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l3draw-paths.dtx
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l3draw-paths.dtx
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% \iffalse meta-comment
%
%% File: l3draw-paths.dtx
%
% Copyright (C) 2018-2021 The LaTeX Project
%
% It may be distributed and/or modified under the conditions of the
% LaTeX Project Public License (LPPL), either version 1.3c of this
% license or (at your option) any later version. The latest version
% of this license is in the file
%
% http://www.latex-project.org/lppl.txt
%
% This file is part of the "l3experimental bundle" (The Work in LPPL)
% and all files in that bundle must be distributed together.
%
% -----------------------------------------------------------------------
%
% The development version of the bundle can be found at
%
% https://github.com/latex3/latex3
%
% for those people who are interested.
%
%<*driver>
\RequirePackage{expl3}
\documentclass[full]{l3doc}
\begin{document}
\DocInput{\jobname.dtx}
\end{document}
%</driver>
% \fi
%
% \title{^^A
% The \pkg{l3draw-paths} package\\ Drawing paths^^A
% }
%
% \author{^^A
% The \LaTeX{} Project\thanks
% {^^A
% E-mail:
% \href{mailto:latex-team@latex-project.org}
% {latex-team@latex-project.org}^^A
% }^^A
% }
%
% \date{Released 2021-02-06}
%
% \maketitle
%
% \begin{implementation}
%
% \section{\pkg{l3draw-paths} implementation}
%
% \begin{macrocode}
%<*package>
% \end{macrocode}
%
% \begin{macrocode}
%<@@=draw>
% \end{macrocode}
%
% This sub-module covers more-or-less the same ideas as
% \texttt{pgfcorepathconstruct.code.tex}, though using the expandable FPU
% means that the implementation often varies. At present, equivalents of the
% following are currently absent:
% \begin{itemize}
% \item \cs{pgfpatharcto}, \cs{pgfpatharctoprecomputed}: These are
% extremely specialised and are very complex in implementation. If the
% functionality is required, it is likely that it will be set up from
% scratch here.
% \item \cs{pgfpathparabola}: Seems to be unused other than defining
% a Ti\emph{k}Z interface, which itself is then not used further.
% \item \cs{pgfpathsine}, \cs{pgfpathcosine}: Need to see exactly how
% these need to work, in particular whether a wider input range is
% needed and what approximation to make.
% \item \cs{pgfpathcurvebetweentime}, \cs{pgfpathcurvebetweentimecontinue}:
% These don't seem to be used at all.
% \end{itemize}
%
% \begin{variable}
% {\l_@@_path_tmp_tl, \l_@@_path_tmpa_fp, \l_@@_path_tmpb_fp}
% Scratch space.
% \begin{macrocode}
\tl_new:N \l_@@_path_tmp_tl
\fp_new:N \l_@@_path_tmpa_fp
\fp_new:N \l_@@_path_tmpb_fp
% \end{macrocode}
% \end{variable}
%
% \subsection{Tracking paths}
%
% \begin{variable}{\g_@@_path_lastx_dim, \g_@@_path_lasty_dim}
% The last point visited on a path.
% \begin{macrocode}
\dim_new:N \g_@@_path_lastx_dim
\dim_new:N \g_@@_path_lasty_dim
% \end{macrocode}
% \end{variable}
%
% \begin{variable}
% {
% \g_@@_path_xmax_dim,
% \g_@@_path_xmin_dim,
% \g_@@_path_ymax_dim,
% \g_@@_path_ymin_dim
% }
% The limiting size of a path.
% \begin{macrocode}
\dim_new:N \g_@@_path_xmax_dim
\dim_new:N \g_@@_path_xmin_dim
\dim_new:N \g_@@_path_ymax_dim
\dim_new:N \g_@@_path_ymin_dim
% \end{macrocode}
% \end{variable}
%
% \begin{macro}{\@@_path_update_limits:nn}
% \begin{macro}{\@@_path_reset_limits:}
% Track the limits of a path and (perhaps) of the picture as a whole.
% (At present the latter is always true: that will change as more complex
% functionality is added.)
% \begin{macrocode}
\cs_new_protected:Npn \@@_path_update_limits:nn #1#2
{
\dim_gset:Nn \g_@@_path_xmax_dim
{ \dim_max:nn \g_@@_path_xmax_dim {#1} }
\dim_gset:Nn \g_@@_path_xmin_dim
{ \dim_min:nn \g_@@_path_xmin_dim {#1} }
\dim_gset:Nn \g_@@_path_ymax_dim
{ \dim_max:nn \g_@@_path_ymax_dim {#2} }
\dim_gset:Nn \g_@@_path_ymin_dim
{ \dim_min:nn \g_@@_path_ymin_dim {#2} }
\bool_if:NT \l_draw_bb_update_bool
{
\dim_gset:Nn \g_@@_xmax_dim
{ \dim_max:nn \g_@@_xmax_dim {#1} }
\dim_gset:Nn \g_@@_xmin_dim
{ \dim_min:nn \g_@@_xmin_dim {#1} }
\dim_gset:Nn \g_@@_ymax_dim
{ \dim_max:nn \g_@@_ymax_dim {#2} }
\dim_gset:Nn \g_@@_ymin_dim
{ \dim_min:nn \g_@@_ymin_dim {#2} }
}
}
\cs_new_protected:Npn \@@_path_reset_limits:
{
\dim_gset:Nn \g_@@_path_xmax_dim { -\c_max_dim }
\dim_gset:Nn \g_@@_path_xmin_dim { \c_max_dim }
\dim_gset:Nn \g_@@_path_ymax_dim { -\c_max_dim }
\dim_gset:Nn \g_@@_path_ymin_dim { \c_max_dim }
}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@@_path_update_last:nn}
% A simple auxiliary to avoid repetition.
