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- <?php
- namespace Grafika\Gd\DrawingObject;
- use Grafika\DrawingObject\CubicBezier as Base;
- use Grafika\DrawingObjectInterface;
- use Grafika\Gd\Image;
- use Grafika\ImageInterface;
- /**
- * Class CubicBezier
- * @package Grafika
- */
- class CubicBezier extends Base implements DrawingObjectInterface
- {
- /**
- * @param ImageInterface $image
- * @return Image
- */
- public function draw($image)
- {
- // Localize vars
- $width = $image->getWidth();
- $height = $image->getHeight();
- $gd = $image->getCore();
- list($x0, $y0) = $this->point1;
- list($x1, $y1) = $this->control1;
- list($x2, $y2) = $this->control2;
- list($x3, $y3) = $this->point2;
- $this->plot($gd, $x0, $y0, $x1, $y1, $x2, $y2, $x3, $y3);
- $type = $image->getType();
- $file = $image->getImageFile();
- return new Image($gd, $file, $width, $height, $type); // Create new image with updated core
- }
- protected function plot($gd, $x0, $y0, $x1, $y1, $x2, $y2, $x3, $y3)
- { /* plot any cubic Bezier curve */
- $n = 0;
- $i = 0;
- $xc = $x0 + $x1 - $x2 - $x3;
- $xa = $xc - 4 * ($x1 - $x2);
- $xb = $x0 - $x1 - $x2 + $x3;
- $xd = $xb + 4 * ($x1 + $x2);
- $yc = $y0 + $y1 - $y2 - $y3;
- $ya = $yc - 4 * ($y1 - $y2);
- $yb = $y0 - $y1 - $y2 + $y3;
- $yd = $yb + 4 * ($y1 + $y2);
- $fx0 = $x0;
- $fx1 = 0;
- $fx2 = 0;
- $fx3 = 0;
- $fy0 = $y0;
- $fy1 = 0;
- $fy2 = 0;
- $fy3 = 0;
- $t1 = $xb * $xb - $xa * $xc;
- $t2 = 0;
- $t = array();
- /* sub-divide curve at gradient sign changes */
- if ($xa == 0) { /* horizontal */
- if (abs($xc) < 2 * abs($xb)) {
- $t[$n++] = $xc / (2.0 * $xb);
- } /* one change */
- } else {
- if ($t1 > 0.0) { /* two changes */
- $t2 = sqrt($t1);
- $t1 = ($xb - $t2) / $xa;
- if (abs($t1) < 1.0) {
- $t[$n++] = $t1;
- }
- $t1 = ($xb + $t2) / $xa;
- if (abs($t1) < 1.0) {
- $t[$n++] = $t1;
- }
- }
- }
- $t1 = $yb * $yb - $ya * $yc;
- if ($ya == 0) { /* vertical */
- if (abs($yc) < 2 * abs($yb)) {
- $t[$n++] = $yc / (2.0 * $yb);
- } /* one change */
- } else {
- if ($t1 > 0.0) { /* two changes */
- $t2 = sqrt($t1);
- $t1 = ($yb - $t2) / $ya;
- if (abs($t1) < 1.0) {
- $t[$n++] = $t1;
- }
- $t1 = ($yb + $t2) / $ya;
- if (abs($t1) < 1.0) {
- $t[$n++] = $t1;
- }
- }
- }
- for ($i = 1; $i < $n; $i++) /* bubble sort of 4 points */ {
- if (($t1 = $t[$i - 1]) > $t[$i]) {
- $t[$i - 1] = $t[$i];
- $t[$i] = $t1;
- $i = 0;
- }
- }
- $t1 = -1.0;
