Channels: Edit › Transform works on a targeted alpha channel (#2835) (#2845)

edit.transform without a "target" (or "layer") param now follows the Channels panel: a targeted alpha channel or the Quick Mask transforms instead of the layer. Edit › Transform › Rotate 180°/90° and Flip Horizontal/Vertical are routed to the panel target like the paint and filter commands, so they turn a targeted alpha channel, the Quick Mask or an unlinked layer mask within its frame (one undo step). The Background no longer greys the transforms when a channel is targeted. Flips scorecard row BUG-207-4. Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-11 12:38:36 +02:00 · 2026-10-11 12:38:36 +02:00 · 7609834df8
parent d79fc5e8ef
commit 7609834df8
6 changed files with 106 additions and 15 deletions
--- a/crates/engine/src/channel_cmds.rs
+++ b/crates/engine/src/channel_cmds.rs
@ -569,6 +569,15 @@ fn routed(id: &str) -> bool {
        || crate::fill_key_cmds::IDS.contains(&id)
        // Pasting into a targeted mask or channel (#1035).
        || matches!(id, "edit.paste" | "edit.pasteSpecial.pasteInPlace" | "edit.pasteSpecial.pasteInto" | "edit.pasteSpecial.pasteOutside")
+        // Edit › Transform › Rotate/Flip turn a targeted mask or channel (#2835).
+        || matches!(
+            id,
+            "edit.transform.rotate180"
+                | "edit.transform.rotate90Cw"
+                | "edit.transform.rotate90Ccw"
+                | "edit.transform.flipHorizontal"
+                | "edit.transform.flipVertical"
+        )
        || matches!(
            id,
            "paint.cloneStamp"
--- a/crates/engine/src/extra_cmds.rs
+++ b/crates/engine/src/extra_cmds.rs
@ -333,11 +333,21 @@ fn clouds(s: &mut Session, p: &Value, difference: bool) -> Result<Value> {

 // ---------- transform presets ----------

-fn transform_preset(s: &mut Session, kind: &str) -> Result<Value> {
+/// The presets' params: like Free Transform, they follow the Channels and Layers panel target.
+const TRANSFORM_TARGET: &str =
+    r#"{"target":"pixels"|"mask"|"quickMask"|{"channel":i}=Channels panel target (an unlinked mask, an alpha channel or the Quick Mask turns alone)}"#;
+
+fn transform_preset(s: &mut Session, p: &Value, kind: &str) -> Result<Value> {
    let d = s.active().ok_or(EngineError::NoDocument)?;
-    let id = d.active_layer.ok_or(EngineError::Other("no active layer".into()))?;
-    let l = d.doc.layer(id).ok_or(EngineError::NoLayer(id))?;
-    let b = crate::transform_cmds::transform_bounds(&d.doc, l);
+    // A targeted alpha channel, the Quick Mask or an unlinked layer mask turns by itself (#2835).
+    let (b, mut params) = match crate::transform_cmds::lone_target(&d.doc, d.active_layer, p)? {
+        Some(surf) => (crate::transform_cmds::target_bounds(&d.doc, surf), json!({"target": p.get("target")})),
+        None => {
+            let id = d.active_layer.ok_or(EngineError::Other("no active layer".into()))?;
+            let l = d.doc.layer(id).ok_or(EngineError::NoLayer(id))?;
+            (crate::transform_cmds::transform_bounds(&d.doc, l), json!({"layer": id.0}))
+        }
+    };
    if b.is_empty() {
        return Err(EngineError::Other("nothing to transform".into()));
    }
@ -351,7 +361,9 @@ fn transform_preset(s: &mut Session, kind: &str) -> Result<Value> {
        "flipHorizontal" => [-1.0, 0.0, 0.0, 1.0, sx, 0.0],
        _ => [1.0, 0.0, 0.0, -1.0, 0.0, sy],
    };
-    s.execute("edit.transform", json!({"layer": id.0, "matrix": m, "interpolation": "nearest"}))
+    params["matrix"] = json!(m);
+    params["interpolation"] = json!("nearest");
+    s.execute("edit.transform", params)
 }

