===================================================================
RCS file: /home/cvs/OpenXM_contrib/gnuplot/term/Attic/tkcanvas.trm,v
retrieving revision 1.1.1.1
retrieving revision 1.1.1.2
diff -u -p -r1.1.1.1 -r1.1.1.2
--- OpenXM_contrib/gnuplot/term/Attic/tkcanvas.trm	2000/01/09 17:01:16	1.1.1.1
+++ OpenXM_contrib/gnuplot/term/Attic/tkcanvas.trm	2000/01/22 14:16:30	1.1.1.2
@@ -1,5 +1,5 @@
 /*
- * $Id: tkcanvas.trm,v 1.1.1.1 2000/01/09 17:01:16 maekawa Exp $
+ * $Id: tkcanvas.trm,v 1.1.1.2 2000/01/22 14:16:30 maekawa Exp $
  *
  */
 
@@ -57,6 +57,21 @@
  * adapted to the new terminal layout by Alex Woo (Sept. 1996)
  */
 
+/*
+ * extended interactive Tk/Tcl capabilities 
+ * Thomas Sefzick, March 1999, t.sefzick@fz-juelich.de
+ *
+ * added the perltk.trm code written by Slaven Rezic <eserte@cs.tu-berlin.de>,
+ * the variable 'tk_perl' switches between tcl/tk and perltk code.
+ * 'linewidth' and 'justify text' added, ends of plotted lines are now rounded.
+ * if 'perltk' is chosen, perl code is produced, otherwise tcl code.
+ * Thomas Sefzick, May 1999, t.sefzick@fz-juelich.de
+ *
+ * scale plot to fit into the actual size of the canvas as reported by
+ * the window manager (the canvas itself doesn't report its real size).
+ * Matt Willis, October 1999, mattbwillis@my-deja.com
+ */
+
 #include "driver.h"
 
 #ifdef TERM_REGISTER
@@ -64,6 +79,7 @@ register_term(tkcanvas)
 #endif
 
 #ifdef TERM_PROTO
+TERM_PUBLIC void TK_options __PROTO((void));
 TERM_PUBLIC void TK_init __PROTO((void));
 TERM_PUBLIC void TK_graphics __PROTO((void));
 TERM_PUBLIC void TK_text __PROTO((void));
@@ -72,6 +88,9 @@ TERM_PUBLIC void TK_move __PROTO((unsigned int x, unsi
 TERM_PUBLIC void TK_vector __PROTO((unsigned int x, unsigned int y));
 TERM_PUBLIC void TK_put_text __PROTO((unsigned int x, unsigned int y, char *str));
 TERM_PUBLIC void TK_reset __PROTO((void));
+TERM_PUBLIC int TK_justify_text __PROTO((enum JUSTIFY));
+TERM_PUBLIC int TK_set_font __PROTO((char *font));
+TERM_PUBLIC void TK_linewidth __PROTO((double linewidth));
 
 #define TK_XMAX 1000
 #define TK_YMAX 1000
@@ -88,89 +107,474 @@ TERM_PUBLIC void TK_reset __PROTO((void));
 #ifndef TERM_PROTO_ONLY
 #ifdef TERM_BODY
 
-static int tk_angle = 0;
+/* plot2d.c */
+extern double min_array[], max_array[], base_array[], log_base_array[];
+extern TBOOLEAN log_array[];
+/* graphics.c */
+extern int xleft, xright, ybot, ytop;
+extern TBOOLEAN is_3d_plot;
+
+/* static int tk_angle = 0; unused, for now */
 static int tk_lastx;
 static int tk_lasty;
 static int tk_color = 0;
-static char *tk_colors[] = { "black", "gray", "red", "blue", "green", "brown", "magenta", "cyan" };
+static char tk_anchor[7] = "w";
+static double tk_linewidth = 1.0;
+static int tk_perl = 0;
+static int tk_interactive = 0;
+static char *tk_colors[] = {
+    "black", "gray", "red", "blue", "green", "brown", "magenta", "cyan"
+};
 
