PHP 5.6.29 Released

imagearc

(PHP 4, PHP 5, PHP 7)

imagearcDesenha um elipse parcial

Descrição

int imagearc ( resource $image , int $cx , int $cy , int $w , int $h , int $s , int $e , int $color )

imagearc() desenha um elipse parcial centrado em cx, cy (o canto superior esquerdo é 0, 0) na imagem representada por image. W e h representa respectivamente a largura e altura enquanto os pontos de início e final são representados em graus pelos parâmetros s e e. 0° esta localizado na posição de três horas, e o arco é desenhado no sentido horário.

Exemplo #1 Desenhando um círculo com imagearc()

<?php

// cria uma imagem de 200 * 200
$img imagecreate(200200);

// aloca algumas cores
$white imagecolorallocate($img255255255);
$black imagecolorallocate($img000);   
// desenha um círculo preto 
imagearc($img1001001501500360$black); 

// envia a imagem para o browser
header("Content-type: image/png");
imagepng($img);
   
// libera a mémoria
imagedestroy($img);

?>

Veja também imageellipse(), imagefilledellipse(), e imagefilledarc().

add a note add a note

User Contributed Notes 19 notes

up
3
chandlerklebs at gmail dot com
4 years ago
This is an example script I wrote for myself to help me learn how to used the imagearc functions. Maybe if will also help others.

<?php
//example PHP script of imagearc functions
$image_width=360;$image_height=360;
$img = imagecreatetruecolor($image_width,$image_height); //make image variable

//create a background color by making a filled rectangle
$color = imagecolorallocate($img,255,255,255);
imagefilledrectangle($img,0,0,$image_width,$image_height,$color);

$r=$image_width/2 - $image_width/32 ; //radius
$cx=$image_width/2;
$cy=$image_height/2;

$color = imagecolorallocate($img,0,0,0);
imagearc($img, $cx, $cy, $r*2, $r*20, 360, $color); //regular outlines arc

imagefilledarc($img, $cx, $cy, $r*1, $r*10, 90, $color,IMG_ARC_CHORD); //filled triangle with chord of circle
imagefilledarc($img, $cx, $cy, $r*1, $r*1180, 270, $color,IMG_ARC_PIE); //pie slice

$font_number=5; //can use built in fonts numbered 1 to 5
$string="Hello world!";
imagestring($img, $font_number, $cx-(imagefontwidth($font_number)*strlen($string))/2, $cy-120, $string, $color);

header("Content-type: image/png");
imagepng($img);// output image in the browser

$filename="imagearc";
imagepng($img,"./frames/$filename.png",9); //make highly compressed png

imagedestroy($img);
?>
up
3
lucas dot delmas at live dot fr
3 years ago
The imagearc function has a precision of one degree. The function truncates the $start and $end values to the inferior degree.

For example if the starting angle you calculated is : -178.62450462172°
and the ending angle is : -152.78056427917°
imagearc will draw a curve from -178° to -152°.

If you need accurate curves drawing, you need to use a loop to draw little step-by-step lines. By creating a large number of short enough lines, you will create the impression of a curve with accuracy.
up
2
nojer2 at yahoo dot com
15 years ago
Here's a dashed circle function:

<?php
function dashedcircle($im, $cx, $cy, $radius, $colour, $dashsize=5) {

  
$dash=false;
   for (
$angle=0; $angle<=(180+$dashsize); $angle+=$dashsize) {
     
$x = ($radius * cos(deg2rad($angle)));
     
$y = ($radius * sin(deg2rad($angle)));

      if (
$dash) {
        
imageline($im, $cx+$px, $cy+$py, $cx+$x, $cy+$y, $colour);
        
imageline($im, $cx-$px, $cx-$py, $cx-$x, $cy-$y, $colour);
      }
     
$dash=!$dash;
     
$px=$x;
     
$py=$y;
   }
}
?>
up
1
mojiro at awmn dot net
10 years ago
A previous for the Rotated (Filled)Ellipse note from(nojer2 at yahoo dot com, 02-Apr-2001 12:06) has a mistake, at the second arc. Replace them with the following listing.

