使用相关命令时似乎存在错误。就我而言,我发现绘制平滑曲线会错误地绘制曲线的情况。
检查以下情况(第一种是完全相对,最后一种是完全绝对),其中命令的相对使用绘制错误,而绝对命令则按预期工作。
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{svg.path}
\begin{document}
% Original
\begin{tikzpicture}
\draw svg "M 256 8 C 119 8 8 119 8 256 s 111 248 248 248 s 248 -111 248 -248 S 393 8 256 8 z";
\end{tikzpicture}
% Mix of relative
\begin{tikzpicture}
\draw svg "M 256 8 C 119 8 8 119 8 256 s 111 248 248 248 S 504 393 504 256 S 393 8 256 8 z";
\end{tikzpicture}
% Mix of relative
\begin{tikzpicture}
\draw svg "M 256 8 C 119 8 8 119 8 256 S 119 504 256 504 s 248 -111 248 -248 S 393 8 256 8 z";
\end{tikzpicture}
% Full absolute
\begin{tikzpicture}
\draw svg "M256 8 C 119 8 8 119 8 256 S 119 504 256 504 S 504 393 504 256 S 393 8 256 8 z";
\end{tikzpicture}
\end{document}
答案1
s
在运算符定义中
\pgfparserdef{svgpath}{all}{the letter s} { \pgf@lib@svg@finish@prev \pgf@lib@svg@read@nums{4}{\pgf@lib@svg@curveto@rel@smooth} } \def\pgf@lib@svg@curveto@rel@smooth{% \ifnum\pgf@lib@svg@count=0\relax% nothing read \else% % Draw curve % Compute first control point \ifx\pgf@lib@svg@bezier@last\pgfutil@empty% \def\pgf@lib@svg@first@cp{\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}} \else \def\pgf@lib@svg@first@cp{ \pgfpointadd {\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}} {\pgfpointdiff {\pgf@lib@svg@bezier@last} {\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}} } } \fi \pgfpathcurveto {\pgf@lib@svg@first@cp} {\pgfpointadd{\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}}{\pgfqpoint{\pgf@lib@svg@get@num{0}pt}{\pgf@lib@svg@get@num{1}pt}}}% {\pgfpointadd{\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}}{\pgfqpoint{\pgf@lib@svg@get@num{2}pt}{\pgf@lib@svg@get@num{3}pt}}}% % Clear quadratic last point and save new last control point: \let\pgf@lib@svg@quad@last=\pgfutil@empty% \pgf@process{\pgfpointadd{\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}}{\pgfqpoint{\pgf@lib@svg@get@num{2}pt}{\pgf@lib@svg@get@num{3}pt}}} \edef\pgf@lib@svg@bezier@last{\noexpand\pgfqpoint{\the\pgf@x}{\the\pgf@y}}% % update \advance\pgf@lib@svg@last@x by\pgf@lib@svg@get@num{2}pt% \advance\pgf@lib@svg@last@y by\pgf@lib@svg@get@num{3}pt% % Go on \pgf@lib@svg@read@nums{4}{\pgf@lib@svg@curveto@rel@smooth} \fi }
以下行(目前是pgflibrarysvg.path.code.tex
\pgf@process{\pgfpointadd{\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}}{\pgfqpoint{\pgf@lib@svg@get@num{2}pt}{\pgf@lib@svg@get@num{3}pt}}} \edef\pgf@lib@svg@bezier@last{\noexpand\pgfqpoint{\the\pgf@x}{\the\pgf@y}}%
是错误的。这是因为\pgf@lib@svg@get@num{2}
和{3}
是前一条曲线的端点。但标准说它应该记住前一条曲线的第二个控制点。如果你把数字改成{0}
和,{1}
它就会按预期工作。
(我怀疑该行是从第 300 行复制而来的,而在C
操作符中, {2}
and {3}
do 表示第二个控制点。)
这是 MWE
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{svg.path}
\makeatletter
\def\pgf@lib@svg@curveto@rel@smooth{%
\ifnum\pgf@lib@svg@count=0\relax% nothing read
\else%
% Draw curve
% Compute first control point
\ifx\pgf@lib@svg@bezier@last\pgfutil@empty%
\def\pgf@lib@svg@first@cp{\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}}
\else
\def\pgf@lib@svg@first@cp{
\pgfpointadd
{\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}}
{\pgfpointdiff
{\pgf@lib@svg@bezier@last}
{\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}}
}
}
\fi
\pgfpathcurveto
{\pgf@lib@svg@first@cp}
{\pgfpointadd{\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}}{\pgfqpoint{\pgf@lib@svg@get@num{0}pt}{\pgf@lib@svg@get@num{1}pt}}}%
{\pgfpointadd{\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}}{\pgfqpoint{\pgf@lib@svg@get@num{2}pt}{\pgf@lib@svg@get@num{3}pt}}}%
% Clear quadratic last point and save new last control point:
\let\pgf@lib@svg@quad@last=\pgfutil@empty%
\pgf@process{\pgfpointadd{\pgfqpoint{\pgf@lib@svg@last@x}{\pgf@lib@svg@last@y}}{\pgfqpoint{\pgf@lib@svg@get@num{0}pt}{\pgf@lib@svg@get@num{1}pt}}} %%%%%% fixing this line
\edef\pgf@lib@svg@bezier@last{\noexpand\pgfqpoint{\the\pgf@x}{\the\pgf@y}}%
% update
\advance\pgf@lib@svg@last@x by\pgf@lib@svg@get@num{2}pt%
\advance\pgf@lib@svg@last@y by\pgf@lib@svg@get@num{3}pt%
% Go on
\pgf@lib@svg@read@nums{4}{\pgf@lib@svg@curveto@rel@smooth}
\fi
}
\begin{document}
% Original
\begin{tikzpicture}
\draw svg "M 256 8 C 119 8 8 119 8 256 s 111 248 248 248 s 248 -111 248 -248 S 393 8 256 8 z";
\end{tikzpicture}
% Mix of relative
\begin{tikzpicture}
\draw svg "M 256 8 C 119 8 8 119 8 256 s 111 248 248 248 S 504 393 504 256 S 393 8 256 8 z";
\end{tikzpicture}
% Mix of relative
\begin{tikzpicture}
\draw svg "M 256 8 C 119 8 8 119 8 256 S 119 504 256 504 s 248 -111 248 -248 S 393 8 256 8 z";
\end{tikzpicture}
% Full absolute
\begin{tikzpicture}
\draw svg "M256 8 C 119 8 8 119 8 256 S 119 504 256 504 S 504 393 504 256 S 393 8 256 8 z";
\end{tikzpicture}
\end{document}