- $t[$n] = 1.0; /* begin / end point */
- for ($i = 0; $i <= $n; $i++) { /* plot each segment separately */
- $t2 = $t[$i]; /* sub-divide at $t[$i-1], $t[$i] */
- $fx1 = ($t1 * ($t1 * $xb - 2 * $xc) - $t2 * ($t1 * ($t1 * $xa - 2 * $xb) + $xc) + $xd) / 8 - $fx0;
- $fy1 = ($t1 * ($t1 * $yb - 2 * $yc) - $t2 * ($t1 * ($t1 * $ya - 2 * $yb) + $yc) + $yd) / 8 - $fy0;
- $fx2 = ($t2 * ($t2 * $xb - 2 * $xc) - $t1 * ($t2 * ($t2 * $xa - 2 * $xb) + $xc) + $xd) / 8 - $fx0;
- $fy2 = ($t2 * ($t2 * $yb - 2 * $yc) - $t1 * ($t2 * ($t2 * $ya - 2 * $yb) + $yc) + $yd) / 8 - $fy0;
- $fx0 -= $fx3 = ($t2 * ($t2 * (3 * $xb - $t2 * $xa) - 3 * $xc) + $xd) / 8;
- $fy0 -= $fy3 = ($t2 * ($t2 * (3 * $yb - $t2 * $ya) - 3 * $yc) + $yd) / 8;
- $x3 = floor($fx3 + 0.5);
- $y3 = floor($fy3 + 0.5); /* scale bounds to int */
- if ($fx0 != 0.0) {
- $fx1 *= $fx0 = ($x0 - $x3) / $fx0;
- $fx2 *= $fx0;
- }
- if ($fy0 != 0.0) {
- $fy1 *= $fy0 = ($y0 - $y3) / $fy0;
- $fy2 *= $fy0;
- }
- if ($x0 != $x3 || $y0 != $y3) /* segment $t1 - $t2 */ {
- $this->plotCubicSegment($gd, $x0, $y0, $x0 + $fx1, $y0 + $fy1, $x0 + $fx2, $y0 + $fy2, $x3, $y3);
- }
- $x0 = $x3;
- $y0 = $y3;
- $fx0 = $fx3;
- $fy0 = $fy3;
- $t1 = $t2;
- }
- }
- protected function plotCubicSegment($gd, $x0, $y0, $x1, $y1, $x2, $y2, $x3, $y3)
- { /* plot limited anti-aliased cubic Bezier segment */
- $f = 0;
- $fx = 0;
- $fy = 0;
- $leg = 1;
- $sx = $x0 < $x3 ? 1 : -1;
- $sy = $y0 < $y3 ? 1 : -1; /* step direction */
- $xc = -abs($x0 + $x1 - $x2 - $x3);
- $xa = $xc - 4 * $sx * ($x1 - $x2);
- $xb = $sx * ($x0 - $x1 - $x2 + $x3);
- $yc = -abs($y0 + $y1 - $y2 - $y3);
- $ya = $yc - 4 * $sy * ($y1 - $y2);
- $yb = $sy * ($y0 - $y1 - $y2 + $y3);
- $ab = 0;
- $ac = 0;
- $bc = 0;
- $ba = 0;
- $xx = 0;
- $xy = 0;
- $yy = 0;
- $dx = 0;
- $dy = 0;
- $ex = 0;
- $px = 0;
- $py = 0;
- $ed = 0;
- $ip = 0;
- $EP = 0.01;
- /* check for curve restrains */
- /* slope P0-P1 == P2-P3 and (P0-P3 == P1-P2 or no slope change) */
- assert(($x1 - $x0) * ($x2 - $x3) < $EP && (($x3 - $x0) * ($x1 - $x2) < $EP || $xb * $xb < $xa * $xc + $EP));
- assert(($y1 - $y0) * ($y2 - $y3) < $EP && (($y3 - $y0) * ($y1 - $y2) < $EP || $yb * $yb < $ya * $yc + $EP));
- if ($xa == 0 && $ya == 0) { /* quadratic Bezier */
- $sx = floor((3 * $x1 - $x0 + 1) / 2);
- $sy = floor((3 * $y1 - $y0 + 1) / 2); /* new midpoint */
- $this->plotQuadSegment($gd, $x0, $y0, $sx, $sy, $x3, $y3);
- return;
- }