 // ---------- selection / clipboard ----------
@ -723,14 +735,29 @@ pub fn specs() -> Vec<CommandSpec> {
            has_pixels,
            stroke
        ),
-        spec!("edit.transform.rotate180", "Rotate 180°", &["Edit", "Transform"], None, "{}", has_layer, |s, _| transform_preset(s, "rotate180")),
-        spec!("edit.transform.rotate90Cw", "Rotate 90° Clockwise", &["Edit", "Transform"], None, "{}", has_layer, |s, _| transform_preset(s, "rotate90Cw")),
-        spec!("edit.transform.rotate90Ccw", "Rotate 90° Counter Clockwise", &["Edit", "Transform"], None, "{}", has_layer, |s, _| transform_preset(
+        spec!("edit.transform.rotate180", "Rotate 180°", &["Edit", "Transform"], None, TRANSFORM_TARGET, has_layer, |s, p| transform_preset(
            s,
-            "rotate90Ccw"
+            p,
+            "rotate180"
+        )),
+        spec!("edit.transform.rotate90Cw", "Rotate 90° Clockwise", &["Edit", "Transform"], None, TRANSFORM_TARGET, has_layer, |s, p| transform_preset(
+            s,
+            p,
+            "rotate90Cw"
+        )),
+        spec!("edit.transform.rotate90Ccw", "Rotate 90° Counter Clockwise", &["Edit", "Transform"], None, TRANSFORM_TARGET, has_layer, |s, p| {
+            transform_preset(s, p, "rotate90Ccw")
+        }),
+        spec!("edit.transform.flipHorizontal", "Flip Horizontal", &["Edit", "Transform"], None, TRANSFORM_TARGET, has_layer, |s, p| transform_preset(
+            s,
+            p,
+            "flipHorizontal"
+        )),
+        spec!("edit.transform.flipVertical", "Flip Vertical", &["Edit", "Transform"], None, TRANSFORM_TARGET, has_layer, |s, p| transform_preset(
+            s,
+            p,
+            "flipVertical"
        )),
-        spec!("edit.transform.flipHorizontal", "Flip Horizontal", &["Edit", "Transform"], None, "{}", has_layer, |s, _| transform_preset(s, "flipHorizontal")),
-        spec!("edit.transform.flipVertical", "Flip Vertical", &["Edit", "Transform"], None, "{}", has_layer, |s, _| transform_preset(s, "flipVertical")),
        spec!(
            "edit.pasteSpecial.pasteInto",
            "Paste Into",
--- a/crates/engine/src/transform_cmds.rs
+++ b/crates/engine/src/transform_cmds.rs
@ -391,7 +391,21 @@ fn quad_param(p: &Value) -> Option<[[f64; 2]; 4]> {
    Some(q)
 }

+/// `p`, with the Channels panel's targeted alpha channel or Quick Mask as its `"target"` when it
+/// names neither a target nor a layer (#2835).
+fn with_panel_target(s: &Session, p: &Value) -> Value {
+    let mut p = if p.is_object() { p.clone() } else { json!({}) };
+    if p.get("target").is_none()
+        && p.get("layer").is_none()
+        && let (Some(m), Some(Value::Object(t))) = (p.as_object_mut(), crate::channel_cmds::targeted_channel(s))
+    {
+        m.extend(t);
+    }
+    p
+}
+
 fn transform(s: &mut Session, p: &Value) -> Result<Value> {
+    let p = &with_panel_target(s, p);
    let st = s.active().ok_or(EngineError::NoDocument)?;
    let id = match p.get("layer").and_then(Value::as_u64) {
        Some(v) => Some(LayerId(v)),
@ -752,6 +766,36 @@ mod tests {
        assert_eq!(active_bounds(&s), Rect::new(10, 10, 30, 20), "layer untouched");
    }

