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//! Tools to control view alignment.
/// Specifies the alignment along both horizontal and vertical directions.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub struct Align {
/// Horizontal alignment policy
pub h: HAlign,
/// Vertical alignment policy
pub v: VAlign,
}
impl Align {
/// Creates a new Align object from the given alignments.
pub fn new(h: HAlign, v: VAlign) -> Self {
Align { h, v }
}
/// Creates a top-left alignment.
pub fn top_left() -> Self {
Align::new(HAlign::Left, VAlign::Top)
}
/// Creates a top-right alignment.
pub fn top_right() -> Self {
Align::new(HAlign::Right, VAlign::Top)
}
/// Creates a top-center alignment.
pub fn top_center() -> Self {
Align::new(HAlign::Center, VAlign::Top)
}
/// Creates a bottom-left alignment.
pub fn bot_left() -> Self {
Align::new(HAlign::Left, VAlign::Bottom)
}
/// Creates a bottom-right alignment.
pub fn bot_right() -> Self {
Align::new(HAlign::Right, VAlign::Bottom)
}
/// Creates a bottom-center alignment.
pub fn bot_center() -> Self {
Align::new(HAlign::Center, VAlign::Bottom)
}
/// Creates a center-right alignment.
pub fn center_left() -> Self {
Align::new(HAlign::Left, VAlign::Center)
}
/// Creates a center-right alignment.
pub fn center_right() -> Self {
Align::new(HAlign::Right, VAlign::Center)
}
/// Creates an alignment centered both horizontally and vertically.
pub fn center() -> Self {
Align::new(HAlign::Center, VAlign::Center)
}
}
/// Horizontal alignment
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum HAlign {
/// Place the element to the left of available space
Left,
/// Place the element horizontally in the center of available space
Center,
/// Place the element to the right of available space
Right,
}
/// Vertical alignment
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum VAlign {
/// Place the element at the top of available space
Top,
/// Place the element vertically in the center of available space
Center,
/// Place the element at the bottom of available space
Bottom,
}
impl HAlign {
/// Returns the offset required to position a view.
///
/// When drawing a view with size `content` when the available size is
/// `container`, printing at the resulting offset will align the view as
/// desired.
pub fn get_offset(&self, content: usize, container: usize) -> usize {
if container < content {
0
} else {
match *self {
HAlign::Left => 0,
HAlign::Center => (container - content) / 2,
HAlign::Right => container - content,
}
}
}
}
impl VAlign {
/// Returns the offset required to position a view.
///
/// When drawing a view with size `content` when the available size is
/// `container`, printing at the resulting offset will align the view as
/// desired.
pub fn get_offset(&self, content: usize, container: usize) -> usize {
if container < content {
0
} else {
match *self {
VAlign::Top => 0,
VAlign::Center => (container - content) / 2,
VAlign::Bottom => container - content,
}
}
}
}