imagefilledpolygon

(PHP 4, PHP 5, PHP 7)

imagefilledpolygon画一多边形并填充

说明

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

imagefilledpolygon()image 图像中画一个填充了的多边形。

points 参数是一个按顺序包含有多边形各顶点的 xy 坐标的数组。

num_points 参数是顶点的总数,必须大于 3。

Example #1 imagefilledpolygon() 例子

<?php
// 建立多边形各顶点坐标的数组
$values = array(
            
40,  50,  // Point 1 (x, y)
            
20,  240// Point 2 (x, y)
            
60,  60,  // Point 3 (x, y)
            
24020,  // Point 4 (x, y)
            
50,  40,  // Point 5 (x, y)
            
10,  10   // Point 6 (x, y)
            
);

// 创建图像
$image imagecreatetruecolor(250250);

// 设定颜色
$bg   imagecolorallocate($image200200200);
$blue imagecolorallocate($image00255);

// 画一个多边形
imagefilledpolygon($image$values6$blue);

// 输出图像
header('Content-type: image/png');
imagepng($image);
imagedestroy($image);
?>

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User Contributed Notes 9 notes

up
3
tatlar at yahoo dot com
13 years ago
<?php function _makeFiveSidedStar( $x, $y, $radius, $shape='polygon', $spiky=NULL ) {
   
// $x, $y co-ords of origin (in pixels), $radius (in pixels), $shape - 'polygon' or 'star', $spikiness - ratio between 0 and 1
   
$point = 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 // 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' ) ;
// Put values into imagepolygon function. You need to define the $image and $color, and flush it out to an image type.?>
up
1
jylyn at hotmail dot com
12 years ago
In spite of what it says about requiring more than 3 vertices, it is possible to draw a triangle with this function!
up
1
martin at eksperimentrum dot dk
1 year ago
How to draw a simple 6-sided star img where x,y is center of the star and s is the size:

function drawStar($img, $x, $y, $s, $color) {
    $x=$x-$s/2;
    $y=$y-$s/4;
    $points=array($x,$y, $x+$s/2,$y+$s, $x+$s,$y);
    imagefilledpolygon($img, $points, 3, $color);
    $points=array($x,2/3*$s+$y, $x+$s/2,$y-$s/3, $x+$s,2/3*$s+$y);
    imagefilledpolygon($img, $points, 3, $color);
}
up
0
Steween
2 years ago
My version of drawStar (with examples)

<?php
header
("Content-type: image/png");

/* drawStar or regular polygon
    $x, $y  -> Position in the image
    $radius -> Radius of the star
    $spikes -> Number of spikes (min 2)
    $ratio  -> Ratio between outer and inner points
    $dir    -> Rotation 270° for having an up spike( with ratio<1)
*/
function drawStar($x, $y, $radius, $spikes=5, $ratio=0.5, $dir=270) {
   
$coordinates = array();
   
$angle = 360 / $spikes ;
    for(
$i=0; $i<$spikes; $i++){
       
$coordinates[] = $x + (       $radius * cos(deg2rad($dir+$angle*$i)));
       
$coordinates[] = $y + (       $radius * sin(deg2rad($dir+$angle*$i)));
       
$coordinates[] = $x + ($ratio*$radius * cos(deg2rad($dir+$angle*$i + $angle/2)));
       
$coordinates[] = $y + ($ratio*$radius * sin(deg2rad($dir+$angle*$i + $angle/2)));
    }
    return
$coordinates ;
}

// 14*20+24*2 = 328 Examples
$im = imagecreate(800,600);
    
imagecolorallocate($im,   0,   0,   0);
$w = imagecolorallocate($im, 255, 255, 255);
$r = imagecolorallocate($im, 255,   0,   0);
for (
$spikes=2; $spikes<16; $spikes++) { //[2-15]
   
for ($ratio=1; $ratio<21; $ratio++) { //[0.1-2.0]
       