% \begin{macrocode}
\cs_new_protected:Npn \@@_path_update_last:nn #1#2
{
\dim_gset:Nn \g_@@_path_lastx_dim {#1}
\dim_gset:Nn \g_@@_path_lasty_dim {#2}
}
% \end{macrocode}
% \end{macro}
%
% \subsection{Corner arcs}
%
% At the level of path \emph{construction}, rounded corners are handled
% by inserting a marker into the path: that is then picked up once the
% full path is constructed. Thus we need to set up the appropriate
% data structures here, such that this can be applied every time it is
% relevant.
%
% \begin{variable}{\l_@@_corner_xarc_dim, \l_@@_corner_yarc_dim}
% The two arcs in use.
% \begin{macrocode}
\dim_new:N \l_@@_corner_xarc_dim
\dim_new:N \l_@@_corner_yarc_dim
% \end{macrocode}
% \end{variable}
%
% \begin{variable}{\l_@@_corner_arc_bool}
% A flag to speed up the repeated checks.
% \begin{macrocode}
\bool_new:N \l_@@_corner_arc_bool
% \end{macrocode}
% \end{variable}
%
% \begin{macro}{\draw_path_corner_arc:nn}
% Calculate the arcs, check they are non-zero.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_corner_arc:nn #1#2
{
\dim_set:Nn \l_@@_corner_xarc_dim {#1}
\dim_set:Nn \l_@@_corner_yarc_dim {#2}
\bool_lazy_and:nnTF
{ \dim_compare_p:nNn \l_@@_corner_xarc_dim = { 0pt } }
{ \dim_compare_p:nNn \l_@@_corner_yarc_dim = { 0pt } }
{ \bool_set_false:N \l_@@_corner_arc_bool }
{ \bool_set_true:N \l_@@_corner_arc_bool }
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@@_path_mark_corner:}
% Mark up corners for arc post-processing.
% \begin{macrocode}
\cs_new_protected:Npn \@@_path_mark_corner:
{
\bool_if:NT \l_@@_corner_arc_bool
{
\@@_softpath_roundpoint:VV
\l_@@_corner_xarc_dim
\l_@@_corner_yarc_dim
}
}
% \end{macrocode}
% \end{macro}
%
% \subsection{Basic path constructions}
%
% \begin{macro}{\draw_path_moveto:n, \draw_path_lineto:n}
% \begin{macro}{\@@_path_moveto:nn, \@@_path_lineto:nn}
% \begin{macro}{\draw_path_curveto:nnn}
% \begin{macro}{\@@_path_curveto:nnnnnn}
% At present, stick to purely linear transformation support and skip the
% soft path business: that will likely need to be revisited later.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_moveto:n #1
{
\@@_point_process:nn
{ \@@_path_moveto:nn }
{ \draw_point_transform:n {#1} }
}
\cs_new_protected:Npn \@@_path_moveto:nn #1#2
{
\@@_path_update_limits:nn {#1} {#2}
\@@_softpath_moveto:nn {#1} {#2}
\@@_path_update_last:nn {#1} {#2}
}
\cs_new_protected:Npn \draw_path_lineto:n #1
{
\@@_point_process:nn
{ \@@_path_lineto:nn }
{ \draw_point_transform:n {#1} }
}
\cs_new_protected:Npn \@@_path_lineto:nn #1#2
{
\@@_path_mark_corner:
\@@_path_update_limits:nn {#1} {#2}
\@@_softpath_lineto:nn {#1} {#2}
\@@_path_update_last:nn {#1} {#2}
}
\cs_new_protected:Npn \draw_path_curveto:nnn #1#2#3
{
\@@_point_process:nnnn
{
\@@_path_mark_corner:
\@@_path_curveto:nnnnnn
}
{ \draw_point_transform:n {#1} }
{ \draw_point_transform:n {#2} }
{ \draw_point_transform:n {#3} }
}
\cs_new_protected:Npn \@@_path_curveto:nnnnnn #1#2#3#4#5#6
{
\@@_path_update_limits:nn {#1} {#2}
\@@_path_update_limits:nn {#3} {#4}
\@@_path_update_limits:nn {#5} {#6}
\@@_softpath_curveto:nnnnnn {#1} {#2} {#3} {#4} {#5} {#6}
\@@_path_update_last:nn {#5} {#6}
}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\draw_path_close:}
% A simple wrapper.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_close:
{
\@@_path_mark_corner:
\@@_softpath_closepath:
}
% \end{macrocode}
% \end{macro}
%
% \subsection{Canvas path constructions}
%
% \begin{macro}{\draw_path_canvas_moveto:n, \draw_path_canvas_lineto:n}
% \begin{macro}{\draw_path_canvas_curveto:nnn}
% Operations with no application of the transformation matrix.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_canvas_moveto:n #1
{ \@@_point_process:nn { \@@_path_moveto:nn } {#1} }
\cs_new_protected:Npn \draw_path_canvas_lineto:n #1
{ \@@_point_process:nn { \@@_path_lineto:nn } {#1} }
\cs_new_protected:Npn \draw_path_canvas_curveto:nnn #1#2#3
{
\@@_point_process:nnnn
{
\@@_path_mark_corner:
\@@_path_curveto:nnnnnn
}
{#1} {#2} {#3}
}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \subsection{Computed curves}
%
% More complex operations need some calculations. To assist with those, various
% constants are pre-defined.
