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Diffstat (limited to 'lib/svg/rendering.py')
| -rw-r--r-- | lib/svg/rendering.py | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/lib/svg/rendering.py b/lib/svg/rendering.py new file mode 100644 index 00000000..41ed53d7 --- /dev/null +++ b/lib/svg/rendering.py @@ -0,0 +1,253 @@ +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)) |