Image Trace: pressing and holding the eye button shows the source image

The Image Trace panel had no way to compare a trace with its source image except changing View and changing it back. The panel now has an eye button to the right of View, enabled with an Image Trace object selected. While it is held down, the canvas draws the selected Image Trace objects with their source image, whatever their View, and draws their View again on release. The document, its View and the undo history are unchanged. The renderer takes the objects in RenderOptions::trace_source, which is also part of the canvas frame key and the raster-effect cache key.
2026-10-24 09:46:59 -06:00 · 2026-10-24 19:02:08 +07:00
parent bef464ea97
commit 2ff8699989
33 changed files with 166 additions and 3 deletions
@@ -2130,6 +2130,7 @@ impl Renderer {
        if reads.images {
            let o = f.opts;
            (doc.images, self.dim_images.map(f32::to_bits), o.smooth_images, o.image_mips, o.trace_views, o.progressive_placed).hash(&mut h);
+            o.trace_source.as_deref().hash(&mut h);
        }
        if reads.brushes {
            self.brushes.library_key(f.doc, self.stamp).hash(&mut h);
@@ -159,6 +159,10 @@ pub struct RenderOptions {
    /// Screen view: Image Trace objects draw as their View asks (outlines, the source image…);
    /// off, they draw their tracing result, as exports and printing do.
    pub trace_views: bool,
+    /// Screen view with `trace_views` on: the Image Trace objects drawn with the Source Image view
+    /// for this render only, whatever View they have (the Image Trace panel's eye button, while it
+    /// is held down).
+    pub trace_source: Option<Arc<Vec<NodeId>>>,
    /// Images are sampled smoothly when scaled or rotated; off, each pixel takes its nearest image
    /// pixel (Pixel Preview with File Handling › Display Bitmaps as Anti-aliased Images off).
    pub smooth_images: bool,
@@ -266,6 +270,7 @@ impl Default for RenderOptions {
            anti_alias: AntiAlias::Art,
            progressive_placed: false,
            trace_views: false,
+            trace_source: None,
            smooth_images: true,
            isolated: None,
            precise: false,
@@ -1301,8 +1306,8 @@ impl Renderer {
    /// What `n` draws inside its transparency group (`knockout`: its children knock each other out).
    fn draw_content(&mut self, ctx: &mut RenderContext, f: &Frame, n: &Node, knockout: bool) {
        match &n.kind {
-            NodeKind::Group { children, clip: false } if f.opts.trace_views && !f.opts.outline && n.trace_view() != TraceView::Result => {
-                self.draw_trace_view(ctx, f, children, n.trace_view(), knockout)
+            NodeKind::Group { children, clip: false } if f.opts.trace_views && !f.opts.outline && Self::trace_view(f, n) != TraceView::Result => {
+                self.draw_trace_view(ctx, f, children, Self::trace_view(f, n), knockout)
            }
            NodeKind::Layer { children, clip: false, .. } | NodeKind::Group { children, clip: false } => {
                self.draw_children(ctx, f, children, knockout)
@@ -1429,6 +1434,15 @@ impl Renderer {
        self.live_root = outer;
    }

+    /// The View `n` draws with on screen: Source Image when it is an Image Trace object listed in
+    /// [`RenderOptions::trace_source`], else its own.
+    fn trace_view(f: &Frame, n: &Node) -> TraceView {
+        match &f.opts.trace_source {
+            Some(ids) if n.extras().trace.is_some() && ids.contains(&n.id) => TraceView::Source,
+            _ => n.trace_view(),
+        }
+    }
+
    /// An Image Trace object's `children` (the hidden source image, then the traced shapes) as
    /// `view` shows them on screen.
    fn draw_trace_view(&mut self, ctx: &mut RenderContext, f: &Frame, children: &[Arc<Node>], view: TraceView, knockout: bool) {
@@ -579,6 +579,57 @@ fn outline_view_draws_paths_from_kept_geometry() {
    }
 }

+/// An Image Trace object listed in `trace_source` draws its source image on screen whatever its
+/// View, also inside a group whose raster effect a renderer keeps; without the list, and in
+/// exports, it draws its result. A group that is not an Image Trace object draws its members.
