summaryrefslogtreecommitdiff
path: root/metapost/context/base/mpiv/mp-grap.mpiv
diff options
context:
space:
mode:
Diffstat (limited to 'metapost/context/base/mpiv/mp-grap.mpiv')
-rw-r--r--metapost/context/base/mpiv/mp-grap.mpiv1706
1 files changed, 1706 insertions, 0 deletions
diff --git a/metapost/context/base/mpiv/mp-grap.mpiv b/metapost/context/base/mpiv/mp-grap.mpiv
new file mode 100644
index 000000000..4fd8ee5bd
--- /dev/null
+++ b/metapost/context/base/mpiv/mp-grap.mpiv
@@ -0,0 +1,1706 @@
+%D \module
+%D [ file=mp-grap.mpiv,
+%D version=2012.10.16, % 2008.09.08 and earlier,
+%D title=\CONTEXT\ \METAPOST\ graphics,
+%D subtitle=graph packagesupport,
+%D author=Hans Hagen \& Alan Braslau,
+%D date=\currentdate,
+%D copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
+%C
+%C This module is part of the \CONTEXT\ macro||package and is
+%C therefore copyrighted by \PRAGMA. See licen-en.pdf for
+%C details.
+
+if known context_grap : endinput ; fi ;
+
+boolean context_grap ; context_grap := true ;
+
+% Below is a modified graph.mp
+
+show numbersystem, numberprecision ;
+
+%if epsilon/4 = 0 :
+if numbersystem <> "double" :
+ errmessage "The graph macros require the double precision number system." ;
+ endinput ;
+fi
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% $Id : graph.mp,v 1.2 2004/09/19 21 :47 :10 karl Exp $
+% Public domain.
+
+% Macros for drawing graphs
+
+% begingraph(width,height) begin a new graph
+% setcoords(xtype,ytype) sets up a new coordinate system (log,-linear..)
+% setrange(lo,hi) set coord ranges (numeric and string args OK)
+% gdraw <file or path> [with...] draw a line in current coord system
+% gfill <file or path> [with...] fill a region using current coord system
+% gdrawarrow .., gdrawdblarrow.. like gdraw, but with 1 or 2 arrowheads
+% augment<path name>(loc) append given coordinates to a polygonal path
+% glabel<suffix>(pic,loc) place label pic near graph coords or time loc
+% gdotlabel<suffix>(pic,loc) same with dot
+% OUT loc value for labels relative to whole graph
+% gdata(file,s,text) read coords from file ; evaluate t w/ tokens s[]
+% auto.<x or y> default x or y tick locations (for interation)
+% tick.<bot|top|..>(fmt,u) draw centered tick from given side at u w/ format
+% itick.<bot|top|..>(fmt,u) draw inward tick from given side at u w/ format
+% otick.<bot|top|..>(fmt,u) draw outward tick at coord u ; label format fmt
+% grid.<bot|top|..>(fmt,u) draw grid line at u with given side labeled
+% autogrid([itick|.. bot|..],..) iterate over auto.x, auto.y, drawing tick/grids
+% frame.[bot|top..] draw frame (or one side of the frame)
+% graph_frame_needed := false ; after begingraph, not to draw a frame at all
+% graph_background := color ; fill color for frame, if defined
+% endgraph end of graph--the result is a picture
+
+% option `plot <picture>' draws picture at each path knot, turns off pen
+% graph_template.<tickcmd> template paths for tick marks and grid lines
+% graph_margin_fraction.low,
+% graph_margin_fraction.high fractions determining margins when no setrange
+% graph_log_marks[], graph_lin_marks, graph_exp_marks loop text strings used by auto.<x or y>
+% graph_minimum_number_of_marks, graph_log_minimum numeric parameters used by auto.<x or y>
+% Autoform is the format string used by autogrid
+% Autoform_X, Autoform_Y if defined, are used instead
+
+% Other than the above-documented user interface, all externally visible names
+% are of the form X_.<suffix>, Y_.<suffix>, or Z_.<suffix>, or they start
+% with `graph_'
+
+% Used to depend on :
+
+% input string.mp
+
+% Private version of a few marith macros, fixed for double math...
+
+newinternal Mzero ; Mzero := -16384; % Anything at least this small is treated as zero
+newinternal mlogten ; mlogten := mlog(10) ;
+newinternal largestmantissa ; largestmantissa := 2**52 ; % internal double warningcheck
+newinternal singleinfinity ; singleinfinity := 2**128 ;
+newinternal doubleinfinity ; doubleinfinity := 2**1024 ;
+%Mzero := -largestmantissa ; % Note that we get arithmetic overflows if we set to -doubleinfinity
+
+% Safely convert a number to mlog form, trapping zero.
+
+vardef graph_mlog primary x =
+ if unknown x: whatever
+ elseif x=0: Mzero
+ else: mlog(abs x) fi
+enddef ;
+
+vardef graph_exp primary x =
+ if unknown x: whatever
+ elseif x<=Mzero: 0
+ else: mexp(x) fi
+enddef ;
+
+% and add the following for utility/completeness
+% (replacing the definitions in mp-tool.mpiv).
+
+vardef logten primary x =
+ if unknown x: whatever
+ elseif x=0: Mzero
+ else: mlog(abs x)/mlog(10) fi
+enddef ;
+
+vardef ln primary x =
+ if unknown x: whatever
+ elseif x=0: Mzero
+ else: mlog(abs x)/256 fi
+enddef ;
+
+vardef exp primary x =
+ if unknown x: whatever
+ elseif x<= Mzero: 0
+ else: (mexp 256)**x fi
+enddef ;
+
+vardef powten primary x =
+ if unknown x: whatever
+ elseif x<= Mzero: 0
+ else: 10**x fi
+enddef ;
+
+% Convert x from mlog form into a pair whose xpart gives a mantissa and whose
+% ypart gives a power of ten.
+
+vardef graph_Meform(expr x) =
+ if x<=Mzero : origin
+ else :
+ save e, m ; e=floor(x/mlogten)-3; m := mexp(x-e*mlogten) ;
+ if abs m<1000 : m := m*10 ; e := e-1 ; elseif abs m>=10000 : m := m/10 ; e := e+1 ; fi
+ (m, e)
+ fi
+enddef ;
+
+% Modified from above.
+
+vardef graph_Feform(expr x) =
+ interim warningcheck :=0 ;
+ if x=0 : origin
+ else :
+ save e, m ; e=floor(if x<0 : -mlog(-x) else : mlog(x) fi/mlogten)-3; m := x/(10**e) ;
+ if abs m<1000 : m := m*10 ; e := e-1 ; elseif abs m>=10000 : m := m/10 ; e := e+1 ; fi
+ (m, e)
+ fi
+enddef ;
+
+vardef graph_error(expr x,s) =
+ interim showstopping :=0 ;
+ show x ; errmessage s ;
+enddef ;
+
+%%%%%%%%%%%%%%%%%%%%%%%% Data structures, begingraph %%%%%%%%%%%%%%%%%%%%%%%%
+
+vardef Z_@# = (X_@#,Y_@#) enddef ; % used in place of plain.mp's z convention
+
+def graph_suffix(suffix $) = % convert from x or y to X_ or Y_
+ if str$="x" : X_ else : Y_ fi
+enddef ;
+
+% New :
+
+save graph_background ; color graph_background ; % if defined, fill the frame.
+save graph_close_file ; boolean graph_close_file ; graph_close_file = false ;
+
+def begingraph(expr w, h) =
+ begingroup
+ save X_, Y_ ;
+ X_.graph_coordinate_type =
+ Y_.graph_coordinate_type = linear ; % coordinate system for each axis
+ Z_.graph_dimensions = (w,h) ; % dimensions of graph not counting axes etc.
+ %also, Z_.low, Z_.high user-specified coordinate ranges in units used in graph_current_graph
+
+ save graph_finished_graph ;
+ picture graph_finished_graph ; % the finished part of the graph
+ graph_finished_graph = nullpicture ;
+ save graph_current_graph ;
+ picture graph_current_graph ; % what has been drawn in current coords
+ graph_current_graph = nullpicture ;
+ save graph_current_bb ;
+ picture graph_current_bb ; % picture whose bbox is graph_current_graph's w/ linewidths 0
+ graph_current_bb = nullpicture ;
+ save graph_last_drawn ;
+ picture graph_last_drawn ; % result of last gdraw or gfill
+ graph_last_drawn = nullpicture ;
+ save graph_last_path ;
+ path graph_last_path ; % last gdraw or gfill path in data coordinates.
+ save graph_plot_picture ;
+ picture graph_plot_picture ; % a picture from the `plot' option known when plot allowed
+ save graph_foreground ;
+ color graph_foreground ; % drawing color, if set.