-TERM_PUBLIC void TK_init()
+TERM_PUBLIC void
+TK_options()
 {
-    fputs("\
-proc gnuplot can {\n\
-$can delete all\n\
-set cmx [lindex [$can configure -width] 4]\n\
-set cmy [lindex [$can configure -height] 4]\n",
-	  gpoutfile);
+    tk_perl = 0;
+    tk_interactive = 0;
 
-    tk_lastx = tk_lasty = tk_color = 0;
+    if (!END_OF_COMMAND) {
+	if (almost_equals(c_token, "p$erltk")) {
+	    tk_perl = 1;
+	    c_token++;
+	}
+	if (almost_equals(c_token, "i$nteractive")) {
+	    tk_interactive = 1;
+	    c_token++;
+	}
+    }
+
+    sprintf(term_options, "%s %s",
+	    tk_perl ? "perltk" : "",
+	    tk_interactive ? "interactive" : "");
 }
 
+TERM_PUBLIC void
+TK_init()
+{
+}
 
-TERM_PUBLIC void TK_graphics()
+TERM_PUBLIC void
+TK_graphics()
 {
+	/*
+	* the resulting tcl or perl code takes the actual width and height
+	* of the defined canvas and scales the plot to fit.
+	* => NOTE: this makes 'set size' useless !!!
+	* unless the original width and height is taken into account
+	* by some tcl or perl code, that's why the 'gnuplot_plotarea' and
+	* 'gnuplot_axisranges' procedures are supplied.
+	*/
+    if (tk_perl) {
+	fputs("\
+sub gnuplot {\n\
+my($can) = @_;\n\
+$can->delete('all');\n\
+my $cmx = ($can->configure(-width))[4];\n\
+my $cmy = ($can->configure(-height))[4];\n\
+my $cmx = $can->width - 2 * $can->cget(-border);\n\
+if ($cmx <= 1) {\n$cmx = ($can->cget(-width));\n}\n\
+my $cmy = $can->height - 2 * $can->cget(-border);\n\
+if ($cmy <= 1) {\n$cmy = ($can->cget(-height));\n}\n",
+	      gpoutfile);
+    } else {
+	fputs("\
+proc gnuplot can {\n\
+$can delete all\n\
+set cmx [expr [winfo width $can]-2*[$can cget -border]]\n\
+if {$cmx <= 1} {set cmx [$can cget -width]}\n\
+set cmy [expr [winfo height $can]-2*[$can cget -border]]\n\
+if {$cmy <= 1} {set cmy [$can cget -height]}\n",
+	      gpoutfile);
+    }
+    tk_lastx = tk_lasty = tk_color = 0;
 }
 
-
-TERM_PUBLIC void TK_reset()
+TERM_PUBLIC void
+TK_reset()
 {
 }
 
-TERM_PUBLIC void TK_linetype(linetype)
+TERM_PUBLIC void
+TK_linetype(linetype)
 int linetype;
 {
     tk_color = (linetype + 2) & 7;
 }
 
-TERM_PUBLIC void TK_move(x, y)
+TERM_PUBLIC void
+TK_linewidth(linewidth)
+double linewidth;
+{
+    tk_linewidth = linewidth;
+}
+
+TERM_PUBLIC void
+TK_move(x, y)
 unsigned int x, y;
 {
     tk_lastx = x;
     tk_lasty = 1000 - y;
 }
 
+#define TK_REAL_VALUE(value,axis) \
+ (log_array[axis])\
+ ?pow(base_array[axis],min_array[axis]+value*(max_array[axis]-min_array[axis]))\
+ :min_array[axis]+value*(max_array[axis]-min_array[axis])
 
