refactor add_commands() out into commands module

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))