Don't show clip thumbs on when clip is too small (<16 pixels).

Related to #439

src/timeline2/view/qml/Clip.qml

@@ -67,7 +67,7 @@ Rectangle {
     property color borderColor: "#000000"
     property bool forceReloadThumb
     property bool isComposition: false
-    property bool hideClipViews: false
+    property bool hideClipViews: scrollStart > (clipDuration * timeline.scaleFactor) || scrollStart + scrollView.width < 0 || clipRoot.width < 16
     property int slipOffset: boundValue(outPoint - maxDuration + 1, trimmingOffset, inPoint)
     property int scrollStart: scrollView.contentX - (clipRoot.modelStart * timeline.scaleFactor)
     property int mouseXPos: mouseArea.mouseX
@@ -81,7 +81,6 @@ Rectangle {
     signal trimmedOut(var clip, bool shiftTrim, bool controlTrim)
 
     onScrollStartChanged: {
-        clipRoot.hideClipViews = scrollStart > (clipDuration * timeline.scaleFactor) || scrollStart + scrollView.width < 0
         if (!clipRoot.hideClipViews && clipRoot.width > scrollView.width) {
             if (effectRow.item && effectRow.item.kfrCanvas) {
                 effectRow.item.kfrCanvas.requestPaint()
@@ -359,7 +358,7 @@ Rectangle {
             //clip: true
             asynchronous: true
             visible: status == Loader.Ready
-            source: clipRoot.hideClipViews || clipRoot.itemType == 0 || clipRoot.itemType === ProducerType.Color ? "" : parentTrack.isAudio ? (timeline.showAudioThumbnails ? "ClipAudioThumbs.qml" : "") : timeline.showThumbnails ? "ClipThumbs.qml" : ""
+            source: (clipRoot.hideClipViews || clipRoot.itemType == 0 || clipRoot.itemType === ProducerType.Color) ? "" : parentTrack.isAudio ? (timeline.showAudioThumbnails ? "ClipAudioThumbs.qml" : "") : timeline.showThumbnails ? "ClipThumbs.qml" : ""
         }
 
         Rectangle {

src/timeline2/view/qml/ClipThumbs.qml

@@ -30,7 +30,8 @@ Row {
         // container.width / thumbRow.thumbWidth will display all frames showThumbnails
         // 1: only show first thumbnail
         // 0: will disable thumbnails
-        model: parentTrack.trackThumbsFormat === 0 ? 2 : parentTrack.trackThumbsFormat === 1 ? Math.ceil(container.width / thumbRow.thumbWidth) : parentTrack.trackThumbsFormat === 2 ? 1 : 0
+        // Track trackThumbsFormat is: 2 = In frame only, 0 = in/out, 1 = All frames, 3 = No thumbs
+        model: parentTrack.trackThumbsFormat === 0 ?  (container.width > thumbRow.thumbWidth ? 2 : 1) : parentTrack.trackThumbsFormat === 1 ? Math.ceil(container.width / thumbRow.thumbWidth) : parentTrack.trackThumbsFormat === 2 ? 1 : 0
         property int startFrame: clipRoot.inPoint
         property int endFrame: clipRoot.outPoint
         property real imageWidth: Math.max(thumbRow.thumbWidth, container.width / thumbRepeater.count)