551438b9be
* Add new methods
BView::BeginLayer(uint8 opacity)
BView::EndLayer()
* All drawing between begin and end of a layer is redirected onto an
intermediate bitmap. When ending the layer, this bitmap is
composited onto the view with the opacity given when the layer was
started.
* Layers can be nested arbitrarily and will be blended onto each
other in order. There can also be any arbitrary interleaving of
layer begin/end and drawing operations.
* Internally, drawing commands are redirected into a BPicture between
BeginLayer and EndLayer (but client code need not know or care
about this). Client code can also start/end other BPictures while
inside a layer.
* Uses the PictureBoundingBoxPlayer to determine the size of the
layer bitmap before allocating and drawing into it, so it does not
allocate more memory than necessary and -- more importantly -- it
will not alpha-composite more pixels than necessary.
* Drawing mode is always set to B_OP_ALPHA, blend mode to
(B_PIXEL_ALPHA, B_ALPHA_COMPOSITE) while inside layers. This is
necessary for (a) correct compositing output and (b) for
redirection of drawing into the intermediate bitmap, which uses the
renderer_region offset (in B_OP_COPY, the Painter does not use the
AGG renderer methods, it directly accesses the pixel data. This
would access out-of-bounds without the offset, so B_OP_COPY cannot
be allowed.)
To ensure these modes aren't changed, BView::SetDrawingMode()
and BView::SetBlendingMode() are ignored while inside a layer.
* The main motivation behind this new API is WebKit, which internally
expects such a layers functionality to be present. A performant and
reusable implementation of this functionality can only be done
server-side in app_server.
Haiku
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Haiku is an open-source operating system that specifically targets personal computing. Inspired by the BeOS, Haiku is fast, simple to use, easy to learn and yet very powerful.
Goals
- Sensible defaults with minimal configuration required.
- Clean, clear, concise code.
- Unified desktop environment.
Trying Haiku
Haiku provides pre-built nightly images and release images. Haiku is compatible with a large variety of hardware, but in case you don't want to "take the plunge" and install Haiku on bare metal, you can install it on a virtual machine (VM) instead. If you've never used a VM before, you can follow one of the "Emulating Haiku" guides.
Compiling Haiku
See ReadMe.Compiling.
Contributing
Haiku is a meritocratic open source project with a large variety of tasks. Even if you can't write code, you can still help! Haiku needs designers, (technical) writers, translators, testers... Get involved and help out!
Contributing code
If you're submitting a patch to us, please make sure you're following the patch submitting guidelines.
If you're having trouble finding something in the source tree, you can use one of our OpenGrok servers:
- http://xref.plausible.coop/ (provided by Landon Fuller)
- http://code.metager.de/source/xref/haiku (provided by MetaGer)
Contributing documentation
The main piece of documentation that still needs work are the API docs (found
in the tree at docs/user). Just find an undocumented class, write
documentation for it, and submit a patch.
Contributing translations
See wiki:i18n.
Contributing software ports
See HaikuPorts.