Files
Templated-PPT-Master/runtime/ppt-master/scripts/pptx_to_svg/fill_to_svg.py
T

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28 KiB
Python

"""DrawingML fill -> SVG fill conversion.
Handles:
- <a:solidFill> -> fill="#XXXXXX" (+ fill-opacity)
- <a:noFill/> -> fill="none"
- <a:gradFill> -> linearGradient/radialGradient in <defs>, fill="url(#id)"
- <a:blipFill> -> handled by pic_to_svg (this module short-circuits)
Returned FillResult is a struct of attribute dict + optional <defs> XML so the
slide assembler can collect gradient defs without conflicting IDs.
"""
from __future__ import annotations
import math
import re
from dataclasses import dataclass, field
from decimal import Decimal
from xml.etree import ElementTree as ET
from .color_resolver import (
COLOR_TAGS,
ColorPalette,
find_color_elem,
resolve_color,
resolve_solid_fill_color,
validate_no_fill,
)
from .emu_units import (
ANGLE_UNIT,
NS,
PERCENT_UNIT,
fmt_num,
format_ooxml_alpha,
format_ooxml_unit_ratio,
)
_OOXML_INTEGER_RE = re.compile(r"[+-]?[0-9]+")
_OOXML_PERCENT_LITERAL_RE = re.compile(
r"[+-]?(?:[0-9]+(?:\.[0-9]*)?|\.[0-9]+)%"
)
_OOXML_FULL_CIRCLE = 360 * ANGLE_UNIT
_OOXML_PERCENTAGE_MIN = Decimal(-(2**31)) / Decimal(PERCENT_UNIT)
_OOXML_PERCENTAGE_MAX = Decimal(2**31 - 1) / Decimal(PERCENT_UNIT)
_SVG_RADIAL_FOCUS_TOLERANCE = Decimal(1) / Decimal(PERCENT_UNIT)
_DRAWINGML_FILL_NAMES = (
"noFill",
"solidFill",
"gradFill",
"blipFill",
"pattFill",
"grpFill",
)
_DRAWINGML_FILL_TAGS = {
f"{{{NS['a']}}}{name}": name for name in _DRAWINGML_FILL_NAMES
}
@dataclass
class FillResult:
"""Resolved fill: SVG attributes to apply + optional <defs> entries."""
attrs: dict[str, str] = field(default_factory=dict)
defs: list[str] = field(default_factory=list) # XML strings of <linearGradient>/<radialGradient>
@classmethod
def none_fill(cls) -> "FillResult":
return cls(attrs={"fill": "none"})
@classmethod
def inherit(cls) -> "FillResult":
# No fill resolved — let caller decide whether to default
return cls()
def resolve_fill(
sp_pr: ET.Element | None,
palette: ColorPalette | None,
*,
id_prefix: str = "g",
id_seq: list[int] | None = None,
placeholder_hex: str | None = None,
) -> FillResult:
"""Inspect <p:spPr>'s fill children and emit an SVG fill descriptor.
Args:
sp_pr: <p:spPr> or any element that may directly hold a fill child.
palette: ColorPalette for scheme color resolution.
id_prefix: prefix for generated gradient IDs.
id_seq: external counter (single-element list) so callers can share
unique gradient IDs across the whole slide.
Returns:
FillResult. If no recognized fill is found, result.attrs is empty —
the caller should apply its own default (typically transparent /
inherit from the source SVG).
"""
if sp_pr is None:
return FillResult.inherit()
handlers = {
"noFill": _resolve_no_fill,
"solidFill": _resolve_solid_fill,
"gradFill": _resolve_grad_fill,
"blipFill": _resolve_blip_fill,
"pattFill": _resolve_patt_fill,
}
fill_name = _drawingml_fill_name(sp_pr)
fill_elem = sp_pr if fill_name is not None else None
if fill_elem is None:
fill_children = []
for child in sp_pr:
child_name = _drawingml_fill_name(child)
if child_name is not None:
fill_children.append((child, child_name))
if len(fill_children) > 1:
raise ValueError(
"DrawingML container must contain at most one fill"
)
if not fill_children:
return FillResult.inherit()
fill_elem, fill_name = fill_children[0]
if fill_name == "grpFill":
raise ValueError("Unsupported DrawingML fill: grpFill")
return handlers[fill_name](
fill_elem,
palette,
id_prefix,
id_seq,
placeholder_hex,
)
def _drawingml_fill_name(elem: ET.Element) -> str | None:
"""Return one exact DrawingML fill tag name or reject a namespace alias."""
