha"
id="feComposite1981"
operator="in" />
</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 = (end + start) / 2.0
stitch_direction = (end - start)
stitch_angle = math.atan2(stitch_direction.y, stitch_direction.x)
stitch_length = max(0, stitch_length - 0.2 * PIXELS_PER_MM)
# create the path by filling in the length in the template
path = simplepath.parsePath(stitch_path % stitch_length)
# rotate the path to match the stitch
rotation_center_x = -stitch_length / 2.0
rotation_center_y = stitch_height / 2.0
simplepath.rotatePath(path, stitch_angle, cx=rotation_center_x, cy=rotation_center_y)
# move the path to the location of the stitch
simplepath.translatePath(path, stitch_center.x - rotation_center_x, stitch_center.y - rotation_center_y)
return simplepath.formatPath(path)
def color_block_to_point_lists(color_block):
point_lists = [[]]
for stitch in color_block:
if stitch.trim:
if point_lists[-1]:
point_lists.append([])
continue
if not stitch.jump and not stitch.color_change:
point_lists[-1].append(stitch.as_tuple())
# filter out empty point lists
point_lists = [p for p in point_lists if p]
return point_lists
@cache
def get_correction_transform(svg):
transform = get_viewbox_transform(svg)
# we need to correct for the viewbox
transform = simpletransform.invertTransform(transform)
transform = simpletransform.formatTransform(transform)
return transform
def color_block_to_realistic_stitches(color_block, svg):
paths = []
for point_list in color_block_to_point_lists(color_block):
if not point_list:
continue
color = color_block.color.visible_on_white.darker.to_hex_str()
start = point_list[0]
for point in point_list[1:]:
paths.append(inkex.etree.Element(
SVG_PATH_TAG,
{'style': simplestyle.formatStyle(
{
'fill': color,
'stroke': 'none',
'filter': 'url(#realistic-stitch-filter)'
}),
'd': realistic_stitch(start, point),
'transform': get_correction_transform(svg)
}))
start = point
return paths
def color_block_to_paths(color_block, svg):
paths = []
# 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.
for point_list in color_block_to_point_lists(color_block):
color = color_block.color.visible_on_white.to_hex_str()
paths.append(inkex.etree.Element(
SVG_PATH_TAG,
{'style': simplestyle.formatStyle(
{'stroke': color,
'stroke-width': "0.4",
'fill': 'none'}),
'd': "M" + " ".join(" ".join(str(coord) for coord in point) for point in point_list),
'transform': get_correction_transform(svg),
'embroider_manual_stitch': 'true',
'embroider_trim_after': 'true',
}))
# no need to trim at the end of a thread color
if paths:
paths[-1].attrib.pop('embroider_trim_after')
return paths
def render_stitch_plan(svg, stitch_plan, realistic=False):
layer = svg.find(".//*[@id='__inkstitch_stitch_plan__']")
if layer is None:
layer = inkex.etree.Element(SVG_GROUP_TAG,
{'id': '__inkstitch_stitch_plan__',
INKSCAPE_LABEL: _('Stitch Plan'),
INKSCAPE_GROUPMODE: 'layer'})
else:
# delete old stitch plan
del layer[:]
# make sure the layer is visible
layer.set('style', 'display:inline')
for i, color_block in enumerate(stitch_plan):
group = inkex.etree.SubElement(layer,
SVG_GROUP_TAG,
{'id': '__color_block_%d__' % i,
INKSCAPE_LABEL: "color block %d" % (i + 1)})
if realistic:
group.extend(color_block_to_realistic_stitches(color_block, svg))
else:
group.extend(color_block_to_paths(color_block, svg))
svg.append(layer)
if realistic:
defs = svg.find(SVG_DEFS_TAG)
if defs is None:
defs = inkex.etree.SubElement(svg, SVG_DEFS_TAG)
defs.append(inkex.etree.fromstring(realistic_filter))