function test_color_range($color1, $color2, $nsteps, $expected)
{
$info = 'From (' . implode(', ', $color1) . ') To (' . implode(', ', $color2) . ") with {$nsteps} steps";
$colors = color_range($color1, $color2, $nsteps);
if ($colors == $expected) {
echo "Pass: {$info}\n";
} else {
echo "FAIL: {$info}\n" . print_r($colors, True) . "\n";
}
if (($n = count($colors)) != $nsteps) {
echo "FAIL: Bad count {$n} expecting {$nsteps}\n";
}
}
# PHPlot / contrib / color_range : Example
# $Id$
# This is a bar chart with a color gradient for the bars in each group.
require_once 'phplot.php';
require_once 'color_range.php';
$bars_per_group = 10;
$x_values = 4;
mt_srand(1);
$data = array();
for ($i = 0; $i < $x_values; $i++) {
$row = array($i);
for ($j = 0; $j < $bars_per_group; $j++) {
$row[] = mt_rand(0, 100);
}
$data[] = $row;
}
$p = new PHPlot(800, 600);
$p->SetTitle('Example - Bar Chart with gradient colors');
$p->SetDataType('text-data');
$p->SetDataValues($data);
$p->SetPlotAreaWorld(0, 0, $x_values, 100);
# This isn't necessary, as we do know how many data sets (bars_per_group):
$n_data = count_data_sets($data, 'text-data');
# Make a gradient color map:
$colors = color_range($p->SetRGBColor('SkyBlue'), $p->SetRGBColor('DarkGreen'), $n_data);
$p->SetDataColors($colors);
$p->SetXTickLabelPos('none');
$p->SetXTickPos('none');
$p->SetPlotType('bars');
$p->DrawGraph();
# Split color "rrggbb" into separate components. Code is from PHPlot.
function rgb($color)
{
return array(hexdec(substr($color, 1, 2)), hexdec(substr($color, 3, 2)), hexdec(substr($color, 5, 2)));
}
if ($_SERVER['argc'] != 4) {
usage();
}
$color1 = rgb($_SERVER['argv'][1]);
$color2 = rgb($_SERVER['argv'][2]);
$n_col = (int) $_SERVER['argv'][3];
if ($n_col < 2) {
usage();
}
# Build a color map from colors[0]=color1 to colors[$n_col-1]=color2.
$colors = color_range($color1, $color2, $n_col);
# Make a picture:
$w = 800;
$h = 800;
$im = imagecreate($w, $h);
$background = imagecolorresolve($im, 0, 0, 0);
for ($col = 0; $col < $n_col; $col++) {
list($r, $g, $b) = $colors[$col];
$colmap[$col] = imagecolorresolve($im, $r, $g, $b);
}
$margin = 20;
$bar_width = (int) (($w - 2 * $margin) / $n_col);
$x1 = $margin;
$x2 = $x1 + $bar_width;
$y1 = $margin;
$y2 = $h - $margin;