name = _DRAWINGML_FILL_TAGS.get(elem.tag)
if name is not None:
return name
local_name = (
elem.tag.rsplit("}", 1)[-1]
if isinstance(elem.tag, str)
else ""
)
if local_name in _DRAWINGML_FILL_NAMES:
raise ValueError(
f"Invalid DrawingML fill element namespace: {local_name}"
)
return None
# ---------------------------------------------------------------------------
# Per-fill handlers
# ---------------------------------------------------------------------------
def _resolve_no_fill(elem, _palette, _prefix, _seq, _placeholder_hex) -> FillResult:
validate_no_fill(elem)
return FillResult.none_fill()
def _resolve_solid_fill(elem: ET.Element, palette: ColorPalette | None,
_prefix: str, _seq, placeholder_hex: str | None) -> FillResult:
hex_, alpha = resolve_solid_fill_color(
elem,
palette,
placeholder_hex=placeholder_hex,
)
attrs: dict[str, str] = {"fill": hex_}
if alpha < 1.0:
attrs["fill-opacity"] = format_ooxml_alpha(alpha)
return FillResult(attrs=attrs)
def _resolve_grad_fill(elem: ET.Element, palette: ColorPalette | None,
prefix: str, seq, placeholder_hex: str | None) -> FillResult:
"""Convert <a:gradFill> to an SVG linearGradient or radialGradient."""
_validate_gradient_attributes(elem)
_validate_gradient_rotation(elem)
_validate_gradient_flip(elem)
_validate_gradient_tile_rect(elem)
if seq is None:
seq = [0]
seq[0] += 1
grad_id = f"{prefix}grad{seq[0]}"
# Stops
gs_lists = elem.findall("a:gsLst", NS)
if len(gs_lists) != 1:
raise ValueError(
"DrawingML gradient fill requires exactly one gsLst"
)
gradient_stops = [
(gs, _gradient_stop_position(gs))
for gs in _gradient_stop_list(gs_lists[0])
]
if any(
current < previous
for (_, previous), (_, current) in zip(
gradient_stops,
gradient_stops[1:],
)
):
message = "DrawingML gradient stop positions must be nondecreasing"
if palette is None or palette.strict:
raise ValueError(message)
palette._diagnose(
"gradient-stop-order-normalized",
message,
"sort gradient stops by position while preserving equal positions",
)
gradient_stops.sort(key=lambda item: item[1])
stops_xml = []
for gs, pos_pct in gradient_stops:
color_elem = _gradient_stop_color(gs)
hex_, alpha = resolve_color(
color_elem,
palette,
placeholder_hex=placeholder_hex,
)
if hex_ is None:
raise ValueError(
"DrawingML gradient stop color cannot be resolved"
)
opacity_attr = (
f' stop-opacity="{format_ooxml_alpha(alpha)}"'
if alpha < 1.0
else ""
)
stops_xml.append(
f'<stop offset="{format_ooxml_unit_ratio(pos_pct)}" '
f'stop-color="{hex_}"{opacity_attr}/>'
)
# Linear vs radial vs path
linear_directions = elem.findall("a:lin", NS)
path_directions = elem.findall("a:path", NS)
if len(linear_directions) + len(path_directions) > 1:
raise ValueError(
"DrawingML gradient fill must contain at most one lin/path "
"direction"
)
_validate_gradient_child_structure(elem)
lin = linear_directions[0] if linear_directions else None
rad = path_directions[0] if path_directions else None
if lin is not None:
