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feat(char): add rotate_from, scale and baseline jitter, and reflow #450

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Merged
LeadcodeDev merged 3 commits into from
Sep 29, 2026
Merged

feat(char): add rotate_from, scale and baseline jitter, and reflow #450

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a5cc054
feat(char): add rotate_from, scale and baseline jitter, and reflow
LeadcodeDev Sep 29, 2026
46352db
fix(char): satisfy clippy on the reflow width fold and the tilt cast
LeadcodeDev Sep 29, 2026
1b58c82
fix(validate): say that reflow does not reach rich_text
LeadcodeDev Sep 29, 2026
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289 changes: 276 additions & 13 deletions crates/rustmotion-components/src/intrinsic.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -733,22 +733,17 @@ impl IntrinsicMeasure for RichTextIntrinsic {
}
}

use rustmotion_core::engine::animator::{ease, ResolvedCharAnimation};
use rustmotion_core::engine::animator::ResolvedCharAnimation;
use rustmotion_core::engine::renderer::{draw_text_with_fallback, paint_from_hex};
use rustmotion_core::schema::{CharAnimPreset, TextAlign, TextAnimGranularity};
use rustmotion_core::schema::{CharAnimPreset, RotateOrigin, TextAlign, TextAnimGranularity};
use skia_safe::{Canvas, Paint};

pub fn unit_progress(cfg: &ResolvedCharAnimation, idx: usize, time: f64) -> f32 {
let unit_start = cfg.unit_start(idx);
let unit_end = unit_start + cfg.duration as f64;
let raw_t = if time <= unit_start {
0.0
} else if time >= unit_end {
1.0
} else {
(time - unit_start) / (unit_end - unit_start)
};
ease(raw_t, &cfg.easing) as f32
cfg.unit_progress(idx, time)
}

pub fn reflow_progress(cfg: &ResolvedCharAnimation, idx: usize, time: f64) -> f32 {
cfg.reflow_progress(idx, time)
}

fn ink_paint(cfg: &ResolvedCharAnimation, paint: &Paint, t: f32) -> Option<Paint> {
Expand Down Expand Up @@ -799,6 +794,30 @@ pub fn apply_text_anim_preset(
canvas.translate((-center_x, -center_y));
}
}
if let Some(from_deg) = cfg.rotate_from {
if !matches!(preset, CharAnimPreset::RotateIn) {
let angle = from_deg * (1.0 - t.clamp(0.0, 1.0));
let (px, py) = match cfg.rotate_origin {
RotateOrigin::Center => (center_x, center_y),
RotateOrigin::Edge => (cursor_x, center_y),
};
canvas.translate((px, py));
canvas.rotate(angle, None);
canvas.translate((-px, -py));
}
}
let scale_jitter_delta = cfg.scale_jitter_delta(unit_idx);
if scale_jitter_delta.abs() > 1e-6 {
let js = 1.0 + scale_jitter_delta * (1.0 - t.clamp(0.0, 1.0));
canvas.translate((center_x, center_y));
canvas.scale((js, js));
canvas.translate((-center_x, -center_y));
}
let baseline_jitter_delta = cfg.baseline_jitter_delta(unit_idx);
if baseline_jitter_delta.abs() > 1e-6 {
let jy = baseline_jitter_delta * font_size * (1.0 - t.clamp(0.0, 1.0));
canvas.translate((0.0, jy));
}

match preset {
CharAnimPreset::ScaleIn => {
Expand Down Expand Up @@ -948,6 +967,214 @@ pub fn apply_text_anim_preset(
}

#[allow(clippy::too_many_arguments)]
struct ReflowWordToken {
text: String,
is_space: bool,
full_width: f32,
}

fn tokenize_reflow_words(
line: &str,
font: &Font,
emoji_font: &Option<Font>,
letter_spacing: f32,
) -> Vec<ReflowWordToken> {
let mut toks = Vec::new();
let mut chars = line.chars().peekable();
while chars.peek().is_some() {
let mut spaces = String::new();
while let Some(&c) = chars.peek() {
if c.is_whitespace() {
spaces.push(c);
chars.next();
} else {
break;
}
}
if !spaces.is_empty() {
let full_width = measure_text_with_fallback(&spaces, font, emoji_font, letter_spacing);
toks.push(ReflowWordToken {
text: spaces,
is_space: true,
full_width,
});
}
let mut word = String::new();
while let Some(&c) = chars.peek() {
if c.is_whitespace() {
break;
}
word.push(c);
chars.next();
}
if !word.is_empty() {
let full_width = measure_text_with_fallback(&word, font, emoji_font, letter_spacing);
toks.push(ReflowWordToken {
text: word,
is_space: false,
full_width,
});
}
}
toks
}

fn reflowed_word_width(
tok: &ReflowWordToken,
idx: usize,
char_anim: &ResolvedCharAnimation,
time: f64,
) -> f32 {
if tok.is_space {
tok.full_width
} else {
tok.full_width * reflow_progress(char_anim, idx, time)
}
}

