PHP-Handbuch: Should antialias functions be used or not

Beschreibung

bool imageantialias ( resource $image , bool $enabled )

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.

Parameter-Liste

image: Eine von den verschiedenen Erzeugungsfunktionen wie imagecreatetruecolor gelieferte Grafikressource.
enabled: Whether to enable antialiasing or not.

Rückgabewerte

Gibt bei Erfolg TRUE zurück. Im Fehlerfall wird FALSE zurückgegeben.

Changelog

Version	Beschreibung
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.

Beispiele

Beispiel #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);
?>

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

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

Siehe auch

imagecreatetruecolor