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use crate::{api::prelude::*, prelude::*, proc_macros::*};
static ID_SCROLL_BAR_HORIZONTAL: &str = "scroll_bar_horizontal";
static ID_SCROLL_BAR_VERTICAL: &str = "scroll_bar_vertical";
#[derive(Default, AsAny)]
pub struct ScrollIndicatorState {
horizontal_scroll_bar: Entity,
vertical_scroll_bar: Entity,
}
impl State for ScrollIndicatorState {
fn init(&mut self, _: &mut Registry, ctx: &mut Context) {
self.horizontal_scroll_bar = ctx
.entity_of_child(ID_SCROLL_BAR_HORIZONTAL)
.expect("ScrollIndicatorState.init: scroll_bar_horizontal child could not be found.");
self.vertical_scroll_bar = ctx
.entity_of_child(ID_SCROLL_BAR_HORIZONTAL)
.expect("ScrollIndicatorState.init: scroll_bar_vertical child could not be found.");
}
fn update_post_layout(&mut self, _: &mut Registry, ctx: &mut Context) {
let mode = *ctx.widget().get::<ScrollViewerMode>("mode");
if mode.vertical != ScrollMode::Auto && mode.horizontal != ScrollMode::Auto {
return;
}
let size = ctx.widget().get::<Rectangle>("bounds").size();
let content_size = ctx.widget().get::<Rectangle>("content_bounds").size();
let view_port_size = ctx.widget().get::<Rectangle>("view_port_bounds").size();
let padding = *ctx.widget().get::<Thickness>("padding");
let scroll_padding = *ctx.widget().get::<Thickness>("scroll_padding");
if mode.vertical != ScrollMode::Disabled && content_size.height() > view_port_size.height()
{
let mut scroll_bar = ctx.get_widget(self.vertical_scroll_bar);
if *scroll_bar.get::<Visibility>("visibility") != Visibility::Visible {
scroll_bar.set("visibility", Visibility::Visible);
}
scroll_bar
.get_mut::<Rectangle>("bounds")
.set_height(scroll_bar_size(
size.height(),
content_size.height(),
view_port_size.height(),
padding.top() + padding.bottom(),
));
scroll_bar.get_mut::<Rectangle>("bounds").set_y(-offset(
size.height(),
content_size.height(),
scroll_padding.top(),
));
}
if mode.horizontal != ScrollMode::Disabled && content_size.width() > view_port_size.width()
{
let mut scroll_bar = ctx.get_widget(self.horizontal_scroll_bar);
if *scroll_bar.get::<Visibility>("visibility") != Visibility::Visible {
scroll_bar.set("visibility", Visibility::Visible);
}
scroll_bar
.get_mut::<Rectangle>("bounds")
.set_width(scroll_bar_size(
size.width(),
content_size.width(),
view_port_size.width(),
padding.left() + padding.right(),
));
scroll_bar.get_mut::<Rectangle>("bounds").set_x(-offset(
size.width(),
content_size.width(),
scroll_padding.left(),
));
}
}
}
widget!(
ScrollIndicator<ScrollIndicatorState> {
mode: ScrollViewerMode,
scroll_padding: Thickness,
content_bounds: Rectangle,
view_port_bounds: Rectangle,
padding: Thickness
}
);
impl Template for ScrollIndicator {
fn template(self, id: Entity, ctx: &mut BuildContext) -> Self {
self.name("ScrollIndicator")
.v_align("stretch")
.h_align("stretch")
.padding(0.0)
.child(
Grid::new()
.child(
ScrollBar::new()
.id(ID_SCROLL_BAR_HORIZONTAL)
.visibility("collapsed")
.min_height(8.0)
.margin((0.0, 0.0, 0.0, 6.0))
.h_align("end")
.opacity(id)
.build(ctx),
)
.child(
ScrollBar::new()
.id(ID_SCROLL_BAR_VERTICAL)
.visibility("collapsed")
.min_width(8.0)
.margin((0.0, 0.0, 6.0, 0.0))
.height(4.0)
.v_align("end")
.opacity(id)
.build(ctx),
)
.build(ctx),
)
}
fn layout(&self) -> Box<dyn Layout> {
Box::new(PaddingLayout::new())
}
}
fn scroll_bar_size(size: f64, content_size: f64, view_port_size: f64, padding: f64) -> f64 {
(size * view_port_size / content_size) - padding
}
fn offset(size: f64, content_size: f64, offset: f64) -> f64 {
size * offset / content_size
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_scroll_bar_size() {
let size = 50.;
let content_size = 200.;
let view_port_size = 80.0;
let padding = 8.;
assert!(
(scroll_bar_size(size, content_size, view_port_size, padding) - 12.).abs()
< f64::EPSILON
);
}
#[test]
fn test_offset() {
let size = 50.;
let content_size = 200.;
let offset_in = 8.;
assert!((offset(size, content_size, offset_in) - 2.).abs() < f64::EPSILON);
}
}