# ang is 1/60000 deg. 0° = horizontal left-to-right.
_validate_linear_gradient_structure(lin)
angle = _linear_gradient_angle(lin)
_validate_linear_gradient_scaling(lin, angle)
angle_deg = angle / ANGLE_UNIT
x1, y1, x2, y2 = _angle_to_unit_endpoints(angle_deg)
defs_xml = (
f'<linearGradient id="{grad_id}" '
f'x1="{fmt_num(x1, 4)}" y1="{fmt_num(y1, 4)}" '
f'x2="{fmt_num(x2, 4)}" y2="{fmt_num(y2, 4)}">'
+ "".join(stops_xml)
+ "</linearGradient>"
)
elif rad is not None:
_validate_path_gradient_structure(rad)
_validate_path_gradient_type(rad)
focus = _validate_path_gradient_focus(rad)
focus_attrs = ""
if focus is not None:
focus_x = focus["l"]
focus_y = focus["t"]
point_focus = (
focus_x + focus["r"] == Decimal(1)
and focus_y + focus["b"] == Decimal(1)
and Decimal(0) <= focus_x <= Decimal(1)
and Decimal(0) <= focus_y <= Decimal(1)
and (
(focus_x - Decimal("0.5")) ** 2
+ (focus_y - Decimal("0.5")) ** 2
<= Decimal("0.25") + _SVG_RADIAL_FOCUS_TOLERANCE
)
)
if (
point_focus
and (
focus_x != Decimal("0.5")
or focus_y != Decimal("0.5")
)
):
focus_attrs = (
f' fx="{format_ooxml_unit_ratio(float(focus_x))}"'
f' fy="{format_ooxml_unit_ratio(float(focus_y))}"'
)
elif not point_focus and palette is not None:
palette._diagnose(
"path-gradient-focus-normalized",
"DrawingML path gradient focus is not one point within "
"the canonical SVG radial circle",
"center the radial gradient while preserving its stops",
)
# Treat as radial regardless of path="circle" / "rect" / "shape" — SVG
# only has circle/ellipse. Point-style fillToRect retains its focus;
# the outer center and radius remain normalized.
defs_xml = (
f'<radialGradient id="{grad_id}" cx="0.5" cy="0.5" '
f'r="0.5"{focus_attrs}>'
+ "".join(stops_xml)
+ "</radialGradient>"
)
else:
# No direction specified — default to horizontal linear
defs_xml = (
f'<linearGradient id="{grad_id}" x1="0" y1="0" x2="1" y2="0">'
+ "".join(stops_xml)
+ "</linearGradient>"
)
return FillResult(
attrs={"fill": f"url(#{grad_id})"},
defs=[defs_xml],
)
def _gradient_stop_position(gs: ET.Element) -> float:
"""Parse one required DrawingML fixed-percentage stop position."""
raw = gs.get("pos")
if raw is None:
raise ValueError("DrawingML gradient stop requires a pos attribute")
token = raw.strip()
if _OOXML_INTEGER_RE.fullmatch(token) is None:
raise ValueError(
f"Invalid DrawingML gradient stop position: {raw!r}"
)
position = int(token)
if not 0 <= position <= PERCENT_UNIT:
raise ValueError(
f"DrawingML gradient stop position={position} is outside "
f"0..{PERCENT_UNIT}"
)
return position / PERCENT_UNIT
def _gradient_stop_list(gs_list: ET.Element) -> list[ET.Element]:
"""Validate one DrawingML gradient-stop list and return its stops."""
stops = list(gs_list)
stop_tag = f"{{{NS['a']}}}gs"
if (
gs_list.attrib
or (gs_list.text or "").strip()
or any(
stop.tag != stop_tag or (stop.tail or "").strip()
for stop in stops
)
):
raise ValueError("Invalid DrawingML gradient stop list structure")
if len(stops) < 2:
raise ValueError(
"DrawingML gradient fill requires at least two color stops"
)
return stops
def _gradient_stop_color(gs: ET.Element) -> ET.Element:
"""Return the single registered color child of one gradient stop."""
children = list(gs)
color_tags = {f"{{{NS['a']}}}{name}" for name in COLOR_TAGS}
if (
set(gs.attrib) != {"pos"}
or len(children) != 1
or children[0].tag not in color_tags
or (gs.text or "").strip()
or (children[0].tail or "").strip()
):
raise ValueError("Invalid DrawingML gradient stop structure")
return children[0]
def _linear_gradient_angle(lin: ET.Element) -> int:
"""Parse one optional DrawingML positive fixed angle."""
