From 038cbb0e5b5d1d625e2281474ca535fbac65f8d7 Mon Sep 17 00:00:00 2001
From: ronso0 <ronso0@mixxx.org>
Date: Mon, 13 Feb 2023 16:54:40 +0100
Subject: [PATCH 1/2] Tracks view: keep current item visible when the view
 shrinks vertically

---
 src/widget/wtracktableview.cpp | 44 ++++++++++++++++++++++++++++++++++
 src/widget/wtracktableview.h   |  1 +
 2 files changed, 45 insertions(+)

diff --git a/src/widget/wtracktableview.cpp b/src/widget/wtracktableview.cpp
index 2fa1d34a366..12ee903ff77 100644
--- a/src/widget/wtracktableview.cpp
+++ b/src/widget/wtracktableview.cpp
@@ -844,6 +844,50 @@ void WTrackTableView::keyPressEvent(QKeyEvent* event) {
     }
 }
 
+void WTrackTableView::resizeEvent(QResizeEvent* event) {
+    // When the tracks view shrinks in height, e.g. when other skin regions expand,
+    // and if the row was visible before resizing, scroll to it afterwards.
+
+    // these heights are the actual inner region without header, scrollbars and padding
+    int oldHeight = event->oldSize().height();
+    int newHeight = event->size().height();
+
+    if (newHeight >= oldHeight) {
+        QTableView::resizeEvent(event);
+        return;
+    }
+
+    QModelIndex currIndex = currentIndex();
+    int rHeight = rowHeight(0);
+
+    if (!currIndex.isValid() || rHeight <= 0) {
+        QTableView::resizeEvent(event);
+        return;
+    }
+
+    int currRow = currIndex.row();
+    // y-pos of the top edge, negative value means above viewport boundary
+    int posInView = rowViewportPosition(currRow);
+    // Check if the row is visible.
+    // Note: don't use viewport()->height() because that may already have changed (??)
+    bool rowWasVisible = posInView > 0 && posInView - rHeight < oldHeight;
+
+    QTableView::resizeEvent(event);
+
+    if (!rowWasVisible) {
+        return;
+    }
+
+    // TODO(xxx) When resizing, the top row is static, at least on Linux.
+    // If that is true on other OS as well we could calculate the new relative
+    // position before resizing.
+    // Check if the item is fully visible. If not, scroll to show it
+    posInView = rowViewportPosition(currRow);
+    if (posInView - rHeight < 0 || posInView + rHeight > newHeight) {
+        scrollTo(currIndex);
+    }
+}
+
 void WTrackTableView::hideOrRemoveSelectedTracks() {
     QModelIndexList indices = selectionModel()->selectedRows();
     if (indices.isEmpty()) {
diff --git a/src/widget/wtracktableview.h b/src/widget/wtracktableview.h
index 433da9d9733..2999bceb147 100644
--- a/src/widget/wtracktableview.h
+++ b/src/widget/wtracktableview.h
@@ -35,6 +35,7 @@ class WTrackTableView : public WLibraryTableView {
     bool hasFocus() const override;
     void setFocus() override;
     void keyPressEvent(QKeyEvent* event) override;
+    void resizeEvent(QResizeEvent* event) override;
     void activateSelectedTrack() override;
     void loadSelectedTrackToGroup(const QString& group, bool play) override;
     void assignNextTrackColor() override;

From 09896a95b7787e0ff2620ebcf6e083c4a179b82d Mon Sep 17 00:00:00 2001
From: ronso0 <ronso0@mixxx.org>
Date: Thu, 23 Mar 2023 12:46:45 +0100
Subject: [PATCH 2/2] Tracks view: optimize and clean up resizeEvent()

---
 src/widget/wtracktableview.cpp | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/src/widget/wtracktableview.cpp b/src/widget/wtracktableview.cpp
index 12ee903ff77..a45bc30c54d 100644
--- a/src/widget/wtracktableview.cpp
+++ b/src/widget/wtracktableview.cpp
@@ -858,18 +858,18 @@ void WTrackTableView::resizeEvent(QResizeEvent* event) {
     }
 
     QModelIndex currIndex = currentIndex();
-    int rHeight = rowHeight(0);
+    int currRow = currIndex.row();
+    int rHeight = rowHeight(currRow);
 
-    if (!currIndex.isValid() || rHeight <= 0) {
+    if (currRow < 0 || rHeight == 0) { // true if currIndex is invalid
         QTableView::resizeEvent(event);
         return;
     }
 
-    int currRow = currIndex.row();
     // y-pos of the top edge, negative value means above viewport boundary
     int posInView = rowViewportPosition(currRow);
     // Check if the row is visible.
-    // Note: don't use viewport()->height() because that may already have changed (??)
+    // Note: don't use viewport()->height() because that may already have changed
     bool rowWasVisible = posInView > 0 && posInView - rHeight < oldHeight;
 
     QTableView::resizeEvent(event);
@@ -878,9 +878,6 @@ void WTrackTableView::resizeEvent(QResizeEvent* event) {
         return;
     }
 
-    // TODO(xxx) When resizing, the top row is static, at least on Linux.
-    // If that is true on other OS as well we could calculate the new relative
-    // position before resizing.
     // Check if the item is fully visible. If not, scroll to show it
     posInView = rowViewportPosition(currRow);
     if (posInView - rHeight < 0 || posInView + rHeight > newHeight) {