yxxandClaude Code
f49d1245a1
- 新增 app/plot 包：白名单表达式解析（ast 无 eval）+ FunctionPlot 模型 + 静态 SVG 渲染 - HtmlExporter 的 function_plot 节点解析并内嵌 SVG，解析失败回退占位并转诊断 - 新增 test_plot.py（13 个测试）覆盖表达式安全、指令解析、SVG 输出与导出链路集成 Co-Authored-By: Claude Code <noreply@anthropic.com>
224 lines
7.5 KiB
Python
224 lines
7.5 KiB
Python
"""Function Plot → 静态 SVG 渲染。
|
||
|
||
只输出纯几何与 <text> 的 SVG（无 script/foreignObject/内联事件），可安全内嵌 HTML。
|
||
所有文本与颜色都经过转义/校验，不把用户输入直接拼进标记。
|
||
"""
|
||
|
||
from __future__ import annotations
|
||
|
||
import html
|
||
import math
|
||
import re
|
||
from typing import Callable
|
||
|
||
from app.plot.model import FunctionPlot, StaticRenderResult
|
||
from app.plot.parser import PlotParseError, evaluate, parse_expression
|
||
|
||
_WIDTH = 640
|
||
_HEIGHT = 480
|
||
_MARGIN = 52 # 四周留白，放轴刻度与标签
|
||
_SAMPLES = 400
|
||
_PALETTE = ["#0969da", "#d1242f", "#1a7f37", "#8250df", "#bf8700", "#e36209"]
|
||
_COLOR_RE = re.compile(r"^#[0-9a-fA-F]{3,8}$")
|
||
|
||
|
||
def _safe_color(color: str | None, fallback: str) -> str:
|
||
return color.strip() if color and _COLOR_RE.match(color.strip()) else fallback
|
||
|
||
|
||
def _fmt_num(v: float) -> str:
|
||
if v == 0:
|
||
return "0"
|
||
if abs(v) >= 1e6 or abs(v) < 1e-6:
|
||
return f"{v:.2e}"
|
||
return f"{v:.6g}"
|
||
|
||
|
||
def _nice_step(span: float, target_ticks: int = 6) -> float:
|
||
raw = abs(span) / target_ticks
|
||
mag = 10 ** math.floor(math.log10(raw))
|
||
for m in (1, 2, 5, 10):
|
||
if raw <= m * mag:
|
||
return m * mag
|
||
return 10 * mag
|
||
|
||
|
||
def _ticks(lo: float, hi: float, step: float) -> list[float]:
|
||
first = math.ceil(lo / step) * step
|
||
values: list[float] = []
|
||
v = first
|
||
while v <= hi + step * 1e-9:
|
||
values.append(v)
|
||
v += step
|
||
return values
|
||
|
||
|
||
def _compute_range(
|
||
plot: FunctionPlot,
|
||
fns: list[tuple[object, object]],
|
||
xmin: float,
|
||
xmax: float,
|
||
) -> tuple[float, float]:
|
||
"""采样确定 y 范围；指定 range 则优先，否则取有限样本的 min/max 加 5% 余量。"""
|
||
if plot.range is not None:
|
||
return float(plot.range[0]), float(plot.range[1])
|
||
|
||
ys: list[float] = []
|
||
for _expr, tree in fns:
|
||
for i in range(_SAMPLES + 1):
|
||
x = xmin + (xmax - xmin) * i / _SAMPLES
|
||
try:
|
||
y = evaluate(tree, x) # type: ignore[arg-type]
|
||
except (ValueError, ZeroDivisionError, OverflowError):
|
||
continue
|
||
if math.isfinite(y):
|
||
ys.append(y)
|
||
|
||
if not ys:
|
||
return -10.0, 10.0
|
||
lo, hi = min(ys), max(ys)
|
||
if lo == hi:
|
||
lo -= 1.0
|
||
hi += 1.0
|
||
pad = (hi - lo) * 0.05
|
||
return lo - pad, hi + pad
|
||
|
||
|
||
def _polyline(
|
||
tree: object,
|
||
xmin: float,
|
||
xmax: float,
|
||
sx: Callable[[float], float],
|
||
sy: Callable[[float], float],
|
||
color: str,
|
||
) -> str:
|
||
"""采样并把非有限点处断开成多段 polyline，避免画穿渐近线。"""
|
||
segments: list[str] = []
|
||
points: list[str] = []
|
||
for i in range(_SAMPLES + 1):
|
||
x = xmin + (xmax - xmin) * i / _SAMPLES
|
||
try:
|
||
y = evaluate(tree, x) # type: ignore[arg-type]
|
||
except (ValueError, ZeroDivisionError, OverflowError):
|
||
y = math.nan
|
||
if not math.isfinite(y):
|
||
if points:
|
||
segments.append(f'<polyline points="{" ".join(points)}" fill="none" stroke="{color}"/>')
|
||
points = []
|
||
continue
|
||
px = sx(x)
|
||
py = sy(y)
|
||
points.append(f"{px:.2f},{py:.2f}")
|
||
if points:
|
||
segments.append(f'<polyline points="{" ".join(points)}" fill="none" stroke="{color}"/>')
|
||
return "".join(segments)
|
||
|
||
|
||
def _grid(
|
||
xmin: float,
|
||
xmax: float,
|
||
ymin: float,
|
||
ymax: float,
|
||
sx: Callable[[float], float],
|
||
sy: Callable[[float], float],
|
||
) -> str:
|
||
parts: list[str] = []
|
||
for x in _ticks(xmin, xmax, _nice_step(xmax - xmin)):
|
||
