MB size for pages / full book for iBookstore?

Discussion in 'iOS Programming' started by RichardRi, Oct 22, 2013.

  1. RichardRi macrumors newbie

    Sep 27, 2013
    I'm creating a kids' picture book, which I'll sell in the iBookstore.

    Each page is a single image, and I've made the images large, to make the most of future releases of iPad that might have higher resolution screens.

    (Each image is 3543 pixels by 3543 pixels. They're square, so viewers of the book will see a space on the left and the right of their screens.)

    I'm wondering though, if the file size / or page size of my book is going to make it download slow or run slow…

    There are 32 pages in the book. And they're from 1.3MB in size, to 8MB in size.

    The total size of all the images for the book, is 146MB.

    Three questions:

    1. I'd like people to be able to download and look at the book on iPad and iPhone without it seeming slow for most people. Is this going to be too big? If this will be too big, what size would be sensible?

    2. Might it make sense to make a different version for iPhone than for iPad? Is this possible with iBooks Author? What size files would be good for each?

    3. Are both these two things issues: 1, the total size of the book, for the initial download? And 2, the size of each page? (If so, I guess I'll need to make sure each page is optimum, as well as the whole book.)
  2. Duncan C macrumors 6502a

    Duncan C

    Jan 21, 2008
    Northern Virginia
    Creating your art assets at larger than current display sizes might be wise to "future-proof" your content in case there are higher res screens released in the future, or you decide to move to desktop platforms, or whatever.

    However, building an iBook were every single image is MUCH larger than any current device on the market is frankly a bad idea. You will make your app sluggish to use, prone to low-memory crashes, and MUCH larger to download.

    The iPad retina has a screen size of 2048-by-1536 pixels, or about 3.1 megapixels. Your proposed page size of 3543 x 3543 pixels (~12.5 megapixels) will make each page take almost 4 times as much memory and disk space, with absolutely no benefit to the user. Since your app is going to be ALL images, that means your app will be about 4 times bigger. The larger the download, the less people will buy it.

    If you are going to make the images that large (you shouldn't) then you should implement a tiled rendering scheme that loads the images in pieces at different scales. There are sample apps from Apple that show how to do this.

    For most apps, Apple tells you to include artwork at all supported sizes, and then load the appropriate size at runtime. I don't know what they do for iBooks, but I would be shocked if they didn't have a solution for this for iPhones and non-retina iPads.
  3. RichardRi thread starter macrumors newbie

    Sep 27, 2013
    thanks Duncan.

    I'll cut down the size of the images.

    And I'll look into those other two things.

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