imagearc() Drawing of arc line images and circles using gd support in PHP

Draw an arc with explicit angles

imagearc() draws an unfilled arc. Equal width and height create a circle; different dimensions create an elliptical arc.

<?php
$image = imagecreatetruecolor(320, 220);
$background = imagecolorallocate($image, 255, 255, 255);
$blue = imagecolorallocate($image, 30, 90, 200);
imagefilledrectangle($image, 0, 0, 319, 219, $background);
imagearc($image, 160, 110, 180, 180, 20, 300, $blue);

header('Content-Type: image/png');
imagepng($image);
imagedestroy($image);
?>

Current example first; the original tutorial examples below are retained and cleaned up for continued learning.

<?php
header ("Content-type: image/jpeg");
$width=300;$height=300;
$im = @ImageCreate ($width,$height) // added one pixel for border
or die ("Cannot Initialize new GD image stream");

$background_color = ImageColorAllocate ($im, 255, 255, 255);
$text_color = ImageColorAllocate ($im, 255, 0,0);
imagearc($im,150,150,290,290,0,360,$text_color); // outer face
imagearc($im,80,100,50,50,0,360,$text_color); // left eye 
imagearc($im,220,100,50,50,0,360,$text_color); // right eye
imagearc($im,150,150,150,150,45,135,$text_color); // mouth

Imagejpeg ($im);
imagedestroy($im); //memory is removed. 
?>

In above code we maintained $width and $height equal , $start_angle should be 0 (degree ) and $end_angle should be 360 ( degree ).

Syntax

imagearc($image,$center_x,$center_y,$width,$height,
	$start_angle,$end_angle,$color)

`$image`	Image created using ImageCreate() or imagecreatetruecolor()
`$center_x`	x coordinate of center ( X : Horizontal )
`$center_y`	y coordinate of center ( Y : Vertical )
`$width`	Width of the arc
`$height`	Height of the arc
`$start_angle`	Angle of the start in degree. 3 Oclock position is 0 degree.
`$end_angle`	Angle of the end of the arc in degree.
`$color`	Color of the borders by using imagecolorallocate().

Drawing arc, circles and patterns using different colours, width and height by imagearc() in PHP GD

Concentric circle using imagearc()

Common center for all the circles.
Circles using imagearac

<?php
header ("Content-type: image/jpeg");
$width=601;$height=601;
$im = @ImageCreate ($width,$height) // added one pixel for border
or die ("Cannot Initialize new GD image stream");
$gap=20; // change this value to increase the lines 
$background_color = ImageColorAllocate ($im, 255, 255, 255);
$text_color = ImageColorAllocate ($im, 0, 255,250);
imagesetthickness($im,1);
$text_color = ImageColorAllocate ($im, 255, 0,0);
for($i=0;$i<=$width;$i +=$gap){
imagearc($im,$width/2,$height/2,($width)-$i,($height)-$i,0,360,$text_color);
}
Imagejpeg ($im);
imagedestroy($im); //memory is removed. 
?>

Change the colours of the circle by using random numbers between 1 and 255 ( R G B )
Color Circles using imagearac

<?php
header ("Content-type: image/jpeg");
$width=601;$height=601;
$im = @ImageCreate ($width,$height) // added one pixel for border
or die ("Cannot Initialize new GD image stream");
$gap=20; // change this value to increase the lines 
$background_color = ImageColorAllocate ($im, 255, 255, 255);
imagesetthickness($im,1);
$text_color = ImageColorAllocate ($im, 255, 0,0);
for($i=0;$i<=$width;$i +=$gap){
$r=rand(1,255);
$g=rand(1,255);
$b=rand(1,255);	
$text_color = ImageColorAllocate ($im, $r, $g,$b);		
imagearc($im,$width/2,$height/2,($width)-$i,($height)-$i,0,360,$text_color);
}

Imagejpeg ($im);
imagedestroy($im); //memory is removed. 
?>

Circle using imageellipse()

We can also use ellipse functions imageellipse() or imagefilledellipse() to draw circles by using equal width and height. Here there is no need to specify start angle and end angle.
GD functions imagerectangle() imageellipse() imagefilledellipse()
GD imagefilledarc() : Draw filled arcs to create PIE chat
GD imagefilledrectangle() to create Bar Chart

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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Draw Arcs and Circles with imagearc()

Draw an arc with explicit angles

Concentric circle using imagearc()

Circle using imageellipse()

Subhendu Mohapatra