Changes

== Description & Goals==

== Description & Goals==

Just like Read Etexts has advantages over using PDFs with the core Read activity, View Slides has the potential to be easier to use and perform better for books composed of scanned page images than core Read is with scanned page images converted to PDFs.  With PDFs of scanned page images there is often a lag before a page image becomes visible, and moving from page to page can be awkward because there is a point where you see the bottom of one page and the top of the next, rather than cleanly moving from one page to the next.  Getting a full page image to appear in the screen is difficult; with View Slides it is easy and automatic.

Just like Read Etexts has advantages over using PDFs with the core Read activity, View Slides has the potential to be easier to use and perform better for books composed of scanned page images than core Read is with scanned page images converted to PDFs.  With PDFs of scanned page images there is often a lag before a page image becomes visible, and moving from page to page can be awkward because there is a point where you see the bottom of one page and the top of the next, rather than cleanly moving from one page to the next.  Getting a full page image to appear in the screen is difficult; with View Slides it is easy and automatic.

I recommend downloading my own version of "Jack and the Giants" from this page, then downloading the PDF version from the Internet Archive and trying both.  Comparing the two activities side by side with the same content should convince you of the value of this Activity.

You can compare Read with PDF to View Slides by downloading the book "Jack and the Giants" from the Internet Archive in PDF format, then downloading the zipped image format I have created.  Links to both are in the sections below.

 

 

The latest version of Read has excellent support for the Deja Vu format, which is also available from the Internet Archive.  This format is especially designed to compress scanned book pages more than JPEG can without losing image quality.  This format, like PDF, is available from the Internet Archive and may be the format to beat for scanned books.

== Creating Slide Collections ==

== Creating Slide Collections ==

  zip JackAndTheGiants *.jpg

  zip JackAndTheGiants *.jpg

The original archive was about 40 megabytes, my new one was about 6 megabytes.  You can download it [[media:JackAndTheGiants.zip|here]].

The original archive was about 40 megabytes, my new one was about 6 megabytes.  You can download it [http://people.sugarlabs.org/~jdsimmons/JackAndTheGiants.zip here].

If your files are in a supported format already then there is no need to convert them.  Use display to see how they fit on the screen of a computer running at 1024x768.  If they seem to be twice as tall as the screen then you can run this command to shrink them down by 50% and overwrite the original files:

If your files are in a supported format already then there is no need to convert them.  Use display to see how they fit on the screen of a computer running at 1024x768.  If they seem to be twice as tall as the screen then you can run this command to shrink them down by 50% and overwrite the original files:

  zip LoneRangerDell100 *.jpg

  zip LoneRangerDell100 *.jpg

If you use Windows you can use the free [[www.7zip.org 7zip File Manager]] to exract the files from the .cbr and pack them up again in a zip file.

If you use Windows you can use the free [http://www.7zip.org 7zip File Manager] to extract the files from the .cbr and pack them up again in a zip file.

== Current Features ==

== Current Features ==

* I might add an annotation feature that lets you attach notes to a slide.  I'm still thinking about how this would work visually, as well as how I could do it with pygtk.

* I might add an annotation feature that lets you attach notes to a slide.  I'm still thinking about how this would work visually, as well as how I could do it with pygtk.

* I might add a feature to allow multiple bookmarks in a slide collection.  This would be in addition to remembering where you left off when viewing the slides.

* I might add a feature to allow multiple bookmarks in a slide collection.  This would be in addition to remembering where you left off when viewing the slides.

* Any annotations and bookmarks would be stored in an XML file which would go in the Zip file along with the images.  When you share a slide collection these annotations and bookmarks would go with the collection to the recipient.

* Any annotations and bookmarks would be stored in a pickle file which would go in the Zip file along with the images.  When you share a slide collection these annotations and bookmarks would go with the collection to the recipient.

== Bugs ==

== Bugs ==

* Document sharing is reliable but slow.  Currently it uses Tubes to copy a file from one computer to another.  When using Gabble the file is Base 64 encoded and sent using a method that has a lot of overhead, which is necessary because the two computers might be on different networks and have to deal with with firewalls and the like.  You can minimize the problem by shrinking your images with "mogrify" as described above.  This not only improves document sharing, it also improves performance and dramatically cuts down on disk space usage, which is vitally important on the XO!

* Document sharing is reliable but slow.  Currently it uses Tubes to copy a file from one computer to another.  When using Gabble the file is Base 64 encoded and sent using a method that has a lot of overhead, which is necessary because the two computers might be on different networks and have to deal with with firewalls and the like.  You can minimize the problem by shrinking your images with "mogrify" as described above.  This not only improves document sharing, it also improves performance and dramatically cuts down on disk space usage, which is vitally important on the XO!

== Source ==

== Source ==

http://git.sugarlabs.org/projects/viewslides

* http://git.sugarlabs.org/projects/viewslides

 

* [http://activities.sugarlabs.org/en-US/sugar/addon/4039 ASLO page]

[[Category:Activities]]