Hello,
It's my first post here, so I don't know if my issue is at the right location. I'm a developer working on a project using ePub since one year.
My (big) concern today is about the quality of rendering of rasterized text in a cover. I have an image in PNG format (24-bit, so without alpha-channel) containing a background image and the title in foreground (when I say "foreground", it's about perception since there's not any layers anymore).
Well, this cover, embedded in an XHTML document, displays very well in the majority of ePub readers software (tried mainly under Windows 7), but not in some (and surprisingly the worst comes from the biggest software publishers), where the text (which is just pixels) is totally deteriorated (edge lace).
Here are my tests :
- Adobe Digital Editions : VERY BAD
- CoolReader : BAD
- FBReader : GOOD
- Sony Reader for PC : BAD
- Calibre's Reader : GOOD
- Sigil's Reader : GOOD
- EPUBReader for Firefox : GOOD
... etc.
For example, below is a snapshot showing what is displayed in Adobe Digital Editions (at left side) and what is displayed in FBReader (at right side). It's of course unacceptable at left side... But why ADE renders like this ? Pixels are pixels, and not any transformation is wanted.
It's like if ADE would apply some filters which, I guess, would be supposed to improve rendering, but here is simply a disaster. How to work around this (knowing I talk you about cover here, but I could have to manage others images with rasterized text above image elsewhere in the book, and knowing I've absolutely to do text stay pixels/rasterized, neither real HTML text nor vector in SVG format) ?
Rendering of same image : Adobe Digital Editions at left, FBReader at right
Very annoying
How to solve this issue ?