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use super::Draw;
use super::{make_box, BoxStyle};
use crate::types::{BoundingBox, Position, Positioned};
use std::fmt::{self, Debug};
use std::io::{self, Write};
pub struct Viewport<W> {
/// The box describing the visible part of the viewport.
///
/// Generally the size of the terminal, and positioned at 0, 0
pub outer: BoundingBox,
/// The box describing the inner part of the viewport
///
/// Its position is relative to `outer.inner()`, and its size should generally not
/// be smaller than outer
pub inner: BoundingBox,
/// The actual screen that the viewport writes to
pub out: W,
}
impl<W> Debug for Viewport<W> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"Viewport {{ outer: {:?}, inner: {:?}, out: <OUT> }}",
self.outer, self.inner
)
}
}
impl<W> Viewport<W> {
/// Returns true if the (inner-relative) position of the given entity is
/// visible within this viewport
fn visible<E: Positioned>(&self, ent: &E) -> bool {
self.on_screen(ent.position()).within(self.outer.inner())
}
/// Convert the given inner-relative position to one on the actual screen
fn on_screen(&self, pos: Position) -> Position {
pos + self.inner.position + self.outer.inner().position
}
}
impl<W: Write> Viewport<W> {
/// Draw the given entity to the viewport at its position, if visible
pub fn draw<T: Draw>(&mut self, entity: &T) -> io::Result<()> {
if !self.visible(entity) {
return Ok(());
}
write!(
self,
"{}",
(entity.position()
+ self.inner.position
+ self.outer.inner().position)
.cursor_goto()
)?;
entity.do_draw(self)
}
/// Clear whatever is drawn at the given inner-relative position, if visible
pub fn clear(&mut self, pos: Position) -> io::Result<()> {
write!(self, "{} ", self.on_screen(pos).cursor_goto(),)
}
/// Initialize this viewport by drawing its outer box to the screen
pub fn init(&mut self) -> io::Result<()> {
write!(self, "{}", make_box(BoxStyle::Thin, self.outer.dimensions))
}
}
impl<W> Positioned for Viewport<W> {
fn position(&self) -> Position {
self.outer.position
}
}
impl<W: Write> Write for Viewport<W> {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.out.write(buf)
}
fn flush(&mut self) -> io::Result<()> {
self.out.flush()
}
fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
self.out.write_all(buf)
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::types::Dimensions;
// use proptest::prelude::*;
#[test]
fn test_visible() {
assert!(Viewport {
outer: BoundingBox::at_origin(Dimensions { w: 10, h: 10 }),
inner: BoundingBox {
position: Position { x: -10, y: -10 },
dimensions: Dimensions { w: 15, h: 15 },
},
out: (),
}
.visible(&Position { x: 13, y: 13 }));
assert!(!Viewport {
outer: BoundingBox::at_origin(Dimensions { w: 10, h: 10 }),
inner: BoundingBox {
position: Position { x: -10, y: -10 },
dimensions: Dimensions { w: 15, h: 15 },
},
out: (),
}
.visible(&Position { x: 1, y: 1 }));
}
// proptest! {
// #[test]
// fn nothing_is_visible_in_viewport_off_screen(pos: Position, outer: BoundingBox) {
// let invisible_viewport = Viewport {
// outer,
// inner: BoundingBox {
// position: Position {x: -(outer.dimensions.w as i16), y: -(outer.dimensions.h as i16)},
// dimensions: outer.dimensions,
// },
// out: ()
// };
// assert!(!invisible_viewport.visible(&pos));
// }
// }
}
|