- $x1 = ($x1 - $x0) * ($x1 - $x0) + ($y1 - $y0) * ($y1 - $y0) + 1; /* line lengths */
- $x2 = ($x2 - $x3) * ($x2 - $x3) + ($y2 - $y3) * ($y2 - $y3) + 1;
- do { /* loop over both ends */
- $ab = $xa * $yb - $xb * $ya;
- $ac = $xa * $yc - $xc * $ya;
- $bc = $xb * $yc - $xc * $yb;
- $ip = 4 * $ab * $bc - $ac * $ac; /* self intersection loop at all? */
- $ex = $ab * ($ab + $ac - 3 * $bc) + $ac * $ac; /* P0 part of self-intersection loop? */
- $f = $ex > 0 ? 1 : sqrt(1 + 1024 / $x1); /* calculate resolution */
- $ab *= $f;
- $ac *= $f;
- $bc *= $f;
- $ex *= $f * $f; /* increase resolution */
- $xy = 9 * ($ab + $ac + $bc) / 8;
- $ba = 8 * ($xa - $ya);/* init differences of 1st degree */
- $dx = 27 * (8 * $ab * ($yb * $yb - $ya * $yc) + $ex * ($ya + 2 * $yb + $yc)) / 64 - $ya * $ya * ($xy - $ya);
- $dy = 27 * (8 * $ab * ($xb * $xb - $xa * $xc) - $ex * ($xa + 2 * $xb + $xc)) / 64 - $xa * $xa * ($xy + $xa);
- /* init differences of 2nd degree */
- $xx = 3 * (3 * $ab * (3 * $yb * $yb - $ya * $ya - 2 * $ya * $yc) - $ya * (3 * $ac * ($ya + $yb) + $ya * $ba)) / 4;
- $yy = 3 * (3 * $ab * (3 * $xb * $xb - $xa * $xa - 2 * $xa * $xc) - $xa * (3 * $ac * ($xa + $xb) + $xa * $ba)) / 4;
- $xy = $xa * $ya * (6 * $ab + 6 * $ac - 3 * $bc + $ba);
- $ac = $ya * $ya;
- $ba = $xa * $xa;
- $xy = 3 * ($xy + 9 * $f * ($ba * $yb * $yc - $xb * $xc * $ac) - 18 * $xb * $yb * $ab) / 8;
- if ($ex < 0) { /* negate values if inside self-intersection loop */
- $dx = -$dx;
- $dy = -$dy;
- $xx = -$xx;
- $yy = -$yy;
- $xy = -$xy;
- $ac = -$ac;
- $ba = -$ba;
- } /* init differences of 3rd degree */
- $ab = 6 * $ya * $ac;
- $ac = -6 * $xa * $ac;
- $bc = 6 * $ya * $ba;
- $ba = -6 * $xa * $ba;
- $dx += $xy;
- $ex = $dx + $dy;
- $dy += $xy; /* error of 1st step */
- for ($fx = $fy = $f; $x0 != $x3 && $y0 != $y3;) {
- $y1 = min($xy - $dx, $dy - $xy);
- $ed = max($xy - $dx, $dy - $xy); /* approximate error distance */
- $ed = $f * ($ed + 2 * $ed * $y1 * $y1 / (4 * $ed * $ed + $y1 * $y1));
- $y1 = 255 * abs($ex - ($f - $fx + 1) * $dx - ($f - $fy + 1) * $dy + $f * $xy) / $ed;
- if ($y1 < 256) {
- $this->setPixel($gd, $x0, $y0, $y1 / 255);
- } /* plot curve */
- $px = abs($ex - ($f - $fx + 1) * $dx + ($fy - 1) * $dy); /* pixel intensity x move */
- $py = abs($ex + ($fx - 1) * $dx - ($f - $fy + 1) * $dy); /* pixel intensity y move */
- $y2 = $y0;
- do { /* move sub-steps of one pixel */
- if ($ip >= -$EP) /* intersection possible? -> check.. */ {