+    /// The Channels panel targets an alpha channel: Edit › Transform › Flip Horizontal and a
+    /// 50% `edit.transform` (no `target` param) work on the channel, not the layer (BUG-207-4).
+    #[test]
+    fn transforms_follow_the_targeted_alpha_channel() {
+        let mut s = session();
+        s.execute("channel.new", json!({})).unwrap();
+        s.edit("paint channel", |doc, _| {
+            let ch = &mut doc.channels[0].surface;
+            ch.fill_rect(Rect::new(10, 10, 20, 20), &[1.0]);
+            ch.fill_rect(Rect::new(10, 10, 12, 20), &[0.5]);
+            Ok(())
+        })
+        .unwrap();
+        s.execute("channel.target", json!({"channel": 0})).unwrap();
+        let layer = |s: &Session| crate::active_layer_of(s).unwrap().surface().unwrap().read_region(Rect::new(0, 0, 100, 100));
+        let (pixels, past) = (layer(&s), s.active().unwrap().history.past_len());
+        s.execute("edit.transform.flipHorizontal", json!({})).unwrap();
+        // 8-bit channel: 0.5 is stored as 128/255.
+        let ch = |s: &Session, x, y| (s.active().unwrap().doc.channels[0].surface.sample_channel(x, y, 0) * 10.0).round() / 10.0;
+        assert_eq!((ch(&s, 19, 15), ch(&s, 10, 15)), (0.5, 1.0), "the channel flips within its frame");
+        assert!(layer(&s) == pixels, "the layer is untouched");
+        assert_eq!(s.active().unwrap().history.past_len(), past + 1, "one undo step");
+        s.execute("edit.transform", json!({"matrix": [0.5, 0, 0, 0.5, 0, 0], "interpolation": "nearest"})).unwrap();
+        assert_eq!((ch(&s, 7, 7), ch(&s, 15, 15)), (1.0, 0.0), "the channel scales to 50%");
+        assert!(layer(&s) == pixels, "the layer is untouched");
+        s.undo();
+        s.undo();
+        assert_eq!((ch(&s, 10, 15), ch(&s, 19, 15)), (0.5, 1.0));
+    }
+
    #[test]
    fn transform_targets_fail_gracefully() {
        let mut s = session();
--- a/crates/ui-egui/src/enable_rules.rs
+++ b/crates/ui-egui/src/enable_rules.rs
@ -121,6 +121,11 @@ pub fn disabled(app: &crate::PhotocraftApp, id: &str) -> bool {
    if transform && crate::vector_ui::free_transform_path(app).is_some() {
        return false;
    }
+    // So does a targeted alpha channel or the Quick Mask: it transforms instead of the layer (#2835).
+    let target = crate::canvas::paint_target(app);
+    if transform && (target.is_object() || target == "quickMask") {
+        return false;
+    }
    // Editable type can be scaled, rotated and skewed but not distorted (#2630): Photoshop greys
    // Distort and Perspective until the type is rasterized. A targeted unlinked mask or channel of
    // the type layer is pixels, and can be.
@ -177,6 +182,12 @@ mod tests {
        // A selection makes Free Transform available on the Background.
        s.execute("select.all", json!({})).unwrap();
        assert!(!off(&s, "edit.freeTransform"));
+        // So does a targeted alpha channel, which transforms instead of the Background (#2835).
+        s.execute("select.deselect", json!({})).unwrap();
+        s.execute("channel.new", json!({})).unwrap();
+        s.execute("channel.target", json!({"channel": 0})).unwrap();
+        let app = crate::PhotocraftApp::new(s, crate::Services::default());
+        assert!(!disabled(&app, "edit.freeTransform") && !disabled(&app, "edit.transform.flipHorizontal"));
    }

