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<?php |
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namespace ABlocks\Performance; |
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|
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if ( ! defined( 'ABSPATH' ) ) { |
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exit; |
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} |
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|
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use ABlocks\Helper; |
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|
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/** |
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* Performance Suite — image loading optimizations for aBlocks blocks. |
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* |
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* Two independent, opt-in transforms applied to rendered aBlocks block HTML: |
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* - `perf_lazy_images`: `loading="lazy"` + `decoding="async"`, keeping the first |
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* N images eager with `fetchpriority="high"` so the LCP image isn't deferred. |
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* - `perf_image_dimensions`: inject intrinsic `width`/`height` on images that |
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* have neither, so the browser reserves space and Cumulative Layout Shift |
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* (CLS) drops. Dimensions are resolved cheaply — from the `wp-image-{id}` |
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* class (attachment metadata) or the WordPress `-WIDTHxHEIGHT` filename |
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* suffix — with no per-request filesystem reads. |
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* |
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* Operates via the `render_block` filter (scoped to aBlocks blocks) so no |
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* per-block markup changes are needed. |
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*/ |
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class ImageOptimizer { |
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|
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private $image_index = 0; |
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private $eager_count = 1; |
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private $do_lazy = false; |
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private $do_dimensions = false; |
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private $do_responsive = false; |
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|
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public static function init() { |
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if ( is_admin() ) { |
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return; |
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} |
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$self = new self(); |
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$self->do_lazy = (bool) apply_filters( |
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'ablocks/perf/perf_lazy_images', |
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(bool) Helper::get_settings( 'perf_lazy_images', true ) |
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); |
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$self->do_dimensions = (bool) apply_filters( |
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'ablocks/perf/perf_image_dimensions', |
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(bool) Helper::get_settings( 'perf_image_dimensions', true ) |
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); |
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$self->do_responsive = (bool) apply_filters( |
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'ablocks/perf/perf_responsive_images', |
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(bool) Helper::get_settings( 'perf_responsive_images', true ) |
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); |
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if ( ! $self->do_lazy && ! $self->do_dimensions && ! $self->do_responsive ) { |
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return; |
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} |
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$self->eager_count = (int) apply_filters( |
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'ablocks/perf/lcp_eager_count', |
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(int) Helper::get_settings( 'perf_lcp_eager_count', 1 ) |
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); |
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add_filter( 'render_block', [ $self, 'process' ], 20, 2 ); |
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} |
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|
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public function process( $content, $block ) { |
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if ( empty( $block['blockName'] ) || false === strpos( $block['blockName'], 'ablocks' ) ) { |
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return $content; |
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} |
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if ( false === strpos( $content, '<img' ) ) { |
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return $content; |
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} |
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|
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// aBlocks image blocks store the attachment id in their attributes but |
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// don't emit a wp-image-{id} class, and URL→id lookups fail for |
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// intermediate sizes of -scaled images. Use the block's own id as the |
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// authoritative source for its image. |
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$attrs = isset( $block['attrs'] ) ? $block['attrs'] : []; |
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$this->block_image_id = 0; |
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foreach ( [ 'imgId', 'imgIdMobile', 'imgIdTablet' ] as $key ) { |
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if ( ! empty( $attrs[ $key ] ) ) { |
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$this->block_image_id = (int) $attrs[ $key ]; |
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break; |
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} |
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} |
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|
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return preg_replace_callback( |
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'/<img\b[^>]*>/i', |
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[ $this, 'rewrite_img' ], |
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$content |
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); |
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} |
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|
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private function rewrite_img( $matches ) { |
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$tag = $matches[0]; |
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$this->image_index++; |
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$attrs = ''; |
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|
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// Lazy-loading / priority hints. |
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if ( $this->do_lazy ) { |
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$has_loading = false !== stripos( $tag, 'loading=' ); |
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$is_eager = $this->image_index <= $this->eager_count; |
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|
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if ( ! $has_loading ) { |
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// No loading hint yet — add one (idempotent, never overrides markup |
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// that set its own). |
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$attrs .= $is_eager ? ' loading="eager" fetchpriority="high"' : ' loading="lazy"'; |
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if ( false === stripos( $tag, 'decoding=' ) ) { |
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$attrs .= ' decoding="async"'; |
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} |
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} elseif ( $is_eager && false === stripos( $tag, 'fetchpriority=' ) ) { |
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// Above-the-fold image that markup hardcoded as loading="lazy" (e.g. |
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// aBlocks image save output) — upgrade it to eager + high priority so |
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// the likely-LCP image isn't deferred. |
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$tag = preg_replace( |
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'/\bloading=(["\'])(?:lazy|auto)\1/i', |
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'loading="eager" fetchpriority="high"', |
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$tag, |
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1 |
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); |
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} |
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} |
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|
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// CLS fix — reserve space by giving images that have neither width nor |
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// height their intrinsic dimensions. |
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if ( $this->do_dimensions |
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&& false === stripos( $tag, 'width=' ) |
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&& false === stripos( $tag, 'height=' ) ) { |
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$dim = $this->resolve_dimensions( $tag ); |
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if ( $dim ) { |
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$attrs .= ' width="' . (int) $dim[0] . '" height="' . (int) $dim[1] . '"'; |
