Bake window derives itself: %-knob fold, declick pad, Gate held to exhaustion, preview velocity; Hold is the one knob a loop needs

tests/test_sample_chrome.cpp

@@ -2,9 +2,10 @@
 // test framework.
 //
 // Covers: the chrome band's two rows (toolbar over strip row, tiling the band exactly); the
-// toolbar's fixed right-anchored run in order (preview, velocity cell, Mono|Stereo,
-// Browse) with the title taking the remainder; the velocity knob centred in its
-// cell above its label; the piano strip owning its whole row at every width; no rect on the
+// toolbar's fixed right-anchored run in order (Hold, bake, preview, velocity cell,
+// Mono|Stereo, Browse) with the title taking the remainder; the velocity and Hold knobs
+// centred in their cells above their labels; the piano strip owning its whole row at every
+// width; no rect on the
 // toolbar overlapping any other; degenerate bands yielding no inverted rects; and the preview
 // button's play-triangle glyph, which sits inside the button without changing its rect.
 
@@ -63,12 +64,13 @@ static void testToolbarRunIsOrderedRightToLeftWithoutOverlap() {
     CHECK(r.bake.width == kBakeButtonWidth);
     CHECK(r.bake.y == r.preview.y);              // shares the run's button baseline
     CHECK(r.bake.height == r.preview.height);
-    CHECK(r.title.right() <= r.bake.x);          // the title yields to the bake, not the preview
+    CHECK(r.holdCell.right() <= r.bake.x);
+    CHECK(r.title.right() <= r.holdCell.x);      // the title yields to the whole run
     CHECK(r.title.x == band.x + kPad);
     CHECK(r.title.width > 0);
 
     // Every toolbar rect sits inside the toolbar row.
-    const Rect items[] = {r.title, r.bake, r.preview, r.velCell, r.chanMono,
+    const Rect items[] = {r.title, r.holdCell, r.bake, r.preview, r.velCell, r.chanMono,
                           r.chanStereo, r.navBrowse};
     for (const Rect& it : items) {
         CHECK(it.y >= r.toolbar.y && it.bottom() <= r.toolbar.bottom());
@@ -82,16 +84,17 @@ static void testChromePartsNeverOverlapAtAnyWidth() {
         // stay inside its own row, clear of every control.
         CHECK(!overlaps(r.toolbar, r.rootStrip));
         CHECK(r.rootStrip.y >= r.controls.y && r.rootStrip.bottom() <= r.controls.bottom());
-        const Rect items[] = {r.bake, r.preview, r.velCell, r.chanMono, r.chanStereo,
-                              r.navBrowse};
+        const Rect items[] = {r.holdCell, r.bake, r.preview, r.velCell, r.chanMono,
+                              r.chanStereo, r.navBrowse};
         for (const Rect& it : items) {
             CHECK(!overlaps(it, r.rootStrip));
             CHECK(!overlaps(it, r.title));
         }
-        // The run's own members are pairwise disjoint (velKnob/velLabel are inside velCell,
-        // so they are checked against the cell's neighbours, not the cell).
-        for (int i = 0; i < 5; ++i) {
-            for (int j = i + 1; j < 5; ++j) CHECK(!overlaps(items[i], items[j]));
+        // The run's own members are pairwise disjoint (the knob/label pairs are inside their
+        // cells, so they are checked against the cell's neighbours, not the cell).
+        constexpr int kRunCount = static_cast<int>(sizeof(items) / sizeof(items[0]));
+        for (int i = 0; i < kRunCount; ++i) {
+            for (int j = i + 1; j < kRunCount; ++j) CHECK(!overlaps(items[i], items[j]));
         }
     }
 }
@@ -125,6 +128,25 @@ static void testVelocityKnobIsCentredInItsCellAboveTheLabel() {
     CHECK(r.velLabel.x == r.velCell.x && r.velLabel.right() == r.velCell.right());
 }
 
+// The Hold cell reserves its width whether or not the control is drawn — a run laid out
+// conditionally would slide Bake and Preview out from under the pointer whenever a loop is
+// dialled in or out. Its interior follows the velocity cell's grammar exactly.
+static void testHoldCellIsReservedAndFollowsTheVelocityCellGrammar() {
+    const ChromeRects r = chromeRects(chromeBand(), kKnob);
+    CHECK(r.holdCell.width == r.velCell.width);
+    CHECK(r.holdCell.y == r.velCell.y && r.holdCell.height == r.velCell.height);
+    CHECK(r.holdKnob.width == kKnob && r.holdKnob.height == kKnob);
+    CHECK(r.holdKnob.y == r.holdCell.y);
+    CHECK(r.holdKnob.x - r.holdCell.x == r.holdCell.right() - r.holdKnob.right());
+    CHECK(r.holdLabel.y == r.holdKnob.bottom());
+    CHECK(r.holdLabel.bottom() == r.holdCell.bottom());
+    CHECK(r.holdLabel.x == r.holdCell.x && r.holdLabel.right() == r.holdCell.right());
+
+    // Widening the window leaves the reservation alone; the title takes the extra pixels.
+    const ChromeRects wide = chromeRects(chromeBand(1000, 620), kKnob);
+    CHECK(wide.holdCell.width == r.holdCell.width);
+}
+
 static void testDegenerateBandYieldsNoInvertedRects() {
     const ChromeRects empty = chromeRects(Rect{}, kKnob);
     CHECK(empty.toolbar.empty() && empty.controls.empty());
@@ -133,7 +155,8 @@ static void testDegenerateBandYieldsNoInvertedRects() {
     // A band far too narrow for the fixed run: everything collapses left, nothing inverts.
     const ChromeRects tiny = chromeRects(Rect::ltrb(0, 0, 40, kTitleHeight + kChromeRowHeight),
                                          kKnob);
-    const Rect items[] = {tiny.title, tiny.preview, tiny.velCell, tiny.velKnob, tiny.velLabel,
+    const Rect items[] = {tiny.title, tiny.holdCell, tiny.holdKnob, tiny.holdLabel,
+                          tiny.bake, tiny.preview, tiny.velCell, tiny.velKnob, tiny.velLabel,
                           tiny.chanMono, tiny.chanStereo, tiny.navBrowse,
                           tiny.rootStrip};
     for (const Rect& it : items) CHECK(it.right() >= it.x && it.bottom() >= it.y);
@@ -182,6 +205,7 @@ int main() {
     testChromePartsNeverOverlapAtAnyWidth();
     testStripOwnsItsWholeRowAndGrowsWithTheWindow();
     testVelocityKnobIsCentredInItsCellAboveTheLabel();
+    testHoldCellIsReservedAndFollowsTheVelocityCellGrammar();
     testDegenerateBandYieldsNoInvertedRects();
     testPreviewGlyphSitsInsideTheButtonAndPointsRight();
     testPreviewGlyphDegradesRatherThanOverflowing();