imageantialias

(PHP 4 >= 4.3.2, PHP 5, PHP 7, PHP 8)

imageantialiasShould antialias functions be used or not

Descrizione

imageantialias(GdImage $image, bool $enable): bool

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.

Elenco dei parametri

image

Una risorsa immagine, restituita da una delle funzioni di creazione immagine, come imagecreatetruecolor().

enable

Whether to enable antialiasing or not.

Valori restituiti

Restituisce true in caso di successo, false in caso di fallimento.

Log delle modifiche

Versione Descrizione
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.

Esempi

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);
?>

Il precedente esempio visualizzerà qualcosa simile a:

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

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