Struct Column 

pub struct Column<C: Fn(ColumnContent<'_, '_, '_>) -> Option<()>> {
    pub content: C,
    pub gap: f32,
    pub collapse: bool,
}

A container that arranges child elements vertically with optional gaps.

Elements are laid out from top to bottom with configurable spacing between them. Supports page breaking and collapsing behavior for empty elements.

Gap Behavior

Gaps are only applied between elements that have actual height. Elements with None height (collapsed elements) don’t get gaps before or after them.

Collapse Behavior

When collapse: true (default):

• If all children have None height, the column returns None height
• If all children have None width, the column returns None width
• The gaps around a child with a None height are collapsed into one.

When collapse: false:

• Empty columns return Some(0.0) for height/width instead of None
• Useful when you need a column to always occupy space even when empty
• A child with a None height will still have a gap on either side

Page Breaking

In breakable contexts, when a child element causes a page break, the column’s accumulated height is reset and continues on the new page.

Fields

content: C

Closure that gets called for adding the content.

The closure is basically an internal iterator that produces elements by calling ColumnContent::add. For short circuiting with the ? operator ColumnContent::add and this closure return an Option.

If the column is in a context that measures it before drawing (such as BreakWhole), this function will be called twice. In more complicated nested layouts it could be called more than that (though in real world layouts this effect should be minimal as not all containers need a measure pass before drawing). Because of this it’s beneficial to keep expensive computations and allocation outside of this closure.

gap: f32

Vertical spacing between elements in millimeters

collapse: bool

Whether to collapse to None size when all children are collapsed. When false, empty columns return Some(0.0) instead of None.

Implementations

impl<C: Fn(ColumnContent<'_, '_, '_>) -> Option<()>> Column<C>

pub fn new(content: C) -> Self

pub fn with_gap(self, gap: f32) -> Self

pub fn with_collapse(self, collapse: bool) -> Self

Trait Implementations

impl<C: Fn(ColumnContent<'_, '_, '_>) -> Option<()>> Element for Column<C>

fn first_location_usage( &self, ctx: FirstLocationUsageCtx<'_>, ) -> FirstLocationUsage

fn measure(&self, ctx: MeasureCtx<'_>) -> ElementSize

fn draw(&self, ctx: DrawCtx<'_, '_>) -> ElementSize

fn with_padding_top(self, padding: f32) -> Padding<Self>

where Self: Sized,

fn with_vertical_padding(self, padding: f32) -> Padding<Self>

where Self: Sized,

fn debug(self, color: u8) -> Debug<Self>

where Self: Sized,