function printBends($graph)
{
if (!is_array($graph->series)) {
Graph::printEmpty($graph);
}
$image = Graph::create_canvas($graph);
$series_names = array_keys($graph->series);
$series_num = count($series_names);
$y_values = array();
for ($j = 0; $j < $series_num; $j++) {
$x_series[$j] = array_keys($graph->series[$series_names[$j]]);
$num = count($x_series[$j]);
for ($i = 0; $i < $num; $i++) {
$y_series[$j][$i] = $graph->series[$series_names[$j]][$x_series[$j][$i]];
}
$y_values = array_merge($y_values, $y_series[$j]);
}
// string x-series values?
$x_values = array();
for ($j = 0; $j < $series_num; $j++) {
$num = count($x_series[$j]);
for ($i = 0; $i < $num; $i++) {
$x_series[$j][$i] = floatval($x_series[$j][$i]);
}
$x_values = array_merge($x_values, $x_series[$j]);
}
//calculation of active window bounderies
sort($x_values);
$x_values = array_values(array_unique($x_values));
sort($y_values);
$y_values = array_values(array_unique($y_values));
$y_num = count($y_values);
$x_num = count($x_values);
$V_STEP = $y_values[$y_num - 1] / 10;
$H_STEP = round(GRAPH_WIDTH / ($x_num - 1), 0);
$H_WIDTH = ($x_num - 1) * $H_STEP;
$image = Graph::create_grid($image, $H_WIDTH, $H_STEP, $V_STEP, $graph->xname, $graph->yname, $graph->options);
$OFFSET = $H_WIDTH * $x_values[0] / ($x_values[$x_num - 1] - $x_values[0]);
$color_legend = imagecolorallocate($image, $graph->text_color[r], $graph->text_color[g], $graph->text_color[b]);
// prints adjustment points and legend...
for ($j = 0; $j < $series_num; $j++) {
$r = hexdec(substr($graph->plot_colors[$j], 1, 2));
$g = hexdec(substr($graph->plot_colors[$j], 3, 2));
$b = hexdec(substr($graph->plot_colors[$j], 5, 2));
$color[$j] = imagecolorallocate($image, $r, $g, $b);
imagefilledrectangle($image, LEGEND_MARGIN_LEFT - 20, GRAPH_MARGIN_TOP + $j * (GRAPH_HEIGHT / 12), LEGEND_MARGIN_LEFT - 15, GRAPH_MARGIN_TOP + $j * (GRAPH_HEIGHT / 12) + 4, $color[$j]);
imagestring($image, 2, LEGEND_MARGIN_LEFT, GRAPH_MARGIN_TOP + ($j * (GRAPH_HEIGHT / 12) - 5), $series_names[$j], $color_legend);
$num = count($x_series[$j]);
for ($i = 0; $i < $num; $i++) {
$x1 = MARGIN_LEFT - $OFFSET + $H_WIDTH * $x_series[$j][$i] / ($x_values[$x_num - 1] - $x_values[0]);
$y1 = PLOT_BASE - GRAPH_HEIGHT * ($y_series[$j][$i] / $y_values[$y_num - 1]);
imagefilledarc($image, $x1, $y1, 5, 5, 0, 360, $color[$j], 4);
}
}
//prints X-Labels
$num = count($x_values);
$x2 = -$H_STEP;
for ($i = 0; $i < $num; $i++) {
$x1 = MARGIN_LEFT - $OFFSET + $H_WIDTH * $x_values[$i] / ($x_values[$x_num - 1] - $x_values[0]);
if ($x1 - $x2 >= $H_STEP) {
imagestring($image, 2, $x1, XLABEL_MARGIN_TOP, $x_values[$i], $color_legend);
} else {
$x1 = $x2;
}
$x2 = $x1;
}
for ($i = 0; $i < $series_num; $i++) {
$function_string = Graph::createLagrange($x_series[$i], $y_series[$i]);
$parsed_function = Graph::parse_function($function_string);
//plot the function
$n = count($x_series[$i]) - 1;
$old_x = $x_series[$i][0];
$old_y = $y_series[$i][0];
$PLOT_H_STEP = 0.005 * ($x_series[$i][$n] - $x_series[$i][0]);
for ($x = $x_series[$i][0]; $x < $x_series[$i][$n]; $x += $PLOT_H_STEP) {
$y = "\$y = " . $parsed_function . ";";
eval($y);
if ($x < $old_x) {
$old_x = $x_series[$i][0];
$old_y = $y_series[$i][0];
}
$x_norm = MARGIN_LEFT - $OFFSET + $H_WIDTH * $x / ($x_values[$x_num - 1] - $x_values[0]);
$y_norm = max(PLOT_BASE - GRAPH_HEIGHT * ($y / $y_values[$y_num - 1]), PLOT_BASE - GRAPH_HEIGHT);
$y_norm = min($y_norm, PLOT_BASE);
//only plot from the second time on
if ($old_x != $x_series[$i][0]) {
imageline($image, $old_x_norm, $old_y_norm, $x_norm, $y_norm, $color[$i]);
}
$old_x = $x;
$old_x_norm = $x_norm;
$old_y = $y;
$old_y_norm = $y_norm;
}
}
//set content type
header("Content-type: image/jpeg");
//send image
Imagejpeg($image, '', 100);
ImageDestroy($image);
}