-TERM_PUBLIC void TK_vector(x, y)
+#define TK_X_VALUE(value) \
+ (double)(value-xleft)/(double)(xright-xleft)
+
+#define TK_Y_VALUE(value) \
+ (double)((TK_YMAX-value)-ybot)/(double)(ytop-ybot)
+
+TERM_PUBLIC void
+TK_vector(x, y)
 unsigned int x, y;
 {
+	/*
+	* this is the 1st part of the wrapper around the 'create line' command
+	* used to bind some actions to a line segment:
+	* bind {
+	*      normal create line command
+	*      } gnuplot_xy(some coordinates)
+	*/
+    if (tk_interactive && !is_3d_plot) {
+	if (tk_perl)
+	    fprintf(gpoutfile, "$can->bind(");
+	else
+	    fprintf(gpoutfile, "$can bind [\n");
+    }
+	/*
+	 * end of 1st part of wrapper
+	 */
     y = 1000 - y;
-    fprintf(gpoutfile,
-	    "$can create line [expr $cmx * %d /1000] [expr $cmy * %d /1000] [expr $cmx * %d /1000] [expr $cmy * %d /1000] -fill %s\n",
-	    tk_lastx, tk_lasty, x, y, tk_colors[tk_color]);
+	/*
+	 * here is the basic well-known command for plotting a line segment
+	 */
+    if (tk_perl) {
+	fprintf(gpoutfile,"\
+$can->createLine(\
+$cmx * %d / 1000, \
+$cmy * %d / 1000, \
+$cmx * %d / 1000, \
+$cmy * %d / 1000, -fill => q{%s}, -width => %f, -capstyle => q{round})",
+		tk_lastx, tk_lasty, x, y, tk_colors[tk_color], tk_linewidth);
+    } else {
+	fprintf(gpoutfile,"\
+$can create line \
+[expr $cmx * %d /1000] \
+[expr $cmy * %d /1000] \
+[expr $cmx * %d /1000] \
+[expr $cmy * %d /1000] -fill %s -width %f -capstyle round\n",
+		tk_lastx, tk_lasty, x, y, tk_colors[tk_color], tk_linewidth);
+    }
+
+	/*
+	 * this is the 2nd part of the wrapper around the 'create line'
+	 * command, it generates a mechanism which calls 'gnuplot_xy' for
+	 * the line segment pointed to by the mouse cursor when a mouse
+	 * button is pressed 
+	 */
+    if (tk_interactive && !is_3d_plot) {
+	if (tk_perl) {
+	    /* Ev('W') not needed here, supplied anyhow, WHY ??? */
+	    fprintf(gpoutfile,"\
+, '<Button>' => \
+[\\&gnuplot_xy, %f, %f, %f, %f, %f, %f, %f, %f,",
+		    TK_REAL_VALUE(TK_X_VALUE(tk_lastx), FIRST_X_AXIS),
+		    TK_REAL_VALUE(TK_Y_VALUE(tk_lasty), FIRST_Y_AXIS),
+		    TK_REAL_VALUE(TK_X_VALUE(tk_lastx), SECOND_X_AXIS),
+		    TK_REAL_VALUE(TK_Y_VALUE(tk_lasty), SECOND_Y_AXIS),
+		    TK_REAL_VALUE(TK_X_VALUE(x), FIRST_X_AXIS),
+		    TK_REAL_VALUE(TK_Y_VALUE(y), FIRST_Y_AXIS),
+		    TK_REAL_VALUE(TK_X_VALUE(x), SECOND_X_AXIS),
+		    TK_REAL_VALUE(TK_Y_VALUE(y), SECOND_Y_AXIS));
+	    if (log_array[FIRST_X_AXIS]) {
+		fprintf(gpoutfile, " %f,",
+			TK_REAL_VALUE(TK_X_VALUE(0.5 * (x + tk_lastx)), FIRST_X_AXIS));
+	    } else {
+		fprintf(gpoutfile, " \"\",");
+	    }
+	    if (log_array[FIRST_Y_AXIS]) {
+		fprintf(gpoutfile, " %f,",
+			TK_REAL_VALUE(TK_Y_VALUE(0.5 * (y + tk_lasty)), FIRST_Y_AXIS));
+	    } else {
+		fprintf(gpoutfile, " \"\",");
+	    }
+	    if (log_array[SECOND_X_AXIS]) {
+		fprintf(gpoutfile, " %f,",
+			TK_REAL_VALUE(TK_X_VALUE(0.5 * (x + tk_lastx)), SECOND_X_AXIS));
+	    } else {
+		fprintf(gpoutfile, " \"\",");
+	    }
+	    if (log_array[SECOND_Y_AXIS]) {
+		fprintf(gpoutfile, " %f",
+			TK_REAL_VALUE(TK_Y_VALUE(0.5 * (y + tk_lasty)), SECOND_Y_AXIS));
+	    } else {
+		fprintf(gpoutfile, " \"\"");
+	    }
+	    fprintf(gpoutfile, "]);\n");
+	} else {
+	    fprintf(gpoutfile,"\
+] <Button> \
+\"gnuplot_xy %%W %f %f %f %f %f %f %f %f",
+		    TK_REAL_VALUE(TK_X_VALUE(tk_lastx), FIRST_X_AXIS),
+		    TK_REAL_VALUE(TK_Y_VALUE(tk_lasty), FIRST_Y_AXIS),
+		    TK_REAL_VALUE(TK_X_VALUE(tk_lastx), SECOND_X_AXIS),
+		    TK_REAL_VALUE(TK_Y_VALUE(tk_lasty), SECOND_Y_AXIS),
+		    TK_REAL_VALUE(TK_X_VALUE(x), FIRST_X_AXIS),
+		    TK_REAL_VALUE(TK_Y_VALUE(y), FIRST_Y_AXIS),
+		    TK_REAL_VALUE(TK_X_VALUE(x), SECOND_X_AXIS),
+		    TK_REAL_VALUE(TK_Y_VALUE(y), SECOND_Y_AXIS));
+	    if (log_array[FIRST_X_AXIS]) {
+		fprintf(gpoutfile, " %f",
+			TK_REAL_VALUE(TK_X_VALUE(0.5 * (x + tk_lastx)), FIRST_X_AXIS));
+	    } else {
+		fprintf(gpoutfile, " {}");
+	    }
+	    if (log_array[FIRST_Y_AXIS]) {
+		fprintf(gpoutfile, " %f",
+			TK_REAL_VALUE(TK_Y_VALUE(0.5 * (y + tk_lasty)), FIRST_Y_AXIS));
+	    } else {
+		fprintf(gpoutfile, " {}");
+	    }
+	    if (log_array[SECOND_X_AXIS]) {
+		fprintf(gpoutfile, " %f",
+			TK_REAL_VALUE(TK_X_VALUE(0.5 * (x + tk_lastx)), SECOND_X_AXIS));
+	    } else {
+		fprintf(gpoutfile, " {}");
+	    }
+	    if (log_array[SECOND_Y_AXIS]) {
+		fprintf(gpoutfile, " %f",
+			TK_REAL_VALUE(TK_Y_VALUE(0.5 * (y + tk_lasty)), SECOND_Y_AXIS));
+	    } else {
+		fprintf(gpoutfile, " {}");
+	    }
+	    fprintf(gpoutfile, "\"\n");
+	}
+    } else {
+	if (tk_perl) {
+	    fprintf(gpoutfile, ";\n");
+	}
+    }
+	/*
+	 * end of the wrapper
+	 */
     tk_lastx = x;
     tk_lasty = y;
 }
 