if ($filled) {
    triangle($im, $cx, $cy, $cx+$px, $cy+$py, $cx+$x, $cy+$y, $colour);
    triangle($im, $cx, $cy, $cx-$px, $cy-$py, $cx-$x, $cy-$y, $colour);
} else {
    imageline($im, $cx+$px, $cy+$py, $cx+$x, $cy+$y, $colour);
    imageline($im, $cx-$px, $cy-$py, $cx-$x, $cy-$y, $colour);
}
up
1
anton dot vandeghinste at telenet dot be
6 years ago
I needed an arc with a thick border and i didn't like to use 359.9 as end angle so i made a function that works pretty well:

<?php
function imagearcthick($image, $x, $y, $w, $h, $s, $e, $color, $thick = 1)
{
    if(
$thick == 1)
    {
        return
imagearc($image, $x, $y, $w, $h, $s, $e, $color);
    }
    for(
$i = 1;$i<($thick+1);$i++)
    {
       
imagearc($image, $x, $y, $w-($i/5), $h-($i/5),$s,$e,$color);
       
imagearc($image, $x, $y, $w+($i/5), $h+($i/5), $s, $e, $color);
    }
}
?>
up
2
eamon at hostelworld dot com
12 years ago
Right...
possibly the easiest way of drawing a filled circle:
Loop through the imagearc function incrementing the diameter by one pixel:
<?
// --- code fragment --- //

for($i=1; $i<$Diameter; $i++){
  imagearc($Image, $CenterX, $CenterY, $i, $i, $Start, $End, $Color);
}

// --------------------- //

?>

This works great for circles with diameters up to about 60 or 70 pixels wide. After that, you start to get pixle gaps.
up
2
jinny at 263 dot net
14 years ago
imagesetstyle() sets the style to be used by all line drawing functions when drawing with the special color .

Here goes a example of drawing a dashed-line circle.enjoy!

<?php

header
("Content-type: image/jpeg");
$im = imagecreate(100,100);

$b   = imagecolorallocate ($im, 0, 0, 0);
$w   = imagecolorallocate ($im, 255, 255, 255);

$style = array ($b,$b,$b,$b,$b,$w,$w,$w,$w,$w);

imagesetstyle ($im, $style);

imagearc($im,50,50,100,100,0,360,IMG_COLOR_STYLED);

imagejpeg($im);
imagedestroy($im);
?>
up
1
marc at resiteit dot com
15 years ago
Round cornered anti-aliased dynamically sized button.

$w=40;
$h=20;
$im = ImageCreate($w,$h);
$white=ImageColorAllocate($im,255,255,255);
ImageFilledRectangle($im,0,0,$w,$h,$white);
imagecolortransparent ($im, $white);
ImageTTFText ($im, $h+ceil($h/3)+1, 0, -1, $h-1, $col1, "arialbd.ttf", "O");
ImageTTFText ($im, $h+ceil($h/3)+1, 0, $w-$h, $h-1, $col1, "arialbd.ttf", "O");
ImageTTFText ($im, $h+ceil($h/3)+1, 0, 1, $h-1, $col1, "arialbd.ttf", "O");
ImageTTFText ($im, $h+ceil($h/3)+1, 0, $w-$h-2, $h-1, $col1, "arialbd.ttf", "O");
$points=array(
    1,round($h/2),
    round($h/4),$h-round($h/4),
    round($h/2),$h,
    $w-(round($h/2)),$h,
    $w-(round($h/4)),$h-round($h/4),
    $w-2,round($h/2),
    $w-round($h/4),round($h/4),
    $w-round($h/2),0,
    round($h/2),0,
    round($h/4),round($h/4)
);
imagefilledpolygon ($im, $points, 10, $col1);

header("content-type: image/gif");
header("Content-Disposition: filename=name.gif");
ImageGif($im);
ImageDestroy($im);
up
0
joe dot tym at gmail dot com
4 years ago
I didn't have much luck with the other two functions, one of them makes circles that look like they've been printed on a dot-matrix printer. This simple function builds a border out of circles, seems to work nicely.

