My question is about how PDF viewers handle fonts used in a PDF that are not embedded.
I'm using software (pdfjs-dist) to generate thumbnails from PDF's and noticed that text is often missing in the resulting image.
Upon further inspection it turns out that fonts are missing on the OS (which is a node docker container (linux)).
Now, I have heard that it's possible to always generate a render from a PDF, using some sort of layer in the PDF that contains vectorized data which you can view,
even when the fonts are not embedded in the PDF nor available in the operating system.
Has anyone heard of this mechanism that can point me to its technical name?
Related
Is there a unified and lightweight method for loading multiple common image file formats in NodeJS which provides read access to individual pixels?
It should support gif, jpeg, and png.
Preferably it would either support other image formats too or provide a way to add more. (webp, etc.)
It does not need to be able to save the file again after modifying pixels, provide metadata access, or anything else.
It doesn't need to be able to load images from URLs.
So far the libraries that support multiple image formats are heavyweight, such as providing full canvas support or full image processing support.
Is there a lightweight way to do this that I'm not finding?
I don't know why I couldn't find this one before posting here:
get-pixels
Given a URL/path, grab all the pixels in an image and return the result as an ndarray. Written in 100% JavaScript, works both in browserify and in node.js and has no external native dependencies.
Currently the following file formats are supported:
PNG
JPEG
GIF
It hasn't had any updates for two years but seems the most lightweight. I'm guessing people might mostly use Jimp these days. It doesn't seem to have external dependencies and is actively developed, but includes a lot of image processing functionality I don't need.
I am using Tableau to do some data representations and the only good quality image export Tableau allows is *.emf
Unfortunately, the online tool I use to put the report together(Canva) does not support emf format.
When I convert the file to jpg or png, the quality is drastically reduced :(
How can I overcome this matter? I tried many things such as opening emf in Illustrator and saving back with CMYK colors and 300dpi and such. But nothing seems to keep the crisp quality of the original emf file.
User Friendly solution:
InkScape opens enhanced windows metafiles, and many other vector-graphical file formats.
It exports to png with choice for output's resolution
It is opensource and available for Linux, windows and Mac OS X.
It is a fact that Tableau's image export feature does not provide many options. In general when I need high quality images, I use one of the below methods depending on the quality I need and the tools available to me at that time:
Screenshot method: If you have a large screen, taking a screenshot directly from Tableau yields better images than the exported ones. If my viz is exported to web, I sometimes enlarge the graphic from my web browser and then take the screenshot.
Converting from PDF: Since PDF can contain vector objects, Tableau's PDF files are in high quality most of the times. If you cannot use these PDF files, you may try converting these files to PNG or JPG files using online or desktop tools. Here is an online tool you may use for this purpose, but be careful about your confidential files when using such online services :)
And there are more ways to convert from PDF but are usually more complicated since they contain some Photoshop steps. I am not sure whether these are easy to apply methods for a lot of files but still you may want to check one of them: https://community.tableau.com/thread/120134
I have cached preview files from Capture One (a photo processing program, similar to Lightroom) where I have lost the originals. Capture One saves previews in their proprietary .cop format and I'm not sure how to go about identifying what's what in there.
There are the strings ETIFFTagInteropIFD and JPEG Embedded TIFF Tags seen in the HEX view which suggests that they are somehow embedding a TIFF in there.
I do have original JPEG files with their corresponding COP-file, but when comparing them there isn't much that's similar - which makes sense I guess, since the preview COP-file is roughly half the size of the original.
What conclusions can I draw from this and what are some good tools for going further?
Is there a direct and fast way to convert XPS (XML Paper Specification) files to SVG format?
I can convert XPS to PDF and then using inkscape to convert them to SVG.
But the PDF->SVG step is very time consuming though this process seems is not CPU consuming.
My understanding is that be cause XPS is a vector based format, converting it to another vector based format like SVG must be feasible and much faster than converting raster based format (though i'm not entirely sure pdf is just raster base) to vector based formats.
BTW, the goal is to display vector based images in browser, and I've XPS files.
libgxps reads XPS and can create SVG files.
I tried it on Cygwin with the xpstosvg command and worked fine.
I tried xpstosvg from the answer above to convert an XPS document with about 100 pages. Unfortunately, the tool produced only one large SVG image with about 90 MB file size, which was not exactly what I was looking for, since the file could not be viewed and I needed one image per page.
Also the manual of the program did not give any hint how to get one image per page. In the end I used an online XPS converter, which really created a SVG image for each page.
I'm starting to venture out from using jpeg and gif files to png, I was wondering if there were any standards for using png beside IE's lack of support for it. I also want to know if there was any current articles about setting I should be using when optimizing for web? Right now I'm using photoshop to do this, should I be using firework instead?
Which optimizations you use depends on the type of image. If your image contains only few colors, you might use png-8, otherwise you may need png-24. Same goes for the use of transparency/alpha blending.
The Photoshop save for web-feature does a fine job, but when your website has a lot of visitors, you may benefit from using PNGCrush for further compressing your images. You can use the YSlow plugin for FireFox to test how much bandwidth you can save by crushing your images.
Also, you can make use of CSS-sprites if your design allows it. This can result in less (but larger) images and therefore less requests and sometimes less bandwidth. But this doen't depend on the type of images you use.
Png is supported by IE, by the way. Only the alpha-transparency is not supported by IE 6, but there are CSS/Javascript trics to work around that, although they do not work for background images.
I wouldn't quit using jpg. Jpg is very useful when it comes to pictures. Png files are convenient for small images like buttons, graphical elements, and for images with large plain areas, like screenshots.