Thread: Glo Image problem
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Old 11-30-2012, 10:23 PM   #7
davidfor
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Posts: 5,893
Karma: 5704423
Join Date: Jul 2011
Location: Sydney, Australia
Device: Kobo Touch, Kobo Glo
Firstly, I am doing this on a Kobo Touch, not a Glo, but the cover handling is identical.

Firstly, where are you looking at this? While reading the book, or in the library lists or the sleep cover? The sleep cover should be nearly the same as when reading the book.

The Kobo devices generate cover images from the first page of the book when they are to be displayed. The images are JPEGs (not GIFs) with a different extension. For some reason Kobo uses "parsed" instead of JPG. With the firmware version you are running (probably 2.1.5 but it hasn't change for any firmware available for a Glo), there can be three cover images generated. These are in different sizes depending on the use. The last part of the generated filename gives the use and size. "N3_LIBRARY_GRID" is used in the library lists, "N3_FULL" is used for the home screen and the sleep cover and "N3_LIBRARY_FULL" is used for the details screen.

When reading the book, the cover page is sized a little differently than the sleep cover because of the page number area at the bottom of the screen. The sleep cover is rendered for the full sceen, but when reading, the page is rendered within the viewable area.

Looking at the cover on my Touch and in Windows with my image viewer, I can see what you mean. The Touch shows the problems you are talking about, but I didn't think they were to bad. I have covers that look a lot worse. Resizing and converting to greyscale on the PC does a much better job. When I put the resized image on my Touch, it showed the problems the same as letting the device do it. The screen is 600*800 and 16-level grey scale, so that should mean it would be display the same. That suggests the driver or software on the device isn't rendering the images as well as it could.

Last thing, you are using the following for the cover:
Code:
    <svg xmlns="http://www.w3.org/2000/svg" height="100%" preserveAspectRatio="xMidYMid" version="1.1" viewBox="0 0 800 1200" xmlns:xlink="http://www.w3.org/1999/xlink">
      <image height="1200" width="800" xlink:href="../Images/cover.jpg"></image>
    </svg>
With this, the image resizes with the viewer, but it is on the left side of the page. I suggest you change to:
Code:
    <svg xmlns="http://www.w3.org/2000/svg" height="100%" width="100%"  preserveAspectRatio="xMidYMid meet" version="1.1" viewBox="0 0 800 1200" xmlns:xlink="http://www.w3.org/1999/xlink">
      <image height="1200" width="800" xlink:href="../Images/cover.jpg"></image>
    </svg>
With that, the image will be centred in the page. To me, that looks a lot better.

Good luck with the book.
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