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|
// Copyright 2016 Joe Wilm, The Alacritty Project Contributors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//! State management for a selection in the grid
//!
//! A selection should start when the mouse is clicked, and it should be
//! finalized when the button is released. The selection should be cleared
//! when text is added/removed/scrolled on the screen. The selection should
//! also be cleared if the user clicks off of the selection.
use std::mem;
use index::{Point, Column, RangeInclusive, Side, Linear, Line};
use grid::ToRange;
/// The area selected
///
/// Contains all the logic for processing mouse position events and providing
/// necessary info the the renderer.
#[derive(Debug)]
pub enum Selection {
/// No current selection or start of a selection
Empty,
Active {
start: Point,
end: Point,
start_side: Side,
end_side: Side
},
}
impl Default for Selection {
fn default() -> Selection {
Selection::Empty
}
}
impl Selection {
/// Create a selection in the default state
#[inline]
pub fn new() -> Selection {
Default::default()
}
/// Clear the active selection
pub fn clear(&mut self) {
mem::replace(self, Selection::Empty);
}
pub fn is_empty(&self) -> bool {
match *self {
Selection::Empty => true,
_ => false
}
}
pub fn update(&mut self, location: Point, side: Side) {
let selection = mem::replace(self, Selection::Empty);
let selection = match selection {
Selection::Empty => {
// Start a selection
Selection::Active {
start: location,
end: location,
start_side: side,
end_side: side
}
},
Selection::Active { start, start_side, .. } => {
// Update ends
Selection::Active {
start: start,
start_side: start_side,
end: location,
end_side: side
}
}
};
mem::replace(self, selection);
}
pub fn span(&self) -> Option<Span> {
match *self {
Selection::Active { ref start, ref end, ref start_side, ref end_side } => {
let (front, tail, front_side, tail_side) = if *start > *end {
// Selected upward; start/end are swapped
(end, start, end_side, start_side)
} else {
// Selected downward; no swapping
(start, end, start_side, end_side)
};
debug_assert!(!(tail < front));
// Single-cell selections are a special case
if start == end {
if start_side == end_side {
return None;
} else {
return Some(Span {
ty: SpanType::Inclusive,
front: *front,
tail: *tail
});
}
}
// The other special case is two adjacent cells with no
// selection: [ B][E ] or [ E][B ]
let adjacent = tail.line == front.line && tail.col - front.col == Column(1);
if adjacent && *front_side == Side::Right && *tail_side == Side::Left {
return None;
}
Some(match (*front_side, *tail_side) {
// [FX][XX][XT]
(Side::Left, Side::Right) => Span {
front: *front,
tail: *tail,
ty: SpanType::Inclusive
},
// [ F][XX][T ]
(Side::Right, Side::Left) => Span {
front: *front,
tail: *tail,
ty: SpanType::Exclusive
},
// [FX][XX][T ]
(Side::Left, Side::Left) => Span {
front: *front,
tail: *tail,
ty: SpanType::ExcludeTail
},
// [ F][XX][XT]
(Side::Right, Side::Right) => Span {
front: *front,
tail: *tail,
ty: SpanType::ExcludeFront
},
})
},
Selection::Empty => None
}
}
}
/// How to interpret the locations of a Span.
#[derive(Debug, Eq, PartialEq)]
pub enum SpanType {
/// Includes the beginning and end locations
Inclusive,
/// Exclude both beginning and end
Exclusive,
/// Excludes last cell of selection
ExcludeTail,
/// Excludes first cell of selection
ExcludeFront,
}
/// Represents a span of selected cells
#[derive(Debug, Eq, PartialEq)]
pub struct Span {
front: Point,
tail: Point,
/// The type says whether ends are included or not.
ty: SpanType,
}
impl Span {
pub fn to_locations(&self, cols: Column) -> (Point, Point) {
match self.ty {
SpanType::Inclusive => (self.front, self.tail),
SpanType::Exclusive => {
(Span::wrap_start(self.front, cols), Span::wrap_end(self.tail, cols))
},
SpanType::ExcludeFront => (Span::wrap_start(self.front, cols), self.tail),
SpanType::ExcludeTail => (self.front, Span::wrap_end(self.tail, cols))
}
}
fn wrap_start(mut start: Point, cols: Column) -> Point {
if start.col == cols - 1 {
Point {
line: start.line + 1,
col: Column(0),
}
} else {
start.col += 1;
start
}
}
fn wrap_end(end: Point, cols: Column) -> Point {
if end.col == Column(0) && end.line != Line(0) {
Point {
line: end.line - 1,
col: cols
}
} else {
Point {
line: end.line,
col: end.col - 1
}
}
}
#[inline]
fn exclude_start(start: Linear) -> Linear {
start + 1
}
#[inline]
fn exclude_end(end: Linear) -> Linear {
if end > Linear(0) {
end - 1
} else {
end
}
}
}
impl ToRange for Span {
fn to_range(&self, cols: Column) -> RangeInclusive<Linear> {
let start = Linear(self.front.line.0 * cols.0 + self.front.col.0);
let end = Linear(self.tail.line.0 * cols.0 + self.tail.col.0);
let (start, end) = match self.ty {
SpanType::Inclusive => (start, end),
SpanType::Exclusive => (Span::exclude_start(start), Span::exclude_end(end)),
SpanType::ExcludeFront => (Span::exclude_start(start), end),
SpanType::ExcludeTail => (start, Span::exclude_end(end))
};
RangeInclusive::new(start, end)
}
}
/// Tests for selection
///
/// There are comments on all of the tests describing the selection. Pictograms
/// are used to avoid ambiguity. Grid cells are represented by a [ ]. Only
/// cells that are comletely covered are counted in a selection. Ends are
/// represented by `B` and `E` for begin and end, respectively. A selected cell
/// looks like [XX], [BX] (at the start), [XB] (at the end), [XE] (at the end),
/// and [EX] (at the start), or [BE] for a single cell. Partially selected cells
/// look like [ B] and [E ].
#[cfg(test)]
mod test {
use index::{Line, Column, Side, Point};
use
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