support channel reordering via dragging header

notes

@@ -45,6 +45,11 @@ project data {
 
 TODO {
     immediate frontburner {
+        - allow swapping channels around
+        
+        double click to rename channel
+        ^ QHeaderView is a QAbstractItemView as of qt5, so can set an item delegate
+        
         create new Project and hook that up to the main window instead of just making an empty pattern
         ( Project::new(), Pattern::new(Project*) )
         make and hook up UI for displaying all existing patterns by index, and for displaying the sequence
@@ -54,18 +59,12 @@ TODO {
         - make pattern editor detect ctrl and alt modifiers
         make everything relevant check if editing is locked
         
-        - figure out what library to use for messagepack
+        - figure out what library to use for messagepack (official msgpack-c)
         implement saving (probably a FileIO helper class)
         hook up new/open/save menu items
     }
     
     ? de-hardcode the "» " (probably just make it a static const variable somewhere?)
-    - implement (top) header span and return channel names
-    double click to rename channel
-    QHeaderView::setSectionsMovable(bool movable)
-    QHeaderView::sectionMoved(int logicalIndex, int oldVisualIndex, int newVisualIndex)
-    ^ need to re-reposition the thing?
-    QHeaderView is a QAbstractItemView as of qt5, so can set an item delegate
     
     pattern background colors (and time signature, duh)
     
@@ -84,6 +83,12 @@ TODO {
 
 use signals/slots to signal project/pattern updates etc.
 
+saving and loading {
+    msgpack object
+    
+    probably have a field of raw data for (some) node saves, and keep it resident in case of plugin crashes
+}
+
 resampler object {
     one used internally for each note
     reference to sample
@@ -104,6 +109,12 @@ JS example of sine panning, -1.0 to +1.0 {
     }
 }
 
+plugin registry {
+    queuing function for static construction
+    PluginInfo base class, virtual function for creating a node of said plugin
+    (separate function for loading from save file?)
+}
+
 lv2 support: lilv (duh) for actual plugin loading, suil for UI embedding
 
 eventually hook luajit up with TLSF allocator to aid in real time (maybe look at nedmalloc too)
@@ -121,6 +132,14 @@ graph+node+port system {
     something something ready flags (all input nodes and containing graph; main graph and command ports always have the bit set)
     
     graphs are also nodes
+    
+    can use locks on processing node-ports since they'll basically never be contended; this allows for editing during playback
+    ^ or just double-buffer the connections
+    UI thread takes full responsibility for both replacement and eventual collection; atomic bool marking is enough threadsafety to deflect the collection timer
+    have to signal playback thread that queues have been invalidated
+    ...or just use locks and a flag since it's probably not worth the added complexity of implementing lockfree to avoid hangups when *fiddling with connections*
+    though we do want a queue system for plugin parameter changes! don't want xruns from fiddling with instruments or mixing
+    (most built-in gadgets can avoid this by nature of aligned power-of-two types (<=8bytes) inherently atomic on modern CPUs)
 }
 
 keybinds {

xybrid/mainwindow.cpp

@@ -36,6 +36,7 @@ MainWindow::MainWindow(QWidget *parent) :
     pattern->channels[0].rows[0].addParam('v', 255);
     pattern->channels[1].rows[0].port = 1;
     pattern->channels[1].rows[0].note = 0;
+    pattern->channels[5].name = "I have a name";
 
     auto pe = t->findChild<Xybrid::UI::PatternEditorView*>("patternEditor");
 

xybrid/ui/patterneditorview.cpp

@@ -26,9 +26,13 @@ PatternEditorView::PatternEditorView(QWidget *parent) : QTableView(parent) {
     hdr->setSectionResizeMode(QHeaderView::Fixed);//ResizeToContents);
     hdr->setTextElideMode(Qt::ElideMiddle);
     hdr->setStretchLastSection(true);
+    hdr->setSectionsMovable(true);
+    hdr->setFirstSectionMovable(true);
 
     // hook up scrolling to update header position
     connect(horizontalScrollBar(), &QScrollBar::valueChanged, this, &PatternEditorView::updateHeaderOffset);
+    // and header swap
+    connect(hdr.get(), &QHeaderView::sectionMoved, this, &PatternEditorView::headerMoved);
 
     horizontalHeader()->setSectionResizeMode(QHeaderView::ResizeToContents);
     verticalHeader()->setSectionResizeMode(QHeaderView::ResizeToContents);
@@ -99,3 +103,25 @@ void PatternEditorView::updateHeader(bool full) {
 void PatternEditorView::updateHeaderOffset(int) {
     updateHeader(false);
 }
+
+void PatternEditorView::headerMoved(int logicalIndex, int oldVisualIndex, int newVisualIndex) {
+    if (logicalIndex == newVisualIndex) return; // assume moving back
+    hdr->moveSection(newVisualIndex, logicalIndex); // maintain straight-through order
+    if (logicalIndex >= hdr->count() - 1) return; // no dragging the endcap :|
+
+    int min = std::min(oldVisualIndex, newVisualIndex);
+    int max = std::max(oldVisualIndex, newVisualIndex);
+    int nf = 0;
+    if (newVisualIndex > oldVisualIndex) nf = min + 1;
+    else nf = max;
+    auto& chn = mdl->getPattern().channels;
+    std::rotate(chn.begin() + min, chn.begin() + nf, chn.begin() + max + 1);
+    this->dataChanged( // update everything
+        mdl->index(0, 0, QModelIndex()),
+        mdl->index(mdl->rowCount() - 1, mdl->columnCount() - 1, QModelIndex())
+    );
+
+    mdl->updateColumnDisplay(); // update geometries and hide flags
+    // and make sure header follows
+    emit hdr->model()->headerDataChanged(Qt::Horizontal, 0, static_cast<int>(chn.size()) - 1);
+}

xybrid/ui/patterneditorview.h

@@ -31,6 +31,7 @@ namespace Xybrid::UI {
         void updateGeometries() override;
         void updateHeader(bool full = false);
         void updateHeaderOffset(int);
+        void headerMoved(int logicalIndex, int oldVisualIndex, int newVisualIndex);
 
         void keyboardSearch(const QString&) override {} // disable accidental search