feat(export): 函数图像静态渲染（function-plot → SVG）
- 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>
This commit is contained in:
Claude Code
@@ -1,7 +1,8 @@
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"""HtmlExporter：Document AST → 完整 HTML5 文档（内嵌基础 CSS）。
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对无法静态表达的节点（mermaid / function_plot）渲染为占位代码块并记 warning，不静默丢失；
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严重内容缺失由 service 层以 EXPORT_UNSUPPORTED_CONTENT 判定，本层只负责逐节点渲染。
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mermaid 等无法静态表达的节点渲染为占位代码块并记 warning，不静默丢失；function_plot
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解析为静态 SVG 内嵌（解析失败回退占位并转诊断）；严重内容缺失由 service 层以
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EXPORT_UNSUPPORTED_CONTENT 判定，本层只负责逐节点渲染。
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"""
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from __future__ import annotations
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@@ -12,9 +13,10 @@ from urllib.parse import urlparse
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from app.contracts import ExportOptions
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from app.export.document import Document, DocumentNode, ExportResult
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from app.plot.parser import parse_source
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from app.plot.render import render_svg
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_MERMAID_WARNING = "mermaid 需前端渲染，已保留为占位代码块"
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_FUNCTION_PLOT_WARNING = "函数图像渲染将在后续版本提供，已保留为占位代码块"
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_RAW_HTML_WARNING = "原始 HTML 已按纯文本转义保留"
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# 链接/图片地址允许的协议；无 scheme 的相对地址视为安全，其余协议一律降级
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@@ -44,6 +46,8 @@ pre { background: #f6f8fa; padding: 14px 16px; border-radius: 6px; overflow-x: a
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pre.code-theme-github-dark { background: #0d1117; color: #c9d1d9; }
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pre code { background: none; padding: 0; }
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pre.mermaid, pre.function-plot { border: 1px dashed #d0d7de; }
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figure.function-plot { margin: 1em 0; text-align: center; }
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figure.function-plot svg { max-width: 100%; height: auto; }
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blockquote { margin: 0.8em 0; padding: 0.2em 1em; border-left: 4px solid #d0d7de; color: #57606a; }
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img { max-width: 100%; }
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table { border-collapse: collapse; margin: 0.8em 0; }
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@@ -193,9 +197,21 @@ class HtmlExporter:
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warnings.append(_MERMAID_WARNING)
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return f'<pre class="mermaid">{html.escape(node.text)}</pre>'
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@staticmethod
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def _format_plot_diagnostic(diag) -> str:
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loc = f"（第 {diag.line} 行）" if diag.line else ""
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return f"函数图像：{diag.message}{loc}"
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def _render_function_plot(self, node: DocumentNode, warnings: list[str]) -> str:
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warnings.append(_FUNCTION_PLOT_WARNING)
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return f'<pre class="function-plot">{html.escape(node.text)}</pre>'
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# 解析 fenced 源码：有合法 plot 且无 error → 内嵌静态 SVG；否则回退占位并转诊断
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parsed = parse_source(node.text)
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for diag in parsed.diagnostics:
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warnings.append(self._format_plot_diagnostic(diag))
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if parsed.plot is None:
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return f'<pre class="function-plot">{html.escape(node.text)}</pre>'
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rendered = render_svg(parsed.plot)
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warnings.extend(rendered.warnings)
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return f'<figure class="function-plot">{rendered.content}</figure>'
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def _render_math_block(self, node: DocumentNode, warnings: list[str]) -> str:
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return f'<div class="math-block">$${html.escape(node.text)}$$</div>'
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@@ -0,0 +1,7 @@
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"""Function Plot：函数图像的白名单表达式解析与静态 SVG 渲染。
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模块划分：
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- model.py FunctionPlot 等内部数据模型（不进 contracts.py，同 Document AST）
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- parser.py function-plot 源码与表达式解析（ast 白名单，绝不 eval/exec）
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- render.py 把 FunctionPlot 渲染为内嵌 SVG（纯几何 + <text>，无脚本）
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"""
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@@ -0,0 +1,55 @@
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"""Function Plot 内部数据模型。
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契约 §12.2 的 FunctionPlot 结构与 §10.4 的 StaticRenderResult 只在导出链路的后端内部
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流转，不进入 HTTP 契约，因此与 Document AST 一样放在独立包内，不进 contracts.py。
