_custom_background_cb()

Cost profile

Measured from the compiled opcodes, not from a stopwatch. Every number here is identical on any machine that runs the same PHP version, and every function in core is ranked by these figures.

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

28–128

Executed per call on PHP 8.4, depending on the branch taken. The body compiles to 139.

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 it touches

• hookthird-party callbacksapply_filters()one call below _custom_background_cb()

Further down the call graph this can also reach option, cache, serialize, transient and query — those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 6 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost _custom_background_cb() can have, taken from its control-flow graph on PHP 8.4.

Across PHP versions

Oldest PHP that compiles this body: 7.4. An instruction is not a fixed amount of time, so a version with the same count is not necessarily the same speed; what the count rules out is a difference in the work itself.

Uses · 9

• set_url_scheme()Sets the scheme for a URL.
• get_background_image()Retrieves background image for custom background.
• get_background_color()Retrieves value for custom background color.
• get_theme_support()Gets the theme support arguments passed when registering that support.
• current_theme_supports()Checks a theme's support for a given feature.
• is_customize_preview()Whether the site is being previewed in the Customizer.
• maybe_hash_hex_color()Ensures that any hex color is properly hashed.
• sanitize_url()Sanitizes a URL for database or redirect usage.
• get_theme_mod()Retrieves theme modification value for the active theme.

Source

View on Trac ↗View on GitHub ↗

1873function _custom_background_cb() {1874	// $background is the saved custom image, or the default image.1875	$background = set_url_scheme( get_background_image() );1876 1877	/*1878	 * $color is the saved custom color.1879	 * A default has to be specified in style.css. It will not be printed here.1880	 */1881	$color = get_background_color();1882 1883	if ( get_theme_support( 'custom-background', 'default-color' ) === $color ) {1884		$color = false;1885	}1886 1887	$type_attr = current_theme_supports( 'html5', 'style' ) ? '' : ' type="text/css"';1888 1889	if ( ! $background && ! $color ) {1890		if ( is_customize_preview() ) {1891			printf( '<style%s id="custom-background-css"></style>', $type_attr );1892		}1893		return;1894	}1895 1896	$style = $color ? 'background-color: ' . maybe_hash_hex_color( $color ) . ';' : '';1897 1898	if ( $background ) {1899		$image = ' background-image: url("' . sanitize_url( $background ) . '");';1900 1901		// Background Position.1902		$position_x = get_theme_mod( 'background_position_x', get_theme_support( 'custom-background', 'default-position-x' ) );1903		$position_y = get_theme_mod( 'background_position_y', get_theme_support( 'custom-background', 'default-position-y' ) );1904 1905		if ( ! in_array( $position_x, array( 'left', 'center', 'right' ), true ) ) {1906			$position_x = 'left';1907		}1908 1909		if ( ! in_array( $position_y, array( 'top', 'center', 'bottom' ), true ) ) {1910			$position_y = 'top';1911		}1912 1913		$position = " background-position: $position_x $position_y;";1914 1915		// Background Size.1916		$size = get_theme_mod( 'background_size', get_theme_support( 'custom-background', 'default-size' ) );1917 1918		if ( ! in_array( $size, array( 'auto', 'contain', 'cover' ), true ) ) {1919			$size = 'auto';1920		}1921 1922		$size = " background-size: $size;";1923 1924		// Background Repeat.1925		$repeat = get_theme_mod( 'background_repeat', get_theme_support( 'custom-background', 'default-repeat' ) );1926 1927		if ( ! in_array( $repeat, array( 'repeat-x', 'repeat-y', 'repeat', 'no-repeat' ), true ) ) {1928			$repeat = 'repeat';1929		}1930 1931		$repeat = " background-repeat: $repeat;";1932 1933		// Background Scroll.1934		$attachment = get_theme_mod( 'background_attachment', get_theme_support( 'custom-background', 'default-attachment' ) );1935 1936		if ( 'fixed' !== $attachment ) {1937			$attachment = 'scroll';1938		}1939 1940		$attachment = " background-attachment: $attachment;";1941 1942		$style .= $image . $position . $size . $repeat . $attachment;1943	}1944	?>1945<style<?php echo $type_attr; ?> id="custom-background-css">1946body.custom-background { <?php echo trim( $style ); ?> }1947</style>1948	<?php1949}

History

Introduced in 3.0.0. 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

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