This patch adds support for JPEG decoding. The JPEG decoder is capable
of handling standard 2x1 horizontal, 2x1 vertical and quartered chroma
subsampling. The implemented Inverse DCT performs with a decent speed.
As of interchange formats, since we tend to ignore the metadata in APPn
markers, the decoder can handle any format compatible with JFIF, which
includes EXIFs and sometimes WebMs too. The decoder does not support
progressive JPEGs yet.
The new ImageDecoder service (available for members of "image" via
/tmp/portal/image) allows you to decode images in a separate process.
This will allow programs to confidently load untrusted images, since
the bulk of the security concerns are sandboxed to a separate process.
The only API right now is a synchronous IPC DecodeImage() call that
takes a shbuf with encoded image data and returns a shared buffer and
metadata for the decoded image.
It also comes with a very simple library for interfacing with the
ImageDecoder service: LibImageDecoderClient. The name is a bit of a
mouthful but I guess we can rename it later if we think of something
nicer to call it.
There's obviously a bit of overhead to spawning a separate process
for every image decode, so this is mostly only appropriate for
untrusted images (e.g stuff downloaded from the web) and not necessary
for trusted local images (e.g stuff in /res)
Port the WebContent service to the new MultiInstance mechanism that
Sergey added. This means that every new WebContentView gets its very
own segregated WebContent process.
The "WebContent" service provides a very restricted instance of LibWeb
running as an unprivileged user account. This will be used to implement
process separation in Browser, among other things.
This first cut of the service only spawns a single WebContent process
when someone connects to /tmp/portal/webcontent. We will soon switch
this over to spawning a new process for each connection.
Since this feature is very immature, we'll be bringing it up inside of
Demos/WebView as a separate demo program. Eventually this will become
a reusable widget that anyone can embed and easily get out-of-process
web content in their GUI.
This is pretty, pretty cool! :^)
We were getting a little overly memey in some places, so let's scale
things back to business-casual.
Informal language is fine in comments, commits and debug logs,
but let's keep the runtime nice and presentable. :^)
I booted the system on a much better screen than the one I normally use
and the variance in contrast between different icons bothered me.
Here's an attempt to fix that, while also redoing some icons that I've
wanted to redo for a while. :^)
Absolutely positioned blocks now register themselves with their
containing block (and note that the containing block of an absolutely
positioned box is the nearest non-statically positioned block ancestor
or the ICB as fallback.)
Containing blocks then drive the layout of their tracked absolutely
positioned descendants as a separate layout pass.
This is very far from perfect but the general direction seems good.
