Support border-image

[jrmuizel]

We need this for rendering Gecko's chrome. We should first come up with an idea of what the interface needs to be.

See also servo/servo#13003

[glennw]

@jrmuizel Do you already have something in mind for the interface to this?

[jrmuizel]

I do not.

[glennw]

I've had a brief look at the specification. It seems like we could modify the existing BorderDisplayItem from:

pub struct BorderDisplayItem {
    pub left: BorderSide,
    pub right: BorderSide,
    pub top: BorderSide,
    pub bottom: BorderSide,
    pub radius: BorderRadius,
}

to something like:

pub struct NormalBorder {     // What should this be called?
    pub left: BorderSide,
    pub right: BorderSide,
    pub top: BorderSide,
    pub bottom: BorderSide,
    pub radius: BorderRadius,
}

pub struct ImageBorder {
    pub image_key: ImageKey,
    // image slice, repeat params etc
    // border widths
}

pub enum BorderDisplayItem {
    Normal(NormalBorder),
    Image(ImageBorder),
}

Does that seem reasonable?

[glennw]

We'd also extend the ImageBorder to be able to specify a gradient or an image key - by extracting the parts of GradientDisplayItem into a standalone Gradient struct.

[mephisto41]

Anyone working on this? Can I take this? Thanks.

[jrmuizel]

@glennw has it largely implemented here: #895
You can coordinate with him to do the unimplemented bits or start hooking it up to Gecko

[mephisto41]

Great! Didn't notice it. I'll hook it up to gecko. Thanks for the info.

[glennw]

This has landed now.