+ save graph_label ;
+ picture graph_label[] ; % labels to place around the whole graph when it is done
+ save graph_autogrid_needed ;
+ boolean graph_autogrid_needed ; % whether autogrid is needed
+ graph_autogrid_needed = true ;
+ save graph_frame_needed ;
+ boolean graph_frame_needed ; % whether frame needs to be drawn
+ graph_frame_needed = true ;
+ save graph_number_of_arrowheads ; % number of arrowheads for next gdraw
+ graph_number_of_arrowheads = 0 ;
+
+ if known graph_background : % new feature!
+ fill origin--(w,0)--(w,h)--(0,h)--cycle withcolor graph_background ;
+ fi
+enddef ;
+
+% Additional variables not explained above :
+% graph_modified_lower, graph_modified_higher pairs giving bounds used in auto<x or y>
+% graph_exponent, graph_comma variables and macros used in auto<x or y>
+% graph_modified_bias
+% an offset to graph_modified_lower and graph_modified_higher to ease computing exponents
+% Some additional variables function as constants. Most can be modified by the
+% user to alter the behavior of these macros.
+% Not very modifiable : log, linear,
+% graph_frame_pair_a, graph_frame_pair_b, graph_margin_pair
+% Modifiable : graph_template.suffix,
+% graph_log_marks[], graph_lin_marks, graph_exp_marks,
+% graph_minimum_number_of_marks,
+% graph_log_minimum, Autoform
+
+
+newinternal log, linear ; % coordinate system codes
+log :=1 ; linear :=2;
+
+% note that mp-tool.mpiv defines log as log10.
+
+%%%%%%%%%%%%%%%%%%%%%% Coordinates : setcoords, setrange %%%%%%%%%%%%%%%%%%%%%%
+
+% Graph-related user input is `user graph coordinates' as specified by arguments
+% to setcoords.
+% `Internal graph coordinates' are used for graph_current_graph, graph_current_bb, Z_.low, Z_.high.
+% Their meaning depends on the appropriate component of Z_.graph_coordinate_type :
+% log means internal graph coords = mlog(user graph coords)
+% -log means internal graph coords = -mlog(user graph coords)
+% linear means internal graph coords = (user graph coords)
+% -linear means internal graph coords = -(user graph coords)
+
+
+vardef graph_set_default_bounds = % Set default Z_.low, Z_.high
+ forsuffixes $=low,high :
+ (if known X_$ : whatever else : X_$ fi, if known Y_$ : whatever else : Y_$ fi)
+ = graph_margin_fraction$[llcorner graph_current_bb,urcorner graph_current_bb] +
+ graph_margin_pair$ ;
+ endfor
+enddef ;
+
+pair graph_margin_pair.low, graph_margin_pair.high ;
+graph_margin_pair.high = -graph_margin_pair.low = (.00002,.00002) ;
+
+% Set $, $$, $$$ so that shifting by $ then transforming by $$ and then $$$ maps
+% the essential bounding box of graph_current_graph into (0,0)..Z_.graph_dimensions.
+% The `essential bounding box' is either what Z_.low and Z_.high imply
+% or the result of ignoring pen widths in graph_current_graph.
+
+vardef graph_remap(suffix $,$$,$$$) =
+ save p_ ;
+ graph_set_default_bounds ;
+ pair p_, $ ; $=-Z_.low;
+ p_ = (max(X_.high-X_.low,.9), max(Y_.high-Y_.low,.9)) ;
+ transform $$, $$$ ;
+ forsuffixes #=$$,$$$ : xpart#=ypart#=xypart#=yxpart#=0 ; endfor
+ (Z_.high+$) transformed $$ = p_ ;
+ p_ transformed $$$ = Z_.graph_dimensions ;
+enddef ;
+
+graph_margin_fraction.low=-.07 ; % bbox fraction for default range start
+graph_margin_fraction.high=1.07 ; % bbox fraction for default range stop
+
+def graph_with_pen_and_color(expr q) =
+ withpen penpart q withcolor
+ if colormodel q=1 :
+ false
+ elseif colormodel q=3 :
+ (greypart q)
+ elseif colormodel q=5 :
+ (redpart q, greenpart q, bluepart q)
+ elseif colormodel q=7 :
+ (cyanpart q, magentapart q, yellowpart q, blackpart q)
+ fi
+enddef ;
+
+% Add picture component q to picture @# and change part p to tp,
+% where p is something from q that needs coordinate transformation.
+% The type of p is pair or path.
+% Pair o is the value of p that makes tp (0,0). This implements the trick
+% whereby using 1 instead of 0 for the width or height or the setbounds path
+% for a label picture suppresses shifting in x or y.
+
+%vardef graph_picture_conversion@#(expr q, o)(text tp) =
+% save p ;
+% if stroked q :
+% path p ; p=pathpart q;
+% addto @# doublepath tp graph_with_pen_and_color(q) dashed dashpart q ;
+% elseif filled q :
+% path p ; p=pathpart q;
+% addto @# contour tp graph_with_pen_and_color(q) ;
+% else :
+% interim truecorners :=0 ;
+% pair p ; p=llcorner q;
+% if urcorner q<>p : p := p + graph_coordinate_multiplication(o-p,urcorner q-p) ; fi
+% addto @# also q shifted ((tp)-llcorner q) ;
+% fi
+%enddef ;
+
+% This new version makes gdraw clip the result to the window defined with setrange
+
+vardef graph_picture_conversion@#(expr q, o)(text tp) =
+ save p ;
+ save do_clip, tp_clipped ; boolean do_clip ; do_clip := true ;
+ picture tp_clipped ; tp_clipped := nullpicture;
+ if stroked q :
+ path p ; p=pathpart q;
+ addto tp_clipped doublepath tp graph_with_pen_and_color(q) dashed dashpart q ;
+ %draw bbox tp_clipped withcolor red ;
+ elseif filled q :
+ path p ; p=pathpart q;
+ addto tp_clipped contour tp graph_with_pen_and_color(q) ;
+ %draw bbox tp_clipped withcolor green ;
+ else :
+ if (urcorner q<>llcorner q) : do_clip := false ; fi % Do not clip the axis labels;
+ interim truecorners := 0 ;
+ pair p ; p=llcorner q;
+ if urcorner q<>p : p := p + graph_coordinate_multiplication(o-p,urcorner q-p) ; fi
+ addto tp_clipped also q shifted ((tp)-llcorner q) ;
+ %draw bbox tp_clipped withcolor if do_clip : cyan else : blue fi ;
+ fi
+ if do_clip :
+ clip tp_clipped to origin--(xpart Z_.graph_dimensions,0)--Z_.graph_dimensions--
+ (0,ypart Z_.graph_dimensions)--cycle ;
+ fi
+ addto @# also tp_clipped ;
+enddef ;
+
+def graph_coordinate_multiplication(expr a,b) = (xpart a*xpart b, ypart a*ypart b) enddef ;
+
+vardef graph_clear_bounds@# = numeric @#.low, @#.high ; enddef;
+
+% Finalize anything drawn in the present coordinate system and set up a new
+% system as requested
+
+vardef setcoords(expr tx, ty) =
+ interim warningcheck :=0 ;
+ if length graph_current_graph>0 :
+ save s, S, T ;
+ graph_remap(s, S, T) ;
+ for q within graph_current_graph :
+ graph_picture_conversion.graph_finished_graph(q,-s,p shifted s transformed S transformed T) ;
+ endfor
+ graph_current_graph := graph_current_bb := nullpicture ;
+ fi
+ graph_clear_bounds.X_ ; graph_clear_bounds.Y_;
+ X_.graph_coordinate_type := tx ; Y_.graph_coordinate_type := ty;
+enddef ;
+
+% Set Z_.low and Z_.high to correspond to given range of user graph
+% coordinates. The text argument should be a sequence of pairs and/or strings
+% with 4 components in all.