#[allow(clippy::too_many_arguments)]
fn paint_reflowing_word_line(
canvas: &Canvas,
font: &Font,
emoji_font: &Option<Font>,
paint: &Paint,
letter_spacing: f32,
align: &TextAlign,
align_width: f32,
line_y: f32,
line: &str,
char_anim: &ResolvedCharAnimation,
time: f64,
base_idx: usize,
) -> usize {
let toks = tokenize_reflow_words(line, font, emoji_font, letter_spacing);

let mut word_counter = 0usize;
let effective_width: f32 = toks
.iter()
.map(|tok| {
if tok.is_space {
tok.full_width
} else {
let idx = base_idx + word_counter;
word_counter += 1;
reflowed_word_width(tok, idx, char_anim, time)
}
})
.sum();

let line_x = match align {
TextAlign::Left => 0.0,
TextAlign::Center => (align_width - effective_width) / 2.0,
TextAlign::Right => align_width - effective_width,
};

let mut cursor_x = line_x;
word_counter = 0;
for tok in &toks {
if tok.is_space {
draw_text_with_fallback(
canvas, &tok.text, font, emoji_font, 0.0, cursor_x, line_y, paint,
);
cursor_x += tok.full_width;
continue;
}
let idx = base_idx + word_counter;
word_counter += 1;
let t = unit_progress(char_anim, idx, time);
let draw_width = reflowed_word_width(tok, idx, char_anim, time);

canvas.save();
apply_text_anim_preset(
canvas,
&tok.text,
font,
emoji_font,
paint,
cursor_x,
line_y,
draw_width,
letter_spacing,
char_anim,
t,
time,
idx,
font.size(),
);
canvas.restore();

cursor_x += draw_width;
}
base_idx + word_counter
}

#[allow(clippy::too_many_arguments)]
fn paint_reflowing_char_line(
canvas: &Canvas,
font: &Font,
emoji_font: &Option<Font>,
paint: &Paint,
letter_spacing: f32,
align: &TextAlign,
align_width: f32,
line_y: f32,
line: &str,
char_anim: &ResolvedCharAnimation,
time: f64,
base_idx: usize,
) -> usize {
let chars_list: Vec<char> = line.chars().collect();
let widths: Vec<f32> = chars_list
.iter()
.map(|ch| {
let (w, _) = font.measure_str(ch.to_string(), None);
w + letter_spacing
})
.collect();

let effective_width: f32 = widths
.iter()
.enumerate()
.map(|(i, w)| w * reflow_progress(char_anim, base_idx + i, time))
.sum();

let line_x = match align {
TextAlign::Left => 0.0,
TextAlign::Center => (align_width - effective_width) / 2.0,
TextAlign::Right => align_width - effective_width,
};

let mut cursor_x = line_x;
for (i, ch) in chars_list.iter().enumerate() {
let idx = base_idx + i;
let ch_str = ch.to_string();
let t = unit_progress(char_anim, idx, time);
let draw_width = widths[i] * reflow_progress(char_anim, idx, time);

canvas.save();
apply_text_anim_preset(
canvas,
&ch_str,
font,
emoji_font,
paint,
cursor_x,
line_y,
draw_width,
0.0,
char_anim,
t,
time,
idx,
font.size(),
);
canvas.restore();

cursor_x += draw_width;
}
base_idx + chars_list.len()
}

pub fn render_char_animation(
canvas: &Canvas,
font: &Font,
Expand All @@ -970,13 +1197,49 @@ pub fn render_char_animation(
continue;
}

let line_y = line_idx as f32 * line_height_val + baseline_offset;

if char_anim.reflow {
global_unit_idx = if is_word_mode {
paint_reflowing_word_line(
canvas,
font,
emoji_font,
paint,
letter_spacing,
&align,
align_width,
line_y,
line,
char_anim,
time,
global_unit_idx,
)
} else {
paint_reflowing_char_line(
canvas,
font,
emoji_font,
paint,
letter_spacing,
&align,
align_width,
line_y,
line,
char_anim,
time,
global_unit_idx,
)
};
continue;
}

let advance_width = measure_text_with_fallback(line, font, emoji_font, letter_spacing);
let line_x = match align {
TextAlign::Left => 0.0,
TextAlign::Center => (align_width - advance_width) / 2.0,
TextAlign::Right => align_width - advance_width,
};
let line_y = line_idx as f32 * line_height_val + baseline_offset;

if is_word_mode {
let mut cursor_x = line_x;
Expand Down
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