+#undef TK_REAL_VALUE
+#undef TK_X_VALUE
+#undef TK_Y_VALUE
 
-TERM_PUBLIC void TK_put_text(x, y, str)
+TERM_PUBLIC void
+TK_put_text(x, y, str)
 unsigned int x, y;
 char *str;
 {
     y = 1000 - y;
-    fprintf(gpoutfile,
-	    "$can create text [expr $cmx * %d /1000] [expr $cmy * %d /1000] -text {%s} -fill %s -anchor w\n",
-	    x, y, str, tk_colors[tk_color]);
+    if (tk_perl) {
+	fprintf(gpoutfile,"\
+$can->createText(\
+$cmx * %d / 1000, \
+$cmy * %d / 1000, \
+-text => q{%s}, -fill => q{%s}, -anchor => '%s', \
+(defined $font ? (-font => $font) : ()));\n",
+		x, y, str, tk_colors[tk_color], tk_anchor);
+    } else {
+	fprintf(gpoutfile,"\
+eval $can create text \
+[expr $cmx * %d /1000] \
+[expr $cmy * %d /1000] \
+-text \\{%s\\} -fill %s -anchor %s\
+ [expr [info exists font]?\"-font \\$font\":{}]\n",
+		x, y, str, tk_colors[tk_color], tk_anchor);
+    }
 }
 