$values = drawStar(40*$ratio-20, $spikes*40-60, 10, $spikes, $ratio/10);
       
imagefilledpolygon($im, $values, count($values)/2, ($ratio % 5 == 0) ? $r : $w);
    }
}
for (
$dir=0; $dir<24; $dir++) {
   
$values = drawStar(30*$dir+20, 580, 10, 2, 1.5, $dir*15);
   
imagefilledpolygon($im, $values, count($values)/2, $w);
   
$values = drawStar(30*$dir+20, 580, 10, 2, 0.2, $dir*15);
   
imagefilledpolygon($im, $values, count($values)/2, $r);
}
imagepng($im);
imagedestroy($im);
?>
up
0
rbenheidorn at gmail dot com
4 years ago
Discovered while working on printing geographical boundaries to an image: if you provide floating point vertices, then the decimal value is automatically truncated. This can cause images drawn with floating point vertices to shift slightly towards the top-left corner. My personal resolution is to round all of the vertices to their nearest whole values, which eliminates this shift.
up
0
austinoblouk at yahoo dot com
10 years ago
Actually the minimum it allows is 3. It says "Total number of vertices, which must be bigger than 3." but it allows 3...
up
0
etnekor at tar dot hu
13 years ago
There is a simple function to draw a filled point with a chosen radius and color.

<?php
function drawPoint($img, $radius, $origo_x, $origo_y, $pointColor)
{
  for (
$i=0;$i<=360;$i++)
  {
   
$pont[] = $origo_x + ($radius * sin(deg2rad($i)));
   
$pont[] = $origo_y - ($radius * cos(deg2rad($i)));
  }
 
reset($pont);
 
ImageFilledPolygon ($img, $pont, (sizeof($pont)/2), $pointColor);
}
?>
up
-2
Arnapou
11 years ago
I discovered that the GD imagefilledpolygon function is incorrect for some drawing with transparent color (for example red 50% : RGBA = 255, 0, 0, 64).

I tried to draw a complex form with lots of points really near (1 pixel of distance) and a transparent red.

The problem was : some border pixels were not drawn by the imagefilledpolygon but were drawn with imagepolygon !?!?

So I wrote my own imagefilledpolygon function which work very well in all case I tested.

<?php
// $points should be an array of coordinates like that :
$points = array(
    array(
0, 0),
    array(
100, 50),
    array(
90, 100),
    array(
50, 50),
    array(
70, 30),
    array(
10, 10),
);
?>

<?php
function myimagefilledpolygon(& $img, $points, $color) {
   
$scanline = 99999;
   
// compute edges
   
$all_edges = array();
   
$n = count($points);
    for(
$i=0; $i<$n; $i++) {
       
$p1 = $points[$i];
        if (
$i == $n-1) { $p2 = $points[0]; } else { $p2 = $points[$i+1]; }
       
$x1 = $p1[0]; $y1 = $p1[1];
       
$x2 = $p2[0]; $y2 = $p2[1];
        if (
$y1 != $y2) {
           
$invslope = ($x2 - $x1)/($y2 - $y1);
            if (
$y1 < $y2 ) {
               
$ymin = $y1;
               
$xval = $x1;
               
$ymax = $y2;
            } else {
               
$ymin = $y2;
               
$xval = $x2;
               
$ymax = $y1;
            }
           
$all_edges[] = array($ymin, $ymax, $xval, $invslope);
            if (
$ymin < $scanline) { $scanline = $ymin; }
        } else {
            if (
$y1 < $scanline) { $scanline = $y1; }
            if (
$y2 < $scanline) { $scanline = $y2; }
        }
    }
   
// draw
   
$active = array();
    do {
       
// add edges to active array
       
$tmp = array();
       
$n = count($all_edges);
        for(
$i=0; $i<$n; $i++) {
            if (
$all_edges[$i][0] == $scanline) {
               
