imagepolygon

(PHP 4, PHP 5, PHP 7)

imagepolygon — 画一个多边形

说明

bool imagepolygon ( resource $image , array $points , int $num_points , int $color )

imagepolygon() 在图像中创建一个多边形。points 是一个 PHP 数组，包含了多边形的各个顶点坐标，即 points[0] = x0，points[1] = y0，points[2] = x1，points[3] = y1，以此类推。num_points 是顶点的总数。

Example #1 imagepolygon() 例子

  <?php
 // create a blank image
 $image  =  imagecreatetruecolor ( 400 ,  300 );

 // fill the background color
 $bg  =  imagecolorallocate ( $image ,  0 ,  0 ,  0 );

 // choose a color for the polygon
 $col_poly  =  imagecolorallocate ( $image ,  255 ,  255 ,  255 );

 // draw the polygon
 imagepolygon ( $image ,
             array (
                     0 ,  0 ,
                     100 ,  200 ,
                     300 ,  200
              ),
              3 ,
              $col_poly );

 // output the picture
 header ( "Content-type: image/png" );
 imagepng ( $image );

 ?>

参见 imagecreate() 和 imagecreatetruecolor() 。

用户评论:

[#1] licson0729 at gmail dot com [2012-05-23 11:21:34]

Here's a function to draw a n-sided star:

<?php function drawStar($img,$x,$y,$radius,$sides,$color,$spikness=0.5) { $point =array(); $t = 0; for($a = 0;$a <= 360;$a += 360/($sides*2)) { $t++; if($t % 2 == 0) { $point[] = $x + ($radius * $spikness) * cos(deg2rad($a)); $point[] = $y + ($radius * $spikness) * sin(deg2rad($a)); }else{ $point[] = $x + $radius * cos(deg2rad($a)); $point[] = $y + $radius * sin(deg2rad($a)); } } return imagepolygon($img,$point,$sides*2,$color); } ?>

[#2] licson0729 at gmail dot com [2012-05-21 10:39:47]

Function to draw a n-sided regular polygon

<?php $img = imagecreatetruecolor(1360,768); function regularPolygon($img,$x,$y,$radius,$sides,$color) { $points = array(); for($a = 0;$a <= 360; $a += 360/$sides) { $points[] = $x + $radius * cos(deg2rad($a)); $points[] = $y + $radius * sin(deg2rad($a)); } return imagepolygon($img,$points,$sides,$color); } regularPolygon($img,1360/2,768/2,300,8,0xffffff);//Test draw header('Content-type: image/png'); imagepng($img); imagedestroy($img); ?>

[#3] tatlar at yahoo dot com [2006-09-11 16:48:08]

Function to get 5-sided polygon (pentagon) or star (pentagram) co-ords.
<?php function _makeFiveSidedStar( $x, $y, $radius, $shape='polygon', $spiky=NULL ) { $point = array() ; // new array $angle = 360 / 5 ; $point[0]['x'] = $x ; $point[0]['y'] = $y - $radius ; $point[2]['x'] = $x + ( $radius * cos( deg2rad( 90 - $angle ) ) ) ; $point[2]['y'] = $y - ( $radius * sin( deg2rad( 90 - $angle ) ) ) ; $point[4]['x'] = $x + ( $radius * sin( deg2rad( 180 - ( $angle*2 ) ) ) ) ; $point[4]['y'] = $y + ( $radius * cos( deg2rad( 180 - ( $angle*2 ) ) ) ) ; $point[6]['x'] = $x - ( $radius * sin( deg2rad( 180 - ( $angle*2 ) ) ) ) ; $point[6]['y'] = $y + ( $radius * cos( deg2rad( 180 - ( $angle*2 ) ) ) ) ; $point[8]['x'] = $x - ( $radius * cos( deg2rad( 90 - $angle ) ) ) ; $point[8]['y'] = $y - ( $radius * sin( deg2rad( 90 - $angle ) ) ) ; if( $shape == 'star' ) { if( $spiky == NULL ) $spiky = 0.5 ; // degree of spikiness, default to 0.5 $indent = $radius * $spiky ; $point[1]['x'] = $x + ( $indent * cos( deg2rad( 90 - $angle/2 ) ) ) ; $point[1]['y'] = $y - ( $indent * sin( deg2rad( 90 - $angle/2 ) ) ) ; $point[3]['x'] = $x + ( $indent * sin( deg2rad( 180 - $angle ) ) ) ; $point[3]['y'] = $y - ( $indent * cos( deg2rad( 180 - $angle ) ) ) ; $point[5]['x'] = $x ; $point[5]['y'] = $y + ( $indent * sin( deg2rad( 180 - $angle ) ) ) ; $point[7]['x'] = $x - ( $indent * sin( deg2rad( 180 - $angle ) ) ) ; $point[7]['y'] = $y - ( $indent * cos( deg2rad( 180 - $angle ) ) ) ; $point[9]['x'] = $x - ( $indent * cos( deg2rad( 90 - $angle/2 ) ) ) ; $point[9]['y'] = $y - ( $indent * sin( deg2rad( 90 - $angle/2 ) ) ) ; } ksort( $point ) ; $coords = array() ; // new array foreach( $point as $pKey=>$pVal ) { if( is_array( $pVal ) ) { foreach( $pVal as $pSubKey=>$pSubVal ) { if( !empty( $pSubVal ) ) array_push( $coords, $pSubVal ) ; } } } return $coords ; } $values = _makeFiveSidedStar( 100, 100, 50, 'star' ) ; ?>

[#4] jsnell at networkninja dot com [2001-02-17 19:07:01]

Here are some handy routines for rotation and translation of polygons. Scaling could be added easily as well.

<?php function translate_point(&$x,&$y,$angle,$about_x,$about_y,$shift_x,$shift_y) { $x -= $about_x; $y -= $about_y; $angle = ($angle / 180) * M_PI; $new_x = $x * cos($angle) - $y * sin($angle); $new_y = $x * sin($angle) + $y * cos($angle); $x = $new_x+ $about_x + $shift_x ; $y = $new_y + $about_y + $shift_y; } function translate_poly($point_array, $angle, $about_x, $about_y,$shift_x,$shift_y) { $translated_poly = Array(); while(count($point_array) > 1) { $temp_x = array_shift($point_array); $temp_y = array_shift($point_array); translate_point($temp_x, $temp_y, $angle, $about_x, $about_y,$shift_x, $shift_y); array_push($translated_poly, $temp_x); array_push($translated_poly, $temp_y); } return $translated_poly; } ?>