+
+vardef setrange(text t) =
+ interim warningcheck :=0 ;
+ save r_ ; r_=0;
+ string r_[]s ;
+ for x_=
+ for p_=t : if pair p_ : xpart p_, ypart fi p_, endfor :
+ r_[incr r_] if string x_ : s fi = x_ ;
+ if r_>2 :
+ graph_set_bounds if r_=3 : X_ else : Y_ fi (r_[r_-2] if unknown r_[r_-2] : s fi, x_) ;
+ fi
+ exitif r_=4 ;
+ endfor
+enddef ;
+
+% @# is X_ or Y_ ; l and h are numeric or string
+
+vardef graph_set_bounds@#(expr l, h) =
+ graph_clear_bounds@# ;
+ if @#graph_coordinate_type>0 :
+ @#low = if unknown l :
+ whatever
+ else :
+ if abs @#graph_coordinate_type=log : graph_mlog fi if string l : scantokens fi l
+ fi ;
+ @#high = if unknown h :
+ whatever
+ else :
+ if abs @#graph_coordinate_type=log : graph_mlog fi if string h : scantokens fi h
+ fi ;
+ else :
+ -@#high = if unknown l :
+ whatever
+ else :
+ if abs @#graph_coordinate_type=log : graph_mlog fi if string l : scantokens fi l
+ fi ;
+ -@#low = if unknown h :
+ whatever
+ else :
+ if abs @#graph_coordinate_type=log : graph_mlog fi if string h : scantokens fi h
+ fi ;
+ fi
+enddef ;
+
+%%%%%%%%%%%%%%%%%%%%%%%%% Converting path coordinates %%%%%%%%%%%%%%%%%%%%%%%%%
+
+% Find the result of scanning path p and using macros tx and ty to adjust the
+% x and y parts of each coordinate pair. Boolean parameter c tells whether to
+% force the result to be polygonal.
+
+vardef graph_scan_path(expr p, c)(suffix tx, ty) =
+ if (str tx="") and (str ty="") : p
+ else :
+ save r_ ; path r_;
+ r_ := graph_pair_adjust(point 0 of p, tx, ty)
+ if path p :
+ for t=1 upto length p :
+ if c : --
+ else : ..controls graph_pair_adjust(postcontrol(t-1) of p, tx, ty)
+ and graph_pair_adjust(precontrol t of p, tx, ty) ..
+ fi
+ graph_pair_adjust(point t of p, tx, ty)
+ endfor
+ if cycle p : &cycle fi
+ fi ;
+ if pair p : point 0 of fi r_
+ fi
+enddef ;
+
+vardef graph_pair_adjust(expr p)(suffix tx, ty) = (tx xpart p, ty ypart p) enddef ;
+
+% Convert path p from user graph coords to internal graph coords.
+
+vardef graph_convert_user_path_to_internal primary p =
+ interim warningcheck :=0 ;
+ if known p :
+ graph_scan_path(p,
+ (abs X_.graph_coordinate_type<>linear) or (abs Y_.graph_coordinate_type<>linear),
+ if abs X_.graph_coordinate_type=log : graph_mlog fi,
+ if abs Y_.graph_coordinate_type=log : graph_mlog fi)
+ transformed (identity
+ if X_.graph_coordinate_type<0 : xscaled -1 fi
+ if Y_.graph_coordinate_type<0 : yscaled -1 fi)
+ fi
+enddef ;
+
+% Convert label location t_ from user graph coords to internal graph coords.
+% The label location should be a pair, or two numbers/strings. If t_ is empty
+% or a single item of non-pair type, just return t_. Unknown coordinates
+% produce unknown components in the result.
+
+vardef graph_label_convert_user_to_internal(text t_) =
+ save n_ ; n_=0;
+ interim warningcheck :=0 ;
+ if 0 for x_=t_ : +1 if pair x_ : +1 fi endfor <= 1 :
+ t_
+ else :
+ n_0 = n_1 = 0 ;
+ point 0 of graph_convert_user_path_to_internal (
+ for x_=
+ for y_=t_ : if pair y_ : xpart y_, ypart fi y_, endfor
+ 0, 0 :
+ if known x_ : if string x_ : scantokens fi x_
+ else : hide(n_[n_] :=whatever) 0
+ fi
+ exitif incr n_=2 ;
+ ,endfor) + (n_0,n_1)
+ fi
+enddef ;
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Reading data files %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% Read a line from file f, extract whitespace-separated tokens ignoring any
+% initial "%", and return true if at least one token is found. The tokens
+% are stored in @#1, @#2, .. with "" in the last @#[] entry.
+
+% String manipulation routines for MetaPost
+% It is harmless to input this file more than once.
+
+vardef isdigit primary d =
+ ("0"<=d)and(d<="9")
+enddef ;
+
+% Number of initial characters of string s where `c <character>' is true
+
+vardef graph_cspan(expr s)(text c) =
+ 0
+ for i=1 upto length s:
+ exitunless c substring (i-1,i) of s;
+ + 1
+ endfor
+enddef ;
+
+% String s is composed of items separated by white space. Lop off the first
+% item and the surrounding white space and return just the item.
+
+vardef graph_loptok suffix s =
+ save t, k;
+ k = graph_cspan(s," ">=);
+ if k > 0 :
+ s := substring(k,infinity) of s ;
+ fi
+ k := graph_cspan(s," "<);
+ string t;
+ t = substring (0,k) of s;
+ s := substring (k,infinity) of s;
+ s := substring (graph_cspan(s," ">=),infinity) of s;
+ t
+enddef ;
+
+vardef graph_read_line@#(expr f) =
+ save n_, s_ ; string s_;
+ s_ = readfrom f ;
+ string @#[] ;
+ if s_<>EOF :
+ @#0 := s_ ;
+ @#1 := graph_loptok s_ ;
+ n_ = if @#1="%" : 0 else : 1 fi ;
+ forever :
+ @#[incr n_] := graph_loptok s_ ;
+ exitif @#[n_]="" ;
+ endfor
+ @#1<>""
+ else : false
+ fi
+enddef ;
+
+% Execute c for each line of data read from file f, and stop at the first
+% line with no data. Commands c can use line number i and tokens $1, $2, ...
+% and j is the number of fields.
+
+def gdata(expr f)(suffix $)(text c) =
+ %boolean flag ; % not used?
+ for i=1 upto largestmantissa :
+ exitunless graph_read_line$(f) ;
+ c
+ endfor
+ if graph_close_file :
+ closefrom f ;
+ fi
+enddef ;
+
+% Read a path from file f. The path is terminated by blank line or EOF.
+
+vardef graph_readpath(expr f) =
+ interim warningcheck :=0 ;
+ save s ;
+ gdata(f, s, if i>1 :--fi
+ if s2="" : ( i, scantokens s1)
+ else : (scantokens s1, scantokens s2) fi
+ )
+enddef ;
+
+% Append coordinates t to polygonal path @#. The coordinates can be numerics,
+% strings, or a single pair.
+
+vardef augment@#(text t) =
+ interim warningcheck := 0 ;
+ if not path begingroup @# endgroup :
+ graph_error(begingroup @# endgroup, "Cannot augment--not a path") ;
+ else :
+ def graph_comma= hide(def graph_comma=,enddef) enddef ;
+ if known @# : @# :=@#-- else : @#= fi
+ (for p=t :
+ graph_comma if string p : scantokens fi p
+ endfor) ;
+ fi
+enddef ;
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Drawing and filling %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% Unknown pair components are set to 0 because glabel and gdotlabel understand
+% unknown coordinates as `0 in absolute units'.
+
+vardef graph_unknown_pair_bbox(expr p) =
+ interim warningcheck:=0 ;
+ if known p : addto graph_current_bb doublepath p ;
+ else :
+ save x,y ;
+ z = llcorner graph_current_bb ;
+ if unknown xpart p : xpart p= else : x := fi 0 ;
+ if unknown ypart p : ypart p= else : y := fi 0 ;
+ addto graph_current_bb doublepath (p+z) ;
+ fi
+ graph_current_bb := image(fill llcorner graph_current_bb..urcorner graph_current_bb--cycle) ;
+enddef ;
+
+% Initiate a gdraw or gfill command. This must be done before scanning the
+% argument, because that could invoke the `if known graph_plot_picture' test in a following
+% plot option .
+
+def graph_addto =
+ def graph_errorbar_text = enddef ;
+ color graph_foreground ;
+ path graph_last_path ;
+ graph_last_drawn := graph_plot_picture := nullpicture ; addto graph_last_drawn
+enddef;
+
+% Handle the part of a gdraw command that uses path or data file p.
+
+def graph_draw expr p =
+ if string p : hide(graph_last_path := graph_readpath(p) ;)
+ graph_convert_user_path_to_internal graph_last_path
+ elseif path p or pair p :
+ hide(graph_last_path := p ;)
+ graph_convert_user_path_to_internal p
+ else : graph_error(p,"gdraw argument should be a data file or a path")
+ origin
+ fi
+ withpen currentpen graph_withlist _op_
+enddef ;
+
+% Handle the part of a gdraw command that uses path or data file p.