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"""
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from __future__ import annotations
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from typing import Literal
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from pydantic import BaseModel, Field
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class FunctionPlotExpression(BaseModel):
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"""单条函数表达式；expression 为数学表达式文本（不含 ``y =`` 前缀）。"""
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expression: str
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label: str | None = None
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color: str | None = None
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class PlotAxes(BaseModel):
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xlabel: str | None = None
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ylabel: str | None = None
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grid: bool = True
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class FunctionPlot(BaseModel):
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version: int = 1
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expressions: list[FunctionPlotExpression]
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domain: tuple[float, float] = (-10.0, 10.0)
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range: tuple[float, float] | None = None
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axes: PlotAxes = Field(default_factory=PlotAxes)
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class PlotDiagnostic(BaseModel):
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severity: Literal["warning", "error"]
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code: str
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message: str
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line: int | None = None
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class FunctionPlotParseResult(BaseModel):
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"""解析结果：任一表达式 error 时 plot 为 None（整块回退占位），仅 warning 时 plot 有效。"""
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plot: FunctionPlot | None = None
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diagnostics: list[PlotDiagnostic] = Field(default_factory=list)
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class StaticRenderResult(BaseModel):
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content: str
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mime_type: str = "image/svg+xml"
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width: int
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height: int
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warnings: list[str] = Field(default_factory=list)
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@@ -0,0 +1,359 @@
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"""Function Plot 表达式解析：白名单数学语法，绝不执行 eval / 函数构造器 / 属性访问。
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安全模型：先用 ``ast.parse(mode='eval')`` 把表达式变成纯 AST（这一步不执行任何代码），
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再逐节点白名单校验（只允许数字、变量 ``x``、常量 ``pi/e``、白名单函数调用与四则/幂
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运算），最后用递归解释器直接计算数值——全程不 ``compile``/``exec`` 字符串。
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"""
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from __future__ import annotations
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import ast
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import math
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import re
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from typing import NoReturn
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from app.plot.model import (
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FunctionPlot,
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FunctionPlotExpression,
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FunctionPlotParseResult,
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PlotAxes,
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PlotDiagnostic,
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)
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# 白名单函数（ln 是 log 的别名）；abs 用内置函数，其余映射到 math
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_FUNCTION_IMPL: dict[str, object] = {
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"sin": math.sin,
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"cos": math.cos,
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"tan": math.tan,
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"asin": math.asin,
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"acos": math.acos,
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"atan": math.atan,
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"sinh": math.sinh,
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"cosh": math.cosh,
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"tanh": math.tanh,
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"exp": math.exp,
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"log": math.log,
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"ln": math.log,
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"log10": math.log10,
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"log2": math.log2,
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"sqrt": math.sqrt,
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"abs": abs,
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}
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_FUNCTIONS = frozenset(_FUNCTION_IMPL)
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_CONSTANTS: dict[str, float] = {"pi": math.pi, "e": math.e}
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_ALLOWED_BINOPS = (ast.Add, ast.Sub, ast.Mult, ast.Div, ast.Pow)
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_ALLOWED_UNARY = (ast.UAdd, ast.USub)
