Questions about v1.4.0

[JQHxx]

My environment is php5.3. I have encountered many problems when converting PDFS to images.
The first problem is that the text in the transferred pictures is not clear and cannot be seen at all
The second issue is that although the total number of pages of a pdf file can be obtained, the output is always the first image

The code is as follows:
$pdf = new \Spatie\PdfToImage\Pdf($pdfPath);

// 获取总页数
$numberOfPages = $pdf->getNumberOfPages();
echo "PDF 总页数：" . $numberOfPages . "
";

// 逐页转换
for ($i = 1; $i <= $numberOfPages; $i++) {
$outputPath = $outputDir . 'page_' . $i . '.png';
// 选择当前页
$pdf->setPage($i)
->setOutputFormat('png')
->setCompressionQuality(90)
->setResolution(300)
->saveImage($outputPath);

echo "已生成：" . $outputPath . "<br>";

}