raw = lin.get("ang")
if raw is None:
return 0
token = raw.strip()
if _OOXML_INTEGER_RE.fullmatch(token) is None:
raise ValueError(f"Invalid DrawingML linear gradient angle: {raw!r}")
angle = int(token)
if not 0 <= angle < _OOXML_FULL_CIRCLE:
raise ValueError(
f"DrawingML linear gradient angle={angle} is outside "
f"0..{_OOXML_FULL_CIRCLE - 1}"
)
return angle
def _validate_linear_gradient_structure(lin: ET.Element) -> None:
"""Require one leaf a:lin with only the registered attributes."""
unsupported = sorted(set(lin.attrib) - {"ang", "scaled"})
if unsupported or list(lin) or (lin.text or "").strip():
details = ", ".join(unsupported) if unsupported else "payload"
raise ValueError(
f"Invalid DrawingML linear gradient structure: {details}"
)
def _validate_linear_gradient_scaling(
lin: ET.Element,
angle: int,
) -> None:
"""Require a scaling mode representable by unit-box SVG geometry."""
scaled = _parse_ooxml_boolean(
lin.get("scaled"),
default=False,
label="linear gradient scaled value",
)
quarter_turn = 90 * ANGLE_UNIT
if not scaled and angle % quarter_turn:
raise ValueError(
"Unscaled non-cardinal DrawingML linear gradients are not "
"representable by the normalized SVG mapping"
)
def _validate_gradient_rotation(gradient: ET.Element) -> None:
"""Require a gradient that rotates with its containing shape."""
rotates_with_shape = _parse_ooxml_boolean(
gradient.get("rotWithShape"),
default=True,
label="gradient rotWithShape value",
)
if not rotates_with_shape:
raise ValueError(
"DrawingML gradients that do not rotate with their shape are "
"not representable by the local SVG mapping"
)
def _validate_gradient_attributes(gradient: ET.Element) -> None:
"""Reject attributes outside the registered gradient-fill contract."""
unsupported = sorted(set(gradient.attrib) - {"flip", "rotWithShape"})
if unsupported:
raise ValueError(
"Unsupported DrawingML gradient fill attribute(s): "
+ ", ".join(unsupported)
)
def _validate_gradient_child_structure(gradient: ET.Element) -> None:
"""Require the registered DrawingML gradient-fill child sequence."""
namespace = NS["a"]
gs_list = f"{{{namespace}}}gsLst"
linear = f"{{{namespace}}}lin"
path = f"{{{namespace}}}path"
tile_rect = f"{{{namespace}}}tileRect"
child_tags = tuple(child.tag for child in gradient)
allowed_sequences = {
(gs_list,),
(gs_list, linear),
(gs_list, path),
(gs_list, tile_rect),
(gs_list, linear, tile_rect),
(gs_list, path, tile_rect),
}
if (
child_tags not in allowed_sequences
or (gradient.text or "").strip()
or any((child.tail or "").strip() for child in gradient)
):
raise ValueError(
"Invalid DrawingML gradient fill child structure"
)
def _validate_gradient_flip(gradient: ET.Element) -> None:
"""Reject gradient tile flipping absent from project SVG."""
flip = gradient.get("flip", "none")
if flip != "none":
raise ValueError(f"Unsupported DrawingML gradient flip: {flip!r}")
def _validate_gradient_tile_rect(gradient: ET.Element) -> None:
"""Accept only the full-area gradient tile rectangle."""
tile_rects = gradient.findall("a:tileRect", NS)
if len(tile_rects) > 1:
raise ValueError(
"DrawingML gradient fill must contain at most one tileRect"
)
if not tile_rects:
return
values = _relative_rect_values(
tile_rects[0],
label="gradient tileRect",
)
for value in values.values():
if value != 0:
raise ValueError(
"Non-zero DrawingML gradient tileRect is not representable "
"by the project SVG gradient mapping"
)
def _validate_path_gradient_focus(
path: ET.Element,
) -> dict[str, Decimal] | None:
"""Validate and return one path-gradient focus rectangle."""