-TERM_PUBLIC void TK_text()
+TERM_PUBLIC int
+TK_justify_text(anchor)
+enum JUSTIFY anchor;
 {
-    fputs("}\n", gpoutfile);
-    fflush(gpoutfile);
+    int return_value;
+
+    switch (anchor) {
+    case RIGHT:
+	strcpy(tk_anchor, "e");
+	return_value = TRUE;
+	break;
+    case CENTRE:
+	strcpy(tk_anchor, "center");
+	return_value = TRUE;
+	break;
+    case LEFT:
+	strcpy(tk_anchor, "w");
+	return_value = TRUE;
+	break;
+    default:
+	strcpy(tk_anchor, "w");
+	return_value = FALSE;
+    }
+    return return_value;
 }
 
+TERM_PUBLIC int
+TK_set_font(font)
+char *font;
+{
+    if (!font || *font == NUL) {
+	if (tk_perl)
+	    fputs("undef $font;\n", gpoutfile);
+	else
+	    fputs("catch {unset $font}\n", gpoutfile);
+    } else {
+	char *name;
+	int size = 0;
+	size_t sep = strcspn(font, ",");
 
+	name = malloc(sep + 1);
+	if (!name)
+	    return FALSE;
+	strncpy(name, font, sep);
+	name[sep] = NUL;
+	if (sep < strlen(font))
+	    sscanf(&(font[sep + 1]), "%d", &size);
+	if (tk_perl) {
+	    fprintf(gpoutfile,"\
+if ($can->can('fontCreate')) {\n\
+$font = $can->fontCreate(-family => q{%s}",
+		    name);
+	    if (size)
+		fprintf(gpoutfile, ", -size => %d", size);
+	    fputs(");\n}\n", gpoutfile);
+	} else {
+	    fprintf(gpoutfile, "set font [font create -family %s", name);
+	    if (size)
+		fprintf(gpoutfile, " -size %d", size);
+	    fputs("]\n", gpoutfile);
+	}
+	free(name);
+    }
+    return TRUE;
+}
+
+TERM_PUBLIC void
+TK_text()
+{
+	/*
+	* when switching back to text mode some procedures are generated which
+	* return important information about plotarea size and axis ranges:
+	* 'gnuplot_plotarea' returns the plotarea size in tkcanvas units
+	* 'gnuplot_axisranges' returns the min. and max. values of the axis
+	* these are essentially needed to set the size of the canvas when the
+	* axis scaling is important.
+	* moreover, a procedure 'gnuplot_xy' is created which contains the
+	* actions bound to line segments (see the above 'TK_vector' code):
+	* if the user has defined a procedure named 'user_gnuplot_coordinates'
+	* then 'gnuplot_xy' calls this procedure, otherwise is writes the
+	* coordinates of the line segment the mouse cursor is pointing to
+	* to standard output.
+	*/
+    if (tk_perl) {
+	fputs("};\n", gpoutfile);
+	if (!is_3d_plot) {
+	    fputs("sub gnuplot_plotarea {\n", gpoutfile);
+	    fprintf(gpoutfile,
+		    "return (%d, %d, %d, %d);\n",
+		    xleft, xright, 1000 - ytop, 1000 - ybot);
+	    fputs("};\n", gpoutfile);
+	    fputs("sub gnuplot_axisranges {\n", gpoutfile);
+	    fprintf(gpoutfile,
+		    "return (%f, %f, %f, %f, %f, %f, %f, %f);\n",
+		    min_array[FIRST_X_AXIS], max_array[FIRST_X_AXIS],
+		    min_array[FIRST_Y_AXIS], max_array[FIRST_Y_AXIS],
+		    min_array[SECOND_X_AXIS], max_array[SECOND_X_AXIS],
+		    min_array[SECOND_Y_AXIS], max_array[SECOND_Y_AXIS]);
+	    fputs("};\n", gpoutfile);
