imagepng
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);
}
?>
imagepolygon
(PHP 4, PHP 5)
imagepolygon — Dessine un polygone
Description
bool imagepolygon
( resource
$image
, array $points
, int $num_points
, int $color
)
imagepolygon() dessine un polygone dans l'image
image.
Liste de paramètres
-
image -
Une ressource d'image, retournée par une des fonctions de création d'images, comme imagecreatetruecolor().
-
points -
Un tableau contenant les sommets du polygone, e.g. :
points[0] = x0 points[1] = y0 points[2] = x1 points[3] = y1 -
num_points -
Le nombre de points (sommets).
-
color -
Un identifiant de couleur créé par la fonction imagecolorallocate().
Valeurs de retour
Cette fonction retourne TRUE en cas de
succès ou FALSE si une erreur survient.
Exemples
Exemple #1 Exemple avec imagepolygon()
<?php
// Création d'une image vide
$image = imagecreatetruecolor(400, 300);
// Alloue une couleur pour le polygone
$col_poly = imagecolorallocate($image, 255, 255, 255);
// Dessine le polygone
imagepolygon($image, array(
0, 0,
100, 200,
300, 200
),
3,
$col_poly);
// Affichage de l'image sur le navigateur
header('Content-type: image/png');
imagepng($image);
imagedestroy($image);
?>
L'exemple ci-dessus va afficher quelque chose de similaire à :
Voir aussi
- imagecreate() - Crée une nouvelle image à palette
- imagecreatetruecolor() - Crée une nouvelle image en couleurs vraies
add a note
User Contributed Notes
imagepolygon
licson0729 at gmail dot com
23-May-2012 11:21
licson0729 at gmail dot com
21-May-2012 10:39
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);
?>
tatlar at yahoo dot com
11-Sep-2006 04:48
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 ;
}
$values = _makeFiveSidedStar( 100, 100, 50, 'star' ) ;
?>
glowell at flash dot net
17-Nov-2005 03:43
Something to be aware of, ImagePolygon appears to convert the array of points passed to it from whatever format they may have been in originally into integers. This means if you pass it an array of floats (after running a rotation routine for example) the floats will be changed to integers INSIDE THE ORIGINAL ARRAY.
An extreme example: if for some reason you had an unit-sized polygon pt-array ( -1<x|y<1 for easy scaling purpose for instance) and for some reason your code calls imagepolygon on it (why? it'd only be a dot anyway) the array would be unusable after that (all either 1s, 0s or -1s). Scaling a unit-sized array, drawing it and then scaling it again will also may have a different result than expected.
Obviously, if the array in its original state is important to your code, it should use a copy of the original array for this call. If your code draws the same polygon multiple times but resizes it for different cases, you should have each size be created off an original template rather than adjusting a single polygon array.
jsnell at networkninja dot com
17-Feb-2001 07:07
Here are some handy routines for rotation and translation of polygons. Scaling could be added easily as well.
<?php
function translate_point(&$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;
}
?>