focus_rects = path.findall("a:fillToRect", NS)
if len(focus_rects) > 1:
raise ValueError(
"DrawingML path gradient must contain at most one fillToRect"
)
if not focus_rects:
return None
values = _relative_rect_values(
focus_rects[0],
label="path gradient fillToRect",
)
return {
edge: values.get(edge, Decimal(0))
for edge in ("l", "t", "r", "b")
}
def _relative_rect_values(
rect: ET.Element,
*,
label: str,
) -> dict[str, Decimal]:
"""Validate one DrawingML relative-rectangle leaf and parse its edges."""
if (
set(rect.attrib) - {"l", "t", "r", "b"}
or list(rect)
or (rect.text or "").strip()
):
raise ValueError(f"Invalid DrawingML {label} structure")
return {
edge: _parse_ooxml_percentage(raw, label=f"{label} {edge}")
for edge, raw in rect.attrib.items()
}
def _parse_ooxml_percentage(raw: str, *, label: str) -> Decimal:
"""Parse one DrawingML ST_Percentage as an exact normalized ratio."""
token = raw.strip()
if _OOXML_INTEGER_RE.fullmatch(token) is not None:
value = Decimal(token) / Decimal(PERCENT_UNIT)
elif _OOXML_PERCENT_LITERAL_RE.fullmatch(token) is not None:
value = Decimal(token[:-1]) / Decimal(100)
else:
raise ValueError(f"Invalid DrawingML {label}: {raw!r}")
if not _OOXML_PERCENTAGE_MIN <= value <= _OOXML_PERCENTAGE_MAX:
raise ValueError(f"Invalid DrawingML {label}: {raw!r}")
return value
def _parse_ooxml_boolean(
raw: str | None,
*,
default: bool,
label: str,
) -> bool:
"""Parse one W3C XML Schema boolean without permissive aliases."""
if raw is None:
return default
token = raw.strip()
if token in {"1", "true"}:
return True
if token in {"0", "false"}:
return False
raise ValueError(f"Invalid DrawingML {label}: {raw!r}")
def _validate_path_gradient_type(path: ET.Element) -> None:
"""Require one registered DrawingML path-shade enum value."""
path_type = path.get("path", "rect")
if path_type not in {"circle", "rect", "shape"}:
raise ValueError(
f"Unsupported DrawingML path gradient type: {path_type!r}"
)
def _validate_path_gradient_structure(path: ET.Element) -> None:
"""Require only the registered path attribute and focus rectangle."""
unsupported = sorted(set(path.attrib) - {"path"})
children = list(path)
fill_to_rect_tag = f"{{{NS['a']}}}fillToRect"
has_invalid_payload = (
(path.text or "").strip()
or any(
child.tag != fill_to_rect_tag or (child.tail or "").strip()
for child in children
)
)
if unsupported or has_invalid_payload:
details = ", ".join(unsupported) if unsupported else "payload"
raise ValueError(
f"Invalid DrawingML path gradient structure: {details}"
)
def _resolve_blip_fill(_elem, _palette, _prefix, _seq, _placeholder_hex) -> FillResult:
"""blipFill on <p:spPr> means a shape filled with an image — handled at
pic_to_svg level. For now mark as transparent so the shape's outline
still draws and pic_to_svg can layer the image on top.
"""
return FillResult.none_fill()
def _resolve_patt_fill(elem: ET.Element, palette: ColorPalette | None,
prefix, seq, placeholder_hex: str | None) -> FillResult:
"""Pattern fills (<a:pattFill prst="..."/> with fg/bg colors)."""
