Python ReportLab AssertionError:路径必须以moveto或rect开头

我使用Python3.6和当前的reportlab和svg2rlg库（截至发帖时）尝试了这一点，但标题中出现了错误：

from reportlab.graphics import renderPDF
from svglib.svglib import svg2rlg

c = Canvas(path+'To Print.pdf')
img27 = svg2rlg(path_to_.svg')
wd27 = img27.width/inch
ht27 = img27.height/inch
renderPDF.draw(img27, c, x=x27, y=y27)

它通常工作正常，我不知道如何排除故障。 我已尝试搜索此错误，但在任何地方都找不到

以下是完整的回溯：

File "/anaconda3/lib/python3.6/site-packages/spyder/utils/site/sitecustomize.py", line 705, in runfile
    execfile(filename, namespace)

  File "/anaconda3/lib/python3.6/site-packages/spyder/utils/site/sitecustomize.py", line 102, in execfile
    exec(compile(f.read(), filename, 'exec'), namespace)

  File "/Users/Drive/Scripts/PDF.py", line 604, in <module>
    renderPDF.draw(img27, c, x=x27, y=y27)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderPDF.py", line 29, in draw
    R.draw(renderScaledDrawing(drawing), canvas, x, y, showBoundary=showBoundary)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 201, in draw
    self.drawNode(drawing)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderPDF.py", line 54, in drawNode
    self.drawNodeDispatcher(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 282, in drawNodeDispatcher
    self.drawGroup(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 311, in drawGroup
    self.drawNode(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderPDF.py", line 54, in drawNode
    self.drawNodeDispatcher(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 282, in drawNodeDispatcher
    self.drawGroup(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 311, in drawGroup
    self.drawNode(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderPDF.py", line 54, in drawNode
    self.drawNodeDispatcher(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 282, in drawNodeDispatcher
    self.drawGroup(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 311, in drawGroup
    self.drawNode(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderPDF.py", line 54, in drawNode
    self.drawNodeDispatcher(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 282, in drawNodeDispatcher
    self.drawGroup(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 311, in drawGroup
    self.drawNode(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderPDF.py", line 54, in drawNode
    self.drawNodeDispatcher(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 282, in drawNodeDispatcher
    self.drawGroup(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 311, in drawGroup
    self.drawNode(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderPDF.py", line 54, in drawNode
    self.drawNodeDispatcher(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 282, in drawNodeDispatcher
    self.drawGroup(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 311, in drawGroup
    self.drawNode(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderPDF.py", line 54, in drawNode
    self.drawNodeDispatcher(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderbase.py", line 278, in drawNodeDispatcher
    self.drawPath(node)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/renderPDF.py", line 183, in drawPath
    isClosed = _renderPath(path, drawFuncs, forceClose=fill and autoclose=='pdf')

  File "/anaconda3/lib/python3.6/site-packages/svglib/svglib.py", line 1075, in patchedRenderPath
    return original_renderPath(path, drawFuncs, **kwargs)

  File "/anaconda3/lib/python3.6/site-packages/reportlab/graphics/shapes.py", line 996, in _renderPath
    drawFuncs[op](*points[i:j])

  File "/anaconda3/lib/python3.6/site-packages/reportlab/pdfgen/pathobject.py", line 127, in close
    self._code_append('h')

  File "/anaconda3/lib/python3.6/site-packages/reportlab/pdfgen/pathobject.py", line 36, in _init_code_append
    assert c.endswith(' m') or c.endswith(' re'), 'path must start with a moveto or rect'

AssertionError: path must start with a moveto or rect

运行文件中的第705行“

File”/anaconda3/lib/python3.6/site-packages/spyder/utils/site/sitecustomize.py”
execfile（文件名、命名空间）
文件“/anaconda3/lib/python3.6/site packages/spyder/utils/site/sitecustomize.py”，第102行，在execfile中
exec（编译（f.read（），文件名，'exec'），命名空间）
文件“/Users/Drive/Scripts/PDF.py”，第604行，在
renderPDF.draw（img27，c，x=x27，y=y27）
文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderPDF.py”，绘图中第29行
R.draw（渲染缩放绘制，画布，x，y，showBoundary=showBoundary）
文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，绘图中第201行
self.drawNode（绘图）
文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderPDF.py”，第54行，在drawNode中
self.drawNodeDispatcher（节点）
drawNodeDispatcher中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第282行
self.drawGroup（节点）
drawGroup中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第311行
self.drawNode（节点）
文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderPDF.py”，第54行，在drawNode中
self.drawNodeDispatcher（节点）
drawNodeDispatcher中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第282行
self.drawGroup（节点）
drawGroup中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第311行
self.drawNode（节点）
文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderPDF.py”，第54行，在drawNode中
self.drawNodeDispatcher（节点）
drawNodeDispatcher中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第282行
self.drawGroup（节点）
drawGroup中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第311行
self.drawNode（节点）
文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderPDF.py”，第54行，在drawNode中
self.drawNodeDispatcher（节点）
drawNodeDispatcher中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第282行
self.drawGroup（节点）
drawGroup中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第311行
self.drawNode（节点）
文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderPDF.py”，第54行，在drawNode中
self.drawNodeDispatcher（节点）
drawNodeDispatcher中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第282行
self.drawGroup（节点）
drawGroup中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第311行
self.drawNode（节点）
文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderPDF.py”，第54行，在drawNode中
self.drawNodeDispatcher（节点）
drawNodeDispatcher中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第282行
self.drawGroup（节点）
drawGroup中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第311行
self.drawNode（节点）
文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderPDF.py”，第54行，在drawNode中
self.drawNodeDispatcher（节点）
drawNodeDispatcher中的文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderbase.py”，第278行
self.drawPath（节点）
文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/renderPDF.py”，第183行，位于drawPath中
isClosed=\u renderPath（路径、drawFuncs、forceClose=fill和autoclose='pdf'）
文件“/anaconda3/lib/python3.6/site packages/svglib/svglib.py”，第1075行，位于patchedRenderPath中
返回原始渲染路径（路径、drawFuncs、**kwargs）
文件“/anaconda3/lib/python3.6/site packages/reportlab/graphics/shapes.py”，第996行，在_renderPath中
drawFuncs[op]（*点[i:j]）
文件“/anaconda3/lib/python3.6/site packages/reportlab/pdfgen/pathobject.py”，第127行，关闭
self.\u code\u append（'h'））
文件“/anaconda3/lib/python3.6/site packages/reportlab/pdfgen/pathobject.py”，第36行，在初始代码中
断言c.endswith（'m'）或c.endswith（'re'），'path必须以moveto或rect开头'
AssertionError:路径必须以moveto或rect开头

最后一个断言似乎过于热心了

File "/anaconda3/lib/python3.6/site-packages/reportlab/pdfgen/pathobject.py", line 36, in _init_code_append
    assert c.endswith(' m') or c.endswith(' re'), 'path must start with a moveto or rect'

此位置的

c

的实际值为“h”（由堆栈跟踪中正上方的调用填充）。如果您只是注释掉assert，它就可以正常工作

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还请让ReportLab的优秀人员知道，以便他们将来能够修复。

请确保您的代码正确无误。什么是

x27

和

y27

？还有，你是什么意思？这通常有效。从中可以看出，在调用

close（）

时，似乎总是会发生此错误。可能此文件

svg

有错误或使用了异常值，模块无法处理。此处也是如此。SVG由matplotlib图生成。如果出现故障，轴不包含任何数据。图不是空的，因为有图例等，只是没有数据。