parts.append(f'<line x1="{sx(x):.2f}" y1="{sy(ymin):.2f}" x2="{sx(x):.2f}" y2="{sy(ymax):.2f}" stroke="#eaeef2"/>')
|
||
for y in _ticks(ymin, ymax, _nice_step(ymax - ymin)):
|
||
parts.append(f'<line x1="{sx(xmin):.2f}" y1="{sy(y):.2f}" x2="{sx(xmax):.2f}" y2="{sy(y):.2f}" stroke="#eaeef2"/>')
|
||
return "".join(parts)
|
||
|
||
|
||
def _axes(
|
||
xmin: float,
|
||
xmax: float,
|
||
ymin: float,
|
||
ymax: float,
|
||
sx: Callable[[float], float],
|
||
sy: Callable[[float], float],
|
||
) -> str:
|
||
parts: list[str] = []
|
||
# 坐标轴：过原点则画在原点，否则贴边，保证始终有参照系
|
||
x_axis_y = 0.0 if ymin <= 0 <= ymax else ymin
|
||
y_axis_x = 0.0 if xmin <= 0 <= xmax else xmin
|
||
parts.append(
|
||
f'<line x1="{sx(xmin):.2f}" y1="{sy(x_axis_y):.2f}" x2="{sx(xmax):.2f}" y2="{sy(x_axis_y):.2f}" stroke="#57606a"/>'
|
||
)
|
||
parts.append(
|
||
f'<line x1="{sx(y_axis_x):.2f}" y1="{sy(ymin):.2f}" x2="{sx(y_axis_x):.2f}" y2="{sy(ymax):.2f}" stroke="#57606a"/>'
|
||
)
|
||
# x 轴刻度数字（画在轴下方）
|
||
for x in _ticks(xmin, xmax, _nice_step(xmax - xmin)):
|
||
parts.append(
|
||
f'<text x="{sx(x):.2f}" y="{sy(x_axis_y) + 14:.2f}" text-anchor="middle" font-size="10" fill="#57606a">{html.escape(_fmt_num(x))}</text>'
|
||
)
|
||
# y 轴刻度数字（画在轴左侧）
|
||
for y in _ticks(ymin, ymax, _nice_step(ymax - ymin)):
|
||
parts.append(
|
||
f'<text x="{sx(y_axis_x) - 6:.2f}" y="{sy(y) + 3:.2f}" text-anchor="end" font-size="10" fill="#57606a">{html.escape(_fmt_num(y))}</text>'
|
||
)
|
||
return "".join(parts)
|
||
|
||
|
||
def _labels(plot: FunctionPlot, sx: Callable[[float], float], sy: Callable[[float], float]) -> str:
|
||
parts: list[str] = []
|
||
if plot.axes.xlabel:
|
||
parts.append(
|
||
f'<text x="{(_WIDTH / 2):.2f}" y="{_HEIGHT - 10:.2f}" text-anchor="middle" font-size="12" fill="#1f2328">{html.escape(plot.axes.xlabel)}</text>'
|
||
)
|
||
if plot.axes.ylabel:
|
||
parts.append(
|
||
f'<text x="16" y="{(_HEIGHT / 2):.2f}" text-anchor="middle" font-size="12" fill="#1f2328" transform="rotate(-90 16 {_HEIGHT / 2:.2f})">{html.escape(plot.axes.ylabel)}</text>'
|
||
)
|
||
return "".join(parts)
|
||
|
||
|
||
def render_svg(plot: FunctionPlot) -> StaticRenderResult:
|
||
"""把已解析的 FunctionPlot 渲染为内嵌 SVG。"""
|
||
warnings: list[str] = []
|
||
xmin, xmax = plot.domain
|
||
if xmin >= xmax:
|
||
warnings.append("domain 无效，回退到 [-10, 10]")
|
||
xmin, xmax = -10.0, 10.0
|
||
|
||
# 重新解析并编译表达式（parse_source 已校验，这里异常只在模型被绕过时触发）
|
||
fns: list[tuple[object, object]] = []
|
||
for expr in plot.expressions:
|
||
try:
|
||
tree = parse_expression(expr.expression)
|
||
except PlotParseError as exc:
|
||
warnings.append(f"表达式无法渲染，已跳过：{expr.expression}（{exc.diagnostic.message}）")
|
||
continue
|
||
fns.append((expr, tree))
|
||
|
||
ymin, ymax = _compute_range(plot, fns, xmin, xmax)
|
||
if plot.range is not None and plot.range[0] >= plot.range[1]:
|
||
warnings.append("range 无效，改用自动范围")
|
||
ymin, ymax = _compute_range(plot, fns, xmin, xmax)
|
||
|
||
def sx(x: float) -> float:
|
||
return _MARGIN + (x - xmin) / (xmax - xmin) * (_WIDTH - 2 * _MARGIN)
|
||
|
||
def sy(y: float) -> float:
|
||
return _HEIGHT - _MARGIN - (y - ymin) / (ymax - ymin) * (_HEIGHT - 2 * _MARGIN)
|
||
|
||
parts: list[str] = [
|
||
f'<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 {_WIDTH} {_HEIGHT}" role="img">'
|
||
]
|
||
if plot.axes.grid:
|
||
parts.append(_grid(xmin, xmax, ymin, ymax, sx, sy))
|
||
parts.append(_axes(xmin, xmax, ymin, ymax, sx, sy))
|
||
for i, (expr, tree) in enumerate(fns):
|
||
color = _safe_color(expr.color, _PALETTE[i % len(_PALETTE)])
|
||
parts.append(_polyline(tree, xmin, xmax, sx, sy, color))
|
||
parts.append(_labels(plot, sx, sy))
|
||
parts.append("</svg>")
|
||
|
||
return StaticRenderResult(
|
||
content="".join(parts),
|
||
width=_WIDTH,
|
||
height=_HEIGHT,
|
||
warnings=warnings,
|
||
)
|