+#[test]
+fn trace_source_draws_the_source_image_of_the_listed_objects() {
+    use vectorcraft_doc::{ImageBlob, ImageObject};
+    let img = image::RgbaImage::from_pixel(1, 1, image::Rgba([255, 0, 0, 255]));
+    let mut png = vec![];
+    img.write_to(&mut std::io::Cursor::new(&mut png), image::ImageFormat::Png).unwrap();
+    let mut d = Document::new(100.0, 100.0);
+    d.images.insert("red".into(), ImageBlob::new("image/png", png));
+    // A group at `x`: the hidden red source image, then a blue traced square over it.
+    let group = |d: &mut Document, x: f64, traced: bool| {
+        let xf = Affine::translate((x, 10.0)) * Affine::scale(20.0);
+        let im = ImageObject { key: "red".into(), width: 1, height: 1, xf, link: None, placement: Default::default(), pixels: None };
+        let mut source = Node::new(d.alloc_id(), NodeKind::Image(Box::new(im)));
+        source.visible = false;
+        let shape = rect_node(d, Rect::new(x, 10.0, x + 20.0, 30.0), Paint::solid(Color::rgb(0.0, 0.0, 1.0)), Paint::None, 0.0);
+        let mut g = Node::group(d.alloc_id(), vec![Arc::new(source), Arc::new(shape)]);
+        if traced {
+            g.extras_mut().trace = Some(Box::new(serde_json::json!({ "view": "tracingResult" })));
+        }
+        g
+    };
+    let plain = group(&mut d, 10.0, true);
+    let blurred = group(&mut d, 40.0, true);
+    let other = group(&mut d, 70.0, false);
+    let ids = Arc::new(vec![plain.id, blurred.id, other.id]);
+    let mut holder = Node::group(d.alloc_id(), vec![Arc::new(blurred)]);
+    holder.appearance.effects.push(vectorcraft_doc::Effect { id: "blur.gaussian".into(), params: serde_json::json!({ "radius": 1 }), visible: true });
+    let l = d.layers[0].id;
+    for n in [plain, holder, other] {
+        d.insert(Some(l), usize::MAX, n).unwrap();
+    }
+    let screen = RenderOptions { trace_views: true, background: Some([255; 4]), ..Default::default() };
+    let held = RenderOptions { trace_source: Some(ids.clone()), ..screen.clone() };
+    let export = RenderOptions { trace_source: Some(ids), background: Some([255; 4]), ..Default::default() };
+    let red = |p: [u8; 4]| p[0] > 200 && p[2] < 60;
+    let blue = |p: [u8; 4]| p[2] > 200 && p[0] < 60;
+    let mut kept = Renderer::new();
+    for (opts, source) in [(&screen, false), (&held, true), (&screen, false), (&export, false)] {
+        for r in [kept.render(&d, 100, 100, Affine::IDENTITY, opts), Renderer::new().render(&d, 100, 100, Affine::IDENTITY, opts)] {
+            for (x, what) in [(20, "the Image Trace object"), (50, "the one in the blurred group")] {
+                let p = r.pixel(x, 20);
+                assert!(if source { red(p) } else { blue(p) }, "{what} with trace_source {source}: {p:?}");
+            }
+            assert!(blue(r.pixel(80, 20)), "the plain group draws its square: {:?}", r.pixel(80, 20));
+        }
+    }
+}
+
 #[test]
 fn artboards_white_on_pasteboard() {
    let d = Document::new(50.0, 50.0);
@@ -419,6 +419,8 @@ pub fn show(app: &mut VectorcraftApp, ui: &mut Ui) {
        rich_black: app.session.prefs.black_on_screen == "rich",
        // A tool's drag on the canvas, during an interaction (not a dialog's preview).
        dragging: app.session.in_interaction() && ui.data(|d| d.get_temp::<Drag>(drag_id())) == Some(Drag::Tool),
+        // The Image Trace panel's eye button, only while a pointer button is down.
