GD and Image Functions
PHP Manual

imageantialias

Should antialias functions be used or not

Description

bool imageantialias(GdImage $image, bool $enable)

Activate the fast drawing antialiased methods for lines and wired polygons. It does not support alpha components. It works using a direct blend operation. It works only with truecolor images.

Thickness and styled are not supported.

Using antialiased primitives with transparent background color can end with some unexpected results. The blend method uses the background color as any other colors. The lack of alpha component support does not allow an alpha based antialiasing method.

Parameters

image

A GdImage object, returned by one of the image creation functions, such as imagecreatetruecolor.

enable

Whether to enable antialiasing or not.

Return Values

Returns true on success or false on failure.

Changelog

Version Description
8.0.0 image expects a GdImage instance now; previously, a valid gd resource was expected.
7.2.0 imageantialias is now generally available. Formerly it was only available if PHP was compiled with the bundled version of the GD library.

Examples

Example #1 A comparison of two lines, one with anti-aliasing switched on

<?php
// Setup an anti-aliased image and a normal image
$aa = imagecreatetruecolor(400, 100);
$normal = imagecreatetruecolor(200, 100);

// Switch antialiasing on for one image
imageantialias($aa, true);

// Allocate colors
$red = imagecolorallocate($normal, 255, 0, 0);
$red_aa = imagecolorallocate($aa, 255, 0, 0);

// Draw two lines, one with AA enabled
imageline($normal, 0, 0, 200, 100, $red);
imageline($aa, 0, 0, 200, 100, $red_aa);

// Merge the two images side by side for output (AA: left, Normal: Right)
imagecopymerge($aa, $normal, 200, 0, 0, 0, 200, 100, 100);

// Output image
header('Content-type: image/png');

imagepng($aa);
imagedestroy($aa);
imagedestroy($normal);
?>

The above example will output something similar to:

Output of example : A comparison of two lines, one with anti-aliasing switched on

See Also

  • imagecreatetruecolor