neovim-gtk/src/render/model_clip_iterator.rs

99 lines
2.5 KiB
Rust

use std::cmp::min;
use std::slice::Iter;
use cairo;
use super::context::CellMetrics;
use ui_model;
pub struct RowView<'a> {
pub line: &'a ui_model::Line,
pub cell_metrics: &'a CellMetrics,
pub line_y: f64,
pub ctx: &'a cairo::Context,
}
impl<'a> RowView<'a> {
pub fn new(
row: usize,
ctx: &'a cairo::Context,
cell_metrics: &'a CellMetrics,
line: &'a ui_model::Line,
) -> Self {
RowView {
line,
line_y: row as f64 * cell_metrics.line_height,
cell_metrics,
ctx,
}
}
}
pub struct ModelClipIterator<'a> {
model_idx: usize,
model_iter: Iter<'a, ui_model::Line>,
cell_metrics: &'a CellMetrics,
ctx: &'a cairo::Context,
}
pub trait ModelClipIteratorFactory {
fn get_clip_iterator<'a>(
&'a self,
ctx: &'a cairo::Context,
cell_metrics: &'a CellMetrics,
) -> ModelClipIterator;
}
impl<'a> Iterator for ModelClipIterator<'a> {
type Item = RowView<'a>;
fn next(&mut self) -> Option<RowView<'a>> {
let next = if let Some(line) = self.model_iter.next() {
Some(RowView::new(
self.model_idx,
self.ctx,
self.cell_metrics,
line,
))
} else {
None
};
self.model_idx += 1;
next
}
}
/// Clip implemented as top - 1/bot + 1
/// this is because in some cases(like 'g' character) drawing character does not fit to calculated bounds
/// and if one line must be repainted - also previous and next line must be repainted to
impl ModelClipIteratorFactory for ui_model::UiModel {
fn get_clip_iterator<'a>(
&'a self,
ctx: &'a cairo::Context,
cell_metrics: &'a CellMetrics,
) -> ModelClipIterator<'a> {
let model = self.model();
let (x1, y1, x2, y2) = ctx.clip_extents();
// in case ctx.translate is used y1 can be less then 0
// in this case just use 0 as top value
let model_clip = ui_model::ModelRect::from_area(cell_metrics, x1, y1.max(0.0), x2, y2);
let model_clip_top = if model_clip.top == 0 {
0
} else {
model_clip.top - 1
};
let model_clip_bot = min(model.len() - 1, model_clip.bot + 1);
ModelClipIterator {
model_idx: model_clip_top,
model_iter: model[model_clip_top..model_clip_bot + 1].iter(),
ctx,
cell_metrics,
}
}
}