+        trace_source: app.ui.trace_hold_source.clone().filter(|_| ui.input(|i| i.pointer.any_down())),
    };
    // Placed documents' bitmaps are being made: draw again when they are ready.
    if vectorcraft_render::placed_document::busy() {
@@ -487,6 +489,8 @@ pub fn show(app: &mut VectorcraftApp, ui: &mut Ui) {
            anti_alias: if app.session.prefs.anti_aliased_artwork { vectorcraft_render::AntiAlias::Art } else { vectorcraft_render::AntiAlias::None },
            progressive_placed: true,
            trace_views: true,
+            // Image Trace › the eye button held: the source image of the selected objects.
+            trace_source: key.trace_source.clone(),
            smooth_images,
            // Isolation mode: the art around the isolated group or layer is dimmed (#833).
            isolated: key.isolated.map(vectorcraft_doc::NodeId),
@@ -3013,6 +3013,7 @@ font-technology	Variable	Променливи
 	Outlines	Контури
 	Outlines with Source Image	Контури с изходно изображение
 	Source Image	Изходно изображение
+	Press and hold to view the source image	Задръжте натиснато, за да видите изходното изображение
 	Image Trace View	Изглед на трасиране на изображение
 	Snap Options	Опции за прилепване
 	Snap to Glyph	Прилепване към глиф
@@ -3932,6 +3932,7 @@ font-technology	Variable	Variabilní
 	View:	Zobrazení:
 	Tracing Result	Výsledek vektorizace
 	Outlines with Source Image	Obrysy se zdrojovým obrazem
+	Press and hold to view the source image	Podržením zobrazíte zdrojový obraz
 	SVG Options	Možnosti SVG
 	Maximize	Maximalizovat
 	Restore	Obnovit
@@ -3675,6 +3675,7 @@ font-technology	Variable	Variable
 	View:	Visning:
 	Tracing Result	Sporingsresultat
 	Outlines with Source Image	Konturer med kildebillede
+	Press and hold to view the source image	Hold nede for at se kildebilledet
 	SVG Options	SVG-indstillinger
 	Maximize	Maksimér
 	Restore	Gendan
@@ -3051,6 +3051,7 @@ effect	Points	Punkte
 	Outlines	Pfade
 	Outlines with Source Image	Pfade mit Quellbild
 	Source Image	Quellbild
+	Press and hold to view the source image	Gedrückt halten, um das Quellbild anzuzeigen
 	Image Trace View	Bildnachzeichner-Ansicht
 	Snap Options	Einrastoptionen
 	Snap to Glyph	An Glyphe ausrichten
@@ -1881,6 +1881,7 @@ font-technology	Variable	Μεταβλητές
 	Absolute	Απόλυτο
 	View:	Προβολή:
 	Outlines	Περιγράμματα
+	Press and hold to view the source image	Πατήστε παρατεταμένα για να δείτε την αρχική εικόνα
 	Snap to Grid	Προσκόλληση στο πλέγμα
 	Snap to Pixel	Προσκόλληση σε εικονοστοιχείο
 	Snap to Point	Προσκόλληση σε σημείο
@@ -3081,6 +3081,7 @@ font-technology	Variable	Variables
 	Outlines	Contornos
 	Outlines with Source Image	Contornos con imagen de origen
 	Source Image	Imagen de origen
+	Press and hold to view the source image	Mantén pulsado para ver la imagen de origen
 	Image Trace View	Vista del calco de imagen
 	Snap Options	Opciones de ajuste
 	Snap to Glyph	Ajustar a glifo
@@ -3856,6 +3856,7 @@ font-technology	Variable	Muuttuvat
 	View:	Näkymä:
 	Tracing Result	Jäljityksen tulos
 	Outlines with Source Image	Ääriviivat ja lähdekuva
+	Press and hold to view the source image	Pidä painettuna nähdäksesi lähdekuvan
 	SVG Options	SVG-asetukset
 	Maximize	Suurenna
 	Restore	Palauta
@@ -3078,6 +3078,7 @@ font-technology	Variable	Variables
 	Outlines	Contours
 	Outlines with Source Image	Tracés avec l’image source
 	Source Image	Image source
+	Press and hold to view the source image	Maintenez le bouton enfoncé pour afficher l’image source
 	Image Trace View	Affichage de la vectorisation de l’image
 	Snap Options	Options de magnétisme
 	Snap to Glyph	Magnétisme du glyphe
@@ -2039,6 +2039,7 @@ file-filter	Templates	Sablonok
 	The file writes keys and modifiers as codes. Check the proposed meanings and answer the codes that are not known yet.	A fájl a billentyűket és a módosítóbillentyűket kódként tárolja. Ellenőrizd a javasolt jelentéseket, és add meg a még ismeretlen kódok jelentését.