+
+def graph_fill expr p =
+ if string p : hide(graph_last_path := graph_readpath(p) --cycle ;)
+ graph_convert_user_path_to_internal graph_last_path
+ elseif cycle p : hide(graph_last_path := p ;)
+ graph_convert_user_path_to_internal p
+ else : graph_error(p,"gfill argument should be a data file or a cyclic path")
+ origin..cycle
+ fi graph_withlist _op_
+enddef ;
+
+def gdraw = graph_addto doublepath graph_draw enddef ;
+def gfill = graph_addto contour graph_fill enddef ;
+
+% This is used in graph_draw and graph_fill to allow postprocessing graph_last_drawn
+
+def graph_withlist text t_ = t_ ; graph_post_draw; enddef;
+
+def witherrorbars(text t) text options =
+ hide(
+ def graph_errorbar_text = t enddef ;
+ save pic ; picture pic ; pic := image(draw origin _op_ options ;) ;
+ if color colorpart pic : graph_foreground := colorpart pic ; fi
+ )
+ options
+enddef ;
+
+% new feature: graph_errorbars
+
+picture graph_errorbar_picture ; graph_errorbar_picture := image(draw (left--right) scaled .5 ;) ;
+%picture graph_xbar_picture ; graph_xbar_picture := image(draw (down--up) scaled .5 ;) ;
+%picture graph_ybar_picture ; graph_ybar_picture := image(draw (left--right) scaled .5 ;) ;
+
+vardef graph_errorbars(text t) =
+ if known graph_last_path :
+ save n, p, q ; path p ; pair q ;
+ save pic ; picture pic[] ; pic0 := nullpicture ;
+ pic1 := if known graph_xbar_picture : graph_xbar_picture
+ elseif known graph_errorbar_picture : graph_errorbar_picture rotated 90
+ else : nullpicture fi ;
+ pic2 := if known graph_ybar_picture : graph_ybar_picture
+ elseif known graph_errorbar_picture : graph_errorbar_picture
+ else : nullpicture fi ;
+ if length pic1>0 :
+ pic1 := pic1 scaled graph_shapesize ;
+ setbounds pic1 to origin..cycle ;
+ fi
+ if length pic2>0 :
+ pic2 := pic2 scaled graph_shapesize ;
+ setbounds pic2 to origin..cycle ;
+ fi
+ for i=0 upto length graph_last_path :
+ clearxy ; z = point i of graph_last_path ;
+ n := 1 ;
+ for $=t :
+ if known $ :
+ q := if path $ : if length $>i : point i of $ else : origin fi
+ elseif pair $ : $ elseif numeric $ : ($,$) else : origin fi ;
+ if q<>origin :
+ p := graph_convert_user_path_to_internal ((
+ if n=1 :
+ (-xpart q,0)--(ypart q,0)
+ else :
+ (0,-xpart q)--(0,ypart q)
+ fi ) shifted z) ;
+ addto pic0 doublepath p ;
+ if length pic[n]>0 :
+ if ypart q<>0 :
+ addto pic0 also pic[n] shifted point 1 of p ;
+ fi
+ if xpart q<>0 :
+ addto pic0 also pic[n] rotated 180 shifted point 0 of p ;
+ fi
+ fi
+ fi
+ fi
+ exitif incr n>3 ;
+ endfor
+ endfor
+ if length pic0>0 :
+ save bg, fg ; color bg, fg ;
+ bg := if known graph_background : graph_background else : background fi ;
+ fg := if known graph_foreground : graph_foreground else : black fi ;
+ addto graph_current_graph also pic0 withpen currentpen scaled 2 _op_ withcolor bg ;
+ addto graph_current_graph also pic0 withpen currentpen scaled .5 _op_ withcolor fg ;
+ fi
+ fi
+enddef ;
+
+% Set graph_plot_picture so the postprocessing step will plot picture p at each path knot.
+% Also select nullpen to suppress stroking.
+
+def plot expr p =
+ if known graph_plot_picture :
+ withpen nullpen
+ hide (graph_plot_picture := image(
+ if bounded p : for q within p : graph_addto_currentpicture q endfor % Save memory
+ else : graph_addto_currentpicture p
+ fi graph_setbounds origin..cycle))
+ fi
+enddef ;
+
+% This hides a semicolon that could prematurely end graph_withlist's text argument
+
+def graph_addto_currentpicture primary p = addto currentpicture also p ; enddef;
+def graph_setbounds = setbounds currentpicture to enddef ;
+
+def gdrawarrow = graph_number_of_arrowheads := 1 ; gdraw enddef;
+def gdrawdblarrow = graph_number_of_arrowheads := 2 ; gdraw enddef;
+
+% Post-process the filled or stroked picture graph_last_drawn as follows : (1) update
+% the bounding box information ; (2) transfer it to graph_current_graph unless the pen has
+% been set to nullpen to disable stroking ; (3) plot graph_plot_picture at each knot.
+
+vardef graph_post_draw =
+ save p ; path p ; p = pathpart graph_last_drawn ;
+ graph_unknown_pair_bbox(p) ;
+ if filled graph_last_drawn or not graph_is_null(penpart graph_last_drawn) :
+ addto graph_current_graph also graph_last_drawn ;
+ fi
+ graph_errorbars(graph_errorbar_text) ;
+ if length graph_plot_picture>0 :
+ for i=0 upto length p if cycle p : -1 fi :
+ addto graph_current_graph also graph_plot_picture shifted point i of p ;
+ endfor
+ picture graph_plot_picture ;
+ fi
+ if graph_number_of_arrowheads>0 :
+ graph_draw_arrowhead(p, graph_with_pen_and_color(graph_last_drawn)) ;
+ if graph_number_of_arrowheads>1 :
+ graph_draw_arrowhead(reverse p, graph_with_pen_and_color(graph_last_drawn)) ;
+ fi
+ graph_number_of_arrowheads := 0 ;
+ fi
+enddef ;
+
+vardef graph_is_null(expr p) = (urcorner p=origin) and (llcorner p=origin) enddef ;
+
+vardef graph_draw_arrowhead(expr p)(text w) = % Draw arrowhead for path p, with list w
+ %save r ; r := angle(precontrol infinity of p shifted -point infinity of p) ;
+ addto graph_current_graph also
+ image(fill arrowhead (graph_arrowhead_extent(precontrol infinity of p,point infinity of p)) w ;
+ draw arrowhead (graph_arrowhead_extent(precontrol infinity of p,point infinity of p)) w
+ undashed ;
+%if (r mod 90 <> 0) : % orientation can be wrong due to remapping
+% draw textext("\tfxx " & decimal r) shifted point infinity of p withcolor blue ;
+%fi
+ graph_setbounds point infinity of p..cycle ;
+ ) ; % rotatedabout(point infinity of p,-r) ;
+enddef ;
+
+vardef graph_arrowhead_extent(expr p, q) =
+ if p<>q : (q - 100pt*unitvector(q-p)) -- fi
+ q
+enddef ;
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Drawing labels %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% Argument c is a drawing command that needs an additional argument p that gives
+% a location in internal graph coords. Draw in graph_current_graph enclosed in a setbounds
+% path. Unknown components of p cause the setbounds path to have width or height 1 instead of 0.
+% Then graph_unknown_pair_bbox sets these components to 0 and graph_picture_conversion
+% suppresses subsequent repositioning.
+
+def graph_draw_label(expr p)(suffix $)(text c) =
+ save sdim_ ; pair sdim_;
+ sdim_ := (if unknown xpart p : 1+ fi 0, if unknown ypart p : 1+ fi 0) ;
+ graph_unknown_pair_bbox(p) ;
+ addto graph_current_graph also
+ image(c(p) ; graph_setbounds p--p+sdim_--cycle) _op_
+enddef ;
+
+% Stash the result drawing command c in the graph_label table using with list w and
+% an index based on angle mfun_laboff$.
+
+vardef graph_stash_label(suffix $)(text c) text w =
+ graph_label[1.5+angle mfun_laboff$ /90] = image(c(origin) w) ;
+enddef ;
+
+def graph_label_location primary p =
+ if pair p : graph_draw_label(p)
+ elseif numeric p : graph_draw_label(point p of pathpart graph_last_drawn)
+ else : graph_stash_label
+ fi
+enddef ;
+
+% Place label p at user graph coords t using with list w. (t is a time, a pair
+% or 2 numerics or strings).
+
+vardef glabel@#(expr p)(text t) text w =
+ graph_label_location graph_label_convert_user_to_internal(t) (@#,label@#(p)) w ; enddef;
+
+% Place label p at user graph coords t using with list w and draw a dot there.
+% (t is a time, a pair, or 2 numerics or strings).
+
+vardef gdotlabel@#(expr p)(text t) text w =
+ graph_label_location graph_label_convert_user_to_internal(t) (@#,dotlabel@#(p)) w ; enddef;
+
+def OUT = enddef ; % location text for outside labels
+
+%%%%%%%%%%%%%%%%%%%%%%%%%% Grid lines, ticks, etc. %%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% Grid lines and tick marks are transformed versions of the templates below.
+% In the template paths, (0,0) is on the edge of the frame and inward is to
+% the right.
