# MatrixView

> A matrix product worked out entry by entry: a × b = c, centered on (x, y).

Page: https://fframes-kit.pages.dev/docs/math/matrix-view/
Cargo feature: `math` (`fframes-kit = { version = "..", features = ["math"] }`)

A matrix product worked out entry by entry: `a × b = c`, centered on `(x, y)`. From
`delay`, every `step` seconds the next entry of the product is written, row by row, while its
row of `a` and column of `b` are highlighted. `product(a, b)` is the multiplication, `None`
when the sizes do not fit. Gallery scene: `MatrixView`.

Gallery clip of `MatrixView`: https://fframes-kit.pages.dev/media/scenes/MatrixView-b12c4ce8.mp4

```rust
use fframes_kit::prelude::*;
use fframes_kit::kits::math::product;

fn figure<'a>(ui: &mut Ui<'a, '_, '_>) -> Svgr<'a> {
    ui.show(MatrixView {
        a: vec![vec![1.0, 2.0, 0.0], vec![-1.0, 3.0, 1.0]],
        b: vec![vec![2.0, 1.0], vec![0.0, 1.0], vec![4.0, -2.0]],
        delay: 1.0,
        step: 0.8,
        ..ui.defaults()
    })
}

let c = product(&[vec![1.0, 2.0]], &[vec![3.0], vec![4.0]]);
assert_eq!(c, Some(vec![vec![11.0]]));
```

## API

Components are plain structs. Set the fields you need and fill the rest with `..ui.defaults()`: the defaults below come from the current theme (`theme.` values are fields of `Theme`).

### MatrixView

| Field | Type | Default | Description |
| --- | --- | --- | --- |
| `a` | `Vec<Vec<f64>>` | `vec![vec![1.0, 2.0], vec![3.0, 4.0]]` | The left matrix, as rows of entries. |
| `b` | `Vec<Vec<f64>>` | `vec![vec![5.0, 6.0], vec![7.0, 8.0]]` | The right matrix, as rows of entries; its row count must equal the column count of `a`, otherwise nothing is drawn. |
| `x` | `f32` | `960.0` | Horizontal middle of the three matrices, in pixels of the canvas. |
| `y` | `f32` | `540.0` | Vertical middle of the matrices, in pixels of the canvas. |
| `gap` | `f32` | `theme.spacing.lg` | Pixels between the matrices and the signs. |
| `delay` | `f32` | `0.5` | Seconds after the container's start before the first entry is worked out. |
| `step` | `f32` | `0.8` | Seconds each entry of the product takes; its row and column highlight meanwhile. |
| `decimals` | `usize` | `2` | Most digits after the decimal point of the written entries. |
| `highlight` | `Color` | `theme.colors.highlight` | Colour of the highlight on the current row of `a` and column of `b`. |
| `result_color` | `Color` | `theme.colors.accent` | Colour of the entries of the product. |
| `matrices_enter` | `Option<FadeIn>` | `Some(FadeIn::themed(theme))` | Fade in of the matrices; `None` shows them from the start. |

Feature `math` · [Source](https://github.com/khanhthanhdev/fframes-kit/blob/main/fframes-kit/src/kits/math/matrix_view.rs#L27)