theme-customizer-long-example.php

<?php

function acme_theme_customizer( $wp_customizer ) {

	$wp_customizer->add_section(
		'acme_header_section',
		array(
			'title'    => __( 'Header Settings', 'acme' ),
			'priority' => 200
		)
	);

	$wp_customizer->add_setting(
		'acme_header_text_color',
		array(
			'default'   => '',
			'transport' => 'postMessage'
		)
	);

	$wp_customizer->add_control(
		new WP_Customize_Color_Control(
		    $wp_customizer,
		    'acme_header_text_color',
		    array(
		        'label'      => __( 'Text Color', 'acme' ),
		        'section'    => 'acme_header_section',
		        'settings'   => 'acme_header_text_color'
		    )
		)
	);
	
	$wp_customizer->add_setting(
		'acme_header_background_image',
		array(
			'default'   => '',
			'transport' => 'postMessage'
		)
	);

	$wp_customizer->add_control(
		new WP_Customize_Image_Control(
            $wp_customizer,
            'acme_header_background_image',
            array(
                'label'          => __( 'Background Image', 'acme' ),
                'section'        => 'acme_header_section',
                'settings'       => 'acme_header_background_image',
            )
        )
	);
	
	$wp_customizer->add_setting(
		'acme_header_background_color',
		array(
			'default'   => '',
			'transport' => 'postMessage'
		)
	);

	$wp_customizer->add_control(
		new WP_Customize_Color_Control(
		    $wp_customizer,
		    'acme_header_background_color',
		    array(
		        'label'      => __( 'Background Color', 'acme' ),
		        'section'    => 'acme_header_section',
		        'settings'   => 'acme_header_background_color'
		    )
		)
	);

} // end acme_theme_customizer
add_action( 'customize_register', 'acme_theme_customizer' );

theme-customizer-modular-example-less-duplication.php

<?php
function enable_theme_customization__acme( $wp_customizer ) {
	$wp_customizer->add_section(
		'header_section__acme',
		array(
			'title'    => __( 'Header Settings', 'acme' ),
			'priority' => 200
		)
	);

	allow_customization_of__acme(
		__( 'Text Color', 'acme' ),
		$which_is_a = 'Color',
		$and_call_it = 'header_text_color__acme',
		$wp_customizer
	);

	allow_customization_of__acme(
		__( 'Background Image', 'acme' ),
		$which_is_an = 'Image',
		$and_call_it = 'header_background_image__acme',
		$wp_customizer
	);

	allow_customization_of__acme(
		__( 'Background Color', 'acme' ),
		$which_is_a = 'Color',
		$and_call_it = 'header_background_color__acme',
		$wp_customizer
	);
		
} add_action( 'customize_register', 'enable_theme_customization__acme' );

function allow_customization_of__acme( $label, $option_type, $option_id, $wp_customizer ) {
	$wp_customizer->add_setting(
		$option_id,
		array(
			'default'   => '',
			'transport' => 'postMessage'
		)
	);

	$control_class_name = "WP_Customize_{$option_type}_Control";

	$wp_customizer->add_control(
		new $control_class_name(
		    $wp_customizer,
		    $option_id,
		    array(
		        'label'      => $label,
		        'section'    => 'header_section__acme',
		        'settings'   => $option_id
		    )
		)
	);
}

theme-customizer-modular-example.php

<?php

function acme_theme_customizer( $wp_customizer ) {

	// Header
	$wp_customizer->add_section(
		'acme_header_section',
		array(
			'title'    => __( 'Header Settings', 'acme' ),
			'priority' => 200
		)
	);

	_acme_add_header_color_picker( $wp_customizer );
	_acme_add_header_background_color_picker( $wp_customizer );
	_acme_add_header_background_image_picker( $wp_customizer );
	
} // end acme_theme_customizer
add_action( 'customize_register', 'acme_theme_customizer' );

function _acme_add_header_color_picker( $wp_customizer ) {

	$wp_customizer->add_setting(
		'acme_header_text_color',
		array(
			'default'   => '',
			'transport' => 'postMessage'
		)
	);

	$wp_customizer->add_control(
		new WP_Customize_Color_Control(
		    $wp_customizer,
		    'acme_header_text_color',
		    array(
		        'label'      => __( 'Text Color', 'acme' ),
		        'section'    => 'acme_header_section',
		        'settings'   => 'acme_header_text_color'
		    )
		)
	);

} // end _acme_add_header_color_picker

function _acme_add_header_background_image_picker( $wp_customizer ) {

	$wp_customizer->add_setting(
		'acme_header_background_image',
		array(
			'default'   => '',
			'transport' => 'postMessage'
		)
	);

	$wp_customizer->add_control(
		new WP_Customize_Image_Control(
            		$wp_customizer,
        		'acme_header_background_image',
            		array(
                		'label'          => __( 'Background Image', 'acme' ),
                		'section'        => 'acme_header_section',
                		'settings'       => 'acme_header_background_image',
            		)
		)
	);

} // end _acme_add_header_background_image_picker

function _acme_add_header_background_color_picker( $wp_customizer ) {

	$wp_customizer->add_setting(
		'acme_header_background_color',
		array(
			'default'   => '',
			'transport' => 'postMessage'
		)
	);

	$wp_customizer->add_control(
		new WP_Customize_Color_Control(
		    $wp_customizer,
		    'acme_header_background_color',
		    array(
		        'label'      => __( 'Background Color', 'acme' ),
		        'section'    => 'acme_header_section',
		        'settings'   => 'acme_header_background_color'
		    )
		)
	);

} // _acme_add_header_background_color_picker