本文翻譯自：Convert PDF to image with high resolution
I'm trying to use the command line program convert to take a PDF into an image (JPEG or PNG). 我正在嘗試使用命令行程序convert PDF轉換爲圖像（JPEG或PNG）。 Here is one of the PDFs that I'm trying to convert. 這是我要轉換的PDF之一 。
I want the program to trim off the excess white-space and return a high enough quality image that the superscripts can be read with ease. 我希望程序修剪掉多餘的空白並返回足夠高質量的圖像，以便可以輕鬆讀取上標。
This is my current best attempt . 這是我目前的最佳嘗試 。 As you can see, the trimming works fine, I just need to sharpen up the resolution quite a bit. 如您所見，修整效果很好，我只需要稍微提高一下分辨率即可。 This is the command I'm using: 這是我正在使用的命令：
convert -trim 24.pdf -resize 500% -quality 100 -sharpen 0x1.0 24-11.jpg
I've tried to make the following conscious decisions: 我嘗試做出以下有意識的決定：
- resize it larger (has no effect on the resolution) 調整它的大小（對分辨率沒有影響）
- make the quality as high as possible 使質量儘可能高
- use the
-sharpen(I've tried a range of values) 使用-sharpen（我嘗試了一系列值）
Any suggestions please on getting the resolution of the image in the final PNG/JPEG higher would be greatly appreciated! 任何關於在最終的PNG / JPEG中獲得更高圖像分辨率的建議，將不勝感激！
#1樓
參考：https://stackoom.com/question/RiGM/將PDF轉換爲高分辨率圖像
#2樓
它還可以爲您帶來良好的效果：
exec("convert -geometry 1600x1600 -density 200x200 -quality 100 test.pdf test_image.jpg");
#3樓
Personally I like this. 我個人喜歡這樣。
convert -density 300 -trim test.pdf -quality 100 test.jpg
It's a little over twice the file size, but it looks better to me. 它是文件大小的兩倍多，但對我來說看起來更好。
-density 300 sets the dpi that the PDF is rendered at. -density 300設置渲染PDF的dpi。
-trim removes any edge pixels that are the same color as the corner pixels. -trim刪除與角像素顏色相同的所有邊緣像素。
-quality 100 sets the JPEG compression quality to the highest quality. -quality 100將JPEG壓縮質量設置爲最高質量。
Things like -sharpen don't work well with text because they undo things your font rendering system did to make it more legible. -sharpen之類的東西不能很好地與文本配合使用，因爲它們會撤消字體渲染系統所做的使它更清晰的事情。
If you actually want it blown up use resize here and possibly a larger dpi value of something like targetDPI * scalingFactor That will render the PDF at the resolution/size you intend. 如果您確實希望將其炸燬，請在此處使用調整大小，並可能使用較大的dpi值，例如targetDPI * scalingFactor ，它將以您想要的分辨率/大小呈現PDF。
Descriptions of the parameters on imagemagick.org are here 在這裏 imagemagick.org上的參數說明
#4樓
I have found it both faster and more stable when batch-processing large PDFs into PNGs and JPGs to use the underlying gs (aka Ghostscript) command that convert uses. 當將大型PDF批量處理爲PNG和JPG以使用convert使用的基礎gs （又名Ghostscript）命令時，我發現它既更快又更穩定。
You can see the command in the output of convert -verbose and there are a few more tweaks possible there (YMMV) that are difficult / impossible to access directly via convert . 您可以在convert -verbose的輸出中看到命令，並且那裏還有一些可能的調整（YMMV），很難/不可能直接通過convert訪問。
However, it would be harder to do your trimming and sharpening using gs , so, as I said, YMMV! 但是，使用gs修剪和銳化將更加困難，因此，正如我所說的，YMMV！
#5樓
One more suggestion is that you can use GIMP. 另一個建議是您可以使用GIMP。
Just load the PDF file in GIMP->save as .xcf and then you can do whatever you want to the image. 只需將GIMP-> PDF文件加載爲.xcf，然後就可以對圖像執行任何操作。
#6樓
PNG file you attached looks really blurred. 您附加的PNG文件看起來真的很模糊。 In case if you need to use additional post-processing for each image you generated as PDF preview, you will decrease performance of your solution. 如果您需要對作爲PDF預覽生成的每個圖像進行額外的後期處理，則會降低解決方案的性能。
2JPEG can convert PDF file you attached to a nice sharpen JPG and crop empty margins in one call: 2JPEG可以轉換您附加到一個不錯的JPG的PDF文件，並在一次調用中裁剪空白邊距：
2jpeg.exe -src "C:\In\*.*" -dst "C:\Out" -oper Crop method:autocrop