 	Click, then press the key this code stands for (Esc cancels)	Kattints, majd nyomd le azt a billentyűt, amelyet ez a kód jelöl (Esc: mégse)
 	Press a key…	Nyomj le egy billentyűt…
+	Press and hold to view the source image	Tartsd lenyomva a forráskép megtekintéséhez
 	from your earlier imports	a korábbi importálásaidból
 	from the format's public description	a formátum nyilvános leírásából
 	not known yet	még ismeretlen
@@ -3675,6 +3675,7 @@ font-technology	Variable	Variabel
 	View:	Tampilan:
 	Tracing Result	Hasil penelusuran
 	Outlines with Source Image	Kontur dengan gambar sumber
+	Press and hold to view the source image	Tekan dan tahan untuk melihat gambar sumber
 	SVG Options	Opsi SVG
 	Maximize	Maksimalkan
 	Restore	Pulihkan
@@ -3115,6 +3115,7 @@ mark-style	Japanese	Giapponese
 	Outlines	Contorni
 	Outlines with Source Image	Contorni con immagine di origine
 	Source Image	Immagine di origine
+	Press and hold to view the source image	Tieni premuto per visualizzare l'immagine di origine
 	Image Trace View	Vista del ricalco immagine
 	Snap Options	Opzioni di aggancio
 	Snap to Glyph	Aggancia a glifo
@@ -2889,6 +2889,7 @@ mark-style	Japanese	日本式
 	Outlines	アウトライン
 	Outlines with Source Image	アウトライン（元画像付き）
 	Source Image	元画像
+	Press and hold to view the source image	押している間、元画像を表示
 	Image Trace View	画像トレースの表示
 	Snap Options	スナップオプション
 	Snap to Unit	単位にスナップ
@@ -3456,6 +3456,7 @@ font-technology	Variable	ცვლადი
 	View:	ხედი:
 	Tracing Result	ვექტორიზაციის შედეგი
 	Outlines with Source Image	კონტურები საწყისი გამოსახულებით
+	Press and hold to view the source image	ხანგრძლივად დააჭირეთ საწყისი გამოსახულების სანახავად
 	SVG Options	SVG-ის პარამეტრები
 	Maximize	გაშლა
 	Restore	აღდგენა
@@ -2883,6 +2883,7 @@ mark-style	Japanese	일본식
 	Outlines	윤곽선
 	Outlines with Source Image	원본 이미지 포함 윤곽선
 	Source Image	원본 이미지
+	Press and hold to view the source image	누르고 있는 동안 원본 이미지 보기
 	Image Trace View	이미지 추적 보기
 	Snap Options	스냅 옵션
 	Snap to Unit	단위에 스냅
@@ -3689,6 +3689,7 @@ font-technology	Variable	Variabel
 	View:	Weergave:
 	Tracing Result	Traceringresultaat
 	Outlines with Source Image	Contouren met bronafbeelding
+	Press and hold to view the source image	Ingedrukt houden om de bronafbeelding te bekijken
 	SVG Options	SVG-opties
 	Maximize	Maximaliseren
 	Restore	Herstellen
@@ -3771,6 +3771,7 @@ font-technology	Variable	Zmienne
 	View:	Widok:
 	Tracing Result	Wynik obrysu
 	Outlines with Source Image	Kontury z obrazem źródłowym
+	Press and hold to view the source image	Przytrzymaj, aby wyświetlić obraz źródłowy
 	SVG Options	Opcje SVG
 	Maximize	Maksymalizuj
 	Restore	Przywróć
@@ -3294,6 +3294,7 @@ font-technology	Variable	Variáveis
 	Outlines	Contornos
 	Outlines with Source Image	Contornos com imagem de origem
 	Source Image	Imagem de origem
+	Press and hold to view the source image	Mantenha pressionado para ver a imagem de origem
 	Image Trace View	Exibição de vetorização de imagem
