PDF_lineto()

(PHP 4, PECL pdflib >= 1.0.0)

Draw a line

说明

PDF_lineto(resource $p,float $x,float $y): bool

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。

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);
}

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) );
}