<?php
function imagearcunfilled($image,$x,$y,$width,$height,$border_thickness, $color) {

       
imagesetthickness($image, 1);

       
$x_radius = $width / 2;
       
$y_radius = $height / 2;

        for (
$i = 0; $i < 360; $i++) {
                if (
TRUE) {
                       
$x2 = $x + cos($i) * $x_radius;
                       
$y2 = $y + sin($i) * $y_radius;
                       
imagefilledarc($image,$x2,$y2,$border_thickness,$border_thickness,0,360,$color,IMG_ARC_PIE);
                }
        }
}
?>
up
0
jerryscript at aol dot com
12 years ago
[note-Apache/1.3.29 (Win32) PHP/4.3.4]

The imagearc (and imageellipse) functions do not accept line thicknesses when drawn from 0 to 360 degrees.

Drawing from 0 to 359 and again from 359 to 360 does create an ellipse with the current line thickness.

Jerry
up
0
Anonymous
13 years ago
Please note that in order to draw a complete circle or ellipse (without using the imageellipse) you mustn't use 0 for both s and e. If you do this you will get, umm, nothing. Instead set s to 0 and e to 360 to get a complete circle or ellipse.
up
0
foripepe at yahoo dot com
15 years ago
To fill an arc (DiameterX != DiameterY):

<?
function imagefilledarc($Image, $CenterX, $CenterY, $DiameterX, $DiameterY, $Start, $End, $Color) {
    // To draw the arc
    imagearc($Image, $CenterX, $CenterY, $DiameterX, $DiameterY, $Start, $End, $Color);
    // To close the arc with 2 lines between the center and the 2 limits of the arc
    $x = $CenterX + (cos(deg2rad($Start))*($DiameterX/2));
    $y = $CenterY + (sin(deg2rad($Start))*($DiameterY/2));
    imageline($Image, $x, $y, $CenterX, $CenterY, $Color);
    $x = $CenterX + (cos(deg2rad($End))*($DiameterX/2));
    $y = $CenterY + (sin(deg2rad($End))*($DiameterY/2));
    imageline($Image, $x, $y, $CenterX, $CenterY, $Color);
    // To fill the arc, the starting point is a point in the middle of the closed space
    $x = $CenterX + (cos(deg2rad(($Start+$End)/2))*($DiameterX/4));
    $y = $CenterY + (sin(deg2rad(($Start+$End)/2))*($DiameterY/4));
    imagefilltoborder($Image, $x, $y, $Color, $Color);
}
?>

To close the arc with 2 lines (DiameterX != DiameterY):

<?
function imagenofilledarc($Image, $CenterX, $CenterY, $DiameterX, $DiameterY, $Start, $End, $Color) {
    // To draw the arc
    imagearc($Image, $CenterX, $CenterY, $DiameterX, $DiameterY, $Start, $End, $Color);
    // To close the arc with 2 lines between the center and the 2 limits of the arc
    $x = $CenterX + (cos(deg2rad($Start))*($DiameterX/2));
    $y = $CenterY + (sin(deg2rad($Start))*($DiameterY/2));
    imageline($Image, $x, $y, $CenterX, $CenterY, $Color);
    $x = $CenterX + (cos(deg2rad($End))*($DiameterX/2));
    $y = $CenterY + (sin(deg2rad($End))*($DiameterY/2));
    imageline($Image, $x, $y, $CenterX, $CenterY, $Color);
}
?>

An example:
<?
    $destImage = imagecreate( 216, 152 );
    $c0 = imagecolorallocate( $destImage, 0, 255, 255 );
    $c1 = imagecolorallocate( $destImage, 0, 0, 0 );
    $c2 = imagecolorallocate( $destImage, 255, 0, 0 );
    ImageFilledRectangle ( $destImage, 0, 0, 216, 152, $c0 );
    imagefilledarc( $destImage, 108, 76, 180, 80, 0, 130, $c1 );
    imagenofilledarc( $destImage, 108, 76, 180, 80, 0, 130, $c2 );
    header("content-type: image/PNG");
    ImagePNG( $destImage );
    ImageDestroy( $destImage );
?>
up
0
nojer2 at yahoo dot com
15 years ago
Here's the function to draw rotated ellipses again. This time I've optimised it a bit, fixed the no-fill bug, and used a 'squishratio' rather than a 'radiusmodifier', to make the curves perfect, so ignore my previous version.

