microbit_text/
image.rs

1//! Static 5×5 black-and-white images.
2
3use tiny_led_matrix::{Render, MAX_BRIGHTNESS};
4
5/// A 5×5 image supporting only two levels of brightness (on and off).
6///
7/// Uses 5 bytes of storage.
8///
9/// For display, each pixel is treated as having brightness either 0 or
10/// [MAX_BRIGHTNESS].
11///
12/// [MAX_BRIGHTNESS]: tiny_led_matrix::MAX_BRIGHTNESS
13
14#[derive(Copy, Clone, Debug)]
15pub struct BitImage (
16    [u8; 5]
17);
18
19impl BitImage {
20
21    /// Constructs a BitImage from an array of brightnesses.
22    ///
23    /// The data should be an array of 5 rows (top first), each of which is an
24    /// array of 5 values (left first). Each value should be either 0 or 1.
25    ///
26    /// # Example
27    ///
28    /// ```
29    /// const HEART: BitImage = BitImage::new(&[
30    ///     [0, 1, 0, 1, 0],
31    ///     [1, 0, 1, 0, 1],
32    ///     [1, 0, 0, 0, 1],
33    ///     [0, 1, 0, 1, 0],
34    ///     [0, 0, 1, 0, 0],
35    /// ]);
36    /// ```
37    pub const fn new(im: &[[u8; 5]; 5]) -> BitImage {
38        const fn row_byte(row: [u8; 5]) -> u8 {
39            row[0] | row[1]<<1 | row[2]<<2 | row[3]<<3 | row[4]<<4
40        }
41        BitImage([
42            row_byte(im[0]),
43            row_byte(im[1]),
44            row_byte(im[2]),
45            row_byte(im[3]),
46            row_byte(im[4]),
47        ])
48    }
49
50    /// Returns a new blank BitImage.
51    ///
52    /// All pixel values are 0.
53    pub const fn blank() -> BitImage {
54        BitImage([0; 5])
55    }
56
57}
58
59impl Render for BitImage {
60    fn brightness_at(&self, x: usize, y: usize) -> u8 {
61        let rowdata = self.0[y];
62        if rowdata & (1<<x) != 0 {MAX_BRIGHTNESS as u8} else {0}
63    }
64}
65
66impl Render for &BitImage {
67    fn brightness_at(&self, x: usize, y: usize) -> u8 {
68        BitImage::brightness_at(self, x, y)
69    }
70}
71
microbit_text/image.rs

microbit_text/
image.rs