- if ($dx + $xx > $xy || $dy + $yy < $xy) {
- goto exits;
- }
- } /* two x or y steps */
- $y1 = 2 * $ex + $dx; /* save value for test of y step */
- if (2 * $ex + $dy > 0) { /* x sub-step */
- $fx--;
- $ex += $dx += $xx;
- $dy += $xy += $ac;
- $yy += $bc;
- $xx += $ab;
- } else {
- if ($y1 > 0) {
- goto exits;
- }
- } /* tiny nearly cusp */
- if ($y1 <= 0) { /* y sub-step */
- $fy--;
- $ex += $dy += $yy;
- $dx += $xy += $bc;
- $xx += $ac;
- $yy += $ba;
- }
- } while ($fx > 0 && $fy > 0); /* pixel complete? */
- if (2 * $fy <= $f) { /* x+ anti-aliasing pixel */
- if ($py < $ed) {
- $this->setPixel($gd, $x0 + $sx, $y0, $py / $ed);
- } /* plot curve */
- $y0 += $sy;
- $fy += $f; /* y step */
- }
- if (2 * $fx <= $f) { /* y+ anti-aliasing pixel */
- if ($px < $ed) {
- $this->setPixel($gd, $x0, $y2 + $sy, $px / $ed);
- } /* plot curve */
- $x0 += $sx;
- $fx += $f; /* x step */
- }
- }
- break; /* finish curve by line */
- exits:
- if (2 * $ex < $dy && 2 * $fy <= $f + 2) { /* round x+ approximation pixel */
- if ($py < $ed) {
- $this->setPixel($gd, $x0 + $sx, $y0, $py / $ed);
- } /* plot curve */
- $y0 += $sy;
- }
- if (2 * $ex > $dx && 2 * $fx <= $f + 2) { /* round y+ approximation pixel */
- if ($px < $ed) {
- $this->setPixel($gd, $x0, $y2 + $sy, $px / $ed);
- } /* plot curve */
- $x0 += $sx;
- }
- $xx = $x0;
- $x0 = $x3;
- $x3 = $xx;
- $sx = -$sx;
- $xb = -$xb; /* swap legs */
- $yy = $y0;
- $y0 = $y3;
- $y3 = $yy;
- $sy = -$sy;
- $yb = -$yb;
- $x1 = $x2;
- } while ($leg--); /* try other end */
- $this->plotLine($gd, $x0, $y0, $x3, $y3); /* remaining part in case of cusp or crunode */
- }
- protected function plotQuadSegment($gd, $x0, $y0, $x1, $y1, $x2, $y2)
- { /* draw an limited anti-aliased quadratic Bezier segment */
- $sx = $x2 - $x1;
- $sy = $y2 - $y1;
- $xx = $x0 - $x1;
- $yy = $y0 - $y1;
- $xy = $dx = $dy = $err = $ed = 0;
- $cur = $xx * $sy - $yy * $sx; /* $curvature */
- if ($sx * (int)$sx + $sy * (int)$sy > $xx * $xx + $yy * $yy) { /* begin with longer part */
- $x2 = $x0;
- $x0 = $sx + $x1;
- $y2 = $y0;
- $y0 = $sy + $y1;
- $cur = -$cur; /* swap P0 P2 */
- }
- if ($cur != 0) { /* no straight line */
- $xx += $sx;
- $xx *= $sx = $x0 < $x2 ? 1 : -1; /* x step direction */
- $yy += $sy;
- $yy *= $sy = $y0 < $y2 ? 1 : -1; /* y step direction */
- $xy = 2 * $xx * $yy;
- $xx *= $xx;
- $yy *= $yy; /* differences 2nd degree */
- if ($cur * $sx * $sy < 0) { /* negat$ed $curvature? */
