PHP Manual: Enable or disable interlace

Description

bool imageinterlace(GdImage $image, boolnull $enable = null)

imageinterlace turns the interlace bit on or off.

If the interlace bit is set and the image is used as a JPEG image, the image is created as a progressive JPEG.

Parameters

image: A GdImage object, returned by one of the image creation functions, such as imagecreatetruecolor.
interlace: If true, the image will be interlaced, if false the interlace bit is turned off. Passing null will result in the interlacing behavior not being changed.

Return Values

Returns true if the interlace bit is set for the image, false otherwise.

Changelog

Version	Description
8.0.5	imageinterlace returns a bool now; previously it returned an int (non-zero for interlaced images, zero otherwise).
8.0.0	`image` expects a GdImage instance now; previously, a valid `gd` resource was expected.
8.0.0	`enable` expects a bool now; previously it expected an int.

Examples

Example #1 Turn on interlacing using imageinterlace

<?php
// Create an image instance
$im = imagecreatefromgif('php.gif');

// Enable interlancing
imageinterlace($im, true);

// Save the interlaced image
imagegif($im, './php_interlaced.gif');
imagedestroy($im);
?>