chore: Add document page sizes method to extract layout faster

Author: benconda

src/Document.php

@@ -36,6 +36,36 @@ public function getPageCount(): int
         return $this->ffi->FPDF_GetPageCount($this->handler);
     }
 
+    public function getPageSizeByIndex(int $pageIndex): ?Size
+    {
+        $size = $this->ffi->new('FS_SIZEF');
+
+        $result = $this->ffi->FPDF_GetPageSizeByIndexF(
+            $this->handler,
+            $pageIndex,
+            \FFI::addr($size),
+        );
+
+        if (0 === $result) {
+            return null;
+        }
+
+        return new Size(
+            $size->width,
+            $size->height,
+        );
+    }
+
+    /**
+     * @return list<Size>
+     */
+    public function pageSizeIterator(): iterable
+    {
+        for ($index = 0; $index < $this->getPagesCount(); ++$index) {
+            yield $this->getPageSizeByIndex($index);
+        }
+    }
+
     public function loadPage(int $pageIndex): ?Page
     {
         $pageHandler = $this->ffi->FPDF_LoadPage($this->handler, $pageIndex);

tests/unit/DocumentTest.php

@@ -38,6 +38,37 @@ public function testRenderAllPagesIterable(): void
         self::assertCount(38, $files);
     }
 
+    public function testGetPageSizeByIndex(): void
+    {
+        $notice = $this->loadDocument('notice');
+        $size = $notice->getPageSizeByIndex(0);
+        self::assertSame(595, (int)$size->width);
+        self::assertSame(841, (int)$size->height);
+
+        $badIndex = $notice->getPageSizeByIndex(-5);
+        self::assertNull($badIndex);
+
+        $badIndex2 = $notice->getPageSizeByIndex(1000);
+        self::assertNull($badIndex2);
+    }
+
+    public function testPageSizeIterator()
+    {
+        $layout = [];
+        $notice = $this->loadDocument('yolo');
+        foreach ($notice->pageSizeIterator() as $size) {
+            $layout[] = [
+                'width' => (int)$size->width,
+                'height' => (int)$size->height,
+            ];
+        }
+        self::assertCount(36, $layout);
+        foreach ($layout as $pageSize) {
+            self::assertSame(595, $pageSize['width']);
+            self::assertSame(841, $pageSize['height']);
+        }
+    }
+
     public function testSaveFlattenedCopy(): void
     {
         $cerfaDoc = $this->loadDocument('cerfa_13750-05');