$active[] = $all_edges[$i];
            } else {
               
$tmp[] = $all_edges[$i];
            }
        }
       
$all_edges = $tmp;
       
// remove previous edges from active array
       
$tmp = array();
       
$n = count($active);
        for(
$i=0; $i<$n; $i++) {
            if (
$active[$i][1] > $scanline) {
               
$tmp[] = $active[$i];
            }
        }
       
$active = $tmp;
       
// sort active tab
       
$n = count($active);
        for(
$i=0; $i<$n-1; $i++) {
           
$min = $i;
            for(
$k=$i+1; $k<$n; $k++) {
                if (
$active[$k][2] < $active[$min][2]) { $min = $k; }
            }
            if (
$i != $min) {
               
$tmp = $active[$i];
               
$active[$i] = $active[$min];
               
$active[$min] = $tmp;
            }
        }
       
// draw
       
$n = count($active);
        for(
$i=0; $i<$n; $i+=2) {
            if (
$i+1 < $n) {
                if (
$tmp[$i][2] == $active[$i+1][2]) {
                   
imagesetpixel($img, round($active[$i][2]), $scanline, $color);
                } else {
                   
imageline($img, round($active[$i][2]), $scanline, round($active[$i+1][2]), $scanline, $color);
                }
            }
        }
       
// increment x values
       
$n = count($active);
        for(
$i=0; $i<$n; $i++) { $active[$i][2] += $active[$i][3]; }
       
$scanline++;
    } while (
count($all_edges) + count($active) > 0);
}
?>
up
-1
webmaster at mywebsolution dot de
11 years ago
Just thought that 'tatlar at yahoo dot com's function has some redundant code in it, so I tried to "improve" it. Now you can choose a variable number of spikes.

<?php
error_reporting
(E_ALL);
function
drawStar($x, $y, $radius, $spikes=5) {
   
// $x, $y -> Position in the image
    // $radius -> Radius of the star
    // $spikes -> Number of spikes

   
$coordinates = array();
   
$angel = 360 / $spikes ;

   
// Get the coordinates of the outer shape of the star
   
$outer_shape = array();
    for(
$i=0; $i<$spikes; $i++){
       
$outer_shape[$i]['x'] = $x + ($radius * cos(deg2rad(270 - $angel*$i)));
       
$outer_shape[$i]['y'] = $y + ($radius * sin(deg2rad(270 - $angel*$i)));
    }

   
// Get the coordinates of the inner shape of the star
   
$inner_shape = array();
    for(
$i=0; $i<$spikes; $i++){
       
$inner_shape[$i]['x'] = $x + (0.5*$radius * cos(deg2rad(270-180 - $angel*$i)));
       
$inner_shape[$i]['y'] = $y + (0.5*$radius * sin(deg2rad(270-180 - $angel*$i)));
    }

   
// Bring the coordinates in the right order
   
foreach($inner_shape as $key => $value){
        if(
$key == (floor($spikes/2)+1))
             break;
       
$inner_shape[] = $value;
        unset(
$inner_shape[$key]);
    }

   
// Reset the keys
   
$i=0;
    foreach(
$inner_shape as $value){
       
$inner_shape[$i] = $value;
       
$i++;
    }

   
// "Merge" outer and inner shape
   
foreach($outer_shape as $key => $value){
        
$coordinates[] = $outer_shape[$key]['x'];
        
$coordinates[] = $outer_shape[$key]['y'];
        
$coordinates[] = $inner_shape[$key]['x'];
        
$coordinates[] = $inner_shape[$key]['y'];
    }

   
// Return the coordinates
   
return $coordinates ;
}

// Example
$spikes = 5;

$values = drawStar(250, 250, 200, $spikes);
$im = imagecreate(500,500);
imagecolorallocate($im,0,0,0);
$w = imagecolorallocate($im, 255, 255, 255);
imagefilledpolygon($im, $values, $spikes*2, $w);
imageGIF($im);
imagedestroy($im);
?>
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