    /// With several layers selected, Rasterize is judged by the whole selection, not by the layer
--- a/docs/scorecard.md
+++ b/docs/scorecard.md
@ -14,7 +14,7 @@ Generated by `cargo xtask scorecard` from `perf/budgets.toml`, `perf/baseline.js
 | [Automation](#automation) | 3 | 2 | 6 | 630 of 630 menu items live (100.0%) |
 | [Reliability](#reliability) | 5 | 2 | 0 | never-crash lints on 28 of 28 crates; panic_hunt present |
 | [Distribution](#distribution) | 4 | 4 | 3 |  |
-| [Open bugs](#open-bugs) | 22 | 2 | 8 |  |
+| [Open bugs](#open-bugs) | 23 | 2 | 7 |  |

 ## Performance

@ -297,7 +297,7 @@ Never-crash attribute on 28 of 28 crate roots.
 | BUG-207-1 | Retouch tools respect the paint target (mask, alpha channel, Quick Mask) | done | [#207](https://github.com/storytold/photocraft/issues/207) | run_stroke paints channel_cmds::target_surface; retouch_strokes_paint_the_targeted_mask (retouch_ui.rs) and engine retouch_cmds/tests.rs (e2444ce, #234) |
 | BUG-207-2 | Sample All Layers applies to Blur, Sharpen and Smudge | done | [#207](https://github.com/storytold/photocraft/issues/207) | retouch_ui.rs passes sampleAllLayers to paint.blur/sharpen/smudge; sample_all_layers_reaches_the_command (e2444ce, #234) |
 | BUG-207-3 | Smudge mixes premultiplied RGBA (no dark fringe at transparent edges) | done | [#207](https://github.com/storytold/photocraft/issues/207) | paint/src/retouch.rs premultiplies; smudge_into_transparency_leaves_no_dark_fringe (e2444ce, #234) |
-| BUG-207-4 | edit.transform transforms a targeted alpha channel | missing | [#207](https://github.com/storytold/photocraft/issues/207) | transform_cmds.rs transform() has no target handling |
+| BUG-207-4 | edit.transform transforms a targeted alpha channel | done | [#207](https://github.com/storytold/photocraft/issues/207) | edit.transform follows a targeted alpha channel or Quick Mask (explicit target since #242, Channels panel target with no target/layer param since #2835); Edit > Transform > Rotate/Flip are routed to the target too; transforms_follow_the_targeted_alpha_channel |
 | BUG-207-5 | Tests: per-tool mask/channel targeting, Sample All Layers, no smudge fringe | missing | [#207](https://github.com/storytold/photocraft/issues/207) | Only smudge_drags_colour_along_the_stroke (retouch.rs:407) |
 | BUG-208-1 | Shift while dragging a Rect/Elliptical Marquee constrains to a square/circle | done | [#208](https://github.com/storytold/photocraft/issues/208) | canvas.rs marquee_corners applies Shift via Drag::marquee_mods; marquee_tests.rs::shift_during_the_drag_draws_a_square_and_the_readout_follows covers the drag |
 | BUG-208-2 | Alt while dragging a marquee draws from the centre | done | [#208](https://github.com/storytold/photocraft/issues/208) | canvas.rs marquee_corners centres Alt drags; marquee_tests.rs::alt_draws_from_the_centre_and_shift_alt_a_centred_circle verifies rectangles and ellipses |
--- a/scorecard/bugs.toml
+++ b/scorecard/bugs.toml
@ -184,9 +184,9 @@ note = "paint/src/retouch.rs premultiplies; smudge_into_transparency_leaves_no_d
 [[item]]
 id = "BUG-207-4"
 target = "edit.transform transforms a targeted alpha channel"
-status = "missing"
+status = "done"
 issue = 207
-note = "transform_cmds.rs transform() has no target handling"
+note = "edit.transform follows a targeted alpha channel or Quick Mask (explicit target since #242, Channels panel target with no target/layer param since #2835); Edit > Transform > Rotate/Flip are routed to the target too; transforms_follow_the_targeted_alpha_channel"

 [[item]]
 id = "BUG-207-5"