%
% \begin{macro}{\draw_path_curveto:nn}
% \begin{macro}{\@@_path_curveto:nnnn}
% \begin{variable}{\c_@@_path_curveto_a_fp, \c_@@_path_curveto_b_fp}
% A quadratic curve with one control point $(x_{\mathrm{c}},
% y_{\mathrm{c}})$. The two required control points are then
% \[
% x_{1} = \frac{1}{3}x_{\mathrm{s}} + \frac{2}{3}x_{\mathrm{c}}
% \quad
% y_{1} = \frac{1}{3}y_{\mathrm{s}} + \frac{2}{3}y_{\mathrm{c}}
% \]
% and
% \[
% x_{2} = \frac{1}{3}x_{\mathrm{e}} + \frac{2}{3}x_{\mathrm{c}}
% \quad
% x_{2} = \frac{1}{3}y_{\mathrm{e}} + \frac{2}{3}y_{\mathrm{c}}
% \]
% using the start (last) point $(x_{\mathrm{s}}, y_{\mathrm{s}})$
% and the end point $(x_{\mathrm{s}}, y_{\mathrm{s}})$.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_curveto:nn #1#2
{
\@@_point_process:nnn
{ \@@_path_curveto:nnnn }
{ \draw_point_transform:n {#1} }
{ \draw_point_transform:n {#2} }
}
\cs_new_protected:Npn \@@_path_curveto:nnnn #1#2#3#4
{
\fp_set:Nn \l_@@_path_tmpa_fp { \c_@@_path_curveto_b_fp * #1 }
\fp_set:Nn \l_@@_path_tmpb_fp { \c_@@_path_curveto_b_fp * #2 }
\use:x
{
\@@_path_mark_corner:
\@@_path_curveto:nnnnnn
{
\fp_to_dim:n
{
\c_@@_path_curveto_a_fp * \g_@@_path_lastx_dim
+ \l_@@_path_tmpa_fp
}
}
{
\fp_to_dim:n
{
\c_@@_path_curveto_a_fp * \g_@@_path_lasty_dim
+ \l_@@_path_tmpb_fp
}
}
{
\fp_to_dim:n
{ \c_@@_path_curveto_a_fp * #3 + \l_@@_path_tmpa_fp }
}
{
\fp_to_dim:n
{ \c_@@_path_curveto_a_fp * #4 + \l_@@_path_tmpb_fp }
}
{#3}
{#4}
}
}
\fp_const:Nn \c_@@_path_curveto_a_fp { 1 / 3 }
\fp_const:Nn \c_@@_path_curveto_b_fp { 2 / 3 }
% \end{macrocode}
% \end{variable}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\draw_path_arc:nnn}
% \begin{macro}{\draw_path_arc:nnnn}
% \begin{macro}{\@@_path_arc:nnnn}
% \begin{macro}{\@@_path_arc:nnNnn}
% \begin{macro}
% {
% \@@_path_arc_auxi:nnnnNnn,
% \@@_path_arc_auxi:fnnnNnn,
% \@@_path_arc_auxi:fnfnNnn
% }
% \begin{macro}{\@@_path_arc_auxii:nnnNnnnn}
% \begin{macro}{\@@_path_arc_auxiii:nn}
% \begin{macro}{\@@_path_arc_auxiv:nnnn}
% \begin{macro}{\@@_path_arc_auxv:nn, \@@_path_arc_auxvi:nn}
% \begin{macro}{\@@_path_arc_add:nnnn}
% \begin{variable}{\l_@@_path_arc_delta_fp, \l_@@_path_arc_start_fp}
% \begin{variable}{\c_@@_path_arc_90_fp,\c_@@_path_arc_60_fp}
% Drawing an arc means dividing the total curve required into sections:
% using Bézier curves we can cover at most $90^{\circ}$ at once. To allow
% for later manipulations, we aim to have roughly equal last segments to
% the line, with the split set at a final part of $115^{\circ}$.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_arc:nnn #1#2#3
{ \draw_path_arc:nnnn {#1} {#2} {#3} {#3} }
\cs_new_protected:Npn \draw_path_arc:nnnn #1#2#3#4
{
\use:x
{
\@@_path_arc:nnnn
{ \fp_eval:n {#1} }
{ \fp_eval:n {#2} }
{ \fp_to_dim:n {#3} }
{ \fp_to_dim:n {#4} }
}
}
\cs_new_protected:Npn \@@_path_arc:nnnn #1#2#3#4
{
\fp_compare:nNnTF {#1} > {#2}