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} |
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} |
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|
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// Responsive delivery — add a width-descriptor srcset + sizes so the |
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// browser downloads a right-sized file instead of the full image (the |
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// single biggest mobile payload win). Only when the image maps to an |
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// attachment and doesn't already declare srcset. |
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if ( $this->do_responsive && false === stripos( $tag, 'srcset=' ) ) { |
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$attrs .= $this->responsive_attrs( $tag ); |
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} |
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|
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if ( '' === $attrs ) { |
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return $tag; |
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} |
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return preg_replace( '/^<img\b/', '<img' . $attrs, $tag, 1 ); |
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} |
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|
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/** |
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* Build ` srcset="…" sizes="…"` for an image that maps to an attachment, |
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* using WordPress core's generators (which read the already-stored metadata, |
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* no filesystem work). Returns '' when the image can't be mapped or has no |
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* alternate sizes. |
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*/ |
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private function responsive_attrs( $tag ) { |
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$id = $this->resolve_attachment_id( $tag ); |
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if ( ! $id ) { |
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return ''; |
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} |
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$size = $this->resolve_dimensions( $tag ); |
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$size = $size ? $size : 'full'; |
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|
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$srcset = wp_get_attachment_image_srcset( $id, $size ); |
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if ( ! $srcset ) { |
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return ''; |
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} |
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$sizes = wp_get_attachment_image_sizes( $id, $size ); |
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$out = ' srcset="' . esc_attr( $srcset ) . '"'; |
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if ( $sizes && false === stripos( $tag, 'sizes=' ) ) { |
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$out .= ' sizes="' . esc_attr( $sizes ) . '"'; |
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} |
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return $out; |
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} |
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|
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/** |
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* Resolve an image's intrinsic [width, height] without touching the |
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* filesystem: first from the attachment metadata (via the wp-image-{id} |
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* class, matching the exact rendered size), then from WordPress's |
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* `-WIDTHxHEIGHT` resized-filename convention. Returns null when unknown. |
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*/ |
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private function resolve_dimensions( $tag ) { |
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$src = $this->get_attr( $tag, 'src' ); |
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|
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$id = $this->resolve_attachment_id( $tag ); |
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if ( $id ) { |
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$dim = $this->dimensions_from_attachment( $id, $src ); |
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if ( $dim ) { |
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return $dim; |
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} |
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} |
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|
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if ( $src && preg_match( '/-(\d+)x(\d+)\.(?:jpe?g|png|gif|webp|avif|bmp)(?:\?.*)?$/i', $src, $m ) ) { |
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return [ (int) $m[1], (int) $m[2] ]; |
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} |
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|
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return null; |
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} |
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|
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/** |
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* Resolve the attachment id for an <img>: prefer the WordPress `wp-image-{id}` |
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* class, otherwise map the src URL back to an attachment (aBlocks image blocks |
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* don't emit the class). URL lookups are cached per request — and only run |
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* when the class is absent — so the DB is hit at most once per unique URL. |
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*/ |
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private $id_cache = []; |
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private $block_image_id = 0; |
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private function resolve_attachment_id( $tag ) { |
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if ( preg_match( '/wp-image-(\d+)/', $tag, $m ) ) { |
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return (int) $m[1]; |
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} |
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// The current block's stored attachment id (authoritative for aBlocks |
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// image blocks, which don't emit the class). |
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if ( $this->block_image_id ) { |
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return $this->block_image_id; |
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} |
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$src = $this->get_attr( $tag, 'src' ); |
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if ( ! $src ) { |
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return 0; |
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} |
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if ( ! array_key_exists( $src, $this->id_cache ) ) { |
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$this->id_cache[ $src ] = (int) attachment_url_to_postid( $src ); |
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} |
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return $this->id_cache[ $src ]; |
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} |
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|
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/** |
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* Pull width/height from an attachment's stored metadata, preferring the |
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* registered sub-size whose file matches the rendered src, falling back to |
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* the full-size dimensions. |
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*/ |
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private function dimensions_from_attachment( $id, $src ) { |
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if ( ! $id ) { |
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return null; |
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} |
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$meta = wp_get_attachment_metadata( $id ); |
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if ( ! is_array( $meta ) || empty( $meta['width'] ) || empty( $meta['height'] ) ) { |
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return null; |
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} |
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if ( $src && ! empty( $meta['sizes'] ) && is_array( $meta['sizes'] ) ) { |
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$base = wp_basename( strtok( $src, '?' ) ); |
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foreach ( $meta['sizes'] as $size ) { |
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if ( isset( $size['file'], $size['width'], $size['height'] ) && $size['file'] === $base ) { |
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return [ (int) $size['width'], (int) $size['height'] ]; |
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} |
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} |
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} |
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return [ (int) $meta['width'], (int) $meta['height'] ]; |
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} |
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|
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private function get_attr( $tag, $name ) { |
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if ( preg_match( '/\b' . preg_quote( $name, '/' ) . '=(["\'])(.*?)\1/i', $tag, $m ) ) { |
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return $m[2]; |
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} |
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return ''; |
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} |
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} |
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|
