With PHP JpGraph PiePlotC (a donut) how can I set borders?

Question

Ideally, I'd like to set slice borders but not circumference border.
I tried this:

$p1 = new PiePlotC($data);
$p1->ShowBorder(true);
$p1->SetColor('blue');

I also tried $p1->ShowBorder(false, true);
No border appeared.
I noticed that the theme: UniversalTheme set the border to false.
I remmed those lines out of the theme.

case 'PiePlot':
            {
                //$plot->SetCenter(0.5, 0.45);
                //$plot->ShowBorder(false);
                //$plot->SetSliceColors($this->GetThemeColors());
                break;
            }

That did not help.
The pie slice colors did appear even though I remmed that line out.
I know that theme is the one used because I had to rem:
$plot->SetCenter(0.5, 0.45); out to be able to move the pie.
That worked.

I think it's a bad design to have the theme overwrite settings set by the client (user). The user's settings should override the theme.

How can I set borders for each slice in a PiePlotC?
Also, how can I set the size (line width) of the borders?

<?php 
require_once($_SERVER['DOCUMENT_ROOT'] . '/Business/Config.php');
require_once (BASE_PATH . '/PHPJpGraph/jpgraph.php');
require_once (BASE_PATH . '/PHPJpGraph/jpgraph_pie.php');
 
$data = array(50,28,25,27,31,20);
 
// A new pie graph
$graph = new PieGraph(1000,1000,'auto');
$graph->SetFrame(false);
$graph->title->Set("PiePlotC");
$graph->title->SetFont(FF_ARIAL,FS_BOLD,18);
$graph->title->SetMargin(8); // Add a little bit more margin from the top

$p1 = new PiePlotC($data);
//$p1->clearTheme();
$p1->ShowBorder(true);
$p1->SetColor('blue');
//$p1->SetBorder($aWeight, $aColor);

$p1->SetLabelType(PIE_VALUE_ABS);
$p1->value->SetFormat("%d");
$p1->SetSize(0.35);
$p1->SetCenter(0.5, 0.5);
$p1->value->SetFont(FF_ARIAL,FS_BOLD,12);
$p1->value->Show(); 
$p1->SetMidSize(0.75);
$p1->midtitle->Set("Test mid\nRow 1\nRow 2");
$p1->midtitle->SetFont(FF_ARIAL,FS_NORMAL,12);

$p1->SetMidColor('white');
$p1->SetLabelType(PIE_VALUE_ABS);
$lbl = array("adam\n%.1f","bertil\n%.1f","johan\n%.1f",
         "peter\n%.1f","daniel\n%.1f","erik\n%.1f%%");
         
$p1->SetLabels($lbl);
$graph->Add($p1);
$graph->Stroke();

Answer 1

Right after the new PieGraph clear the default theme using $graph->clearTheme(); and see if that helps.

$graph = new PieGraph(1000,1000,'auto');
$graph->clearTheme();

I find nothing in the examples or documentation that indicates that the borders and size for pie slices may be changed. You may want to see if using ExplodeAll $p1->ExplodeAll(5); would help. There are also options to explode 1 or more slices but not all of them. And there are several themes provide as well as the option to set the colors of each slice yourself.