{ \@@_path_arc:nnNnn {#1} {#2} - {#3} {#4} }
{ \@@_path_arc:nnNnn {#1} {#2} + {#3} {#4} }
}
\cs_new_protected:Npn \@@_path_arc:nnNnn #1#2#3#4#5
{
\fp_set:Nn \l_@@_path_arc_start_fp {#1}
\fp_set:Nn \l_@@_path_arc_delta_fp { abs( #1 - #2 ) }
\fp_while_do:nNnn { \l_@@_path_arc_delta_fp } > { 90 }
{
\fp_compare:nNnTF \l_@@_path_arc_delta_fp > { 115 }
{
\@@_path_arc_auxi:ffnnNnn
{ \fp_to_decimal:N \l_@@_path_arc_start_fp }
{ \fp_eval:n { \l_@@_path_arc_start_fp #3 90 } }
{ 90 } {#2}
#3 {#4} {#5}
}
{
\@@_path_arc_auxi:ffnnNnn
{ \fp_to_decimal:N \l_@@_path_arc_start_fp }
{ \fp_eval:n { \l_@@_path_arc_start_fp #3 60 } }
{ 60 } {#2}
#3 {#4} {#5}
}
}
\@@_path_mark_corner:
\@@_path_arc_auxi:fnfnNnn
{ \fp_to_decimal:N \l_@@_path_arc_start_fp }
{#2}
{ \fp_eval:n { abs( \l_@@_path_arc_start_fp - #2 ) } }
{#2}
#3 {#4} {#5}
}
% \end{macrocode}
% The auxiliary is responsible for calculating the required points.
% The \enquote{magic} number required to determine the length of the
% control vectors is well-established for a right-angle:
% $\frac{4}{3}(\sqrt{2} - 1) = 0.552\,284\,75$. For other cases, we follow
% the calculation used by \pkg{pgf} but with the second common case of
% $60^{\circ}$ pre-calculated for speed.
% \begin{macrocode}
\cs_new_protected:Npn \@@_path_arc_auxi:nnnnNnn #1#2#3#4#5#6#7
{
\use:x
{
\@@_path_arc_auxii:nnnNnnnn
{#1} {#2} {#4} #5 {#6} {#7}
{
\fp_to_dim:n
{
\cs_if_exist_use:cF
{ c_@@_path_arc_ #3 _fp }
{ 4/3 * tand( 0.25 * #3 ) }
* #6
}
}
{
\fp_to_dim:n
{
\cs_if_exist_use:cF
{ c_@@_path_arc_ #3 _fp }
{ 4/3 * tand( 0.25 * #3 ) }
* #7
}
}
}
}
\cs_generate_variant:Nn \@@_path_arc_auxi:nnnnNnn { fnf , ff }
% \end{macrocode}
% We can now calculate the required points. As everything here is
% non-expandable, that is best done by using \texttt{x}-type expansion
% to build up the tokens. The three points are calculated out-of-order,
% since finding the second control point needs the position of the end
% point. Once the points are found, fire-off the fundamental path
% operation and update the record of where we are up to. The final
% point has to be
% \begin{macrocode}
\cs_new_protected:Npn \@@_path_arc_auxii:nnnNnnnn #1#2#3#4#5#6#7#8
{
\tl_clear:N \l_@@_path_tmp_tl
\@@_point_process:nn
{ \@@_path_arc_auxiii:nn }
{
\@@_point_transform_noshift:n
{ \draw_point_polar:nnn {#7} {#8} { #1 #4 90 } }
}
\@@_point_process:nnn
{ \@@_path_arc_auxiv:nnnn }
{
\draw_point_transform:n
{ \draw_point_polar:nnn {#5} {#6} {#1} }
}
{
\draw_point_transform:n
{ \draw_point_polar:nnn {#5} {#6} {#2} }
}
\@@_point_process:nn
{ \@@_path_arc_auxv:nn }
{
\@@_point_transform_noshift:n
{ \draw_point_polar:nnn {#7} {#8} { #2 #4 -90 } }
}
\exp_after:wN \@@_path_curveto:nnnnnn \l_@@_path_tmp_tl
\fp_set:Nn \l_@@_path_arc_delta_fp { abs ( #2 - #3 ) }
\fp_set:Nn \l_@@_path_arc_start_fp {#2}
}
% \end{macrocode}
% The first control point.