+
+path graph_template.tick, graph_template.itick, graph_template.otick, graph_template.grid ;
+graph_template.tick = (-3.5bp,0)--(3.5bp,0) ;
+graph_template.itick = origin--(7bp,0) ;
+graph_template.otick = (-7bp,0)--origin ;
+graph_template.grid = origin--(1,0) ;
+
+vardef tick@#(expr f,u) text w = graph_tick_label(@#,@,false,f,u,w) ; enddef;
+
+vardef itick@#(expr f,u) text w = graph_tick_label(@#,@,false,f,u,w) ; enddef;
+
+vardef otick@#(expr f,u) text w = graph_tick_label(@#,@,false,f,u,w) ; enddef;
+
+vardef grid@#(expr f,u) text w = graph_tick_label(@#,@,true,f,u,w) ; enddef;
+
+
+% Produce a tick or grid mark for label suffix $, graph_template suffix $$,
+% coordinate value u, and with list w. Boolean c tells whether graph_template$$
+% needs scaling by X_.graph_dimensions or Y_.graph_dimensions,
+% and f gives a format string or a label picture.
+
+def graph_tick_label(suffix $,$$)(expr c, f, u)(text w) =
+ graph_draw_label(graph_label_convert_user_to_internal(graph_generate_label_position($,u)),,
+ draw graph_gridline_picture$($$,c,f,u,w) shifted)
+enddef ;
+
+% Generate label positioning arguments appropriate for label suffix $ and
+% coordinate u.
+
+def graph_generate_label_position(suffix $)(expr u) =
+ if pair u : u elseif xpart mfun_laboff.$=0 : u,whatever else : whatever,u fi
+enddef ;
+
+% Generate a picture of a grid line labeled with coordinate value u, picture
+% or format string f, and with list w. Suffix @# is bot, top, lft, or rt,
+% suffix $ identifies entries in the graph_template table, and boolean c tells
+% whether to scale graph_template$.
+
+vardef graph_gridline_picture@#(suffix $)(expr c, f, u)(text w) =
+ if unknown u : graph_error(u,"Label coordinate should be known") ; nullpicture
+ else :
+ save p ; path p;
+ interim warningcheck :=0 ;
+ graph_autogrid_needed :=false ;
+ p = graph_template$ zscaled -mfun_laboff@#
+ if c : graph_xyscale fi
+ shifted (((.5 + mfun_laboff@# dotprod (.5,.5)) * mfun_laboff@#) graph_xyscale) ;
+ image(draw p w ;
+ label@#(if string f : format(f,u) else : f fi, point 0 of p))
+ fi
+enddef ;
+
+def graph_xyscale = xscaled X_.graph_dimensions yscaled Y_.graph_dimensions enddef ;
+
+% Draw the frame or the part corresponding to label suffix @# using with list w.
+
+vardef frame@# text w =
+ graph_frame_needed :=false ;
+ picture p_ ;
+ p_ = image(draw
+ if str@#<>"" : subpath round(angle mfun_laboff@#*graph_frame_pair_a+graph_frame_pair_b) of fi
+ unitsquare graph_xyscale w) ;
+ graph_draw_label((whatever,whatever),,draw p_ shifted) ;
+enddef ;
+
+pair graph_frame_pair_a ; graph_frame_pair_a=(1,1)/90; % unitsquare subpath is linear in label angle
+pair graph_frame_pair_b ; graph_frame_pair_b=(.75,2.25);
+
+%%%%%%%%%%%%%%%%%%%%%%%%%% Automatic grid selection %%%%%%%%%%%%%%%%%%%%%%%%%%
+
+string graph_log_marks[] ; % marking options per decade for logarithmic scales
+string graph_lin_marks ; % mark spacing options per decade for linear scales
+string graph_exp_marks ; % exponent spacing options for logarithmic scales
+newinternal graph_minimum_number_of_marks, graph_log_minimum ;
+graph_minimum_number_of_marks := 4 ; % minimum number marks generated by auto.x or auto.y
+graph_log_minimum := mlog 3 ; % revert to uniform marks when largest/smallest < this
+
+def Gfor(text t) = for i=t endfor enddef ; % to shorten the mark templates below
+
+graph_log_marks[1]="1,2,5" ;
+graph_log_marks[2]="1,1.5,2,3,4,5,7" ;
+graph_log_marks[3]="1Gfor(6upto10 :,i/5)Gfor(5upto10 :,i/2)Gfor(6upto9 :,i)" ;
+graph_log_marks[4]="1Gfor(11upto20 :,i/10)Gfor(11upto25 :,i/5)Gfor(11upto19 :,i/2)" ;
+graph_log_marks[5]="1Gfor(21upto40 :,i/20)Gfor(21upto50 :,i/10)Gfor(26upto49 :,i/5)" ;
+graph_lin_marks="10,5,2" ; % start with 10 and go down; a final `,1' is appended
+graph_exp_marks="20,10,5,2,1" ;
+
+Ten_to0 = 1 ;
+Ten_to1 = 10 ;
+Ten_to2 = 100 ;
+Ten_to3 = 1000 ;
+Ten_to4 = 10000 ;
+
+% Determine the X_ or Y_ bounds on the range to be covered by automatic grid
+% marks. Suffix @# is X_ or Y_. The result is log or linear to specify the
+% type of grid spacing to use. Bounds are returned in variables local to
+% begingraph..endgraph : pairs graph_modified_lower and graph_modified_higher
+% are upper and lower bounds in
+% `modified exponential form'. In modified exponential form, (x,y) means
+% (x/1000)*10^y, where 1000<=abs x<10000.
+
+vardef graph_bounds@# =
+ interim warningcheck :=0 ;
+ save l, h ;
+ graph_set_default_bounds ;
+ if @#graph_coordinate_type>0 : (l,h) else : -(h,l) fi = (@#low, @#high) ;
+ if abs @#graph_coordinate_type=log :
+ graph_modified_lower := graph_Meform(l)+graph_modified_bias ;
+ graph_modified_higher := graph_Meform(h)+graph_modified_bias ;
+ if h-l >= graph_log_minimum : log else : linear fi
+ else :
+ graph_modified_lower := graph_Feform(l)+graph_modified_bias ;
+ graph_modified_higher := graph_Feform(h)+graph_modified_bias ;
+ linear
+ fi
+enddef ;
+
+pair graph_modified_bias ; graph_modified_bias=(0,3);
+pair graph_modified_lower, graph_modified_higher ;
+
+% Scan graph_log_marks[k] and evaluate tokens t for each m where l<=m<=h.
+
+def graph_scan_marks(expr k, l, h)(text t) =
+ for m=scantokens graph_log_marks[k] :
+ exitif m>h ;
+ if m>=l : t fi
+ endfor
+enddef ;
+
+% Scan graph_log_marks[k] and evaluate tokens t for each m and e where m*10^e belongs
+% between l and h (inclusive), where both l and h are in modified exponent form.
+
+def graph_scan_mark(expr k, l, h)(text t) =
+ for e=ypart l upto ypart h :
+ graph_scan_marks(k, if e>ypart l : 1 else : xpart l/1000 fi,
+ if e<ypart h : 10 else : xpart h/1000 fi, t)
+ endfor
+enddef ;
+
+% Select a k for which graph_scan_mark(k,...) gives enough marks.
+
+vardef graph_select_mark =
+ save k ;
+ k = 0 ;
+ forever :
+ exitif unknown graph_log_marks[k+1] ;
+ exitif 0 graph_scan_mark(incr k, graph_modified_lower, graph_modified_higher, +1)
+ >= graph_minimum_number_of_marks ;
+ endfor
+ k
+enddef ;
+
+% Try to select an exponent spacing from graph_exp_marks. If successful, set @# and
+% return true
+
+vardef graph_select_exponent_mark@# =
+ numeric @# ;
+ for e=scantokens graph_exp_marks :
+ @# = e ;
+ exitif floor(ypart graph_modified_higher/e) -
+ floor(graph_modified_exponent_ypart(graph_modified_lower)/e)
+ >= graph_minimum_number_of_marks ;
+ numeric @# ;
+ endfor
+ known @#
+enddef ;
+
+vardef graph_modified_exponent_ypart(expr p) = ypart p if xpart p=1000 : -1 fi enddef ;
+
+% Compute the mark spacing d between xpart graph_modified_lower and xpart graph_modified_higher.
