ConFoo 2025

    imagepolygon

    (PHP 4, PHP 5, PHP 7, PHP 8)

    imagepolygon — Draws a polygon

    Description

    Signature as of PHP 8.0.0 (not supported with named arguments)

    imagepolygon(GdImage $image, array $points, int $color): bool

    Alternative signature (deprecated as of PHP 8.1.0)

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

    imagepolygon() creates a polygon in the given image.

    Parameters

    image

    A GdImage object, returned by one of the image creation functions, such as 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), which must be at least 3.

    If this parameter is omitted as per the second signature, points must have an even number of elements, and num_points is assumed to be count($points)/2.
    color

    A color identifier created with imagecolorallocate().

    Return Values

    Returns true on success or false on failure.

    Changelog

    Version Description
    8.1.0 The parameter num_points has been deprecated.
    8.0.0 image expects a GdImage instance now; previously, a valid gd resource was expected.

    Examples

    Example #1 imagepolygon() example

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

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

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

    The above example will output something similar to:

    Output of example : imagepolygon()

    See Also

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    User Contributed Notes 3 notes

    up
    3
    tatlar at yahoo dot com
    18 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
    2
    licson0729 at gmail dot com
    12 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
    -2
    jsnell at networkninja dot com
    23 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;
    }
    ?>
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