 	Stroke (X), double-click for the Color Picker	Traço (X), clique duas vezes para o seletor de cores
 	Swap Fill and Stroke (Shift+X)	Trocar preenchimento e traço (Shift+X)
@@ -3111,6 +3111,7 @@ mark-style	Japanese	Японский
 	Outlines	Контуры
 	Outlines with Source Image	Контуры с исходным изображением
 	Source Image	Исходное изображение
+	Press and hold to view the source image	Удерживайте, чтобы увидеть исходное изображение
 	Image Trace View	Просмотр трассировки изображения
 	Snap Options	Параметры привязки
 	Snap to Glyph	Привязать к глифу
@@ -3013,6 +3013,7 @@ font-technology	Variable	Variabla
 	Outlines	Konturlinjer
 	Outlines with Source Image	Konturlinjer med källbild
 	Source Image	Källbild
+	Press and hold to view the source image	Håll ned för att visa källbilden
 	Image Trace View	Vy för bildkalkering
 	Snap Options	Fästalternativ
 	Snap to Glyph	Fäst mot glyf
@@ -2921,6 +2921,7 @@ font-technology	Variable	Değişken
 	Outlines	Ana hatlar
 	Outlines with Source Image	Kaynak Resimli Ana Hatlar
 	Source Image	Kaynak Resim
+	Press and hold to view the source image	Kaynak resmi görmek için basılı tutun
 	Image Trace View	Görüntü İzleme Görünümü
 	Snap Options	Yapış Seçenekleri
 	Snap to Glyph	Glif'e Yapış
@@ -3108,6 +3108,7 @@ effect	Points	Точки
 	Outlines	Контури
 	Outlines with Source Image	Контури з вихідним зображенням
 	Source Image	Вихідне зображення
+	Press and hold to view the source image	Утримуйте, щоб побачити вихідне зображення
 	Image Trace View	Перегляд трасування зображення
 	Snap Options	Параметри прив’язки
 	Snap to Glyph	Прив’язати до гліфу
@@ -1779,6 +1779,7 @@ file-filter	Templates	Mẫu
 	The file writes keys and modifiers as codes. Check the proposed meanings and answer the codes that are not known yet.	Tệp ghi phím và phím bổ trợ dưới dạng mã. Hãy kiểm tra các nghĩa được đề xuất và trả lời những mã chưa biết.
 	Click, then press the key this code stands for (Esc cancels)	Bấm, rồi nhấn phím mà mã này biểu thị (Esc để hủy)
 	Press a key…	Nhấn một phím…
+	Press and hold to view the source image	Nhấn giữ để xem ảnh nguồn
 	from your earlier imports	từ các lần nhập trước của bạn
 	from the format's public description	từ mô tả công khai của định dạng
 	not known yet	chưa biết
@@ -2947,6 +2947,7 @@ font-script	Japanese	汉字
 	Outlines	轮廓
 	Outlines with Source Image	轮廓（带源图像）
 	Source Image	源图像
+	Press and hold to view the source image	按住以查看源图像
 	Image Trace View	图像描摹视图
 	Snap Options	对齐选项
 	Snap to Glyph	靠齐字符
@@ -3878,6 +3878,7 @@ font-script	Japanese	漢字
 	Outlines	外框
 	Outlines with Source Image	外框（含來源影像）
 	Source Image	來源影像
+	Press and hold to view the source image	按住以檢視來源影像
 	Image Trace View	影像描圖檢視
 	Snap Options	靠齊選項
 	Snap to Glyph	靠齊字符
@@ -430,6 +430,9 @@ pub struct CacheKey {
    pub rich_black: bool,
    /// Colour and style of guide paths ([`vectorcraft_render::RenderOptions::guide`]).
    pub guide: ([u8; 3], bool),
+    /// The Image Trace objects drawn with their source image
+    /// ([`vectorcraft_render::RenderOptions::trace_source`]).