<?php
function rotatedellipse($im, $cx, $cy, $width, $height, $rotateangle, $colour, $filled=true) {
  
$step=2;
  
$cosangle=cos(deg2rad($rotateangle));
  
$sinangle=sin(deg2rad($rotateangle));

  
$squishratio = $height/$width;
  
$nopreviouspoint = true;
   for (
$angle=0; $angle<=(180+$step); $angle+=$step) {
      
     
$ox = ($width * cos(deg2rad($angle)));
     
$oy = ($width * sin(deg2rad($angle))) * $squishratio;

     
$x =  + (($ox * $cosangle) - ($oy * $sinangle));
     
$y = $centrey + (($ox * $sinangle) + ($oy * $cosangle));
 
      if (
$nopreviouspoint) {
       
$px=$x;
       
$py=$y;
       
$nopreviouspoint=false;
      }

      if (
$filled) {
        
triangle($im, $cx, $cy, $cx+$px, $cy+$py, $cx+$x, $cy+$y, $colour);
        
triangle($im, $cx, $cy, $cx-$px, $cx-$py, $cx-$x, $cy-$y, $colour);
      } else {
        
imageline($im, $cx+$px, $cy+$py, $cx+$x, $cy+$y, $colour);
        
imageline($im, $cx-$px, $cx-$py, $cx-$x, $cy-$y, $colour);
      }
     
$px=$x;
     
$py=$y;
   }
}

function
triangle($im, $x1,$y1, $x2,$y2, $x3,$y3, $colour) {
  
$coords = array($x1,$y1, $x2,$y2, $x3,$y3);
  
imagefilledpolygon($im, $coords, 3, $colour);
}
?>
up
0
travis at duluth dot com
16 years ago
The wierd thing is that the first two integers tell where to place the "circle".
So for example I first create the "pallet" to place the circle on.
$image = imagecreate(500, 500); 
(this makes a huge 500x500 gif :) )
$colorBody = imagecolorallocate($image, 0, 0, 0);
(make the default color of the "pallet" black
$circleColor = imagecolorallocate($image, 255, 0, 255);
(going to make the circle an ugly pink color)
imagearc($image, 250, 250, 300, 300, 0, 360, $circleColor);
Places the image in the center (250,250) and the circle is 300 pixels in diameter.

Hope this helps.

Travis Kent Beste
up
-1
ajim1417 at gmail dot com
6 years ago
I wrote a simple function that can draws an arc counter-clockwisekly. Here it is :

<?php

function imagearcCC(&$im, $cx, $cy, $w, $h, $s, $e, $c) {
$start = 360 - $e;
$end = 360 - $s;
return
imagearc($im, $cx, $cy, $w, $h, $start, $end, $c);
}

?>

The params of this function is exactly the same as the usual imagearc function.
up
-1
logang at deltatee dot com
13 years ago
Heres a function to make a curve between two points... This will be a downward curve but it wouldn't be hard to make a similar function to make an upward curve. The first point has to be to the left of the second point ($x1 < $x2), and height is actually backwards. The larger height is the less of a crest the curve has. I imagine with a few modifications this functions could make upward curves as well.

function ImageCurveDown ($image, $x1, $y1, $x2, $y2, $height, $color) {
    $presicion = 1;

    for ($left = ($x1-$x2); $left < 0; $left++){
        if ($y1 < $y2) {
            $cy = $y2 + $height;
            $cx = $x1 - $left;
        } else {
            $cy = $y1 + $height;
            $cx = $x2 + $left;
        }
        $nx1 = abs($x1 - $cx);
        $ny1 = abs($y1 - $cy);
        $nx2 = abs($x2 - $cx);
        $ny2 = abs($y2 - $cy);

