fix curve formula window

Author: hexqnt

src/app/ui/formula_window.rs

@@ -2,6 +2,13 @@
 
 use super::*;
 
+const FORMULA_WINDOW_DEFAULT_HEIGHT: f32 = 520.0;
+const FORMULA_WINDOW_MIN_WIDTH: f32 = 450.0;
+const FORMULA_WINDOW_MIN_HEIGHT: f32 = 320.0;
+const FORMULA_WINDOW_SCREEN_MARGIN: f32 = 24.0;
+const FORMULA_WINDOW_CONTENT_MARGIN_X: f32 = 60.0;
+const FORMULA_WINDOW_FALLBACK_CHAR_WIDTH: f32 = 8.0;
+
 pub(super) fn ui_formula_window(app: &mut CurveFitApp, ctx: &egui::Context) {
     if !app.panel.show_formula_window {
         return;
@@ -21,12 +28,15 @@ pub(super) fn ui_formula_window(app: &mut CurveFitApp, ctx: &egui::Context) {
         app.optimization_loss_metric,
     );
     let mut is_open = app.panel.show_formula_window;
+    let dark_mode = ctx.global_style().visuals.dark_mode;
+    let window_width = formula_window_width(app, ctx, &formula_info, dark_mode);
     egui::Window::new(tr(language, "Model Formula", "Формула модели"))
         .open(&mut is_open)
-        .default_size(egui::vec2(860.0, 520.0))
-        .min_width(560.0)
-        .min_height(320.0)
-        .resizable(true)
+        .default_size(egui::vec2(window_width, FORMULA_WINDOW_DEFAULT_HEIGHT))
+        .min_width(window_width)
+        .max_width(window_width)
+        .min_height(FORMULA_WINDOW_MIN_HEIGHT)
+        .resizable([false, true])
         .show(ctx, |ui| {
             let formula_window_hint = tr(
                 language,
@@ -94,3 +104,75 @@ pub(super) fn ui_formula_window(app: &mut CurveFitApp, ctx: &egui::Context) {
         });
     app.panel.show_formula_window = is_open;
 }
+
+fn formula_window_width(
+    app: &mut CurveFitApp,
+    ctx: &egui::Context,
+    formula_info: &ModelFormulaInfo,
+    dark_mode: bool,
+) -> f32 {
+    let content_width = formula_info
+        .sections
+        .iter()
+        .map(|section| formula_section_width(app, ctx, section, dark_mode))
+        .fold(0.0_f32, f32::max);
+    let target_width = content_width + FORMULA_WINDOW_CONTENT_MARGIN_X;
+    let max_width = (ctx.content_rect().width() - 2.0 * FORMULA_WINDOW_SCREEN_MARGIN).max(320.0);
+    let min_width = FORMULA_WINDOW_MIN_WIDTH.min(max_width);
+    target_width.clamp(min_width, max_width)
+}
+
+fn formula_section_width(
+    app: &mut CurveFitApp,
+    ctx: &egui::Context,
+    section: &FormulaReferenceSection,
+    dark_mode: bool,
+) -> f32 {
+    let formula_width = app
+        .cached_formula_svg(&section.render_latex, dark_mode)
+        .ok()
+        .and_then(|(_, bytes)| svg_width(&bytes))
+        .unwrap_or_else(|| plain_text_width(section.plain_text.as_str()));
+
+    let text_width = text_lines_width(
+        ctx,
+        egui::TextStyle::Small,
+        [section.title.as_str(), section.description.as_str()].into_iter(),
+    );
+
+    formula_width.max(text_width)
+}
+
+fn text_lines_width<'a>(
+    ctx: &egui::Context,
+    text_style: egui::TextStyle,
+    texts: impl Iterator<Item = &'a str>,
+) -> f32 {
+    let font_id = text_style.resolve(&ctx.global_style());
+    ctx.fonts_mut(|fonts| {
+        texts
+            .flat_map(str::lines)
+            .map(str::trim)
+            .filter(|line| !line.is_empty())
+            .map(|line| {
+                fonts
+                    .layout_no_wrap(line.to_owned(), font_id.clone(), egui::Color32::WHITE)
+                    .size()
+                    .x
+            })
+            .fold(0.0_f32, f32::max)
+    })
+}
+
+fn plain_text_width(text: &str) -> f32 {
+    text.lines()
+        .map(|line| line.chars().count() as f32 * FORMULA_WINDOW_FALLBACK_CHAR_WIDTH)
+        .fold(0.0_f32, f32::max)
+}
+
+fn svg_width(bytes: &[u8]) -> Option<f32> {
+    let svg = std::str::from_utf8(bytes).ok()?;
+    let after_attr = svg.split_once(r#"width=""#)?.1;
+    let raw_width = after_attr.split_once('"')?.0;
+    raw_width.parse().ok()
+}