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28 строки
1.6 KiB
Plaintext
28 строки
1.6 KiB
Plaintext
How to add a new WebRender display item from a Gecko Display item, the general flow is to:
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(1) Force layout to create a new active layer for the gecko display item.
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(2) Plumb the data needed for the display item from content through WebRenderBridgeParent on the parent side.
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(3) From WebRenderBridgeParent, call out into bindings.rs and implement the appropriate WR calls.
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More detailed steps are:
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1) Force layout to create an active layer for the gecko display item.
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See http://searchfox.org/mozilla-central/rev/0f254a30d684796bcc8b6e2a102a0095d25842bb/layout/generic/nsTextFrame.cpp#4983
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as an example for text layers. Ping Matt Woodrow or Markus Stange for help.
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The Active layer part comes from nsDisplayText::GetLayerState
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2) Create the new display item layer:
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See text layer:
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http://searchfox.org/mozilla-central/rev/0f254a30d684796bcc8b6e2a102a0095d25842bb/gfx/layers/Layers.h#2403
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The layer should have all the information to display the item.
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3) Create the WebRender equivalent layer. In YourLayerType::RenderLayer, serialize the data needed for the layer type.
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4) If you need to add a custom IPC serialization mechanism, do it in WebRenderMessageUtils.h
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5) Create a WebRender command to process the new layer type in WebRenderMessages.ipdlh. These are the struct OpDPPushYourLayerTypeHere
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6) Add a new function in WebRender.h that will call out into webrender to render your display item.
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7) In WebRenderBridgeParent::ProcessWebRenderCommands, call out to the new function in (6).
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8) Fill out the function in (6) in bindings.rs to make webrender do the right thing. Generally, it's just push a display item.
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