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本文档使用 PHP中文网手册 发布
(PHP 4, PECL pdflib >= 1.0.0)
PDF_lineto — Draw a line
$p
, float $x
, float $y
)
Draws a line from the current point to another point. 成功时返回 TRUE
, 或者在失败时返回 FALSE
。
[#1] rod-php at thecomplex dot com [2002-10-01 10:20:38]
function find_angle ($x1, $y1, $x2, $y2) {
// This function takes two points (x1,y1) and (x2,y2)
// as inputs and finds the slope and angle of a line
// between those two points. It returns the angle
// and slope in an array. I can't figure out how to
// return a NULL value, so if the two input points
// are in a vertical line, the function returns
// $angle = 90 and $slope = 0. I know this is wrong.
if (($x2-$x1) != 0) {
$slope = ($y2-$y1)/($x2-$x1);
// Get rotation angle by finding the arctangent of the slope
$angle = rad2deg(atan($slope));
if ($x1 > $x2) {
$angle = 180+$angle;
} elseif ($y1 > $y2) {
$angle = 360+$angle;
}
} else {
// Vertical line has no slope, 90deg angle
$angle = 90;
# unset ($slope);
$slope = 0;
}
return array ($angle, $slope);
}
[#2] rod-php at thecomplex dot com [2002-10-01 10:18:50]
function find_length ($x1, $y1, $x2, $y2) {
// Find distance between two points (x1,y1) and (x2,y2)
// Also useful to find length of a line.
return sqrt( pow($x2-$x1,2) + pow($y2-$y1,2) );
}