feat: deterministic image composer - OG + square variants, branding, baked caption (v0.17.0) (#152)

Composer slots between provider bytes and sideload: corner-marked featured,
branded 1200x630 OG + 1080x1080 square with baked clamped caption, capability
ladder (Imagick -> resize-only -> pass-through, never blocks publish).
Alt-text bug fix (caption, not model name). Vendored brand PNGs + OFL Poppins.

QA: APPROVE-WITH-P2-NOTES @ 6f76df1 (qa-reviews/prautoblogger/2026-06-11-6f76df1.md)
CEO greenlight: 2026-06-11 in chat.

Agent-Session: cto-image-composer-merge-20260611

includes/core/class-image-composer-editor.php

@@ -0,0 +1,114 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * phpcs:ignore WordPress.Files.FileName.InvalidClassFileName -- class naming convention differs from WordPress standard
+ *
+ * Resize-only composer rung backed by wp_get_image_editor() (GD path).
+ *
+ * Used when Imagick is unusable: emits unbranded, caption-free center-crops
+ * at each variant's exact dimensions. Variants that would require upscaling
+ * (e.g. a 1080×1080 square from a 1200×632 base — WP's editor never upscales
+ * on crop-resize) are skipped; the OG crop is always achievable from the
+ * standard base. Output is GD PNG, which embeds no timestamps, so this rung
+ * is deterministic too.
+ *
+ * Triggered by: PRAutoBlogger_Image_Composer when the capability probe says 'gd'.
+ * Dependencies: wp_get_image_editor(), get_temp_dir(), PRAutoBlogger_Logger.
+ *
+ * @see core/class-image-composer.php — Orchestrator + degradation ladder.
+ * @see core/class-image-composer-imagick.php — The full-fidelity rung this replaces.
+ */
+class PRAutoBlogger_Image_Composer_Editor {
+
+	/**
+	 * Render resize-only variants for the requested roles.
+	 *
+	 * Side effects: temp file write/delete per variant; debug log on skips.
+	 *
+	 * @param string                               $bytes  Base image bytes.
+	 * @param string[]                             $roles  Variant roles to attempt ('og', 'square').
+	 * @param array<string, array<string, mixed>>  $layout Layout geometry (for target dimensions).
+	 *
+	 * @return array<int, array{bytes: string, mime_type: string, width: int, height: int, role: string}>
+	 *               Successfully resized variants only (possibly empty).
+	 */
+	public function compose_variants( string $bytes, array $roles, array $layout ): array {
+		$variants = array();
+
+		foreach ( $roles as $role ) {
+			$target_w = (int) ( $layout[ $role ]['width'] ?? 0 );
+			$target_h = (int) ( $layout[ $role ]['height'] ?? 0 );
+			if ( $target_w < 1 || $target_h < 1 ) {
+				continue;
+			}
+
+			$resized = $this->cover_crop( $bytes, $target_w, $target_h );
+			if ( null === $resized ) {
+				PRAutoBlogger_Logger::instance()->debug(
+					sprintf( 'Resize-only %s variant skipped (editor failure or would upscale).', $role ),
+					'image_composer'
+				);
+				continue;
+			}
+
+			$resized['role'] = $role;
+			$variants[]      = $resized;
+		}
+
+		return $variants;
+	}
+
+	/**
+	 * Center-crop bytes to exact dimensions with the portable WP editor.
+	 *
+	 * @param string $bytes    Source image bytes.
+	 * @param int    $target_w Target width in px.
+	 * @param int    $target_h Target height in px.
+	 *
+	 * @return array{bytes: string, mime_type: string, width: int, height: int}|null
+	 *               Null when the editor fails or cannot hit the exact size
+	 *               without upscaling.
+	 */
+	private function cover_crop( string $bytes, int $target_w, int $target_h ): ?array {
+		$temp = get_temp_dir() . uniqid( 'prab_compose_', true ) . '.png';
+		// phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_file_put_contents -- temp file, same pattern as the sideloader.
+		if ( false === file_put_contents( $temp, $bytes ) ) {
+			return null;
+		}
+
+		try {
+			$editor = wp_get_image_editor( $temp );
+			if ( is_wp_error( $editor ) ) {
+				return null;
+			}
+			if ( is_wp_error( $editor->resize( $target_w, $target_h, true ) ) ) {
+				return null;
+			}
+
+			$size = $editor->get_size();
+			if ( (int) $size['width'] !== $target_w || (int) $size['height'] !== $target_h ) {
+				return null; // Exact size not reachable without upscaling.
+			}
+
+			if ( is_wp_error( $editor->save( $temp, 'image/png' ) ) ) {
+				return null;
+			}
+			// phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents -- temp file we just wrote.
+			$out = file_get_contents( $temp );
+
+			return false === $out ? null : array(
+				'bytes'     => $out,
+				'mime_type' => 'image/png',
+				'width'     => $target_w,
+				'height'    => $target_h,
+			);
+		} catch ( \Throwable $e ) {
+			PRAutoBlogger_Logger::instance()->debug( 'WP image editor crop threw: ' . $e->getMessage(), 'image_composer' );
+			return null;
+		} finally {
+			// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- best-effort temp cleanup.
+			@unlink( $temp );
+		}
+	}
+}