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Website Programming in PHP / MYSQL
imageline
(PHP 4, PHP 5)
imageline — Draw a line
Description
bool imageline
( resource $image
, int $x1
, int $y1
, int $x2
, int $y2
, int $color
)
imageline() draws a line between the two given points.
Parameters
- image
-
An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
- x1
-
x-coordinate for first point
- y1
-
y-coordinate for first point
- x2
-
x-coordinate for second point
- y2
-
y-coordinate for second point
- color
-
The line color. A color identifier created with imagecolorallocate()
Return Values
Returns TRUE on success or FALSE on failure.
Examples
Example #1 Drawing a thick line
<?php
function imagelinethick($image, $x1, $y1, $x2, $y2, $color, $thick = 1)
{
/* this way it works well only for orthogonal lines
imagesetthickness($image, $thick);
return imageline($image, $x1, $y1, $x2, $y2, $color);
*/
if ($thick == 1) {
return imageline($image, $x1, $y1, $x2, $y2, $color);
}
$t = $thick / 2 - 0.5;
if ($x1 == $x2 || $y1 == $y2) {
return imagefilledrectangle($image, round(min($x1, $x2) - $t), round(min($y1, $y2) - $t), round(max($x1, $x2) + $t), round(max($y1, $y2) + $t), $color);
}
$k = ($y2 - $y1) / ($x2 - $x1); //y = kx + q
$a = $t / sqrt(1 + pow($k, 2));
$points = array(
round($x1 - (1+$k)*$a), round($y1 + (1-$k)*$a),
round($x1 - (1-$k)*$a), round($y1 - (1+$k)*$a),
round($x2 + (1+$k)*$a), round($y2 - (1-$k)*$a),
round($x2 + (1-$k)*$a), round($y2 + (1+$k)*$a),
);
imagefilledpolygon($image, $points, 4, $color);
return imagepolygon($image, $points, 4, $color);
}
?>