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_DIRECTIVE_KEYS = frozenset({"domain", "range", "xlabel", "ylabel", "grid"})
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_NUMBER_RE = re.compile(r"^(\d+\.?\d*|\.\d+)([eE][+-]?\d+)?$")
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class PlotParseError(Exception):
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"""表达式解析/校验失败，携带可定位诊断。"""
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def __init__(self, diagnostic: PlotDiagnostic) -> None:
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super().__init__(diagnostic.message)
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self.diagnostic = diagnostic
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def _unsafe(message: str) -> NoReturn:
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raise PlotParseError(
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PlotDiagnostic(severity="error", code="FUNCTION_PLOT_EXPRESSION_UNSAFE", message=message)
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)
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def _is_number(tok: str) -> bool:
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return bool(_NUMBER_RE.match(tok))
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def _tokenize(s: str) -> list[str]:
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"""把预处理后的表达式切成数字/标识符/运算符/括号 token。"""
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tokens: list[str] = []
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i = 0
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n = len(s)
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while i < n:
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ch = s[i]
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if ch.isspace():
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i += 1
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continue
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if ch.isdigit() or ch == ".":
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j = i
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while j < n and (s[j].isdigit() or s[j] == "."):
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j += 1
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# 科学计数法：数字后紧跟 e/E[+-]数字 视为同一数字
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if j < n and s[j] in "eE":
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k = j + 1
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if k < n and s[k] in "+-":
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k += 1
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if k < n and s[k].isdigit():
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while k < n and s[k].isdigit():
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k += 1
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j = k
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tokens.append(s[i:j])
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i = j
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continue
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if ch.isalpha() or ch == "_":
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j = i
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while j < n and (s[j].isalnum() or s[j] == "_"):
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j += 1
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tokens.append(s[i:j])
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i = j
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continue
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if ch == "*" and i + 1 < n and s[i + 1] == "*":
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tokens.append("**")
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i += 2
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continue
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tokens.append(ch)
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i += 1
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return tokens
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def _is_value_end(tok: str) -> bool:
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"""该 token 之后允许补乘号（数字/右括号/变量 x/常量）。"""
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return tok == ")" or _is_number(tok) or tok == "x" or tok in _CONSTANTS
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def _is_value_start(tok: str) -> bool:
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"""该 token 可作为乘号右侧起点（左括号/数字/任意标识符，含函数名）。"""
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return tok == "(" or _is_number(tok) or (tok and (tok[0].isalpha() or tok[0] == "_"))
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def _insert_implicit_multiplication(s: str) -> str:
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"""补隐式乘法：2x、2(x+1)、(x+1)(x-1)、x sin(x) 等；函数名后的 ``(`` 是调用不补。"""
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tokens = _tokenize(s)
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out: list[str] = []
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prev: str | None = None
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for tok in tokens:
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if prev is not None and _is_value_end(prev) and _is_value_start(tok):
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out.append("*")
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out.append(tok)
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prev = tok
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return "".join(out)
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def _preprocess(expr: str) -> str:
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"""``^`` 视为幂，补隐式乘法后再交给 ast.parse。"""
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return _insert_implicit_multiplication(expr.replace("^", "**"))
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def _check_node(node: ast.AST) -> None:
