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<?php |
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namespace nstdio\svg\util; |
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/** |
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* Class Bezier |
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* |
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* @package nstdio\svg\util |
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* @author Edgar Asatryan <[email protected]> |
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*/ |
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class Bezier |
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{ |
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const EPSILON = 0.00001; |
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public static function quadraticBBox($p0x, $p0y, $p1x, $p1y, $p2x, $p2y) |
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{ |
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$devx = $p0x + $p2x - 2 * $p1x; |
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$devy = $p0y + $p2y - 2 * $p1y; |
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self::avoidDivisionByZero($devy); |
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self::avoidDivisionByZero($devx); |
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$tx = ($p0x - $p1x) / $devx; |
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$ty = ($p0y - $p1y) / $devy; |
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self::checkBezierInterval($tx); |
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self::checkBezierInterval($ty); |
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$txByTX = $p0x * pow(1 - $tx, 2) + 2 * $tx * $p1x * (1 - $tx) + $p2x * $tx * $tx; |
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$tyByTX = $p0y * pow(1 - $tx, 2) + 2 * $tx * $p1y * (1 - $tx) + $p2y * $tx * $tx; |
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$txByTY = $p0x * pow(1 - $ty, 2) + 2 * $ty * $p1x * (1 - $ty) + $p2x * $ty * $ty; |
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$tyByTY = $p0y * pow(1 - $ty, 2) + 2 * $ty * $p1y * (1 - $ty) + $p2y * $ty * $ty; |
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$x1 = min($txByTX, $p0x, $p2x, $txByTY); |
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$y1 = min($tyByTX, $p0y, $p2y, $tyByTY); |
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$x2 = max($txByTX, $p0x, $p2x, $txByTY); |
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$y2 = max($tyByTX, $p0y, $p2y, $tyByTY); |
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return [ |
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'width' => $x2 - min($x2, $x1), |
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'height' => max($y2, $y1) - min($y2, $y1), |
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'x' => min($x2, $x1), |
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'y' => min($y2, $y1), |
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]; |
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} |
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public static function cubicBBox($p0x, $p0y, $p1x, $p1y, $p2x, $p2y, $p3x, $p3y) |
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{ |
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$ax = $p3x - $p0x + 3 * ($p1x - $p2x); |
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$bx = 2 * ($p0x - 2 * $p1x + $p2x); |
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$cx = $p1x - $p0x; |
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$ay = $p3y - $p0y + 3 * ($p1y - $p2y); |
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$by = 2 * ($p0y - 2 * $p1y + $p2y); |
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$cy = $p1y - $p0y; |
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$txRoots = self::getRoots($ax, $bx, $cx); |
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$tyRoots = self::getRoots($ay, $by, $cy); |
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$tv0x = self::getCubicValue(0, $p0x, $p1x, $p2x, $p3x); |
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$tv1x = self::getCubicValue($txRoots[0], $p0x, $p1x, $p2x, $p3x); |
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$tv2x = self::getCubicValue($txRoots[1], $p0x, $p1x, $p2x, $p3x); |
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$tv3x = self::getCubicValue(1, $p0x, $p1x, $p2x, $p3x); |
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$tv0y = self::getCubicValue(0, $p0y, $p1y, $p2y, $p3y); |
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$tv1y = self::getCubicValue($tyRoots[0], $p0y, $p1y, $p2y, $p3y); |
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$tv2y = self::getCubicValue($tyRoots[1], $p0y, $p1y, $p2y, $p3y); |
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$tv3y = self::getCubicValue(1, $p0y, $p1y, $p2y, $p3y); |
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$x1 = min($tv0x, $tv1x, $tv2x, $tv3x, $p0x, $p3x); |
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$y1 = min($tv0y, $tv1y, $tv2y, $tv3y, $p0y, $p3y); |
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$x2 = max($tv0x, $tv1x, $tv2x, $tv3x, $p0x, $p3x); |
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$y2 = max($tv0y, $tv1y, $tv2y, $tv3y, $p0y, $p3y); |
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return [ |
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'width' => $x2 - min($x2, $x1), |
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'height' => max($y2, $y1) - min($y2, $y1), |
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'x' => min($x2, $x1), |
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'y' => min($y2, $y1), |
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]; |
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} |
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public static function getRoots($a, $b, $c) |
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{ |
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$dis = $b * $b - 4 * $a * $c; |
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if ($dis < 0) { |
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return null; |
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} |
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self::avoidDivisionByZero($a); |
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$disSqrt = sqrt($dis); |
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$root1 = (-$b + $disSqrt) / (2 * $a); |
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$root2 = (-$b - $disSqrt) / (2 * $a); |
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self::checkBezierInterval($root1); |
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self::checkBezierInterval($root2); |
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return [$root1, $root2]; |
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} |
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private static function getCubicValue($t, $p0, $p1, $p2, $p3) |
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{ |
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$omt = 1 - $t; |
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$value = $p0 * $omt * $omt *$omt + |
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3 * $p1 * $t * $omt * $omt + |
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3 * $p2 * $t * $t * $omt + |
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$p3 * $t * $t * $t; |
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return $value; |
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} |
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/** |
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* @param $value |
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*/ |
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private static function avoidDivisionByZero(&$value) |
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{ |
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if ($value === 0) { |
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$value = self::EPSILON; |
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} |
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} |
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/** |
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* @param $t |
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*/ |
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private static function checkBezierInterval(&$t) |
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{ |
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if ($t > 1 || $t < 0) { |
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$t = 0; |
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} |
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} |
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} |
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nstdio /
SVGMagick