+
+vardef graph_tick_mark_spacing =
+ interim warningcheck :=0 ;
+ save m, n, d ;
+ m = graph_minimum_number_of_marks ;
+ n = 1 for i=1 upto
+ (mlog(xpart graph_modified_higher-xpart graph_modified_lower) - mlog m)/mlogten :
+ *10 endfor ;
+ if n<=1000 :
+ for x=scantokens graph_lin_marks :
+ d = n*x ;
+ exitif 0 graph_generate_numbers(d,+1)>=m ;
+ numeric d ;
+ endfor
+ fi
+ if known d : d else : n fi
+enddef ;
+
+def graph_generate_numbers(expr d)(text t) =
+ for m = d*ceiling(xpart graph_modified_lower/d) step d until xpart graph_modified_higher :
+ t
+ endfor
+enddef ;
+
+% Evaluate tokens t for exponents e in multiples of d in the range determined
+% by graph_modified_lower and graph_modified_higher.
+
+def graph_generate_exponents(expr d)(text t) =
+ for e = d*floor(graph_modified_exponent_ypart(graph_modified_lower)/d+1)
+ step d until d*floor(ypart graph_modified_higher/d) : t
+ endfor
+enddef ;
+
+% Adjust graph_modified_lower and graph_modified_higher so their exponent parts match
+% and they are in true exponent form ((x,y) means x*10^y). Return the new exponent.
+
+vardef graph_match_exponents =
+ interim warningcheck := 0 ;
+ save e ;
+ e+3 = if graph_modified_lower=graph_modified_bias : ypart graph_modified_higher
+ elseif graph_modified_higher=graph_modified_bias : ypart graph_modified_lower
+ else : max(ypart graph_modified_lower, ypart graph_modified_higher) fi ;
+ forsuffixes $=graph_modified_lower, graph_modified_higher :
+ $ := (xpart $ for i=ypart $ upto e+2 : /(10) endfor, e) ;
+ endfor
+ e
+enddef ;
+
+% Assume e is an integer and either m=0 or 1<=abs(m)<10000. Find m*(10^e)
+% and represent the result as a string if its absolute value would be at least
+% 4096 or less than .1. It is OK to return 0 as a string or a numeric.
+
+vardef graph_factor_and_exponent_to_string(expr m, e) =
+ if (e>3)or(e<-4) :
+ decimal m & "e" & decimal e
+ elseif e>=0 :
+ if abs m<infinity/Ten_to[e] :
+ m*Ten_to[e]
+ else : decimal m & "e" & decimal e
+ fi
+ else :
+ save x ; x=m/Ten_to[-e];
+ if abs x>=.1 : x else : decimal m & "e" & decimal e fi
+ fi
+enddef ;
+
+def auto suffix $ =
+ hide(def graph_comma= hide(def graph_comma=,enddef) enddef)
+ if graph_bounds.graph_suffix($)=log :
+ if graph_select_exponent_mark.graph_exponent :
+ graph_generate_exponents(graph_exponent,
+ graph_comma graph_factor_and_exponent_to_string(1,e))
+ else :
+ graph_scan_mark(graph_select_mark, graph_modified_lower, graph_modified_higher,
+ graph_comma graph_factor_and_exponent_to_string(m,e))
+ fi
+ else :
+ hide(graph_exponent :=graph_match_exponents)
+ graph_generate_numbers(graph_tick_mark_spacing,
+ graph_comma graph_factor_and_exponent_to_string(m,graph_exponent))
+ fi
+enddef ;
+
+string Autoform ; Autoform = "%g";
+
+%vardef autogrid(suffix tx, ty) text w =
+% graph_autogrid_needed :=false ;
+% if str tx<>"" : for x=auto.x : tx(Autoform,x) w ; endfor fi
+% if str ty<>"" : for y=auto.y : ty(Autoform,y) w ; endfor fi
+%enddef ;
+
+% We redefine autogrid, adding the possibility of differing X and Y
+% formats.
+
+% string Autoform_X ; Autoform_X := "@.0e" ;
+% string Autoform_Y ; Autoform_Y := "@.0e" ;
+
+vardef autogrid(suffix tx, ty) text w =
+ graph_autogrid_needed := false ;
+ if str tx <> "" :
+ for x=auto.x :
+ tx (
+ if string Autoform_X :
+ if Autoform_X <> "" :
+ Autoform_X
+ else :
+ Autoform
+ fi
+ else :
+ Autoform
+ fi,
+ x
+ ) w ;
+ endfor
+ fi
+ if str ty <> "" :
+ for y=auto.y :
+ ty (
+ if string Autoform_Y :
+ if Autoform_Y <> "" :
+ Autoform_Y
+ else :
+ Autoform
+ fi
+ else :
+ Autoform
+ fi,
+ y
+ ) w ;
+ endfor
+ fi
+enddef ;
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% endgraph %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+def endgraph =
+ if graph_autogrid_needed : autogrid(otick.bot, otick.lft) ; fi
+ if graph_frame_needed : frame ; fi
+ setcoords(linear,linear) ;
+ interim truecorners :=1 ;
+ for b=bbox graph_finished_graph :
+ setbounds graph_finished_graph to b ;
+ for i=0 step .5 until 3.5 :
+ if known graph_label[i] :
+ addto graph_finished_graph also graph_label[i] shifted point i of b ;
+ fi
+ endfor
+ endfor
+ graph_finished_graph
+ endgroup
+enddef ;
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% We format in luatex (using \mathematics{}) ...
+% we could pass via variables and save escaping as that is inefficient
+
+if unknown context_mlib :
+
+ vardef escaped_format(expr s) =
+ "" for n=0 upto length(s) : &
+ if ASCII substring (n,n+1) of s = 37 :
+ "@"
+ else :
+ substring (n,n+1) of s
+ fi
+ endfor
+ enddef ;
+
+ vardef strfmt(expr f, x) = % maybe use mfun_ namespace
+ "\MPgraphformat{" & escaped_format(f) & "}{" & mfun_tagged_string(x) & "}"
+ enddef ;
+
+ vardef varfmt(expr f, x) = % maybe use mfun_ namespace
+ "\MPformatted{" & escaped_format(f) & "}{" & mfun_tagged_string(x) & "}"
+ enddef ;
+
+ vardef format (expr f, x) = textext(strfmt(f,x)) enddef ;
+ vardef formatted(expr f, x) = textext(varfmt(f,x)) enddef ;
+
+fi ;
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% A couple of extensions :
+
+% Define a function plotsymbol() returning a picture : 10 different shapes,
+% unfilled outline, interior filled with different shades of the background.
+% This allows overlapping points on a plot to be more distinguishable.
+
+vardef graph_shapesize = (.33BodyFontSize) enddef ;
+
+path graph_shape[] ; % (internal) symbol path
+
+graph_shape[0] := (0,0) ; % point
+graph_shape[1] := fullcircle ; % circle
+graph_shape[2] := (up -- down) scaled .5 ; % vertical bar
+
+for i = 3 upto 9 : % polygons
+ graph_shape[i] :=
+ for j = 0 upto i-1 :
+ (up scaled .5) rotated (360j/i) --
+ endfor cycle ;
+endfor
+
+graph_shape[12] := graph_shape[2] rotated +90 ; % horizontal line
+graph_shape[22] := graph_shape[2] rotated +45 ; % backslash
+graph_shape[32] := graph_shape[2] rotated -45 ; % slash
+graph_shape[13] := graph_shape[3] rotated 180 ; % down triangle
+graph_shape[23] := graph_shape[3] rotated -90 ; % right triangle
+graph_shape[33] := graph_shape[3] rotated +90 ; % left triangle
+graph_shape[14] := graph_shape[4] rotated +45 ; % square
+graph_shape[15] := graph_shape[5] rotated 180 ; % down pentagon
+graph_shape[16] := graph_shape[6] rotated +90 ; % turned hexagon
+graph_shape[17] := graph_shape[7] rotated 180 ;
+graph_shape[18] := graph_shape[8] rotated +22.5 ;
+
+numeric l ;
+
+for j = 5 upto 9 :
+ l := length(graph_shape[j]) ;
+ pair p[] ;
+ for i = 0 upto l :
+ p[i] = whatever [point i of graph_shape[j],
+ point (i+2 mod l) of graph_shape[j]] ;
+ p[i] = whatever [point (i+1 mod l) of graph_shape[j],
+ point (i+l-1 mod l) of graph_shape[j]] ;
+ endfor
+ graph_shape[20+j] := for i = 0 upto l : point i of graph_shape[j]--p[i]--endfor cycle ;
+endfor
+
+path s ; s := graph_shape[4] ;
+path q ; q := s scaled .25 ;
+numeric l ; l := length(s) ;
+
+pair p[] ;
+
+graph_shape[24] := for i = 0 upto l-1 :
+ hide(
+ p[i] = whatever [point i of s, point (i+1 mod l) of s] ;
+ p[i] = whatever [point i of q, point (i-1+l mod l) of q] ;
+ p[i+l] = whatever [point i of s, point (i+1 mod l) of s] ;
+ p[i+l] = whatever [point i+1 of q, point (i+2 mod l) of q] ;
+ )
+ point i of q -- p[i] -- p[i+l] --
+endfor cycle ;
+
+graph_shape[34] := graph_shape[24] rotated 45 ;
+
+% usage : gdraw p plot plotsymbol( 1,1) ; % a filled circle
+% usage : gdraw p plot plotsymbol(14,0) ; % a square
+% usage : gdraw p plot plotsymbol( 4,.5) ; % a 50% filled diamond
+
+def stars(expr f) = plotsymbol(25,f) enddef ; % a 5-point star
+def points(expr f) = plotsymbol( 0,f) enddef ;
+def circles(expr f) = plotsymbol( 1,f) enddef ;
+def crosses(expr f) = plotsymbol(34,f) enddef ;
+def squares(expr f) = plotsymbol(14,f) enddef ;
+def diamonds(expr f) = plotsymbol( 4,f) enddef ; % a turned square
+def uptriangles(expr f) = plotsymbol( 3,f) enddef ;
+def downtriangles(expr f) = plotsymbol(13,f) enddef ;
+def lefttriangles(expr f) = plotsymbol(33,f) enddef ;
+def righttriangles(expr f) = plotsymbol(23,f) enddef ;
+
+% f (fill) is color, numeric or boolean, otherwise background.
