Quote:
Originally Posted by Joques
The ones that are in the ebook are 502x714, almost exactly half of your already shrunk files, and bad enough that several of the location names are really hard to make out. Edit: And those are the ones that take up 300kB of space.
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I was skeptical when you had written "No compression at all, it seems.", but the uncompressed size for 714x502 is 350KB, not much larger than the 300KB for the files in the book. Uncompressed size for the files on the web site is 2.8MB, also not much larger than the 2.7MB JPEGs that are there.
I made 714x504 (same 0.3486328125 scaling to both dimensions) JPEG and PNG images from the 2048x1448 JPEGS on the web site, and got 142KB and 125KB sizes respectively. Both look about the same. Some of the text is difficult on a 96dpi monitor. I hate to think about trying it 167 dpi or 200dpi e-ink. 250 dpi e-ink or LCD is likely impossible. In any case, the publisher could have reduced the size of the book by almost a megabyte by going with PNG, maybe even a full megabyte starting with a clean image with no JPEG artifacts.
Since all 5 maps have a huge amount of identical content, an even more drastic bloat reduction will be possible when SVG support in EPUB readers gets decent. The same underlying image with only the constant text could be used for all the maps with the shaded regions and changed text as SVG overlays.
It looks like maybe the quality setting on the JPEG files was cranked well into diminishing returns territory with the result of all the worst features of JPEG with essentially none of the compression.
JPEG does not do well on regions of solid color or sharp edges. These figures are nothing but sharp edges and solid colors.
Quote:
Originally Posted by Joques
Like I said - having hi-res maps on a tablet beside the ereader is ideal for me, more important really than having hi-res maps in the ebook file as it is so much work going back and forth between map and text.
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It has been so long since I played with putting bare image files on a reader, that I had forgotten about the possibility. That does seem like a good workaround when such images are available.