Fix that seekbar preview frames are sometimes cut off

app/src/main/java/com/github/libretube/helpers/PlayerHelper.kt

@@ -437,7 +437,7 @@ object PlayerHelper {
                 for (x in 0 until frames.framesPerPageX) {
                     val endPosition = startPosition + frames.durationPerFrame
                     if (position in startPosition until endPosition) {
-                        return PreviewFrame(url, x, y, frames.framesPerPageX, frames.framesPerPageY)
+                        return PreviewFrame(url, x, y, frames.frameWidth, frames.frameHeight)
                     }
                     startPosition = endPosition
                 }

app/src/main/java/com/github/libretube/obj/PreviewFrame.kt

@@ -4,6 +4,6 @@ data class PreviewFrame(
     val previewUrl: String,
     val positionX: Int,
     val positionY: Int,
-    val framesPerPageX: Int,
-    val framesPerPageY: Int,
+    val frameWidth: Int,
+    val frameHeight: Int,
 )

app/src/main/java/com/github/libretube/util/BitmapUtil.kt

@@ -8,14 +8,12 @@ object BitmapUtil {
      * Cut off a new bitmap from the image that contains multiple preview thumbnails
      */
     fun cutBitmapFromPreviewFrame(bitmap: Bitmap, previewFrame: PreviewFrame): Bitmap {
-        val heightPerFrame = bitmap.height / previewFrame.framesPerPageY
-        val widthPerFrame = bitmap.width / previewFrame.framesPerPageX
         return Bitmap.createBitmap(
             bitmap,
-            previewFrame.positionX * widthPerFrame,
-            previewFrame.positionY * heightPerFrame,
-            widthPerFrame,
-            heightPerFrame,
+            previewFrame.positionX * previewFrame.frameWidth,
+            previewFrame.positionY * previewFrame.frameHeight,
+            previewFrame.frameWidth,
+            previewFrame.frameHeight,
         )
     }
 }