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"""白名单校验：任何越界节点都抛 FUNCTION_PLOT_EXPRESSION_UNSAFE。"""
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if isinstance(node, ast.Constant):
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if isinstance(node.value, bool) or not isinstance(node.value, (int, float)):
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_unsafe(f"不支持的常量 {node.value!r}")
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return
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if isinstance(node, ast.Name):
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if node.id == "x" or node.id in _CONSTANTS:
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return
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_unsafe(f"未知标识符 {node.id!r}")
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if isinstance(node, ast.BinOp):
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if not isinstance(node.op, _ALLOWED_BINOPS):
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_unsafe(f"不支持的运算符 {type(node.op).__name__}")
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_check_node(node.left)
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_check_node(node.right)
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return
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if isinstance(node, ast.UnaryOp):
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if not isinstance(node.op, _ALLOWED_UNARY):
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_unsafe(f"不支持的运算符 {type(node.op).__name__}")
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_check_node(node.operand)
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return
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if isinstance(node, ast.Call):
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if not isinstance(node.func, ast.Name) or node.func.id not in _FUNCTIONS:
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_unsafe(f"不支持的函数调用 {ast.dump(node.func)!r}")
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if node.keywords:
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_unsafe("函数调用不支持关键字参数")
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for arg in node.args:
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_check_node(arg)
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return
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_unsafe(f"不支持的语法 {type(node).__name__}")
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def parse_expression(expr: str) -> ast.Expression:
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"""把数学表达式解析为已通过白名单校验的 AST（可直接交给 evaluate）。"""
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preprocessed = _preprocess(expr)
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try:
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tree = ast.parse(preprocessed, mode="eval")
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except SyntaxError as exc:
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raise PlotParseError(
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PlotDiagnostic(
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severity="error",
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code="FUNCTION_PLOT_PARSE_FAILED",
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message=f"表达式语法错误：{exc.msg}",
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)
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) from exc
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_check_node(tree.body)
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return tree
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def evaluate(expr_ast: ast.Expression, x: float) -> float:
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"""递归解释已校验 AST 得到数值，全程不编译/执行代码。"""
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return _eval_node(expr_ast.body, x)
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def _eval_node(node: ast.AST, x: float) -> float:
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if isinstance(node, ast.Constant):
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return float(node.value)
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if isinstance(node, ast.Name):
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return x if node.id == "x" else _CONSTANTS[node.id]
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if isinstance(node, ast.BinOp):
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left = _eval_node(node.left, x)
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right = _eval_node(node.right, x)
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if isinstance(node.op, ast.Add):
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return left + right
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if isinstance(node.op, ast.Sub):
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return left - right
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if isinstance(node.op, ast.Mult):
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return left * right
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if isinstance(node.op, ast.Div):
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return left / right
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return left**right
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if isinstance(node, ast.UnaryOp):
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value = _eval_node(node.operand, x)
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return -value if isinstance(node.op, ast.USub) else value
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if isinstance(node, ast.Call):
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args = [_eval_node(arg, x) for arg in node.args]
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return _FUNCTION_IMPL[node.func.id](*args) # type: ignore[operator]