% \begin{macrocode}
\cs_new_protected:Npn \@@_path_arc_auxiii:nn #1#2
{
\@@_path_arc_aux_add:nn
{ \g_@@_path_lastx_dim + #1 }
{ \g_@@_path_lasty_dim + #2 }
}
% \end{macrocode}
% The end point: simple arithmetic.
% \begin{macrocode}
\cs_new_protected:Npn \@@_path_arc_auxiv:nnnn #1#2#3#4
{
\@@_path_arc_aux_add:nn
{ \g_@@_path_lastx_dim - #1 + #3 }
{ \g_@@_path_lasty_dim - #2 + #4 }
}
% \end{macrocode}
% The second control point: extract the last point, do some
% rearrangement and record.
% \begin{macrocode}
\cs_new_protected:Npn \@@_path_arc_auxv:nn #1#2
{
\exp_after:wN \@@_path_arc_auxvi:nn
\l_@@_path_tmp_tl {#1} {#2}
}
\cs_new_protected:Npn \@@_path_arc_auxvi:nn #1#2#3#4#5#6
{
\tl_set:Nn \l_@@_path_tmp_tl { {#1} {#2} }
\@@_path_arc_aux_add:nn
{ #5 + #3 }
{ #6 + #4 }
\tl_put_right:Nn \l_@@_path_tmp_tl { {#3} {#4} }
}
\cs_new_protected:Npn \@@_path_arc_aux_add:nn #1#2
{
\tl_put_right:Nx \l_@@_path_tmp_tl
{ { \fp_to_dim:n {#1} } { \fp_to_dim:n {#2} } }
}
\fp_new:N \l_@@_path_arc_delta_fp
\fp_new:N \l_@@_path_arc_start_fp
\fp_const:cn { c_@@_path_arc_90_fp } { 4/3 * (sqrt(2) - 1) }
\fp_const:cn { c_@@_path_arc_60_fp } { 4/3 * tand(15) }
% \end{macrocode}
% \end{variable}
% \end{variable}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\draw_path_arc_axes:nnnn}
% A simple wrapper.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_arc_axes:nnnn #1#2#3#4
{
\draw_transform_triangle:nnn { 0cm , 0cm } {#3} {#4}
\draw_path_arc:nnn {#1} {#2} { 1pt }
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\draw_path_ellipse:nnn}
% \begin{macro}{\@@_path_ellipse:nnnnnn}
% \begin{macro}[EXP]
% {
% \@@_path_ellipse_arci:nnnnnn ,
% \@@_path_ellipse_arcii:nnnnnn ,
% \@@_path_ellipse_arciii:nnnnnn ,
% \@@_path_ellipse_arciv:nnnnnn
% }
% \begin{variable}{\c_@@_path_ellipse_fp}
% Drawing an ellipse is an optimised version of drawing an arc, in particular
% reusing the same constant. We need to deal with the ellipse in four parts
% and also deal with moving to the right place, closing it and ending up
% back at the center. That is handled on a per-arc basis, each in a
% separate auxiliary for readability.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_ellipse:nnn #1#2#3
{
\@@_point_process:nnnn
{ \@@_path_ellipse:nnnnnn }
{ \draw_point_transform:n {#1} }
{ \@@_point_transform_noshift:n {#2} }
{ \@@_point_transform_noshift:n {#3} }
}
\cs_new_protected:Npn \@@_path_ellipse:nnnnnn #1#2#3#4#5#6
{
\use:x
{
\@@_path_moveto:nn
{ \fp_to_dim:n { #1 + #3 } } { \fp_to_dim:n { #2 + #4 } }
\@@_path_ellipse_arci:nnnnnn {#1} {#2} {#3} {#4} {#5} {#6}
\@@_path_ellipse_arcii:nnnnnn {#1} {#2} {#3} {#4} {#5} {#6}
\@@_path_ellipse_arciii:nnnnnn {#1} {#2} {#3} {#4} {#5} {#6}
\@@_path_ellipse_arciv:nnnnnn {#1} {#2} {#3} {#4} {#5} {#6}
}
\@@_softpath_closepath:
\@@_path_moveto:nn {#1} {#2}
}
\cs_new:Npn \@@_path_ellipse_arci:nnnnnn #1#2#3#4#5#6
{
\@@_path_curveto:nnnnnn
{ \fp_to_dim:n { #1 + #3 + #5 * \c_@@_path_ellipse_fp } }
{ \fp_to_dim:n { #2 + #4 + #6 * \c_@@_path_ellipse_fp } }
{ \fp_to_dim:n { #1 + #3 * \c_@@_path_ellipse_fp + #5 } }
{ \fp_to_dim:n { #2 + #4 * \c_@@_path_ellipse_fp + #6 } }
{ \fp_to_dim:n { #1 + #5 } }
{ \fp_to_dim:n { #2 + #6 } }
}
\cs_new:Npn \@@_path_ellipse_arcii:nnnnnn #1#2#3#4#5#6
{
\@@_path_curveto:nnnnnn
