Enable or disable interlace

# imageinterlace

(PHP 4, PHP 5, PHP 7, PHP 8)

imageinterlace — Enable or disable interlace

### Description

imageinterlace(GdImage `$image`, ?bool `$enable` = `null`): bool

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().

`enable`

  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');
?>`
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