Leave a panorama frame out without leaving the page

A frame that did not fit ended the job with its name, and the only way
on was Back, a smaller selection and every frame read, demosaiced and
searched for keypoints again. Each row on the page now has a box. An
unticked frame is left out and the rest are solved again from what the
first pass measured.

dr_pano::align is split for it: match_pairs does the matching and the
pairwise RANSAC once over every frame (about 5 s for twelve), and solve
takes a subset of the frames and uses only the links among them (about
0.1 s). Solving a subset by re-aligning it also moved every RANSAC seed,
which are keyed on frame position, and on the fixture set that was
enough to lose a marginal link and strand a neighbour of the frame left
out.

A frame that cannot be placed no longer stops the job either. Its row
names it and Merge stays off until it is unticked; the headless example
leaves such frames out the same way, and takes --leave-out N to try it.

ui/dr-ui/ui/app.slint

@@ -616,6 +616,7 @@ export component AppWindow inherits Window {
     callback merge-confirm();
     callback merge-abandon();
     callback merge-projection-picked(int);
+    callback merge-frame-toggled(int, bool);
     callback merge-border-picked(int);
     /// A fill knob turned: its name and the new value.
     callback merge-fill-knob(string, float);
@@ -1182,6 +1183,7 @@ in property <bool> panel-visible: true;
             merge() => { root.merge-confirm(); }
             abandon() => { root.merge-abandon(); }
             projection-picked(i) => { root.merge-projection-picked(i); }
+            frame-toggled(i, on) => { root.merge-frame-toggled(i, on); }
             border-picked(i) => { root.merge-border-picked(i); }
             fill-knob(name, value) => { root.merge-fill-knob(name, value); }
             close() => { root.merge-close(); }

ui/dr-ui/ui/merge.slint

@@ -7,11 +7,13 @@
 // one. The difference is the pause in the middle: the job aligns, this
 // page shows what it found, and nothing is written until the photographer
 // presses Merge (FR-MRG-1). A frame that could not be placed is named on
-// its row and the button stays off (FR-MRG-5).
+// its row and the button stays off (FR-MRG-5) until it is unticked: each
+// row's box keeps or leaves out its frame, and the job aligns again over
+// the ones kept without reading any of them again.
 
 import { Theme } from "theme.slint";
 import { Button, PanelHeading, Label, Value, Caption, Panel, ProgressBar } from "widgets.slint";
-import { Segmented, SliderRow } from "controls.slint";
+import { Segmented, SliderRow, Check } from "controls.slint";
 
 /// One source frame's line in the alignment table.
 export struct MergeFrameRow {
@@ -19,6 +21,8 @@ export struct MergeFrameRow {
     /// "yaw −55.9° · pitch −1.6°", or why it is not aligned.
     detail: string,
     aligned: bool,
+    /// Whether the frame is in the alignment; unticked, it is left out.
+    included: bool,
 }
 
 export component MergePage inherits Rectangle {
@@ -75,6 +79,8 @@ export component MergePage inherits Rectangle {
     callback merge();
     callback abandon();
     callback projection-picked(int);
+    /// A frame's box: its index in `frames`, and whether to keep it.
+    callback frame-toggled(int, bool);
     callback border-picked(int);
     /// A knob turned: its name ("scale", "erosion", "coarse", "band",
     /// "mirror", "feather") and the new value.
@@ -276,18 +282,28 @@ export component MergePage inherits Rectangle {
                 Panel {
                     PanelHeading { text: "Frames"; }
 
-                    for row in root.frames: HorizontalLayout {
+                    // Controlled: the tick follows the report the job sends
+                    // back, so a box never claims a frame the alignment on
+                    // screen does not have.
+                    for row[i] in root.frames: HorizontalLayout {
                         spacing: Theme.gap;
-                        Label {
-                            text: row.name;
-                            width: 160px;
-                            overflow: elide;
+                        Check {
+                            label: row.name;
+                            width: 200px;
+                            checked: row.included;
+                            controlled: true;
+                            toggled(on) => {
+                                if (!root.running && !root.done) {
+                                    root.frame-toggled(i, on);
+                                }
+                            }
                         }
                         Caption {
                             text: row.detail;
-                            warn: !row.aligned;
+                            warn: row.included && !row.aligned;
                             overflow: elide;
                             horizontal-stretch: 1;
+                            vertical-alignment: center;
                         }
                     }