Struct SizeCx 

pub struct SizeCx<'a>(/* private fields */);

Size and scale interface

This interface is provided to widgets in crate::Layout::size_rules. It may also be accessed through crate::event::EventCx::size_cx, DrawCx::size_cx.

Most methods get or calculate the size of some feature. These same features may be drawn through DrawCx.

Implementations

impl<'a> SizeCx<'a>

pub fn re<'b>(&'b self) -> SizeCx<'b>

where 'a: 'b,

Reborrow with a new lifetime

Rust allows references like &T or &mut T to be “reborrowed” through coercion: essentially, the pointer is copied under a new, shorter, lifetime. Until rfcs#1403 lands, reborrows on user types require a method call.

Calling this method is zero-cost.

pub fn scale_factor(&self) -> f32

Get the scale factor

“Traditional” PC screens have a scale factor of 1; high-DPI screens may have a factor of 2 or higher. This may be fractional and may be adjusted to suit the device type (e.g. a phone or desktop monitor) as well as the user’s preference.

One could use this value to calculate physical size, but be warned that the result may be quite inaccurate on anything other than a desktop monitor: 25.4 mm = 1 inch = (96 * scale_factor) pixels

To calculate screen pixel sizes from virtual pixel sizes:

use kas_core::cast::*;
let size: i32 = (100.0 * scale_factor).cast_ceil();

This value may change during a program’s execution (e.g. when a window is moved to a different monitor); in this case all widgets will be resized via crate::Layout::size_rules.

pub fn dpem(&self) -> f32

The Em size of the standard font in pixels

The Em is a unit of typography (variously defined as the point-size of the font, the height of the font or the width of an upper-case M).

This method returns the size of 1 Em in physical pixels, derived from the font size in use by the theme and the screen’s scale factor.

pub fn min_element_size(&self) -> i32

The smallest reasonable size for a visible (non-frame) component

This is used as a suggestion by some heuristics.

pub fn min_scroll_size(&self, axis: impl Directional) -> i32

The minimum size of a scrollable area

pub fn grip_len(&self) -> i32

The length of the grip (draggable handle) on a scroll bar or slider

This is the length in line with the control. The size on the opposite axis is assumed to be equal to the feature size as reported by Self::feature.

pub fn scroll_bar_width(&self) -> i32

The width of a vertical scroll bar

This value is also available through Self::feature.

pub fn margins(&self, style: MarginStyle) -> Margins

Get margin size

pub fn inner_margins(&self) -> Margins

Get margins for MarginStyle::Inner

pub fn tiny_margins(&self) -> Margins

Get margins for MarginStyle::Tiny

pub fn small_margins(&self) -> Margins

Get margins for MarginStyle::Small

pub fn large_margins(&self) -> Margins

Get margins for MarginStyle::Large

pub fn text_margins(&self) -> Margins

Get margins for MarginStyle::Text

pub fn feature(&self, feature: Feature, axis: impl Directional) -> SizeRules

Size rules for a feature

pub fn frame(&self, style: FrameStyle, axis: impl Directional) -> FrameRules

Size of a frame around another element

pub fn text_rules<T: FormattableText>( &self, text: &mut Text<T>, axis: AxisInfo, ) -> SizeRules

Get SizeRules for a text element

The TextClass is used to select a font and controls whether line wrapping is enabled.

Horizontal size without wrapping is simply the size the text. Horizontal size with wrapping is bounded to some width dependant on the theme, and may have non-zero Stretch depending on the size.

Vertical size is the size of the text with or without wrapping, but with the minimum at least the height of one line of text.

Widgets with editable text contents or internal scrolling enabled may wish to adjust the result.

Note: this method partially prepares the text object. It is not required to call this method but it is required to call ConfigCx::text_configure before text display for correct results.