Add drag-and-drop sample loading onto track slots

Source/PluginEditor.cpp

@@ -574,6 +574,14 @@ void TrommelkisteEditor::paint(Graphics& g)
             g.setColour(lnf.accent.withAlpha(alpha));
             g.fillRect(scaled(0), scaled(ry + 4), scaled(3), scaled(ROW_H - 8));
         }
+
+        if (i == dropHoverIndex)
+        {
+            g.setColour(lnf.accent.withAlpha(0.25f));
+            g.fillRect(scaled(COL_FILE), scaled(ry), scaled(COL_DELAY - 8 - COL_FILE), scaled(ROW_H));
+            g.setColour(lnf.accent);
+            g.drawRect(scaled(COL_FILE), scaled(ry), scaled(COL_DELAY - 8 - COL_FILE), scaled(ROW_H), scaled(2));
+        }
     }
 }
 
@@ -653,3 +661,80 @@ void TrommelkisteEditor::mouseDown(const MouseEvent& event)
         }
     }
 }
+
+// ── Drag & drop ────────────────────────────────────────────────
+
+int TrommelkisteEditor::getSlotIndexForPosition(int x, int y) const
+{
+    for (int i = 0; i < NUM_TRACKS; ++i)
+    {
+        const int ry = scaled(TOP + i * ROW_H);
+        if (y >= ry && y < ry + scaled(ROW_H))
+        {
+            if (x >= scaled(COL_FILE) && x < scaled(COL_DELAY - 8))
+                return i;
+            return -1;
+        }
+    }
+    return -1;
+}
+
+bool TrommelkisteEditor::isInterestedInFileDrag(const StringArray& files)
+{
+    for (const auto& f : files)
+    {
+        const File file(f);
+        if (file.hasFileExtension("wav;aiff;aif;flac"))
+            return true;
+    }
+    return false;
+}
+
+void TrommelkisteEditor::fileDragEnter(const StringArray& files, int x, int y)
+{
+    fileDragMove(files, x, y);
+}
+
+void TrommelkisteEditor::fileDragMove(const StringArray&, int x, int y)
+{
+    const int newIndex = getSlotIndexForPosition(x, y);
+    if (newIndex != dropHoverIndex)
+    {
+        dropHoverIndex = newIndex;
+        repaint();
+    }
+}
+
+void TrommelkisteEditor::fileDragExit(const StringArray&)
+{
+    if (dropHoverIndex != -1)
+    {
+        dropHoverIndex = -1;
+        repaint();
+    }
+}
+
+void TrommelkisteEditor::filesDropped(const StringArray& files, int x, int y)
+{
+    if (dropHoverIndex != -1)
+    {
+        dropHoverIndex = -1;
+        repaint();
+    }
+
+    const int idx = getSlotIndexForPosition(x, y);
+    if (idx < 0)
+        return;
+
+    for (const auto& f : files)
+    {
+        const File file(f);
+        if (file.hasFileExtension("wav;aiff;aif;flac"))
+        {
+            proc.loadSample(idx, file);
+            proc.currentSampleIndex[idx] = -1;
+            ui[idx].fileLabel.setText(file.getFileNameWithoutExtension(), dontSendNotification);
+            break;
+        }
+    }
+}

Source/PluginEditor.h

@@ -30,7 +30,8 @@ struct KnobSlider : juce::Slider
     }
 };
 
-class TrommelkisteEditor : public juce::AudioProcessorEditor, private juce::Timer
+class TrommelkisteEditor : public juce::AudioProcessorEditor, private juce::Timer,
+                           public juce::FileDragAndDropTarget
 {
 public:
     TrommelkisteEditor(TrommelkisteProcessor&);
@@ -97,6 +98,8 @@ private:
     void loadForTrack(int idx);
     void updateFileLabel(int idx);
     void refreshPresetCombo();
+    int getSlotIndexForPosition(int x, int y) const;
+    int dropHoverIndex = -1;
 
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(TrommelkisteEditor)
 };