+    pub trace_source: Option<std::sync::Arc<Vec<vectorcraft_doc::NodeId>>>,
 }

 #[derive(Clone, Copy, Debug, Default)]
@@ -135,6 +135,25 @@ fn set_view(app: &mut VectorcraftApp, view: TraceView) {
    }
 }

+/// While `down`, the selected Image Trace objects show their source image on the canvas, whatever
+/// their View. The document and the undo history stay as they are. The panel's eye button next to
+/// View calls it; per the public documentation of the panel, that control is pressed and held to
+/// view the source image
+/// (<https://web.archive.org/web/20250831090623/https://helpx.adobe.com/illustrator/using/image-trace.html>).
+fn hold_source(app: &mut VectorcraftApp, ctx: &egui::Context, down: bool) {
+    let ids = app
+        .session
+        .active()
+        .filter(|_| down)
+        .map(|st| st.selection.objects.iter().copied().filter(|id| st.doc.node(*id).is_some_and(is_trace)).collect::<Vec<_>>())
+        .filter(|ids| !ids.is_empty())
+        .map(std::sync::Arc::new);
+    if ids != app.ui.trace_hold_source {
+        app.ui.trace_hold_source = ids;
+        ctx.request_repaint();
+    }
+}
+
 /// The selected Image Trace object's View row (Control bar, Properties).
 pub(crate) fn view_row(app: &mut VectorcraftApp, ui: &mut Ui, current: TraceView, width: f32) {
    widgets::dim_label(ui, tl!("View:"));
@@ -295,12 +314,19 @@ pub fn show(app: &mut VectorcraftApp, ui: &mut Ui) {
    }
    ui.horizontal(|ui| {
        widgets::dim_label(ui, tl!("View:"));
-        if let Some(v) = view_dropdown(ui, st.view, 170.0) {
+        let eye = 24.0;
+        if let Some(v) = view_dropdown(ui, st.view, (ui.available_width() - eye - ui.spacing().item_spacing.x).min(170.0)) {
            st.view = v;
            if is_trace {
                set_view(app, v);
            }
        }
+        let held = app.ui.trace_hold_source.is_some();
+        let r = widgets::icon_button_enabled(ui, "eye", tl!("Press and hold to view the source image"), held, is_trace, eye);
+        if cfg!(test) {
+            ui.ctx().data_mut(|d| d.insert_temp(egui::Id::new("trace-hold-source"), r.rect));
+        }
+        hold_source(app, ui.ctx(), is_trace && r.is_pointer_button_down_on());
    });
    ui.horizontal(|ui| {
        widgets::dim_label(ui, tl!("Mode:"));
@@ -837,6 +863,39 @@ mod tests {
        }
    }

+    /// Holding the eye button next to View down lists the selected Image Trace object for the
+    /// canvas to draw with its source image; releasing it shows the object's View again. The
+    /// document, its View and the undo history stay as they were. With a plain image selected the
+    /// button is disabled.