{ \fp_to_dim:n { #1 - #3 * \c_@@_path_ellipse_fp + #5 } }
{ \fp_to_dim:n { #2 - #4 * \c_@@_path_ellipse_fp + #6 } }
{ \fp_to_dim:n { #1 - #3 + #5 * \c_@@_path_ellipse_fp } }
{ \fp_to_dim:n { #2 - #4 + #6 * \c_@@_path_ellipse_fp } }
{ \fp_to_dim:n { #1 - #3 } }
{ \fp_to_dim:n { #2 - #4 } }
}
\cs_new:Npn \@@_path_ellipse_arciii:nnnnnn #1#2#3#4#5#6
{
\@@_path_curveto:nnnnnn
{ \fp_to_dim:n { #1 - #3 - #5 * \c_@@_path_ellipse_fp } }
{ \fp_to_dim:n { #2 - #4 - #6 * \c_@@_path_ellipse_fp } }
{ \fp_to_dim:n { #1 - #3 * \c_@@_path_ellipse_fp - #5 } }
{ \fp_to_dim:n { #2 - #4 * \c_@@_path_ellipse_fp - #6 } }
{ \fp_to_dim:n { #1 - #5 } }
{ \fp_to_dim:n { #2 - #6 } }
}
\cs_new:Npn \@@_path_ellipse_arciv:nnnnnn #1#2#3#4#5#6
{
\@@_path_curveto:nnnnnn
{ \fp_to_dim:n { #1 + #3 * \c_@@_path_ellipse_fp - #5 } }
{ \fp_to_dim:n { #2 + #4 * \c_@@_path_ellipse_fp - #6 } }
{ \fp_to_dim:n { #1 + #3 - #5 * \c_@@_path_ellipse_fp } }
{ \fp_to_dim:n { #2 + #4 - #6 * \c_@@_path_ellipse_fp } }
{ \fp_to_dim:n { #1 + #3 } }
{ \fp_to_dim:n { #2 + #4 } }
}
\fp_const:Nn \c_@@_path_ellipse_fp { \fp_use:c { c_@@_path_arc_90_fp } }
% \end{macrocode}
% \end{variable}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\draw_path_circle:nn}
% A shortcut.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_circle:nn #1#2
{ \draw_path_ellipse:nnn {#1} { #2 , 0pt } { 0pt , #2 } }
% \end{macrocode}
% \end{macro}
%
% \subsection{Rectangles}
%
% \begin{macro}{\draw_path_rectangle:nn}
% \begin{macro}{\@@_path_rectangle:nnnn, \@@_path_rectangle_rounded:nnnn}
% Building a rectangle can be a single operation, or for rounded versions will
% involve step-by-step construction.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_rectangle:nn #1#2
{
\@@_point_process:nnn
{
\bool_lazy_or:nnTF
{ \l_@@_corner_arc_bool }
{ \l_@@_matrix_active_bool }
{ \@@_path_rectangle_rounded:nnnn }
{ \@@_path_rectangle:nnnn }
}
{ \draw_point_transform:n {#1} }
{#2}
}
\cs_new_protected:Npn \@@_path_rectangle:nnnn #1#2#3#4
{
\@@_path_update_limits:nn {#1} {#2}
\@@_path_update_limits:nn { #1 + #3 } { #2 + #4 }
\@@_softpath_rectangle:nnnn {#1} {#2} {#3} {#4}
\@@_path_update_last:nn {#1} {#2}
}
\cs_new_protected:Npn \@@_path_rectangle_rounded:nnnn #1#2#3#4
{
\draw_path_moveto:n { #1 + #3 , #2 + #4 }
\draw_path_lineto:n { #1 , #2 + #4 }
\draw_path_lineto:n { #1 , #2 }
\draw_path_lineto:n { #1 + #3 , #2 }
\draw_path_close:
\draw_path_moveto:n { #1 , #2 }
}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\draw_path_rectangle_corners:nn}
% \begin{macro}{\@@_path_rectangle_corners:nnnn}
% Another shortcut wrapper.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_rectangle_corners:nn #1#2
{
\@@_point_process:nnn
{ \@@_path_rectangle_corners:nnnnn {#1} }
{#1} {#2}
}
\cs_new_protected:Npn \@@_path_rectangle_corners:nnnnn #1#2#3#4#5
{ \draw_path_rectangle:nn {#1} { #4 - #2 , #5 - #3 } }
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \subsection{Grids}
%
% \begin{macro}{\draw_path_grid:nnnn}
% \begin{macro}
% {
% \@@_path_grid_auxi:nnnnnn, \@@_path_grid_auxi:ffnnnn,
% \@@_path_grid_auxii:nnnnnn,
% \@@_path_grid_auxiii:nnnnnn, \@@_path_grid_auxiiii:ffnnnn
% }
% \begin{macro}
% {\@@_path_grid_auxiv:nnnnnnnn, \@@_path_grid_auxiv:ffnnnnnn}
% The main complexity here is lining up the grid correctly.
