Manage gnuplot with IPC::Open3, so we allow fancy output filenames, with spaces!

glucometer_graphs.pl

@@ -3,6 +3,7 @@
 use strict;
 use warnings;
 use Getopt::Long;
+use IPC::Open3;
 use Time::Piece;
 
 my $error = "Usage: $0 --input <CSV file> --output <output PDF> [--max <n.n>] [--low <n.n>] [--high <n.n>]\n";
@@ -27,19 +28,17 @@ GetOptions ("input=s"  => \$input,          # The name of the CSV file from whic
             "low:f"    => \$min_glucose,    # The low end of your target blood glucose level
             "max:i"    => \$graph_max,      # The highest displayed glucose level on each graph
             "graphs:i" => \$days_per_page)  # The number of days printed on each page
-      or die $error;
+    or die $error;
 
-die $error unless ( defined $input and defined $output );
-
-open( my $fh, '<:encoding(UTF-8)', $input ) 
+open( my $ifh, '<:encoding(UTF-8)', $input ) 
     or die "Could not open file '$input' $!";
  
-while ( my $row = <$fh> ) {
+while ( my $row = <$ifh> ) {
     chomp( $row );
     push @lines, $row;
 }
 
-close( $fh )
+close( $ifh )
     or warn "close failed: $!";
 
 # Set up basic gnuplot options for reading the CSV data
@@ -98,7 +97,7 @@ reset
 set datafile separator whitespace
 
 set terminal pdf size 29.7cm,21.0cm enhanced font 'Calibri,14' linewidth 1 
-set output '$output'
+#set output '$output'
 set key off
 set style data lines
 set xdata time
@@ -134,7 +133,7 @@ foreach my $d ( sort keys %seen ) {
 
     push @data, qq(
 set title "Daily Glucose Summary for $title" font "Calibri,18"
-set xlabel "Time" offset 0,1
+set xlabel "Time" offset 0,-0.25
 set ylabel "Blood glucose" 
 set xtics left tc rgb "#000000"
 set ytics 2    tc rgb "#000000"
@@ -152,7 +151,7 @@ undefine \$SmoothData$label
 # Add an x grid
 set multiplot previous
 set title "  "
-set xlabel " " offset 0,1
+set xlabel " " offset 0,-0.25
 set ylabel " " 
 set xtics tc rgb "#ffffff00" 
 set ytics tc rgb "#ffffff00"
@@ -173,9 +172,39 @@ push @data, qq(
 unset multiplot
 );
 
-# output the gnuplot data
+# run the data through gnuplot
 $gnuplot_data = join "\n", @data;
-print $gnuplot_data;
-#gnuplot(@data);
+
+open( my $ofh, '>', $output ) 
+    or die "Could not open file '$output' $!";
+
+my ( $pid, $stdin, $stdout, $stderr );
+use Symbol 'gensym'; 
+$stderr = gensym;
+
+$pid = open3( $stdin, $stdout, $stderr, 'gnuplot' );
+
+print $stdin $gnuplot_data;
+close( $stdin );
+
+while ( <$stdout> ) {
+    print $ofh "$_";
+}
+
+while ( <$stderr> ) {
+    warn $_;
+}
+
+close($stdout);
+close($stderr);
+
+waitpid( $pid, 0 );
+my $child_exit_status = $? >> 8;
+
+close( $ofh )
+    or warn "close failed: $!";
+
+#open (GNUPLOT, "|gnuplot");
+#print GNUPLOT $gnuplot_data;
 
 # vim: set expandtab shiftwidth=4 softtabstop=4 :