Modify how height of Plots image is computed.

Height is undefined, and will be set equal to the width when
the image is drawn unless the 'aspect_ratio' axes style is set.
If this style is set, the height is computed to the desired
aspect ratio based on the axes bounding box.

If the height is manually set, use that instead of computing it.

Author: somiaj

lib/Plots/Axes.pm

@@ -151,6 +151,12 @@ The following styles configure aspects about the axes.
 
 =over 5
 
+=item aspect_ratio
+
+If this style is set, then the height of the graph will be computed using
+this aspect_ratio for the size of the image unless explicitly set.
+Default: ''
+
 =item ariaLabel
 
 The ARIA label in JSX graph output. Default is 'Graph'.

lib/Plots/Plot.pm

@@ -20,12 +20,11 @@ use Plots::GD;
 
 sub new {
 	my ($class, %options) = @_;
-	my $size = eval('$main::envir{onTheFlyImageSize}') || 350;
 
 	my $self = bless {
 		imageName => {},
-		width     => $size,
-		height    => $size,
+		width     => eval('$main::envir{onTheFlyImageSize}') || 350,
+		height    => undef,
 		tex_size  => 600,
 		axes      => Plots::Axes->new,
 		colors    => {},
@@ -109,8 +108,20 @@ sub color_init {
 }
 
 sub size {
-	my $self = shift;
-	return wantarray ? ($self->{width}, $self->{height}) : [ $self->{width}, $self->{height} ];
+	my $self   = shift;
+	my $axes   = $self->axes;
+	my $width  = $self->{width};
+	my $height = $self->{height};
+	unless ($height) {
+		if ($axes->style('aspect_ratio')) {
+			my $x_size = $axes->xaxis('max') - $axes->xaxis('min');
+			my $y_size = $axes->yaxis('max') - $axes->yaxis('min');
+			$height = int($axes->style('aspect_ratio') * $width * $y_size / $x_size);
+		} else {
+			$height = $width;
+		}
+	}
+	return wantarray ? ($width, $height) : [ $width, $height ];
 }
 
 sub data {

lib/Plots/Tikz.pm

@@ -157,6 +157,7 @@ sub configure_axes {
 		[
 			trig format plots=rad,
 			view={0}{90},
+			scale only axis,
 			height=$axes_height,
 			width=$axes_width,
 			${axis_on_top}axis x line=$axis_x_line$axis_x_pos,