        if ($y1 < $y2) {
            if ($nx2 == 0 || $ny1 == 0) continue;
            $angle1 = atan($height/$nx2);
            $A1 = $nx2/cos ($angle1);
            $B1 = $ny2/sin ($angle1);
            $angle2 = pi()/2 +atan($left/$ny1);
            $A2 = $nx1/cos ($angle2);
            $B2 = $ny1/sin ($angle2);
        } else {
            if ($ny2 == 0 || $nx1 == 0) continue;
            $angle1 = atan($ny2/$nx2);
            $A1 = abs($nx2/cos ($angle1));
            $B1 = abs($ny2/sin ($angle1));
            $angle2 = atan($height/$nx1);
            $A2 = abs ($nx1/cos ($angle2));
            $B2 = abs($ny1/sin ($angle2));
        }

        if (abs($A1 - $A2) < $presicion && abs ($B1 - $B2) < $presicion) {
            ImageArc($image, $cx, $cy, $A1*2, $B1*2, 180+rad2deg($angle2), 360-rad2deg($angle1), $color);
        }
    }
}
up
-1
timothyhouck at yahoo dot com
16 years ago
To do filled arcs, try something like this:

<?php
$diameter
= 50;
imagearc($image, 25, 25, $diameter, $diameter, $start, $end, $color);
while(
$diameter > 0) {
 
imagearc($image, 25, 25, $diameter, $diameter, $start, $start + 1, $color);
 
imagearc($image, 25, 25, $diameter, $diameter, $end - 1, $end, $color);
 
$diameter--;
}
?>

...well you get the point.  It's a kludge, and *very* slow, but it's free.
up
-2
cbriou at orange-art dot fr
16 years ago
There is another way to fill an arc :

<?php
// To draw the arc
$Color = imagecolorallocate($Image, $Red, $Green, $Blue);
imagearc($Image, $CenterX, $CenterY, $Diameter, $Diameter, $Start, $End, $Color);
// To close the arc with 2 lines between the center and the 2 limits of the arc
$x = $CenterX + (cos(deg2rad($Start))*($Diameter/2));
$y = $CenterY + (sin(deg2rad($Start))*($Diameter/2));
imageline($Image, $x, $y, $CenterX, $CenterY, $Color);
$x = $CenterX + (cos(deg2rad($End))*($Diameter/2));
$y = $CenterY + (sin(deg2rad($End))*($Diameter/2));
imageline($Image, $x, $y, $CenterX, $CenterY, $Color);
// To fill the arc, the starting point is a point in the middle of the closed space
$x = $CenterX + (cos(deg2rad(($Start+$End)/2))*($Diameter/4));
$y = $CenterY + (sin(deg2rad(($Start+$End)/2))*($Diameter/4));
imagefilltoborder($Image, $x, $y, $Color, $Color);
?>
up
-2
arve at skogvold dot as
15 years ago
I found a better way for drawing a pie chart:

header ("Content-type: image/png");
$diameter = 100;
$radius = $diameter / 2;
$centerX = $radius;
$centerY = $radius;

$im = @ImageCreate ($diameter, $diameter)
    or die ("Cannot Initialize new GD image stream");

$background = ImageColorAllocate ($im, 0, 0, 0);
$red = ImageColorAllocate ($im, 176, 0, 0);

function fill_arc($start, $end, $color) {
    global $diameter, $centerX, $centerY, $im, $radius;
    imagearc($im, $centerX, $centerY, $diameter, $diameter, $start, $end, $color);
    imageline($im, $centerX, $centerY, $centerX + cos(deg2rad($start)) * $radius, $centerY + sin(deg2rad($start)) * $radius, $color);
    imageline($im, $centerX, $centerY, $centerX + cos(deg2rad($end)) * $radius, $centerY + sin(deg2rad($end)) * $radius, $color);
    imagefill ($im,$centerX + $radius * 0.5 *cos(deg2rad($start+($end-$start)/2)), $centerY + $radius * 0.5 * sin(deg2rad($start+($end-$start)/2)), $color);
    }


fill_arc(0,30,$red);
// Will make a red filled arc, starting at 0 degrees, ending at 30 degrees

ImagePng ($im);
To Top