(PHP 4, PHP 5, PHP 7, PHP 8)
imagefilledpolygon — Zeichnet ein gefülltes Polygon
Signatur seit PHP 8.0.0 (keine Unterstützung für benannte Argumente)
Alternative Signatur (seit PHP 8.1.0 veraltet)
imagefilledpolygon() erzeugt ein gefülltes Polygon im
Bild, das durch image angegeben wurde.
imageEin GdImage -Objekt, das von einer der Funktionen zur Bilderzeugung, z. B. imagecreatetruecolor() , zurückgegeben wurde.
points
Ein Array, das die x- und
y-Koordinaten der aufeinanderfolgenden
Polygon-Eckpunkte enthält.
num_pointsDie Anzahl der Eckpunkte, die mindestens 3 sein muss.
Wenn dieser Parameter gemäß der zweiten Signatur weggelassen wird, musspoints eine gerade Anzahl von Elementen haben,
und num_points wird angenommen als
count($punkte)/2.
colorEine Farbkennung, die mit imagecolorallocate() erzeugt wurde.
| Version | Beschreibung |
|---|---|
| 8.1.0 |
Der Parameter num_points ist veraltet und sollte
nicht mehr verwendet werden.
|
| 8.0.0 |
image erwartet nun eine
GdImage -Instanz; vorher wurde eine gültige
gd-Ressource erwartet.
|
Beispiel #1 imagefilledpolygon()-Beispiel
<?php
// Initialisiere das Array der Polygon-Punkte
$values = array(
40, 50, // Punkt 1 (x, y)
20, 240, // Punkt 2 (x, y)
60, 60, // Punkt 3 (x, y)
240, 20, // Punkt 4 (x, y)
50, 40, // Punkt 5 (x, y)
10, 10 // Punkt 6 (x, y)
);
// Erzeuge das Bild
$image = imagecreatetruecolor(250, 250);
// Weise Farben zu
$bg = imagecolorallocate($image, 0, 0, 0);
$blue = imagecolorallocate($image, 0, 0, 255);
// Fülle den Hintergrund
imagefilledrectangle($image, 0, 0, 249, 249, $bg);
// Zeichne ein Polygon
imagefilledpolygon($image, $values, $blue);
// Gib das Bild aus
header('Content-type: image/png');
imagepng($image);
?>Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:
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);
}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($im);
?>Discovered while working on printing geographical boundaries to an image: if you provide floating point vertices, then the decimal value is automatically truncated. This can cause images drawn with floating point vertices to shift slightly towards the top-left corner. My personal resolution is to round all of the vertices to their nearest whole values, which eliminates this shift.Actually the minimum it allows is 3. It says "Total number of vertices, which must be bigger than 3." but it allows 3...Just thought that 'tatlar at yahoo dot com's function has some redundant code in it, so I tried to "improve" it. Now you can choose a variable number of spikes.
<?php
error_reporting(E_ALL);
function drawStar($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);
?>In spite of what it says about requiring more than 3 vertices, it is possible to draw a triangle with this function!<?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 $color, and flush it out to an image type.?>There is a simple function to draw a filled point with a chosen radius and color.
<?php
function drawPoint($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);
}
?>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);
}
?>