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140 lines
6.0 KiB
Python
140 lines
6.0 KiB
Python
"""Function Plot → reportlab 矢量 Drawing（供 PDF 内嵌）。
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消费 ``render.compute_geometry`` 的共享几何，产出 ``reportlab.graphics.shapes.Drawing``：
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网格/坐标轴用 ``Line``、曲线用 ``PolyLine``、刻度数字与轴标签用 ``String``。
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reportlab 原点在左下（y-up），与 SVG 的 y-down 相反，故对几何里的像素 y 统一翻转；
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轴标签（ylabel）用 ``Group.rotate`` 旋转为竖向文本。中文字体复用内置 STSong-Light，
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guarded 注册避免与 pdf.py 重复注册。
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"""
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from __future__ import annotations
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from reportlab.graphics.shapes import Drawing, Group, Line, PolyLine, String
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from reportlab.lib.colors import HexColor
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from reportlab.pdfbase import pdfmetrics
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from reportlab.pdfbase.cidfonts import UnicodeCIDFont
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from app.plot.model import FunctionPlot
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from app.plot.math_label import expression_latex, render_math_reportlab
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from app.plot.render import PlotGeometry, _fmt_num, _sx, _sy, compute_geometry
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from app.export.fonts import FONT as _FONT
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_GRID_COLOR = HexColor("#eaeef2")
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_AXIS_COLOR = HexColor("#57606a")
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_LABEL_COLOR = HexColor("#1f2328")
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_TICK_FONT_SIZE = 10
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_LABEL_FONT_SIZE = 12
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def _build_drawing(geo: PlotGeometry, palette=None) -> Drawing:
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"""由共享几何构建矢量 Drawing（坐标翻转后仍沿用 SVG 的像素布局）。"""
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drawing = Drawing(geo.width, geo.height)
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grid_color = HexColor(palette['border']) if palette else _GRID_COLOR
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axis_color = HexColor(palette['muted']) if palette else _AXIS_COLOR
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label_color = HexColor(palette['text']) if palette else _LABEL_COLOR
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# SVG y-down → reportlab y-up：翻转像素 y
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def sx(x: float) -> float:
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return _sx(x, geo.xmin, geo.xmax)
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def sy(y: float) -> float:
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return geo.height - _sy(y, geo.ymin, geo.ymax)
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# 网格
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if geo.grid:
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for x in geo.xticks:
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drawing.add(
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Line(sx(x), sy(geo.ymin), sx(x), sy(geo.ymax), strokeColor=grid_color, strokeWidth=0.5)
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)
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for y in geo.yticks:
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drawing.add(
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Line(sx(geo.xmin), sy(y), sx(geo.xmax), sy(y), strokeColor=grid_color, strokeWidth=0.5)
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)
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# 坐标轴（过原点画在原点，否则贴边，与 SVG 一致）
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drawing.add(
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Line(sx(geo.xmin), sy(geo.x_axis_y), sx(geo.xmax), sy(geo.x_axis_y), strokeColor=axis_color, strokeWidth=0.7)
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)
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drawing.add(
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Line(sx(geo.y_axis_x), sy(geo.ymin), sx(geo.y_axis_x), sy(geo.ymax), strokeColor=axis_color, strokeWidth=0.7)
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)
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# 刻度数字（x 轴下方、y 轴左侧）
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for x in geo.xticks:
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drawing.add(
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String(
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sx(x), sy(geo.x_axis_y) - 14, _fmt_num(x),
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fontName=_FONT, fontSize=_TICK_FONT_SIZE, fillColor=axis_color, textAnchor="middle",
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)
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)
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for y in geo.yticks:
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drawing.add(
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String(
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sx(geo.y_axis_x) - 6, sy(y) - 3, _fmt_num(y),
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fontName=_FONT, fontSize=_TICK_FONT_SIZE, fillColor=axis_color, textAnchor="end",
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)
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)
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# 曲线（非有限点处已由几何断成多段）
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for segments, color in zip(geo.polylines, geo.colors):
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for seg in segments:
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flipped = [(px, geo.height - py) for px, py in seg]
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drawing.add(PolyLine(flipped, strokeColor=HexColor(color), strokeWidth=1.4))
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# 轴标签
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if geo.xlabel:
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drawing.add(
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String(
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geo.width / 2, 10, geo.xlabel,
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fontName=_FONT, fontSize=_LABEL_FONT_SIZE, fillColor=label_color, textAnchor="middle",
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)
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)
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if geo.ylabel:
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# 竖向标签：Group.rotate(90) 在 y-up 坐标下等价于 SVG 的 rotate(-90)。
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# 文本放在组内局部坐标 (0,0)，先平移后旋转得到 T·R（先绕原点旋转、再平移到
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# 目标位置），避免用绝对坐标定位又用相同坐标当旋转中心造成的重复变换，
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# 后者会把标签甩到画布之外（负 x 区域）。
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label = Group()
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label.add(
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String(
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0, 0, geo.ylabel,
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fontName=_FONT, fontSize=_LABEL_FONT_SIZE, fillColor=label_color, textAnchor="middle",
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)
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)
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label.translate(16, geo.height / 2)
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label.rotate(90)
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drawing.add(label)
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return drawing
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def render_drawing(plot: FunctionPlot, width: float | None = None, palette=None, unlimited=False, max_height=None) -> Drawing:
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"""把已解析的 FunctionPlot 渲染为 reportlab Drawing（可直接追加到 platypus story）。
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``width`` 为目标输出宽度（点），用于把 640px 的几何缩放到页面内容宽；省略则按
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原始尺寸输出。缩放只影响 PDF 渲染，不改动共享几何。
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"""
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geo = compute_geometry(plot, unlimited=unlimited)
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if palette:
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from reportlab.lib.colors import HexColor as color
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bg = color(palette['surface'])
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if .2126*bg.red + .7152*bg.green + .0722*bg.blue < .5:
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colors = ['#79c0ff','#ff9b9b','#7ee787','#d2a8ff','#f2cc60','#ffa657']
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geo.colors = [value if plot.expressions[i].color else colors[i % len(colors)] for i,value in enumerate(geo.colors)]
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drawing = _build_drawing(geo, palette)
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legend_height = ((len(plot.expressions)+1)//2)*24
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drawing.height += legend_height
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for index, expression in enumerate(plot.expressions):
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x = 24 + (index % 2) * 310
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visual_top = drawing.height - 4 - (index // 2) * 24
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if expression.label:
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drawing.add(String(x, visual_top - 12, expression.label, fontName=_FONT, fontSize=12,
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fillColor=HexColor(geo.colors[index])))
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else:
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drawing.add(render_math_reportlab(expression_latex(expression.expression), x=x,
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visual_top=visual_top, color=HexColor(geo.colors[index])))
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if width is not None and width > 0:
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drawing.renderScale = min(1.0, width / geo.width, max_height / drawing.height if max_height else 1.0)
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return drawing
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