+    #[test]
+    fn holding_the_eye_button_shows_the_source_image_until_released() {
+        let mut app = traced_app();
+        let ctx = egui::Context::default();
+        crate::theme::install_fonts(&ctx);
+        frame(&mut app, &ctx, vec![]);
+        let id = first_selected(&app).unwrap().id;
+        let undo = |app: &VectorcraftApp| app.session.active().unwrap().history.undo.len();
+        let revision = |app: &VectorcraftApp| app.session.active().unwrap().revision;
+        let (steps, rev) = (undo(&app), revision(&app));
+        let at = ctx.data(|d| d.get_temp::<Rect>(egui::Id::new("trace-hold-source"))).unwrap().center();
+        let press = |pressed| Event::PointerButton { pos: at, button: PointerButton::Primary, pressed, modifiers: Default::default() };
+        frame(&mut app, &ctx, vec![Event::PointerMoved(at), press(true)]);
+        assert_eq!(app.ui.trace_hold_source.as_deref(), Some(&vec![id]), "held: the object shows its source image");
+        frame(&mut app, &ctx, vec![]);
+        assert!(app.ui.trace_hold_source.is_some(), "still held on the next frame");
+        frame(&mut app, &ctx, vec![press(false)]);
+        assert_eq!(app.ui.trace_hold_source, None, "released: the object shows its View again");
+        assert_eq!(undo(&app), steps, "no undo step");
+        assert_eq!(revision(&app), rev, "the document is unchanged");
+        assert_eq!(selected_trace(&app).map(|t| t.1), Some(TraceView::Result), "its View is unchanged");
+        app.run("imageTrace.release", json!({})).unwrap();
+        assert!(matches!(first_selected(&app).unwrap().kind, NodeKind::Image(_)));
+        frame(&mut app, &ctx, vec![]);
+        frame(&mut app, &ctx, vec![Event::PointerMoved(at), press(true)]);
+        assert_eq!(app.ui.trace_hold_source, None, "a plain image has no source image to show");
+        frame(&mut app, &ctx, vec![press(false)]);
+    }
+
    #[test]
    fn properties_can_reopen_the_trace_controls() {
        let mut app = traced_app();
@@ -549,6 +549,10 @@ pub struct UiState {
    /// becoming active, leaves it.
    #[serde(skip)]
    pub home: Option<(Option<u64>, usize)>,
+    /// The Image Trace objects the canvas draws with the Source Image view while the Image Trace
+    /// panel's eye button is held down ([`vectorcraft_render::RenderOptions::trace_source`]).
+    #[serde(skip)]
+    pub trace_hold_source: Option<std::sync::Arc<Vec<vectorcraft_doc::NodeId>>>,
    /// Layers panel › Panel Options… (row size, thumbnails, Show Layers Only, Locate Selected Objects).
    #[serde(default)]
    pub layers_panel: crate::panels::layers::PanelOptions,
@@ -902,6 +906,7 @@ impl Default for UiState {
            move_options: Value::Null,
            dxf_import: Value::Null,
            home: None,
+            trace_hold_source: None,
            layers_panel: Default::default(),
            layers_filter: Default::default(),
            image_trace_advanced: true,
@@ -788,6 +788,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
 - **Image Trace, thin closed outlines:** generated `fit::snap_area_tests` verify nonzero interiors after straightening, opposite closed-boundary winding and Noise controls; see [quality notes](image-trace-quality.md#thin-closed-outlines-with-snap-curves-to-lines). Scores and hours unchanged; open-piece fitting is unchanged.
 - **Image Trace, flattened slivers:** in a Color, Grayscale or Black and White trace with Fills, a traced region whose outline straightens onto one line (a single pixel, or a one-pixel row along an edge, its pieces shared with the regions beside it) is left out instead of becoming a selectable path with no area, which paints nothing. Snap Curves To Lines straightens more outlines, so it leaves out more of these. Without Fills, the region's 1 px stroke draws it, and it is kept. Code-drawn tests in `crates/trace`.
 - **Image Trace, Auto Color rare colours:** the Automatic palette keeps colours too rare for its area count when they are distinct (Oklab) and drawn as coherent regions, at most six, protected from mixed-colour merging and Noise; code-drawn stem, highlight, low-contrast and scattered-noise tests (see [quality notes](image-trace-quality.md#auto-color-keeps-rare-colours)).
+- **Image Trace, source image on hold:** while the eye button next to the Image Trace panel's View is held down, the canvas shows the selected Image Trace objects' source image whatever their View, and shows their View again on release, with no change to the document or the undo history.
 - **Image Trace, large images:** images over 1500 px on a side trace with a warning in the result and the status bar; the anchor limit is 8,000,000 (2,000,000 on the web), measured at about 90 bytes an anchor (see [quality notes](image-trace-quality.md#large-images)).