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raise ValueError("unreachable node")
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def _strip_comment(line: str) -> str:
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return line.split("#", 1)[0].strip()
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def _parse_pair(value: str) -> tuple[float, float]:
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"""解析 ``min, max`` / ``min max`` 数值对。"""
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parts = [p for p in re.split(r"[,，\s]+", value.strip()) if p]
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if len(parts) != 2:
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raise ValueError("需要两个数值")
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return float(parts[0]), float(parts[1])
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def _parse_directive(line: str) -> tuple[str, str] | None:
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"""指令行形如 ``key: value``（表达式不含冒号，冒号是可靠判别）。"""
|
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if ":" not in line or "=" in line:
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return None
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key, _, value = line.partition(":")
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key = key.strip().lower()
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if not key or " " in key:
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return None
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return key, value.strip()
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||||
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def parse_source(source: str) -> FunctionPlotParseResult:
|
||||
"""把 function-plot fenced block 源码解析为 FunctionPlot + 诊断。"""
|
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diagnostics: list[PlotDiagnostic] = []
|
||||
expressions: list[FunctionPlotExpression] = []
|
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domain: tuple[float, float] = (-10.0, 10.0)
|
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range_: tuple[float, float] | None = None
|
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xlabel: str | None = None
|
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ylabel: str | None = None
|
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grid: bool = True
|
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has_error = False
|
||||
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for lineno, raw_line in enumerate(source.splitlines(), start=1):
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line = raw_line.strip()
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||||
if not line or line.startswith("#"):
|
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continue
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directive = _parse_directive(line)
|
||||
if directive is not None:
|
||||
key, value = directive
|
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if key == "domain":
|
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try:
|
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domain = _parse_pair(value)
|
||||
except ValueError:
|
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diagnostics.append(
|
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PlotDiagnostic(
|
||||
severity="warning",
|
||||
code="FUNCTION_PLOT_PARSE_FAILED",
|
||||
message=f"domain 需要两个数值，已忽略：{value!r}",
|
||||
line=lineno,
|
||||
)
|
||||
)
|
||||
elif key == "range":
|
||||
try:
|
||||
range_ = _parse_pair(value)
|
||||
except ValueError:
|
||||
diagnostics.append(
|
||||
PlotDiagnostic(
|
||||
severity="warning",
|
||||
code="FUNCTION_PLOT_PARSE_FAILED",
|
||||
message=f"range 需要两个数值，已忽略：{value!r}",
|
||||
line=lineno,
|
||||
)
|
||||
)
|
||||
elif key == "xlabel":
|
||||
xlabel = value or None
|
||||
elif key == "ylabel":
|
||||
ylabel = value or None
|
||||
elif key == "grid":
|
||||
grid = value.lower() in ("true", "1", "yes", "on")
|
||||
else:
|
||||
diagnostics.append(
|
||||
PlotDiagnostic(
|
||||
severity="warning",
|
||||
code="FUNCTION_PLOT_PARSE_FAILED",
|
||||
message=f"未知指令 {key!r} 已忽略",
|
||||
line=lineno,
|
||||
)
|
||||
)
|
||||
continue
|
||||
|
||||
# 表达式行：y = <expr> 或裸 <expr>
|
||||
expr_text = _strip_comment(line)
|
||||
if not expr_text:
|
||||
continue
|
||||
if "=" in expr_text:
|
||||
lhs, _, rhs = expr_text.partition("=")
|
||||
if lhs.strip().lower() not in ("y", ""):
|
||||
diagnostics.append(
|
||||
PlotDiagnostic(
|
||||
severity="error",
|
||||
code="FUNCTION_PLOT_PARSE_FAILED",
|
||||
message="表达式应形如 'y = <expr>'",
|
||||
line=lineno,
|
||||
)
|
||||
)
|
||||
has_error = True
|
||||
continue
|
||||
expr_text = rhs.strip()
|
||||
if not expr_text:
|
||||
diagnostics.append(
|
||||
PlotDiagnostic(
|
||||
severity="error",
|
||||
code="FUNCTION_PLOT_PARSE_FAILED",
|
||||
message="表达式为空",
|
||||
line=lineno,
|
||||
)
|
||||
)
|
||||
has_error = True
|
||||
continue
|
||||
|
||||
try:
|
||||
parse_expression(expr_text)
|
||||
except PlotParseError as exc:
|
||||
exc.diagnostic.line = lineno
|
||||
diagnostics.append(exc.diagnostic)
|
||||
has_error = True
|
||||
continue
|
||||
expressions.append(FunctionPlotExpression(expression=expr_text))
|
||||
|
||||
if has_error:
|
||||
return FunctionPlotParseResult(plot=None, diagnostics=diagnostics)
|
||||
if not expressions:
|
||||
diagnostics.append(
|
||||
PlotDiagnostic(
|
||||
severity="error",
|
||||
code="FUNCTION_PLOT_PARSE_FAILED",
|
||||
message="没有找到任何函数表达式",
|
||||
)
|
||||
)
|
||||
return FunctionPlotParseResult(plot=None, diagnostics=diagnostics)
|
||||
|
||||
plot = FunctionPlot(
|
||||
expressions=expressions,
|
||||
domain=domain,
|
||||
range=range_,
|
||||
axes=PlotAxes(xlabel=xlabel, ylabel=ylabel, grid=grid),
|
||||
)
|
||||
return FunctionPlotParseResult(plot=plot, diagnostics=diagnostics)
|
||||
@@ -0,0 +1,223 @@
|
||||
"""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,
|
||||
)
|
||||
Reference in New Issue
Block a user