PHP Graphics: Drawing Line, Rectangle, Polygon, Arc, Ellipse, Patterned Line

PHP provides many functions to draw lines, rectangles, polygons, arcs, ellipses and much more. The GD library is utilized for dynamic picture creation. In PHP, we can easily use ​the GD library to make GIF, PNG, or JPG pictures quickly from our code. So there is no need to write HTML and CSS code. We can easily handle this using the PHP programming language.

If you are unsure that you have the GD library, you can run phpinfo() to check that GD support is enabled. On the off chance that you don't have it, you can download it for free.

Drawing Lines

PHP provides the imageline() function to draw a line between the two given points.

imageline ( resource $image , int $x1 , int $y1 , int $x2 , int $y2 , int $color ) : bool

Parameters

$image- An image resource, this is returned by imagecreatetruecolor() function.
$x1- x coordinate for the first point.
$y1- y coordinate for the first point.
$x2- x coordinate for the second point.
$y2- y coordinate for the second point.
$color- color identified by imagecolorallocate().

It returns a boolean value, TRUE on success and FALSE on failure.

Example: imageline()

<?php
$image = ImageCreateTrueColor(270, 150);
imagesavealpha($image, true);
$trans_colour = imagecolorallocatealpha($image, 0, 0, 0, 127);
imagefill($image, 0, 0, $trans_colour);
$x1 = $y1 = 0 ; 
$x2 = 270; $y2 = 150; 
$color = #4a235a; 
ImageLine($image, $x1, $y1, $x2, $y2, $color);
header('Content-type: image/png');
ImagePNG($image);
ImageDestroy($image);
?>

In the above example, the ImageCreateTrueColor() function creates a new true color image. imagesavealpha() function sets a flag to retain full alpha channel information. imagecolorallocatealpha() function allocates a color for an image, i.e., transparent color, which is filled by imagefill() function.

Output: ImageLine()

Drawing Rectangles

PHP provides imagefilledrectangle() function to draw a filled rectangle.

imagefilledrectangle($image, $x1, $y1, $x2, $y2, $color)

Parameters

$image- An image resource. This is returned by the imagecreatetruecolor() function.
$x1, $y1- x and y coordinates for point 1.
$x2, $y2- x and y coordinates for point 2.
$color- color identified by imagecolorallocate().

Example

<?php
$x = 180; $y = 110;
$image=imagecreatetruecolor($x, $y);

//set red color
$red    = imagecolorallocatealpha($image, 255, 0, 0, 75);
imagefilledrectangle($image, 0, 0, $x, $y, $red);

header('Content-type: image/png');
ImagePNG($image);
ImageDestroy($image);
?>

In the above example, we allocate a color for the rectangle using imagecolorallocatealpha() function.

Output: Draw Rectangle

Drawing Polygons

PHP provides ImagePolygon() function to draw polygon.

imagepolygon($image, $points, $numpoints, $color)

Parameters

$image - An image resource, this is returned by imagecreatetruecolor() function.
$points - An array containing polygon vertices.
$numpoints - Total number of points.
$color - color identified by imagecolorallocate()

Example - imagepolygon()

<?php
$x = 250; $y = 210;
$image=imagecreatetruecolor($x, $y);
$white= imagecolorallocatealpha($image, 255, 255, 255, 75);
// Draw the polygon
imagepolygon($image, array(
        10, 10,
	50, 140,
        100, 200,
        220, 180
    ), 4, $white);
header('Content-type: image/png');
ImagePNG($image);
ImageDestroy($image);
?>

Output

Drawing Arcs

PHP provides ImageArc() function for drawing arcs.

ImageArc($image, $x, $y, $width, $height, $start, $end, $color);

Parameters

$image - An image resource, this is returned by imagecreatetruecolor() function.
$x, $y - To set the x and y coordinates of the center.
$width, $height - To set the width and height of an arc.
$start - To set the arc start angle in degree.
$end - To set the arc end angle in degree.
$color - Color identified by imagecolorallocate().

Example - ImageArc()

<?php
$x = 200; $y = 200;
$image=imagecreatetruecolor($x, $y);
$white= imagecolorallocatealpha($image, 255, 255, 255, 75);
// Draw an arc
imagearc($image,  100, 100, 150, 150, 25, 155, $white);
header('Content-type: image/png');
ImagePNG($image);
ImageDestroy($image);
?>

Output

Drawing Ellipses

PHP provides ImageEllipse() function to draw an ellipse.

ImageEllipse($image, $x, $y, $width, $height, $color);

Parameters

$image - An image resource, this is returned by imagecreatetruecolor() function.
$x, $y - To set x and y coordinates of the center.
$width - To set the ellipse width.
$height - To set the ellipse height.
$color - Color identified by imagecolorallocate().

Example - ImageEllipse()

<?php
$x = 150; $y = 200;
$image=imagecreatetruecolor($x, $y);
$yellow = imagecolorallocatealpha($image, 255, 255, 0, 75);
// Draw an ellipse
imageellipse($image, 70, 100, 100, 150, $yellow);
header('Content-type: image/png');
ImagePNG($image);
ImageDestroy($image);
?>

Drawing Patterned Lines

In PHP, we can draw patterned lines with the help of ImageSetStyle() and ImageFilledRectangle() functions. The ImageSetStyle() function sets the style for line drawing.

ImageSetStyle($image, $style)

Parameters

$image - An image resource, this is returned by imagecreatetruecolor() function.
$style - This is an array of pixel colors. To pass this, we have used IMG_COLOR_STYLE in ImageFilledRectangle() function.

Example - ImageSetStyle()

<?php
$x = 50; $y = 50;
$black = 0x000000;
$white = 0xFFFFFF;
$image=imagecreatetruecolor($x, $y);
$style = array($white, $white, $white, $white, $white,
$black, $black, $black, $black, $black);
ImageSetStyle($image, $style);
ImageFilledRectangle($image, 0, 0, 60, 60, IMG_COLOR_STYLED);
header('Content-type: image/png');
ImagePNG($image);
ImageDestroy($image);
?>

Output

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