% To keep it simple, we tidy up the argument ordering first.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_grid:nnnn #1#2#3#4
{
\@@_point_process:nnn
{
\@@_path_grid_auxi:ffnnnn
{ \dim_eval:n { \dim_abs:n {#1} } }
{ \dim_eval:n { \dim_abs:n {#2} } }
}
{#3} {#4}
}
\cs_new_protected:Npn \@@_path_grid_auxi:nnnnnn #1#2#3#4#5#6
{
\dim_compare:nNnTF {#3} > {#5}
{ \@@_path_grid_auxii:nnnnnn {#1} {#2} {#5} {#4} {#3} {#6} }
{ \@@_path_grid_auxii:nnnnnn {#1} {#2} {#3} {#4} {#5} {#6} }
}
\cs_generate_variant:Nn \@@_path_grid_auxi:nnnnnn { ff }
\cs_new_protected:Npn \@@_path_grid_auxii:nnnnnn #1#2#3#4#5#6
{
\dim_compare:nNnTF {#4} > {#6}
{ \@@_path_grid_auxiii:nnnnnn {#1} {#2} {#3} {#6} {#5} {#4} }
{ \@@_path_grid_auxiii:nnnnnn {#1} {#2} {#3} {#4} {#5} {#6} }
}
\cs_new_protected:Npn \@@_path_grid_auxiii:nnnnnn #1#2#3#4#5#6
{
\@@_path_grid_auxiv:ffnnnnnn
{ \fp_to_dim:n { #1 * trunc(#3/(#1)) } }
{ \fp_to_dim:n { #2 * trunc(#4/(#2)) } }
{#1} {#2} {#3} {#4} {#5} {#6}
}
\cs_new_protected:Npn \@@_path_grid_auxiv:nnnnnnnn #1#2#3#4#5#6#7#8
{
\dim_step_inline:nnnn
{#1}
{#3}
{#7}
{
\draw_path_moveto:n { ##1 , #6 }
\draw_path_lineto:n { ##1 , #8 }
}
\dim_step_inline:nnnn
{#2}
{#4}
{#8}
{
\draw_path_moveto:n { #5 , ##1 }
\draw_path_lineto:n { #7 , ##1 }
}
}
\cs_generate_variant:Nn \@@_path_grid_auxiv:nnnnnnnn { ff }
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \subsection{Using paths}
%
% \begin{variable}
% {
% \l_@@_path_use_clip_bool ,
% \l_@@_path_use_fill_bool ,
% \l_@@_path_use_stroke_bool
% }
% Actions to pass to the driver.
% \begin{macrocode}
\bool_new:N \l_@@_path_use_clip_bool
\bool_new:N \l_@@_path_use_fill_bool
\bool_new:N \l_@@_path_use_stroke_bool
% \end{macrocode}
% \end{variable}
%
% \begin{variable}{\l_@@_path_use_bb_bool, \l_@@_path_use_clear_bool}
% Actions handled at the macro layer.
% \begin{macrocode}
\bool_new:N \l_@@_path_use_bb_bool
\bool_new:N \l_@@_path_use_clear_bool
% \end{macrocode}
% \end{variable}
%
% \begin{macro}{\draw_path_use:n, \draw_path_use_clear:n}
% \begin{macro}{\@@_path_use:n}
% \begin{macro}{\@@_path_use_action_draw:, \@@_path_use_action_fillstroke:}
% \begin{macro}{\@@_path_use_stroke_bb:}
% \begin{macro}{\@@_path_use_stroke_bb_aux:NnN}
% There are a range of actions which can apply to a path: they are handled
% in a single function which can carry out several of them. The first step
% is to deal with the special case of clearing the path.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_use:n #1
{
\tl_if_blank:nF {#1}
{ \@@_path_use:n {#1} }
}
\cs_new_protected:Npn \draw_path_use_clear:n #1
{
\bool_lazy_or:nnTF
{ \tl_if_blank_p:n {#1} }
{ \str_if_eq_p:nn {#1} { clear } }
{
\@@_softpath_clear:
\@@_path_reset_limits:
}
{ \@@_path_use:n { #1 , clear } }
}
% \end{macrocode}
% Map over the actions and set up the data: mainly just booleans,
% but with the possibility to cover more complex cases. The business end
% of the function is a series of checks on the various flags, then
% taking the appropriate action(s).
