prototty
Definition of types and traits for describing how to render a type to a grid of
characters (such as a terminal). Also provides an input type to simplify making
an application that works with multiple frontends.
Example
Let's make a title element which renders a single line of text, within
a fixed width rectangle of height 1. The entire source code for this
example is in the "examples/title" directory in this repo.
```rust
extern crate prototty;
use prototty::*;
// Define a type representing the element
pub struct Title {
pub width: u32,
pub text: String,
}
// Define a type representing how the element will be rendered.
pub struct TitleView;
// Describe how a TitleView renders a Title by implementing View.
impl View
for TitleView {
fn view<G: ViewGrid>(&self, title: &Title, offset: Coord, depth: i32, grid: &mut G) {
for (i, ch) in title.text.chars().enumerate() {
if let Some(cell) = grid.get<em>mut(offset + Coord::new(i as i32, 0), depth) {
cell.set</em>character(ch);
cell.set_underline(true);
}
}
}
}</p>
<p>// What if we want a way to rendered titles centered within their width?
pub struct CenteredTitleView;
impl View<Title> for CenteredTitleView {
fn view<G: ViewGrid>(&self, title: &Title, offset: Coord, depth: i32, grid: &mut G) {
let space = ::std::cmp::max(title.width as i32 - title.text.len() as i32, 0) / 2;
for (i, ch) in title.text.chars().enumerate() {
if let Some(cell) = grid.get<em>mut(offset + Coord::new(space + i as i32, 0), depth) {
cell.set</em>character(ch);
cell.set_underline(true);
}
}
}
}</p>
<p>// Let's demonstrate both of these in action by rendering a title
// twice - once left aligned, an once centered:
pub struct DemoTitleView;
impl View<Title> for DemoTitleView {
fn view<G: ViewGrid>(&self, title: &Title, offset: Coord, depth: i32, grid: &mut G) {</p>
<pre><code> // render the title left-aligned in the top-left corner
TitleView.view(title, offset, depth, grid);
// render the title centered 2 lines down
CenteredTitleView.view(title, offset + Coord::new(0, 2), depth, grid);
}
</code></pre>
<p>}</p>
<p>```</p>
<p>We can now render a <code>Title</code> with 3 of different views:
- <code>TitleView</code> renders a <code>Title</code> left-aligned
- <code>CenteredTitleView</code> renders a <code>Title</code> centered within its width
- <code>DemoTitleView</code> renders a <code>Title</code> twice, using the other two views</p>
<p>This isn't much use by itself. To actually get something onto a screen, we'll
need a frontend. Continue this example in:
- <a href="https://github.com/stevebob/prototty/tree/master/unix">prototty-unix</a>
- <a href="https://github.com/stevebob/prototty/tree/master/glutin">prototty-glutin</a>
- <a href="https://github.com/stevebob/prototty/tree/master/wasm">prototty-wasm</a></p>
<p>Or see how to decorate it with a border in <a href="https://github.com/stevebob/prototty/tree/master/common">prototty-common</a>.</p>
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