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WordPress

WP_Image_Editor_GD::flip( bool $horz, bool $vert ): true|WP_Error

Since
3.5.0
Source
wp-includes/class-wp-image-editor-gd.php:448
Flips current image.

Compatibility

WordPress
since 3.5.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$horzbool
Flip along Horizontal Axis.
$vertbool
Flip along Vertical Axis.

Return value

true|WP_Error

Performance profile

How much work a call to WP_Image_Editor_GD::flip() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class
Trivial

Touches nothing outside its own arguments.

Scaling
Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions
26–57

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 64.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
0

Nothing in core calls this; the cost is only what you spend yourself.

What one call costs · 3 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost WP_Image_Editor_GD::flip() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
!is_gd_image()26wp_imagecreatetruecolor(), is_gd_image(), __()
is_gd_image() && imagecopyresampled()45–49wp_imagecreatetruecolor(), is_gd_image(), imagecopyresampled()
is_gd_image() && !imagecopyresampled()53–57wp_imagecreatetruecolor(), is_gd_image(), imagecopyresampled(), __()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev6426–576
8.56426–576
8.46426–576
8.36426–576
8.26426–576
8.16426–5769 fewer instructions than PHP 7.4
7.47326–616

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 4

Source code

	public function flip( $horz, $vert ) {		$w   = $this->size['width'];		$h   = $this->size['height'];		$dst = wp_imagecreatetruecolor( $w, $h ); 		if ( is_gd_image( $dst ) ) {			$sx = $vert ? ( $w - 1 ) : 0;			$sy = $horz ? ( $h - 1 ) : 0;			$sw = $vert ? -$w : $w;			$sh = $horz ? -$h : $h; 			if ( imagecopyresampled( $dst, $this->image, 0, 0, $sx, $sy, $w, $h, $sw, $sh ) ) {				if ( PHP_VERSION_ID < 80000 ) { // imagedestroy() has no effect as of PHP 8.0.					imagedestroy( $this->image );				} 				$this->image = $dst; 				return true;			}		} 		return new WP_Error( 'image_flip_error', __( 'Image flip failed.' ), $this->file );	}

Changelog

Introduced in 3.5.0. Unchanged from 6.7.7 through 7.1.0.

  1. 6.7.7
  2. 6.8.8
  3. 6.9.7
  4. 7.0.4
  5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data
Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/class-wp-image-editor-gd.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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