php如何生成pdf文件

$pdf = new Zend_Pdf();

$page = $pdf->newpage(Zend_Pdf_Page::SIZE_A4);

// 添加文本

$page->drawText('Hello, World!', 100, 100);

// 保存 PDF 文件

$pdf->save('my-pdf.pdf');

include('mpdf/mpdf.php');

$html = '<h1>Hello, World!</h1>';

$mpdf = new mPDF();

$mpdf->WriteHTML($html);

$mpdf->Output('my-pdf.pdf', 'D');

include('tcpdf/tcpdf.php');

$pdf = new TCPDF('L', 'mm', array(297, 210));

$pdf->AddPage();

$pdf->Text(100, 100, 'Hello, World!');

$pdf->Output('my-pdf.pdf', 'D');

include('fpdf/fpdf.php');

$pdf = new FPDF();

$pdf->AddPage();

$pdf->SetFont('Arial', 'B', 16);

$pdf->Cell(0, 10, 'Hello, World!', 0, 1, 'C');

$pdf->Output('my-pdf.pdf', 'D');