SunshinePHP Developer Conference 2015

imagepolygon

(PHP 4, PHP 5)

imagepolygonDraws a polygon

Opis

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

imagepolygon() creates a polygon in the given image.

Parametry

obraz

Zasób obrazu, zwrócony przez jedną z funkcji tworzących obrazy, taką jak imagecreatetruecolor().

points

An array containing the polygon's vertices, e.g.:

points[0] = x0
points[1] = y0
points[2] = x1
points[3] = y1

num_points

Total number of points (vertices).

color

A color identifier created with imagecolorallocate().

Zwracane wartości

Zwraca TRUE w przypadku powodzenia, FALSE w przypadku błędu.

Przykłady

Przykład #1 imagepolygon() example

<?php
// Create a blank image
$image imagecreatetruecolor(400300);

// Allocate a color for the polygon
$col_poly imagecolorallocate($image255255255);

// Draw the polygon
imagepolygon($image, array(
        
0,   0,
        
100200,
        
300200
    
),
    
3,
    
$col_poly);

// Output the picture to the browser
header('Content-type: image/png');

imagepng($image);
imagedestroy($image);
?>

Powyższy przykład wyświetli coś podobnego do:

Output of example : imagepolygon()

Zobacz też:

add a note add a note

User Contributed Notes 5 notes

up
1
tatlar at yahoo dot com
8 years ago
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' ) ;
?>
up
1
glowell at flash dot net
8 years ago
Something to be aware of, ImagePolygon appears to convert the array of points passed to it from whatever format they may have been in originally into integers. This means if you pass it an array of floats (after running a rotation routine for example) the floats will be changed to integers INSIDE THE ORIGINAL ARRAY.

An extreme example: if for some reason you had an unit-sized polygon pt-array ( -1<x|y<1 for easy scaling purpose for instance) and for some reason your code calls imagepolygon on it (why? it'd only be a dot anyway) the array would be unusable after that (all either 1s, 0s or -1s). Scaling a unit-sized array, drawing it and then scaling it again will also may have a different result than expected.

Obviously, if the array in its original state is important to your code, it should use a copy of the original array for this call. If your code draws the same polygon multiple times but resizes it for different cases, you should have each size be created off an original template rather than adjusting a single polygon array.
up
0
licson0729 at gmail dot com
2 years ago
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);
?>
up
0
jsnell at networkninja dot com
13 years ago
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;
/* math:
[x2,y2] = [x,  *  [[cos(a),-sin(a)],
           y]      [sin(a),cos(a)]]
==>
x = x * cos(a) + y*sin(a)
y = x*-sin(a) + y*cos(a)
*/

   
$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;
}
?>
up
-2
licson0729 at gmail dot com
2 years ago
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);
}
?>
To Top