Re: [PATCH] rrd graphs: Switch to SVG output format

I used the Firefox developer tools to check the loading times of the images.

On average, the SVG image is generated 10ms faster: "HTTP Wait" for PNG: ~126ms, for SVG: ~115ms (My test system: Core 159 on Proxmox VM/Xeon 3,3GHz)

Regards, Leo

Am 04.08.2021 um 16:40 schrieb Michael Tremer:

Cool. Thank you.

Did you test if the SVG files can be generated quicker than PNG?

-Michael

...

On 4 Aug 2021, at 13:01, Leo-Andres Hofmann hofmann@leo-andres.de wrote:

The vector graphics can be scaled without becoming blurred.

Signed-off-by: Leo-Andres Hofmann hofmann@leo-andres.de

Hi,

Michael suggested switching to the SVG format for the graphs: https://lists.ipfire.org/pipermail/development/2021-July/010804.html

I have tested this with firefox and chrome, the graphs and error message look fine to me. If someone knows a good SVG validator, I would be happy to get the link :)

Regards, Leo

config/cfgroot/graphs.pl | 2 +- html/cgi-bin/getrrdimage.cgi | 87 +++++++++++++++++++++--------------- 2 files changed, 52 insertions(+), 37 deletions(-)

diff --git a/config/cfgroot/graphs.pl b/config/cfgroot/graphs.pl index 441d4c483..02341eb45 100644 --- a/config/cfgroot/graphs.pl +++ b/config/cfgroot/graphs.pl @@ -40,7 +40,7 @@ my $ERROR;

my @GRAPH_ARGS = ( # Output format

• "--imgformat", "PNG",

• "--imgformat", "SVG",

  # No border "--border", "0",

diff --git a/html/cgi-bin/getrrdimage.cgi b/html/cgi-bin/getrrdimage.cgi index c08247c57..92f8b585d 100644 --- a/html/cgi-bin/getrrdimage.cgi +++ b/html/cgi-bin/getrrdimage.cgi @@ -21,8 +21,7 @@

use strict; use URI; -use GD; -use GD::Text::Wrap; +use Text::Wrap; use experimental 'smartmatch';

# debugging @@ -52,7 +51,7 @@ my $range = lc $query{'range'}; # lower case # Check parameters unless(($origin =~ /^\w+?.cgi$/) && ($graph =~ /^[\w-.,; ]+?$/) && ($range ~~ @Graphs::time_ranges)) { # Send HTTP headers

• _start_png_output();

• _start_svg_output();

  _print_error("URL parameters missing or malformed."); exit;

@@ -76,7 +75,7 @@ unless(($origin ~~ @supported_origins) || ($origin eq "getrrdimage.cgi")) {

### Create graphs ### # Send HTTP headers -_start_png_output(); +_start_svg_output();

# Graphs are first grouped by their origin. # This is because some graph categories require special parameter handling. @@ -204,46 +203,62 @@ if($graphstatus) {

###--- Internal functions ---###

-# Send HTTP headers and switch to binary output +# Send HTTP headers # (don't print any non-image data to STDOUT afterwards) -sub _start_png_output { +sub _start_svg_output { print "Cache-Control: no-cache, no-store\n";

• print "Content-Type: image/png\n";

• print "Content-Type: image/svg+xml\n"; print "\n"; # End of HTTP headers

• binmode(STDOUT);

}

-# Print error message to PNG output +# Print error message to SVG output sub _print_error { my ($message) = @_;

• $message = "- Error -\n \n$message";

• # Create new image with the same size as a graph

• my $img = GD::Image->new($Graphs::image_size{'width'}, $Graphs::image_size{'height'});

• $img->interlaced('true');

• # Basic colors

• my $color_background = $img->colorAllocate(255, 255, 255);

• my $color_border = $img->colorAllocate(255, 0, 0);

• my $color_text = $img->colorAllocate(0, 0, 0);

• # Background and border

• $img->setThickness(2);

• $img->filledRectangle(0, 0, $img->width, $img->height, $color_background);

• $img->rectangle(10, 10, $img->width - 10, $img->height - 10, $color_border);

• # Draw message with line-wrap

• my $textbox = GD::Text::Wrap->new($img,

• text => $message,
  

• width => ($img->width - 50),
  

• color => $color_text,
  

• align => 'center',
  

• line_space => 5,
  

• preserve_nl => 1
  

• # Prepare image options
• my %img = (

• 'width' => $Graphs::image_size{'width'},
  

• 'height' => $Graphs::image_size{'height'},
  

• 'text_center' => int($Graphs::image_size{'width'} / 2),
  

• 'line_height' => 20,
  

• 'font_family' => "DejaVu Sans, Helvetica, sans-serif" # Matching the IPFire theme
  

  );

• $textbox->set_font(gdLargeFont);

• $textbox->draw(25, 25);

• # Get PNG output

• print $img->png;

• # Line-wrap message to fit image (adjust to font width if necessary)
• local($Text::Wrap::columns) = int($img{'width'} / 10);
• $message = wrap('', '', $message);
• # Create new image with fixed background and border
• print <<END

+<?xml version="1.0" encoding="UTF-8"?> +<svg width="$img{'width'}px" height="$img{'height'}px" viewBox="0 0 $img{'width'} $img{'height'}" version="1.1" xmlns="http://www.w3.org/2000/svg">

• <!-- Background -->

• <rect width="100%" height="100%" fill="white"/>

• <rect width="100%" height="100%" fill="none" stroke="red" stroke-width="2" transform="scale(0.95)" transform-origin="center"/>

• <!-- Message -->

• <text x="$img{'text_center'}" y="50" font-size="20" font-family="$img{'font_family'}" text-anchor="middle">- $Lang::tr{'error'} -</text>

• <text x="$img{'text_center'}" y="90" font-size="14" font-family="$img{'font_family'}" text-anchor="middle">

+END +;

• # Print message lines
• my $shift_y = 0; # Shifts text along y-axis
• foreach my $line (split(/\n/, $message)) {

• if($line ne "") { # Don't create empty tspan elements
  

• 	print <<END
  

• <tspan x="$img{'text_center'}" dy="$shift_y">$line</tspan>
  

+END +;

• 	$shift_y = $img{'line_height'};
  

• } else { # Create blank lines by summing up unused line height
  

• 	$shift_y += $img{'line_height'};
  

• }
  

• }
• # Finish SVG output
• print <<END

• </text>

+</svg> +END +; } -- 2.27.0.windows.1