Скачать или смотреть Unix & Linux: How can I convert a PNG to a PDF in high quality so it's not blurry or fuzzy?

Unix & Linux: How can I convert a PNG to a PDF in high quality so it's not blurry or fuzzy?


The Question: There are a lot of questions out there about how to convert a PDF file to a PNG
image, but I'm looking to take a nice sharp PNG file and just basically wrap it
or embed it in a PDF file without having it look blurry or fuzzy.
I realize with imagemagic installed I can do a simple conversion like:
convert sample.png sample.pdf
I've also tried a lot of the switches to set the depth, and also the quality
setting:
convert -quality 100 sample.png sample.pdf
However the PDF still comes out looking blurry / fuzzy.
Here's a sample image:
http://img406.imageshack.us/img406/64...
As a png it's crisp and clean. When I convert it to a PDF, even at the same
size it looks blurry:
http://img803.imageshack.us/img803/99...
How can I convert PNG to a PDF in high quality?

Solutions: Please watch the whole video to see all solutions, in order of how many people found them helpful

== This solution helped 14 people ==
I am almost certain that what you perceive as a loss of quality in the PDF, is
just an effect of your PDF viewer's anti-https://en.wikipedia.org/wiki/Aliasing
feature.
If you use evince to view the PDF, you can see the anti-aliasing feature
automatically switched off at a certain zoom (300% in my quick test). You can
see that vividly when you keep zooming in - you will notice that at some point,
pixels become suddenly clearly visible. That is the point when anti-aliasing
must have been switched off to allow precise image inspection.

== This solution helped 2 people ==
PDF is a vector format (i.e., the file contains a description of lines to
draw), while other formats (JPG, PNG) are raster formats (the file describes
what color to paint each pixel). If you blow a PDF up, it is still just sharp
lines; JPG and PNG show the pixelation.
(OK, OK, I lied. A PDF can also be a raster).

== This solution helped 36 people ==
Try using the -density option. The default resolution is 72 dots per inch. So
try something like -density 300.
For reference see -density in the ImageMagick command-line options
documentation.

== This solution helped 2 people ==
I think that for png-to-pdf -density parameter should small rather than large.
You could try something like convert -quality 100 -density 50

== This solution helped 22 people ==
It can be very complicated to get good pdf output from convert. Try img2pdf
instead. From the readme:
Lossless conversion of images to PDF without unnecessarily re-
encoding JPEG and JPEG2000 files. Thus, no loss of quality and no
unnecessary large output file.
To clarify: PDF can embed lossless JPEG 2000 images (and https://
softwarerecs.stackexchange.com/a/25520). So this conversion is completely
lossless:
convert sample.png -quality 0 sample.jp2
img2pdf -o sample.pdf sample.jp2
(Assuming the JP2 delegate is available of course: check identify -list format
| grep JP2.)

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