Derek/ticket 378. Add "Optional" banner to input box

src/media/MediaDisplayComponent.cpp

@@ -6,6 +6,27 @@
 
 #include <cmath>
 
+void OptionalBannerComponent::paint(Graphics& g)
+{
+    const float cx = static_cast<float>(getWidth()) / 2.0f;
+    const float cy = static_cast<float>(getHeight()) / 2.0f;
+
+    g.setColour(Colour::fromRGB(90, 105, 105));
+    g.fillAll();
+
+    g.setColour(Colours::white);
+    g.setFont(12.0f);
+
+    Graphics::ScopedSaveState state(g);
+    g.addTransform(AffineTransform::rotation(-MathConstants<float>::halfPi, cx, cy));
+
+    Rectangle<float> textBounds(
+        0, 0, static_cast<float>(getHeight()), static_cast<float>(getWidth()));
+    textBounds.setCentre(cx, cy);
+
+    g.drawText("OPTIONAL", textBounds, Justification::centred, false);
+}
+
 namespace
 {
 struct TickScheme
@@ -164,6 +185,8 @@ MediaDisplayComponent::MediaDisplayComponent(String name, bool req, bool fromDAW
     horizontalScrollBar.setAutoHide(false);
     horizontalScrollBar.addListener(this);
 
+    addAndMakeVisible(optionalBanner);
+
     timeAxisStrip = std::make_unique<TimeAxisStrip>(this);
 
     mediaAreaContainer.addAndMakeVisible(overheadPanel);
@@ -335,6 +358,16 @@ void MediaDisplayComponent::resized()
     {
         // Place header beside media
         mainFlexBox.flexDirection = FlexBox::Direction::row;
+
+        if (! isRequired() && isInputTrack() && ! isThumbnailTrack())
+        {
+            mainFlexBox.items.add(FlexItem(optionalBanner).withWidth(24));
+        }
+        else
+        {
+            optionalBanner.setBounds(0, 0, 0, 0);
+        }
+
         // Fixed area for track label and buttons
         mainFlexBox.items.add(FlexItem(headerComponent).withFlex(1).withMaxWidth(40).withMargin(4));
     }

src/media/MediaDisplayComponent.h

@@ -27,6 +27,23 @@ enum class DisplayMode
     Thumbnail // Reduced functionality
 };
 
+class OptionalBannerComponent : public Component
+{
+public:
+    void paint(Graphics& g) override;
+};
+
+class TimeAxisStrip : public Component
+{
+public:
+    explicit TimeAxisStrip(MediaDisplayComponent* ownerIn) : owner(ownerIn) {}
+
+    void paint(Graphics& g) override;
+
+private:
+    MediaDisplayComponent* owner = nullptr;
+};
+
 class ColorablePanel : public Component
 {
 public:
@@ -48,17 +65,6 @@ class ColorablePanel : public Component
     Colour backgroundColor;
 };
 
-class TimeAxisStrip : public Component
-{
-public:
-    explicit TimeAxisStrip(MediaDisplayComponent* ownerIn) : owner(ownerIn) {}
-
-    void paint(Graphics& g) override;
-
-private:
-    MediaDisplayComponent* owner = nullptr;
-};
-
 class MediaDisplayComponent : public Component,
                               public ChangeListener,
                               public ChangeBroadcaster,
@@ -272,6 +278,9 @@ class MediaDisplayComponent : public Component,
     MultiButton::Mode copyFileButtonActiveInfo;
     MultiButton::Mode copyFileButtonInactiveInfo;
 
+    // Banner shown on left edge of optional input tracks
+    OptionalBannerComponent optionalBanner;
+
     // Panel displaying overhead labels
     ColorablePanel overheadPanel { overheadPanelColor };