% \begin{macrocode}
\cs_new_protected:Npn \@@_path_use:n #1
{
\bool_set_false:N \l_@@_path_use_clip_bool
\bool_set_false:N \l_@@_path_use_fill_bool
\bool_set_false:N \l_@@_path_use_stroke_bool
\clist_map_inline:nn {#1}
{
\cs_if_exist:cTF { l_@@_path_use_ ##1 _ bool }
{ \bool_set_true:c { l_@@_path_use_ ##1 _ bool } }
{
\cs_if_exist_use:cF { @@_path_use_action_ ##1 : }
{ \msg_error:nnn { draw } { invalid-path-action } {##1} }
}
}
\@@_softpath_round_corners:
\bool_lazy_and:nnT
{ \l_draw_bb_update_bool }
{ \l_@@_path_use_stroke_bool }
{ \@@_path_use_stroke_bb: }
\@@_softpath_use:
\bool_if:NT \l_@@_path_use_clip_bool
{
\@@_backend_clip:
\bool_set_false:N \l_draw_bb_update_bool
\bool_lazy_or:nnF
{ \l_@@_path_use_fill_bool }
{ \l_@@_path_use_stroke_bool }
{ \@@_backend_discardpath: }
}
\bool_lazy_or:nnT
{ \l_@@_path_use_fill_bool }
{ \l_@@_path_use_stroke_bool }
{
\use:c
{
@@_backend_
\bool_if:NT \l_@@_path_use_fill_bool { fill }
\bool_if:NT \l_@@_path_use_stroke_bool { stroke }
:
}
}
\bool_if:NT \l_@@_path_use_clear_bool
{ \@@_softpath_clear: }
}
\cs_new_protected:Npn \@@_path_use_action_draw:
{
\bool_set_true:N \l_@@_path_use_stroke_bool
}
\cs_new_protected:Npn \@@_path_use_action_fillstroke:
{
\bool_set_true:N \l_@@_path_use_fill_bool
\bool_set_true:N \l_@@_path_use_stroke_bool
}
% \end{macrocode}
% Where the path is relevant to size and is stroked, we need to allow for
% the part which overlaps the edge of the bounding box.
% \begin{macrocode}
\cs_new_protected:Npn \@@_path_use_stroke_bb:
{
\@@_path_use_stroke_bb_aux:NnN x { max } +
\@@_path_use_stroke_bb_aux:NnN y { max } +
\@@_path_use_stroke_bb_aux:NnN x { min } -
\@@_path_use_stroke_bb_aux:NnN y { min } -
}
\cs_new_protected:Npn \@@_path_use_stroke_bb_aux:NnN #1#2#3
{
\dim_compare:nNnF { \dim_use:c { g_@@_ #1#2 _dim } } = { #3 -\c_max_dim }
{
\dim_gset:cn { g_@@_ #1#2 _dim }
{
\use:c { dim_ #2 :nn }
{ \dim_use:c { g_@@_ #1#2 _dim } }
{
\dim_use:c { g_@@_path_ #1#2 _dim }
#3 0.5 \g_@@_linewidth_dim
}
}
}
}
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \subsection{Scoping paths}
%
% \begin{variable}
% {
% \l_@@_path_lastx_dim, \l_@@_path_lasty_dim,
% \l_@@_path_xmax_dim, \l_@@_path_xmin_dim,
% \l_@@_path_ymax_dim, \l_@@_path_ymin_dim
% }
% \begin{variable}{\l_@@_softpath_corners_bool}
% Local storage for global data. There is already a
% \cs{l_@@_softpath_main_tl} for path manipulation, so we can reuse that
% (it is always grouped when the path is being reconstructed).
% \begin{macrocode}
\dim_new:N \l_@@_path_lastx_dim
\dim_new:N \l_@@_path_lasty_dim
\dim_new:N \l_@@_path_xmax_dim
\dim_new:N \l_@@_path_xmin_dim
\dim_new:N \l_@@_path_ymax_dim
\dim_new:N \l_@@_path_ymin_dim
\dim_new:N \l_@@_softpath_lastx_dim
\dim_new:N \l_@@_softpath_lasty_dim
\bool_new:N \l_@@_softpath_corners_bool
% \end{macrocode}
% \end{variable}
% \end{variable}
%
% \begin{macro}{\draw_path_scope_begin:, \draw_path_scope_end:}
% Scoping a path is a bit more involved, largely as there are a number
% of variables to keep hold of.
% \begin{macrocode}
\cs_new_protected:Npn \draw_path_scope_begin:
{
\group_begin:
\dim_set_eq:NN \l_@@_path_lastx_dim \g_@@_path_lastx_dim
\dim_set_eq:NN \l_@@_path_lasty_dim \g_@@_path_lasty_dim
\dim_set_eq:NN \l_@@_path_xmax_dim \g_@@_path_xmax_dim
\dim_set_eq:NN \l_@@_path_xmin_dim \g_@@_path_xmin_dim
\dim_set_eq:NN \l_@@_path_ymax_dim \g_@@_path_ymax_dim
\dim_set_eq:NN \l_@@_path_ymin_dim \g_@@_path_ymin_dim
\dim_set_eq:NN \l_@@_softpath_lastx_dim \g_@@_softpath_lastx_dim
\dim_set_eq:NN \l_@@_softpath_lasty_dim \g_@@_softpath_lasty_dim
\@@_path_reset_limits:
\tl_build_get:NN \g_@@_softpath_main_tl \l_@@_softpath_main_tl