+def plotsymbol(expr n, f) text t =
+ if known graph_shape[n] :
+ image(
+ save bg, fg ; color bg, fg ;
+ bg := if known graph_background : graph_background else : background fi ;
+ save pic ; picture pic ; pic := image(draw origin _op_ t ;) ;
+ if color colorpart pic : graph_foreground := colorpart pic ; fi
+ fg := if known graph_foreground : graph_foreground else : black fi ;
+ save p ; path p ; p = graph_shape[n] scaled graph_shapesize ;
+ draw p withcolor bg withpen currentpen scaled 2 ; % halo
+ currentpen := currentpen scaled .5 ;
+ if cycle p :
+ fill p withcolor
+ if known f :
+ if color f :
+ f
+ elseif numeric f :
+ f[bg,fg]
+ elseif boolean f and f :
+ fg
+ else
+ bg
+ fi
+ else :
+ bg
+ fi ;
+ fi
+ draw p _op_ t ;
+ )
+ else :
+ nullpicture
+ fi
+ t
+enddef ;
+
+% standard resistance color code: rainbow sequence (from /usr/share/X11/rgb.txt)
+color resistance_color[] ; string resistance_name[] ;
+resistance_color0 = (0,0,0) ; resistance_name0 = "black" ;
+resistance_color1 = (165/255,42/255,42/255) ; resistance_name1 = "brown" ;
+resistance_color2 = (1,0,0) ; resistance_name2 = "red" ;
+resistance_color3 = (1,165/255,0) ; resistance_name3 = "orange" ;
+resistance_color4 = (1,1,0) ; resistance_name4 = "yellow" ;
+resistance_color5 = (0,1,0) ; resistance_name5 = "green" ;
+resistance_color6 = (0,0,1) ; resistance_name6 = "blue" ;
+resistance_color7 = (148/255,0,211/255) ; resistance_name7 = "darkviolet" ;
+resistance_color8 = (190/255,190/255,190/255) ; resistance_name8 = "gray" ;
+resistance_color9 = (1,1,1) ; resistance_name9 = "white" ;
+
+%def rainbow(expr f) =
+% ((abs(5f) mod 5) + 2 - floor((abs(5f) mod 5) + 2))
+% [resistance_color[ floor((abs(5f) mod 5) + 2)],
+% resistance_color[ceiling((abs(5f) mod 5) + 2)]]
+%enddef ;
+def rainbow(expr f) =
+ hide(numeric n_ ; n_ = (abs(5f) mod 5) + 2 ;)
+ (n_-floor(n_))[resistance_color[floor n_],resistance_color[ceiling n_]]
+enddef ;
+
+% The following extensions are not specific to graph and could be moved to metafun...
+
+% sort a path. Efficient en memory use, not so efficient in sorting long paths...
+
+vardef sortpath (suffix $) (text t) = % t can be "xpart", "ypart", "length", "angle", ...
+ if path $ :
+ if length $ > 0 :
+ save n, k ; n := length $ ;
+ for i=0 upto n :
+ k := i ;
+ for j=i+1 upto n :
+ if t (point j of $) < t (point k of $) :
+ k := j ;
+ fi
+ endfor
+ if k>i :
+ $ := if i>0 : subpath (0,i-1) of $ -- fi
+ point k of $ --
+ subpath (i,k-1) of $
+ if k<n : -- subpath (k+1,n) of $ fi
+ ;
+ fi
+ endfor
+ fi
+ fi
+enddef ;
+
+% convert a polygon path to a smooth path (useful, e.g. as a guide to the eye)
+
+def smoothpath (suffix $) =
+ if path $ :
+ (for i=0 upto length $ :
+ if i>0 : .. fi
+ (point i of $)
+ endfor )
+ fi
+enddef ;
+
+% return a path of a function func(x) with abscissa running from f to t over n intervals
+
+def makefunctionpath (expr f, t, n) (text func) =
+ (for x=f step ((t-f)/(abs n)) until t :
+ if x<>f : -- fi
+ (x, func)
+ endfor )
+enddef ;
+
+% shift a path, point by point
+%
+% example :
+%
+% p1 := addtopath(p0,(.1normaldeviate,.1normaldeviate)) ;
+
+vardef addtopath (suffix p) (text t) =
+ if path p :
+ (for i=0 upto length p :
+ if i>0 : -- fi
+ hide(clearxy ; z = point i of p ;) z shifted t
+ endfor)
+ fi
+enddef ;
+
+% return a new path of a function func(z) using the same abscissa as an existing path
+
+vardef functionpath (suffix p) (text func) =
+ (for i=0 upto length p :
+ if i>0 : .. fi
+ (hide(x := xpart(point i of p))x,func) %(hide(clearxy ; z = point i of p)x,func)
+ endfor )
+enddef ;
+
+% least-squares "fit" to a polynomial
+%
+% example :
+%
+% path p[] ;
+% numeric a[] ; a0 := 1 ; a1 := .1 ; a2 := .01 ; a3 := .001 ; a4 := 0.0001 ;
+% p0 := makefunctionpath(0,5,10,polynomial_function(a,4,x)) ;
+% p1 := addtopath(p0,(0,.001normaldeviate)) ;
+% gdraw p0 ;
+% gdraw p1 plot plotsymbol(1,.5) ;
+%
+% numeric b[] ;
+% polynomial_fit(p1, b, 4, 1) ;
+% gdraw functionpath(p1,polynomial_function(b,4,x)) ;
+%
+% numeric c[] ;
+% linear_fit(p1, c, 1) ;
+% gdraw functionpath(p1,linear_function(c,x)) dashed evenly ;
+
+% a polynomial function :
+%
+% y = a0 + a1 * x + a2 * x^2 + ... + a[n] * x^n
+
+vardef polynomial_function (suffix $) (expr n, x) =
+ (for j=0 upto n : + $[j]*(x**j) endfor) % no ;
+enddef ;
+
+% find the determinant of a (n+1)*(n+1) matrix ; indices run from 0 to n
+
+vardef det (suffix $) (expr n) =
+ hide(
+ numeric determinant ; determinant := 1 ;
+ save jj ; numeric jj ;
+ for k=0 upto n :
+ if $[k][k]=0 :
+ jj := -1 ;
+ for j=0 upto n :
+ if $[k][j]<>0 :
+ jj := j ;
+ exitif true ;
+ fi
+ endfor
+ if jj<0 :
+ determinant := 0 ;
+ exitif true ;
+ fi
+ for j=k upto n : % interchange the columns
+ temp := $[j][jj] ;
+ $[j][jj] := $[j][k] ;
+ $[j][k] := temp ;
+ endfor
+ determinant = -determinant ;
+ fi
+ exitif determinant=0 ;
+ determinant := determinant * $[k][k] ;
+ if k<n : % subtract row k from lower rows to get a diagonal matrix
+ for j=k+1 upto n :
+ for i=k+1 upto n :
+ $[j][i] := $[j][i]-$[j][k]*$[k][i]/$[k][k] ;
+ endfor
+ endfor
+ fi
+ endfor ;
+ )
+ determinant % no ;
+enddef ;
+
+numeric fit_chi_squared ;
+
+% least-squares fit of a polynomial $ of order n to a path p (unweighted)
+%
+% reference : P. R. Bevington, "Data Reduction and Error Analysis for the Physical
+% Sciences", McGraw-Hill, New York 1969.
