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Using WebP to Reduce Native iOS App Size

6 points by barredo 15y ago

drewcrawford 15y ago
The thumbnail of the eggshell (but not the blowup) was quite pixelated for me. Chrome 16, OS X. http://www.ioncannon.net/wp-content/uploads/2011/06/test2-300x199.webp http://www.ioncannon.net/wp-content/uploads/2011/06/test2-30... (actual thumbnail) http://dl.dropbox.com/u/59605/Screen%20Shot%202012-02-04%20at%206.17.22%20PM.png http://dl.dropbox.com/u/59605/Screen%20Shot%202012-02-04%20a... (how it rendered in Chrome) Is it Chrome-related or did the OP compress with bad settings? As for the TestWebP iOS lib itself, it takes 25 LOC to load an image, which takes 1 LOC with system libraries. Somebody needs to go in and put a category on UIImage to do the heavy lifting. I just ran a grep across about 15 iOS apps I develop and the average size of art assets is about 1MB. So this is a neat hack, and I am sure there are apps out there with 300MB in art assets that could benefit from it. But for the typical app, not worth the effort.
drivebyacct2 15y ago
Could this sort of technique also be done for shrinking caches sizes of apps that are photo-download intensive? I don't know if the size tradeoff is worth the performance hit to reencode files as they're downloaded and cached.
Zev 15y ago
Neat. I don't know if I'd ever use this, but, its a cool hack. Random thoughts off the top of my head, re: making it faster: - Can you can decode into an ARGB buffer, instead of an RGBA buffer? iOS uses ARGB as its native bitmap format, so, there will probably be a bit of a speed bump if you can avoid shuffling bits around as much. - I wonder if using CGDataProviderCreateWithCFData() and passing in a data blob created with CFDataCreateWithBytesNoCopy() to see if any copying bytes around can be reduced. - Maybe cache CGColorSpaceCreateDeviceRGB() somewhere (either just make it static, or in NSThread's threadDictionary). Release on memory warnings and such. - UIImage does a bunch of caching internally. You could mimic it and cache images that have been created, to make it really cheap to re-query for an image/reuse an already-existing image. Again, release on memory warnings and such.

6 points by barredo 15y ago

The thumbnail of the eggshell (but not the blowup) was quite pixelated for me. Chrome 16, OS X. http://www.ioncannon.net/wp-content/uploads/2011/06/test2-300x199.webp http://www.ioncannon.net/wp-content/uploads/2011/06/test2-30... (actual thumbnail) http://dl.dropbox.com/u/59605/Screen%20Shot%202012-02-04%20at%206.17.22%20PM.png http://dl.dropbox.com/u/59605/Screen%20Shot%202012-02-04%20a... (how it rendered in Chrome) Is it Chrome-related or did the OP compress with bad settings? As for the TestWebP iOS lib itself, it takes 25 LOC to load an image, which takes 1 LOC with system libraries. Somebody needs to go in and put a category on UIImage to do the heavy lifting. I just ran a grep across about 15 iOS apps I develop and the average size of art assets is about 1MB. So this is a neat hack, and I am sure there are apps out there with 300MB in art assets that could benefit from it. But for the typical app, not worth the effort.

drivebyacct2 15y ago

Could this sort of technique also be done for shrinking caches sizes of apps that are photo-download intensive? I don't know if the size tradeoff is worth the performance hit to reencode files as they're downloaded and cached.

Zev 15y ago

Neat. I don't know if I'd ever use this, but, its a cool hack. Random thoughts off the top of my head, re: making it faster: - Can you can decode into an ARGB buffer, instead of an RGBA buffer? iOS uses ARGB as its native bitmap format, so, there will probably be a bit of a speed bump if you can avoid shuffling bits around as much. - I wonder if using CGDataProviderCreateWithCFData() and passing in a data blob created with CFDataCreateWithBytesNoCopy() to see if any copying bytes around can be reduced. - Maybe cache CGColorSpaceCreateDeviceRGB() somewhere (either just make it static, or in NSThread's threadDictionary). Release on memory warnings and such. - UIImage does a bunch of caching internally. You could mimic it and cache images that have been created, to make it really cheap to re-query for an image/reuse an already-existing image. Again, release on memory warnings and such.