Thumbnails for PDF

Posting after a long time, have been keeping busy on the academic front lately. So, about the eBook reader, the task I had to do after rendering the pdf view was to generate thumbnails for PDFs dynamically.

The best way you can generate image thumbnails for in PHP is if you use imagemagik. But using that would require users to install imagemagik with ownCloud before using the app, so I decided to rather wait for the thumbnail api to come out and figure out a different solution till then. That ways I get to have even more fun.

I read about the rendering HTML in an HTML canvas element, and decided to give it a try. This was with the help of javascript. In my javascript code, I read the anchor tags for names of the pdf files, create canvas elements and render the scaled version of the PDFs on to the canvases.

The bad part was, this happens only when the page loads and takes time for the thumbnails to load. A better and faster approach would have been to create images and probably store them, so that when the page loads, the images are fetched from the data directory.

What I have figured to remedy this would be to capture the canvas data as an image using the 'toDaraUrl' javascript method and store them in the ownCloud data directory, so that next time when the thumbnails are displayed, they are instead fetched from the data directory. This would reduce the load time to a good extent.

Integration with PDF Viewer Complete

Hi,

Last few days have been really busy with campus placements in college and with absolutely no access to the internet, it was impossible for me to work on the eBook reader. But I bring 2  good news, one is, I have a job now, starting next spring and second, I finally integrated the current PDF viewer with my app.


So, now the eBook reader app, displays a list of PDF files that have been uploaded onto ownCloud and opens them up with the help of the existing PDF viewer. For files within sub-directories, it is possible to navigate through the directories that the app displays and reach the file that you want to view.


The list is super-trashy, but I plan to work on that next. First, the top navigation list has to be built, that shows the path from the root directory of ownCloud (data/username/files/) to the current directory. Then I need to work on creating thumbnails for uploaded PDFs.


Have to speed up big time!

Integration with the Existing PDF viewer

In my last post I talked about working on an Ebook reader for Owncloud. Well, I have started off with the development.


First, I worked on displaying a list of all PDF files amongst the uploaded files on Owncloud, though not very pretty but clean enough to go ahead. This list is basically a list of links, which when clicked should render the PDF view of the file.


Next, I decided to work on rendering the PDF view for the PDF files I found. This unlike I thought, turned out to be a daunting task. On researching and reading codes I found out that the existing PDF viewer was built very closely to the files app. I needed to use the same div tag ids' used in the files app so that when my app runs, the PDF viewer overloads attribute value of my divs' and renders the PDF view.


So, I carefully included all the divs' at appropriate places and tested. The test run rendered the only the skeleton of the PDF view and not the file inside with a pop-up asking me if I wanted to download the file :D


Guess I need to more deeply study the files app.

A Journey Begins

Hi,


My name is Priyanka Menghani, a Software Engineering student in India. My interests are coding alongside rock music playing into my ears! Makes me feel so upbeat. ;)


Basically web-development is my passion, but I would love want to venture out to other areas as well someday. This blog specifically contains all the work I will be doing while developing an eBook reader app for Owncloud.


Please stop by, review my work and give me a piece of your knowledge, I think I have something to learn from each one out there.