- $xx = -$xx;
- $yy = -$yy;
- $xy = -$xy;
- $cur = -$cur;
- }
- $dx = 4.0 * $sy * ($x1 - $x0) * $cur + $xx - $xy; /* differences 1st degree */
- $dy = 4.0 * $sx * ($y0 - $y1) * $cur + $yy - $xy;
- $xx += $xx;
- $yy += $yy;
- $err = $dx + $dy + $xy; /* $error 1st step */
- do {
- $cur = min($dx + $xy, -$xy - $dy);
- $ed = max($dx + $xy, -$xy - $dy); /* approximate $error distance */
- $ed += 2 * $ed * $cur * $cur / (4 * $ed * $ed + $cur * $cur);
- $this->setPixel($gd, $x0, $y0, abs($err - $dx - $dy - $xy) / $ed); /* plot $curve */
- if ($x0 == $x2 || $y0 == $y2) {
- break;
- } /* $curve finish$ed */
- $x1 = $x0;
- $cur = $dx - $err;
- $y1 = 2 * $err + $dy < 0;
- if (2 * $err + $dx > 0) { /* x step */
- if ($err - $dy < $ed) {
- $this->setPixel($gd, $x0, $y0 + $sy, abs($err - $dy) / $ed);
- }
- $x0 += $sx;
- $dx -= $xy;
- $err += $dy += $yy;
- }
- if ($y1) { /* y step */
- if ($cur < $ed) {
- $this->setPixel($gd, $x1 + $sx, $y0, abs($cur) / $ed);
- }
- $y0 += $sy;
- $dy -= $xy;
- $err += $dx += $xx;
- }
- } while ($dy < $dx); /* gradient negates -> close curves */
- }
- $this->plotLine($gd, $x0, $y0, $x2, $y2); /* plot remaining needle to end */
- }
- protected function plotLine($gd, $x0, $y0, $x1, $y1)
- { /* draw a black (0) anti-aliased line on white (255) background */
- $dx = abs($x1 - $x0);
- $sx = $x0 < $x1 ? 1 : -1;
- $dy = -abs($y1 - $y0);
- $sy = $y0 < $y1 ? 1 : -1;
- $err = $dx + $dy;
- $e2 = $x2 = 0; /* $error value e_xy */
- $ed = $dx - $dy == 0 ? 1 : sqrt((float)$dx * $dx + (float)$dy * $dy);
- for (; ;) { /* pixel loop */
- $this->setPixel($gd, $x0, $y0, abs($err - $dx - $dy) / $ed);
- $e2 = $err;
- $x2 = $x0;
- if (2 * $e2 + $dx >= 0) { /* x step */
- if ($x0 == $x1) {
- break;
- }
- if ($e2 - $dy < $ed) {
- $this->setPixel($gd, $x0, $y0 + $sy, ($e2 - $dy) / $ed);
- }
- $err += $dy;
- $x0 += $sx;
- }
- if (2 * $e2 + $dy <= 0) { /* y step */
- if ($y0 == $y1) {
- break;
- }
- if ($dx - $e2 < $ed) {
- $this->setPixel($gd, $x2 + $sx, $y0, ($dx - $e2) / $ed);
- }
- $err += $dx;
- $y0 += $sy;
- }
- }
- }
- /**
- * @param resource $gd
- * @param int $x
- * @param int $y
- * @param float $ar Alpha ratio
- */
- protected function setPixel($gd, $x, $y, $ar)
- {
- list($r, $g, $b) = $this->color->getRgb();
- $c = imagecolorallocatealpha($gd, $r, $g, $b, 127 * $ar);
- imagesetpixel($gd, $x, $y, $c);
- }
- }
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