+	    if (tk_interactive) {
+		fputs("sub gnuplot_xy {\n",
+		      gpoutfile);
+		fputs("my ($win, $x1s, $y1s, $x2s, $y2s, $x1e, $y1e, $x2e, $y2e, $x1m, $y1m, $x2m, $y2m) = @_;\n",
+		      gpoutfile);
+		fputs("if (defined &user_gnuplot_coordinates) {\n",
+		      gpoutfile);
+		fputs("my $id = $win->find('withtag', 'current');\n",
+		      gpoutfile);
+		fputs("user_gnuplot_coordinates $win, $id, $x1s, $y1s, $x2s, $y2s, $x1e, $y1e, $x2e, $y2e, $x1m, $y1m, $x2m, $y2m\n",
+		      gpoutfile);
+		fputs("} else {\n",
+		      gpoutfile);
+		fputs("if (length($x1m)>0) {print \" $x1m\";} else {print \" \", 0.5*($x1s+$x1e);}\n",
+		      gpoutfile);
+		fputs("if (length($y1m)>0) {print \" $y1m\";} else {print \" \", 0.5*($y1s+$y1e);}\n",
+		      gpoutfile);
+		fputs("if (length($x2m)>0) {print \" $x2m\";} else {print \" \", 0.5*($x2s+$x2e);}\n",
+		      gpoutfile);
+		fputs("if (length($y2m)>0) {print \" $y2m\";} else {print \" \", 0.5*($y2s+$y2e);}\n",
+		      gpoutfile);
+		fputs("print \"\\n\"\n",
+		      gpoutfile);
+		fputs("}\n",
+		      gpoutfile);
+		fputs("};\n", gpoutfile);
+	    }
+	}
+    } else {
+	fputs("}\n", gpoutfile);
+	if (!is_3d_plot) {
+	    fputs("proc gnuplot_plotarea {} {\n", gpoutfile);
+	    fprintf(gpoutfile,
+		    "return {%d %d %d %d}\n",
+		    xleft, xright, 1000 - ytop, 1000 - ybot);
+	    fputs("}\n", gpoutfile);
+	    fputs("proc gnuplot_axisranges {} {\n", gpoutfile);
+	    fprintf(gpoutfile,
+		    "return {%f %f %f %f %f %f %f %f}\n",
+		    min_array[FIRST_X_AXIS], max_array[FIRST_X_AXIS],
+		    min_array[FIRST_Y_AXIS], max_array[FIRST_Y_AXIS],
+		    min_array[SECOND_X_AXIS], max_array[SECOND_X_AXIS],
+		    min_array[SECOND_Y_AXIS], max_array[SECOND_Y_AXIS]);
+	    fputs("}\n", gpoutfile);
+	    if (tk_interactive) {
+		fputs("proc gnuplot_xy {win x1s y1s x2s y2s x1e y1e x2e y2e x1m y1m x2m y2m} {\n",
+		      gpoutfile);
+		fputs("if {([llength [info commands user_gnuplot_coordinates]])} {\n",
+		      gpoutfile);
+		fputs("set id [$win find withtag current]\n",
+		      gpoutfile);
+		fputs("user_gnuplot_coordinates $win $id $x1s $y1s $x2s $y2s $x1e $y1e $x2e $y2e $x1m $y1m $x2m $y2m\n",
+		      gpoutfile);
+		fputs("} else {\n", gpoutfile);
+		fputs("if {[string length $x1m]>0} {puts -nonewline \" $x1m\"} else {puts -nonewline \" [expr 0.5*($x1s+$x1e)]\"}\n",
+		      gpoutfile);
+		fputs("if {[string length $y1m]>0} {puts -nonewline \" $y1m\"} else {puts -nonewline \" [expr 0.5*($y1s+$y1e)]\"}\n",
+		      gpoutfile);
+		fputs("if {[string length $x2m]>0} {puts -nonewline \" $x2m\"} else {puts -nonewline \" [expr 0.5*($x2s+$x2e)]\"}\n",
+		      gpoutfile);
+		fputs("if {[string length $y2m]>0} {puts \" $y2m\"} else {puts \" [expr 0.5*($y2s+$y2e)]\"}\n",
+		      gpoutfile);
+		fputs("}\n", gpoutfile);
+		fputs("}\n", gpoutfile);
+	    }
+	}
+    }
+    fflush(gpoutfile);
+}
+
 #endif /* TERM_BODY */
 
