bevy/crates/bevy_ui
Rob Parrett 55b786c2b7
Fix blurry text (#12429)
# Objective

Fixes #12064

## Solution

Prior to #11326, the "global physical" translation of text was rounded.

After #11326, only the "offset" is being rounded.

This moves things around so that the "global translation" is converted
to physical pixels, rounded, and then converted back to logical pixels,
which is what I believe was happening before / what the comments above
describe.

## Discussion

This seems to work and fix an obvious mistake in some code, but I don't
fully grok the ui / text pipelines / math here.

## Before / After and test example

<details>
<summary>Expand Code</summary>

```rust
use std::f32::consts::FRAC_PI_2;

use bevy::prelude::*;
use bevy_internal:🪟:WindowResolution;

const FONT_SIZE: f32 = 25.0;
const PADDING: f32 = 5.0;

fn main() {
    App::new()
        .add_plugins(
            DefaultPlugins.set(WindowPlugin {
                primary_window: Some(Window {
                    resolution: WindowResolution::default().with_scale_factor_override(1.0),
                    ..default()
                }),
                ..default()
            }),
            //.set(ImagePlugin::default_nearest()),
        )
        .add_systems(Startup, setup)
        .run();
}

fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
    commands.spawn(Camera2dBundle::default());

    let font = asset_server.load("fonts/FiraSans-Bold.ttf");

    for x in [20.5, 140.0] {
        for i in 1..10 {
            text(
                &mut commands,
                font.clone(),
                x,
                (FONT_SIZE + PADDING) * i as f32,
                i,
                Quat::default(),
                1.0,
            );
        }
    }

    for x in [450.5, 700.0] {
        for i in 1..10 {
            text(
                &mut commands,
                font.clone(),
                x,
                ((FONT_SIZE * 2.0) + PADDING) * i as f32,
                i,
                Quat::default(),
                2.0,
            );
        }
    }

    for y in [400.0, 600.0] {
        for i in 1..10 {
            text(
                &mut commands,
                font.clone(),
                (FONT_SIZE + PADDING) * i as f32,
                y,
                i,
                Quat::from_rotation_z(FRAC_PI_2),
                1.0,
            );
        }
    }
}

fn text(
    commands: &mut Commands,
    font: Handle<Font>,
    x: f32,
    y: f32,
    i: usize,
    rot: Quat,
    scale: f32,
) {
    let text = (65..(65 + i)).map(|a| a as u8 as char).collect::<String>();

    commands.spawn(TextBundle {
        style: Style {
            position_type: PositionType::Absolute,
            left: Val::Px(x),
            top: Val::Px(y),
            ..default()
        },
        text: Text::from_section(
            text,
            TextStyle {
                font,
                font_size: FONT_SIZE,
                ..default()
            },
        ),
        transform: Transform::from_rotation(rot).with_scale(Vec2::splat(scale).extend(1.)),
        ..default()
    });
}
```

</details>

Open both images in new tabs and swap back and forth. Pay attention to
the "A" and "ABCD" lines.

<details>
<summary>Before</summary>

<img width="640" alt="main3"
src="https://github.com/bevyengine/bevy/assets/200550/248d7a55-d06d-433f-80da-1914803c3551">

</details>

<details>
<summary>After</summary>

<img width="640" alt="pr3"
src="https://github.com/bevyengine/bevy/assets/200550/26a9d292-07ae-4af3-b035-e187b2529ace">

</details>

---------

Co-authored-by: François Mockers <mockersf@gmail.com>
2024-03-13 01:21:10 +00:00
..
src Fix blurry text (#12429) 2024-03-13 01:21:10 +00:00
Cargo.toml Add "all-features = true" to docs.rs metadata for most crates (#12366) 2024-03-08 20:03:09 +00:00