<?php // content="text/plain; charset=utf-8"
require_once 'jpgraph/jpgraph.php';
require_once 'jpgraph/jpgraph_scatter.php';
require_once 'jpgraph/jpgraph_line.php';
require_once 'jpgraph/jpgraph_plotline.php';

$numpoints = 50;
$k         = 0.05;

// Create some data points
for ($i = -$numpoints + 1; $i < 0; ++$i) {
    $datay[$i + $numpoints - 1]    = exp($k * $i) * cos(2 * M_PI / 10 * $i) * 14;
    $datayenv[$i + $numpoints - 1] = exp($k * $i) * 14;
    $datax[$i + $numpoints - 1]    = $i;
}

for ($i = 0; $i < $numpoints; ++$i) {
    $datay[$i + $numpoints - 1]    = exp(-$k * $i) * cos(2 * M_PI / 10 * $i) * 14;
    $datayenv[$i + $numpoints - 1] = exp(-$k * $i) * 14;
    $datax[$i + $numpoints - 1]    = $i;
}

// Setup the basic parameters for the graph
$graph = new Graph\Graph(500, 250);
$graph->SetScale("intlin");

$graph->SetShadow();
$graph->SetBox();
$graph->title->Set("Impuls Example 4");
$graph->title->SetFont(FF_FONT1, FS_BOLD);

// Set some other color then the boring default
$graph->SetColor("lightyellow");
$graph->SetMarginColor("khaki");

// Set legend box specification
$graph->legend->SetFillColor("white");
$graph->legend->SetLineWeight(2);

// Set X-axis at the minimum value of Y-axis (default will be at 0)
$graph->xaxis->SetPos("min"); // "min" will position the x-axis at the minimum value of the Y-axis

// Extend the margin for the labels on the Y-axis and reverse the direction
// of the ticks on the Y-axis
$graph->yaxis->SetLabelMargin(12);
$graph->xaxis->SetLabelMargin(6);
$graph->yaxis->SetTickSide(SIDE_LEFT);
$graph->xaxis->SetTickSide(SIDE_DOWN);

// Add mark graph with static lines
$line = new PlotLine(HORIZONTAL, 0, "black", 2);
$graph->AddLine($line);

// Create a new impuls type scatter plot
$sp1 = new ScatterPlot($datay, $datax);
$sp1->mark->SetType(MARK_SQUARE);
$sp1->mark->SetFillColor("red");
$sp1->mark->SetWidth(3);

$sp1->SetImpuls();
$sp1->SetColor("blue");
$sp1->SetWeight(1);
$sp1->SetLegend("Non-causal signal");

$graph->Add($sp1);

// Create the envelope plot
$ep1 = new Plot\LinePlot($datayenv, $datax);
$ep1->SetStyle("dotted");
$ep1->SetLegend("Positive envelope");

$graph->Add($ep1);

$graph->Stroke();