+
+vardef polynomial_fit (suffix p, $) (expr n) (text t) =
+ if not path p :
+ graph_error(p, "Cannot fit--not a path") ;
+ elseif length p < n :
+ graph_error(p, "Cannot fit--not enough points") ;
+ else :
+ fit_chi_squared := 0 ;
+ % calculate sums of the data
+ save sumx, sumy ; numeric sumx[], sumy[] ;
+ save w ; numeric w ;
+ for i=0 upto 2n :
+ sumx[i] := 0 ;
+ endfor
+ for i=0 upto n :
+ sumy[i] := 0 ;
+ endfor
+ for i=0 upto length p :
+ clearxy ; z = point i of p ;
+ w := 1 ; % weight
+ if known t :
+ if numeric t :
+ w := 1 if t<>0 : /(abs t) fi ;
+ elseif pair t :
+ if t<>origin :
+ w := 1/(abs t) ;
+ fi
+ elseif path t :
+ if length t>= i:
+ if point i of t<>origin :
+ w := 1/(abs point i of t) ;
+ fi
+ else :
+ w := 0 ;
+ fi ;
+ fi
+ fi
+ x1 := w ;
+ for j=0 upto 2n :
+ sumx[j] := sumx[j] + x1 ;
+ x1 := x1 * x ;
+ endfor
+ y1 := y * w ;
+ for j=0 upto n :
+ sumy[j] := sumy[j] + y1 ;
+ y1 := y1 * x ;
+ endfor
+ fit_chi_squared := fit_chi_squared + y*y*w ;
+ endfor
+ % construct matrices and calculate the polynomial coefficients
+ save m ; numeric m[][] ;
+ for j=0 upto n :
+ for k=0 upto n :
+ m[j][k] := sumx[j+k] ;
+ endfor
+ endfor
+ save delta ; numeric delta ;
+ delta := det(m,n) ; % this destroys the matrix m[][], which is OK
+ if delta = 0 :
+ fit_chi_squared := 0 ;
+ for j=0 upto n :
+ $[j] := 0 ;
+ endfor
+ else :
+ for i=0 upto n :
+ for j=0 upto n :
+ for k=0 upto n :
+ m[j][k] := sumx[j+k] ;
+ endfor
+ m[j][i] := sumy[j] ;
+ endfor
+ $[i] := det(m,n) / delta ; % matrix m[][] gets destroyed...
+ endfor
+ for j=0 upto n :
+ fit_chi_squared := fit_chi_squared - 2sumy[j]*$[j] ;
+ for k=0 upto n :
+ fit_chi_squared := fit_chi_squared + $[j]*$[k]*sumx[j+k] ;
+ endfor
+ endfor
+ % normalize by the number of degrees of freedom
+ fit_chi_squared := fit_chi_squared / (length(p) - n) ; % length(p)+1-(n+1)
+ fi
+ fi
+enddef ;
+
+% y = a0 + a1 * x
+%
+% of course a line is just a polynomial of order 1
+
+vardef linear_function (suffix $) (expr x) = polynomial_function($,1,x) enddef ;
+vardef linear_fit (suffix p, $) (text t) = polynomial_fit(p, $, 1, t) ; enddef ;
+
+% and a constant is polynomial of order 0
+
+vardef constant_function (suffix $) (expr x) = polynomial_function($,0,x) enddef ;
+vardef constant_fit (suffix p, $) (text t) = polynomial_fit(p, $, 0, t) ; enddef ;
+
+% y = a1 * exp(a0*x)
+%
+% exp and ln defined in metafun
+
+vardef exponential_function (suffix $) (expr x) = $1*exp($0*x) enddef ;
+
+% since we take a log, this only works for positive ordinates
+
+vardef exponential_fit (suffix p, $) (text t) =
+ save a ; numeric a[] ;
+ save q ; path q[] ; % fit to the log of the ordinate
+ for i=0 upto length p :
+ clearxy ; z = point i of p ;
+ if y>0 :
+ augment.q0(x,ln(y)) ;
+ augment.q1(
+ if known t :
+ if numeric t : (0,ln(t))
+ elseif pair t : (xpart t,ln(ypart t))
+ elseif path t :
+ if length t>=i :
+ hide(z1 = point i of t;)
+ (x1,ln(y1))
+ else :
+ origin
+ fi
+ fi
+ else :
+ (0,1)
+ fi ) ;
+ fi
+ endfor
+ linear_fit(q0,a,q1) ;
+ save e ; e := exp(sqrt(fit_chi_squared)) ;
+ fit_chi_squared := e * e ;
+ $0 := a1 ;
+ $1 := exp(a0) ;
+enddef ;
+
+% y = a1 * x**a0
+
+vardef power_law_function (suffix $) (expr x) = $1*(x**$0) enddef ;
+
+% since we take logs, this only works for positive abscissae and ordinates
+
+vardef power_law_fit (suffix p, $) (text t) =
+ save a ; numeric a[] ;
+ save q ; path q[] ; % fit to the logs of the abscissae and ordinates
+ for i=0 upto length p :
+ clearxy ; z = point i of p ;
+ if (x>0) and (y>0) :
+ augment.q0(ln(x),ln(y)) ;
+ augment.q1(
+ if known t :
+ if numeric t : (0,ln(t))
+ elseif pair t : (ln(xpart t),ln(ypart t))
+ elseif path t :
+ if length t>=i :
+ hide(z1 = point i of t)
+ (ln(x1),ln(y1))
+ else :
+ origin
+ fi
+ fi
+ else :
+ (0,1)
+ fi ) ;
+ fi
+ endfor
+ linear_fit(q0,a,q1) ;
+ save e ; e := exp(sqrt(fit_chi_squared)) ;
+ fit_chi_squared := e * e ;
+ $0 := a1 ;
+ $1 := exp(a0) ;
+enddef ;
+
+% gaussian : y = a2 * exp(-ln(2)*((x-a0)/a1)^2)
+%
+% a1 is the hwhm ; sigma := a1/sqrt(2ln(2)) or a1/1.17741
+
+newinternal lntwo ; lntwo := ln(2) ; % brrr, why not inline it
+
+vardef gaussian_function (suffix $) (expr x) =
+ if $1 = 0 :
+ if x = $0 : $2 else : 0 fi
+ else :
+ $2 * exp(-lntwo*(((x-$0)/$1)**2))
+ fi
+ if known $3 :
+ + $3
+ fi
+enddef ;
+
+% since we take a log, this only works for positive ordinates
+
+vardef gaussian_fit (suffix p, $) (text t) =
+ save a ; numeric a[] ;
+ save q ; path q[] ; % fit to the log of the ordinate
+ for i=0 upto length p :
+ clearxy ; z = point i of p ;
+ if y>0 :
+ augment.q0(x,ln(y)) ;
+ augment.q1(
+ if known t :
+ if numeric t : (0,ln(t))
+ elseif pair t : (xpart t,ln(ypart t))
+ elseif path t :
+ if length t>=i :
+ hide(z1 = point i of t)
+ (x1,ln(y1))
+ else :
+ origin
+ fi
+ fi
+ else :
+ (0,1)
+ fi ) ;
+ fi
+ endfor
+ polynomial_fit(q0,a,2,q1) ;
+ save e ; e := exp(sqrt(fit_chi_squared)) ;
+ fit_chi_squared := e * e ;
+ $1 := sqrt(-lntwo/a2) ;
+ $0 := -.5a1/a2 ;
+ $2 := exp(a0-.25*a1*a1/a2) ;
+ $3 := 0 ; % polynomial_fit will NOT work with a non-zero background!
+enddef ;
+
+% lorentzian: y = a2 / (1 + ((x - a0)/a1)^2)
+
+vardef lorentzian_function (suffix $) (expr x) =
+ if $1 = 0 :
+ if x = $0 : $2 else : 0 fi
+ else :
+ $2 / (1 + ((x - $0)/$1)**2)
+ fi
+ if known $3 :
+ + $3
+ fi
+enddef ;
+
+vardef lorentzian_fit (suffix p, $) (text t) =
+ save a ; numeric a[] ;
+ save q ; path q ; % fit to the inverse of the ordinate
+ for i=0 upto length p :
+ if ypart(point i of p)<>0 :
+ augment.q(xpart(point i of p), 1/ypart(point i of p)) ;
+ fi
+ endfor
+ polynomial_fit(q,a,2,if t <> 0 : 1/(t) else : 0 fi) ;
+ fit_chi_squared := 1/fit_chi_squared ;
+ $0 := -.5a1/a2 ;
+ $2 := 1/(a0-.25a1*a1/a2) ;
+ $1 := sqrt((a0-.25a1*a1/a2)/a2) ;
+ $3 := 0 ; % polynomial_fit will NOT work with a non-zero background!
+enddef ;