fg = elem.find("a:fgClr", NS)
bg = elem.find("a:bgClr", NS)
fg_hex, fg_alpha = resolve_color(
find_color_elem(fg), palette, placeholder_hex=placeholder_hex,
)
bg_hex, bg_alpha = resolve_color(
find_color_elem(bg), palette, placeholder_hex=placeholder_hex,
)
if fg_hex is None:
return FillResult.inherit()
prst = elem.attrib.get("prst", "")
geom = _pattern_foreground(prst, fg_hex, fg_alpha)
if geom is None:
# Unsupported preset → degrade to solid fg color so the shape at
# least carries the right tone. Round-trip will lose the texture.
attrs: dict[str, str] = {"fill": fg_hex}
if fg_alpha < 1.0:
attrs["fill-opacity"] = format_ooxml_alpha(fg_alpha)
return FillResult(attrs=attrs)
tile_w, tile_h, fg_svg = geom
if seq is None:
seq = [0]
seq[0] += 1
pattern_id = f"{prefix}patt{seq[0]}"
bg_rect = ""
if bg_hex is not None:
bg_opacity = (
f' fill-opacity="{format_ooxml_alpha(bg_alpha)}"'
if bg_alpha < 1.0 else ""
)
bg_rect = (
f'<rect width="{tile_w}" height="{tile_h}" '
f'fill="{bg_hex}"{bg_opacity}/>'
)
# Tag with data attributes so the reverse exporter can rebuild <a:pattFill>
# faithfully (preset + fg/bg colors) instead of inferring from path geometry.
bg_attr = f' data-pptx-bg="{bg_hex}"' if bg_hex is not None else ""
pattern_xml = (
f'<pattern id="{pattern_id}" patternUnits="userSpaceOnUse" '
f'width="{tile_w}" height="{tile_h}" '
f'data-pptx-pattern="{prst}" data-pptx-fg="{fg_hex}"{bg_attr}>'
f'{bg_rect}{fg_svg}</pattern>'
)
return FillResult(
attrs={"fill": f"url(#{pattern_id})"},
defs=[pattern_xml],
)
# ---------------------------------------------------------------------------
# Per-preset SVG geometry for <a:pattFill prst="...">
#
# Each handler returns (tile_w, tile_h, foreground_svg). The caller wraps with
# the background rect + <pattern> element. None means "unsupported preset" and
# the caller degrades to a solid fg color.
# ---------------------------------------------------------------------------
def _pattern_foreground(prst: str, fg: str,
fg_alpha: float) -> tuple[int, int, str] | None:
stroke_op = (
f' stroke-opacity="{format_ooxml_alpha(fg_alpha)}"'
if fg_alpha < 1.0 else ""
)
fill_op = (
f' fill-opacity="{format_ooxml_alpha(fg_alpha)}"'
if fg_alpha < 1.0 else ""
)
# Diagonal stripes — tile size and stroke width pick the visual weight.
diag = {
"ltUpDiag": (8, 1.0, "up", False),
"dkUpDiag": (8, 2.0, "up", False),
"wdUpDiag": (16, 1.0, "up", False),
"dashUpDiag": (8, 1.0, "up", True),
"ltDnDiag": (8, 1.0, "dn", False),
"dkDnDiag": (8, 2.0, "dn", False),
"wdDnDiag": (16, 1.0, "dn", False),
"dashDnDiag": (8, 1.0, "dn", True),
}
if prst in diag:
tile, sw, direction, dashed = diag[prst]
dash = ' stroke-dasharray="3 2"' if dashed else ""
if direction == "up":
d = f"M -2 {tile} L {tile} -2 M 0 {tile + 2} L {tile + 2} 0"
else:
d = f"M -2 0 L {tile} {tile + 2} M 0 -2 L {tile + 2} {tile}"
return tile, tile, (
f'<path d="{d}" stroke="{fg}"{stroke_op} '
f'stroke-width="{fmt_num(sw)}" fill="none"{dash}/>'
)
# Horizontal / vertical lines.
line_specs = {
"horz": ("h", 8, 1.0, False),
"ltHorz": ("h", 8, 0.5, False),
"dkHorz": ("h", 8, 2.0, False),
"narHorz": ("h", 4, 1.0, False),
"dashHorz": ("h", 8, 1.0, True),
"vert": ("v", 8, 1.0, False),
"ltVert": ("v", 8, 0.5, False),
"dkVert": ("v", 8, 2.0, False),
"narVert": ("v", 4, 1.0, False),
"dashVert": ("v", 8, 1.0, True),
}
if prst in line_specs:
axis, tile, sw, dashed = line_specs[prst]
dash = ' stroke-dasharray="3 2"' if dashed else ""
mid = tile / 2.0
if axis == "h":
line = (
f'<line x1="0" y1="{fmt_num(mid)}" '
f'x2="{tile}" y2="{fmt_num(mid)}"'
)
else:
line = (
f'<line x1="{fmt_num(mid)}" y1="0" '
f'x2="{fmt_num(mid)}" y2="{tile}"'
)
return tile, tile, (
f'{line} stroke="{fg}"{stroke_op} '
f'stroke-width="{fmt_num(sw)}"{dash}/>'
)