 - **Image Trace, Preview:** the Image Trace panel's Preview checkbox, before Trace, is on by default, and a setting change traces the selected Image Trace object again at once. Off, changes wait in the panel until Trace applies them as one undo step, or until Preview is turned on again. Preview is kept with the UI preferences, and Reset to Default leaves it.
 - **Image Trace small contours:** closed fits too small to form an editable subpath retain their positioned outline, including holes. Source-generated island, hole/winding and stepped-region regressions cover Corners and Noise; defaults, parity scores and estimates are unchanged.
@@ -274,6 +274,7 @@ empty), without opening the dialog.
 | Panels outside the app window (another monitor) | missing | single OS window |
 | Edit Toolbar (•••): the All Tools drawer opens beside the toolbar by its button (Escape or a click outside closes it), dims the tools already in the toolbar; while it is open, tools drag from it onto the toolbar (between two tools, or onto one to join its group), from the toolbar into it, and within the toolbar; each toolbar keeps its edits | done | #1018; `window.editToolbar`, `toolbar.addTool`/`removeTool`/`reset`; the drawer's Reset (Illustrator has it in a drawer menu); dragging a toolbar button moves the tool it shows, not its whole group; New/Manage Toolbars missing; tool flyouts are as wide as their longest translated name and shortcut need (#1616) |
 | Quick Image Trace presets trace at once and leave the panel as it was; the Image Trace button (Control bar, Properties) opens the editable controls | done | Per the public documentation, choosing a preset traces the image with it straight away, and the panel is opened with the Image Trace button in the Control panel or in Properties' Image Trace section (<https://helpx.adobe.com/illustrator/using/image-trace-results-optimization.html>). The controls show Threshold, Paths, Corners and Noise with Advanced open; `panels/image_trace.rs` headless tests (`a_quick_trace_leaves_the_panel_as_it_was`, `sketch_quick_trace_reveals_all_adjustments_and_keeps_the_source` for the button's route). No algorithm parity claim. |
+| Image Trace panel: holding the eye button next to View down shows the selected Image Trace objects' source image on the canvas | done | Per the public documentation, the control next to View is pressed and held to compare the trace result with the source image (<https://web.archive.org/web/20250831090623/https://helpx.adobe.com/illustrator/using/image-trace.html>). On release the objects show their View again; the document, its View and the undo history are unchanged. `RenderOptions::trace_source`; `panels/image_trace.rs` headless test `holding_the_eye_button_shows_the_source_image_until_released`, render test `trace_source_draws_the_source_image_of_the_listed_objects`. The Control bar and Properties have no such button |
 | Live trace result bounds and selection highlights exclude the retained bitmap; source-image views retain it | done | All TraceView modes and rotated result bounds regression-covered; ordinary hidden group behavior retained |
 | Image Trace panel: the Preview checkbox before Trace chooses whether a setting change traces the selected Image Trace object again at once | done | Per the public documentation, Preview shows the result of the current settings and Trace traces with them (<https://web.archive.org/web/20250831090623/https://helpx.adobe.com/illustrator/using/image-trace.html>). Preview is on by default and kept with the UI preferences; Reset to Default leaves it. Off, changes wait in the panel until Trace applies them as one undo step, or until Preview is turned on again. `ui.set {imageTracePreview}`; `panels/image_trace.rs` headless tests (`with_preview_off_a_slider_change_waits_for_trace`, `turning_preview_on_traces_the_changes_that_waited`, `preview_turned_on_with_nothing_selected_traces_when_the_object_is_selected_again`, `settings_that_wait_stay_with_their_object`, `preview_is_kept_with_the_preferences_and_reset_to_default_leaves_it`) |
 | Toolbar without group labels by default, one or two columns; All Tools drawer by flyout group with shortcuts, its menu (Reset, Basic, Advanced) and Show section | done | #1751; a preference brings the labels back; `toolbar.show` sets the Fill/Stroke, Coloring, Draw Mode and Screen Mode controls |