 #ifdef TERM_TABLE
+
 TERM_TABLE_START(tkcanvas)
-    "tkcanvas", "Tk/Tcl canvas widget",
+    "tkcanvas", "Tk/Tcl canvas widget [perltk] [interactive]",
     TK_XMAX, TK_YMAX, TK_VCHAR, TK_HCHAR,
-    TK_VTIC, TK_HTIC, options_null, TK_init, TK_reset,
+    TK_VTIC, TK_HTIC, TK_options, TK_init, TK_reset,
     TK_text, null_scale, TK_graphics, TK_move, TK_vector,
     TK_linetype, TK_put_text, null_text_angle,
-    null_justify_text, do_point, do_arrow, set_font_null
+    TK_justify_text, do_point, do_arrow, TK_set_font,
+    NULL, 0, NULL, NULL, NULL, TK_linewidth
 TERM_TABLE_END(tkcanvas)
-
 #undef LAST_TERM
 #define LAST_TERM tkcanvas
 
@@ -186,24 +590,48 @@ START_HELP(tkcanvas)
 "?terminal tkcanvas",
 "?term tkcanvas",
 "?tkcanvas",
-" This terminal driver generates tk canvas widget commands.  To use it, rebuild",
-" `gnuplot` (after uncommenting or inserting the appropriate line in \"term.h\"),",
-" then",
+" This terminal driver generates Tk canvas widget commands based on Tcl/Tk",
+" (default) or Perl.  To use it, rebuild `gnuplot` (after uncommenting or",
+" inserting the appropriate line in \"term.h\"), then",
 "",
-"  gnuplot> set term tkcanvas",
+"  gnuplot> set term tkcanvas {perltk} {interactive}",
 "  gnuplot> set output 'plot.file'",
 "",
-" After invoking \"wish\", execute the following sequence of tcl commands:",
+" After invoking \"wish\", execute the following sequence of Tcl/Tk commands:",
 "",
 "  % source plot.file",
 "  % canvas .c",
 "  % pack .c",
 "  % gnuplot .c",
 "",
-" The code generated by `gnuplot` creates a tcl procedure called \"gnuplot\"",
-" that takes the name of a canvas as its argument.  When the procedure is,",
+" Or, for Perl/Tk use a program like this:",
+"",
+"  use Tk;",
+"  my $top = MainWindow->new;",
+"  my $c = $top->Canvas;",
+"  $c->pack();",
+"  do \"plot.pl\";",
+"  gnuplot->($c);",
+"  MainLoop;",
+"",
+" The code generated by `gnuplot` creates a procedure called \"gnuplot\"",
+" that takes the name of a canvas as its argument.  When the procedure is",
 " called, it clears the canvas, finds the size of the canvas and draws the plot",
 " in it, scaled to fit.",
+"",
+" For 2-dimensional plotting (`plot`) two additional procedures are defined:",
+" \"gnuplot_plotarea\" will return a list containing the borders of the plotting",
+" area \"xleft, xright, ytop, ybot\" in canvas screen coordinates, while the ranges",
+" of the two axes \"x1min, x1max, y1min, y1max, x2min, x2max, y2min, y2max\" in plot",
+" coordinates can be obtained calling \"gnuplot_axisranges\".",
+" If the \"interactive\" option is specified, mouse clicking on a line segment",
+" will print the coordinates of its midpoint to stdout. Advanced actions",
+" can happen instead if the user supplies a procedure named",
+" \"user_gnuplot_coordinates\", which takes the following arguments:",
+" \"win id x1s y1s x2s y2s x1e y1e x2e y2e x1m y1m x2m y2m\",",
+" the name of the canvas and the id of the line segment followed by the",
+" coordinates of its start and end point in the two possible axis ranges; the",
+" coordinates of the midpoint are only filled for logarithmic axes.",
 "",
 " The current version of `tkcanvas` supports neither `multiplot` nor `replot`."
 END_HELP(tkcanvas)