# Grids / crosses.
if prst == "cross":
return 8, 8, (
f'<line x1="0" y1="4" x2="8" y2="4" stroke="{fg}"{stroke_op} stroke-width="1"/>'
f'<line x1="4" y1="0" x2="4" y2="8" stroke="{fg}"{stroke_op} stroke-width="1"/>'
)
if prst == "diagCross":
d = (
"M -2 8 L 8 -2 M 0 10 L 10 0 "
"M -2 0 L 8 10 M 0 -2 L 10 8"
)
return 8, 8, (
f'<path d="{d}" stroke="{fg}"{stroke_op} stroke-width="1" fill="none"/>'
)
if prst in ("smGrid", "lgGrid"):
tile = 4 if prst == "smGrid" else 16
# Lines along top + left edges; tiles together produce a uniform grid.
return tile, tile, (
f'<path d="M 0 0 L {tile} 0 M 0 0 L 0 {tile}" '
f'stroke="{fg}"{stroke_op} stroke-width="0.5" fill="none"/>'
)
if prst == "dotGrid":
# Dots at corners → tiling yields a uniform dot grid.
return 8, 8, (
f'<circle cx="0" cy="0" r="1" fill="{fg}"{fill_op}/>'
)
if prst == "dotDmnd":
return 8, 8, (
f'<circle cx="0" cy="0" r="1" fill="{fg}"{fill_op}/>'
f'<circle cx="4" cy="4" r="1" fill="{fg}"{fill_op}/>'
)
# Percentage shading — single centered dot whose area matches the target
# density. Approximates PowerPoint's stipple without per-tile artwork.
if prst.startswith("pct"):
try:
pct = float(prst[3:])
except ValueError:
return None
pct = max(0.0, min(pct, 100.0))
tile = 8
radius = math.sqrt(pct / 100.0 * tile * tile / math.pi)
radius = max(0.3, min(radius, tile / 2.0))
return tile, tile, (
f'<circle cx="{tile / 2}" cy="{tile / 2}" '
f'r="{fmt_num(radius, 3)}" fill="{fg}"{fill_op}/>'
)
return None
def _hex_distance(a: str, b: str) -> float:
"""Euclidean distance between two #RRGGBB colors."""
try:
ar, ag, ab = int(a[1:3], 16), int(a[3:5], 16), int(a[5:7], 16)
br, bg, bb = int(b[1:3], 16), int(b[3:5], 16), int(b[5:7], 16)
except (ValueError, IndexError):
return 255.0
return math.sqrt((ar - br) ** 2 + (ag - bg) ** 2 + (ab - bb) ** 2)
# ---------------------------------------------------------------------------
# Geometry helpers
# ---------------------------------------------------------------------------
def _angle_to_unit_endpoints(angle_deg: float) -> tuple[float, float, float, float]:
"""Convert a DrawingML linear gradient angle to SVG x1/y1/x2/y2 in unit box.
DrawingML 0° = horizontal pointing right; angle is clockwise.
SVG default linearGradient is also unit-box (objectBoundingBox).
"""
rad = math.radians(angle_deg % 360)
cos_a = math.cos(rad)
sin_a = math.sin(rad)
# Center of unit box
cx, cy = 0.5, 0.5
# Half-extent in the direction of the angle vector.
# We project the unit box onto the angle direction; the line endpoints are
# the projections of the box corners.
half = abs(cos_a) * 0.5 + abs(sin_a) * 0.5
x1 = cx - cos_a * half
y1 = cy - sin_a * half
x2 = cx + cos_a * half
y2 = cy + sin_a * half
return x1, y1, x2, y2