ProgressBarCache: fix full bar drawing

This is a hack that injects a newline to force this single component to
produce two separate lines for rendering. in order to produce smaller
output, the previous implementation baked both drawings into a single
line using an interest hack with the way that ASS drawings work. Well,
it seems that interesting hack was more with the way that libass
works, and at some point the libass behavior changed, which broke the
rendering.

When a video was fully cached, the bar would become 100% the width of
the canvas. This would cause libass's line-wrapping behavior to
engage, which would result in the bar being drawn incorrectly. This
was fixed by splitting the bar into two separate. Positioned
independently, they do not collide with each other and there is no
problem.

src/ProgressBarCache.moon

@@ -15,21 +15,34 @@ class ProgressBarCache extends BarBase
 	reconfigure: =>
 		super 'bar-cache-'
 		@line[6] = 100
-		@line[8] = @line[8]\format( settings['bar-cache-style'] ) .. 'm 0 0'
-		@line[10] = [[{\p0%s\p1}]]\format settings['bar-cache-background-style']
-		@line[11] = [[]]
+		@line[9] = ''
+		-- TODO: this is a hack
+		@line[10] = '\n'
+		for idx = 1, 9
+			@line[idx + 10] = @line[idx]
+
+		@line[8] = @line[8]\format( settings['bar-cache-style'] )
+		@line[18] = @line[18]\format( settings['bar-cache-background-style'] )
 		@fileDuration = mp.get_property_number 'duration', nil
 
 	resize: =>
 		super!
 		if @fileDuration
 			@coordinateRemap = Window.w/@fileDuration
+
+		-- map position onto background bar
+		@line[12] = @line[2]
 		-- undo BarBase size update
-		@line[9] = [[]]
+		@clobber!
+
+	animate: ( value ) =>
+		super value
+		-- map scale onto background bar
+		@line[14] = @line[4]
 
 	clobber: =>
 		@line[9] = ""
-		@line[11] = ""
+		@line[19] = ""
 
 	redraw: =>
 		super!
@@ -75,25 +88,16 @@ class ProgressBarCache extends BarBase
 						rect = 'm %g 0 l %g 1 %g 1 %g 0'\format rangeStart, rangeStart, rangeEnd, rangeEnd
 						table.insert barDrawing.past, rect
 					elseif rangeStart > progressPosition
-						-- the way ASS handles two drawings in a single line is weird
-						-- (drawing coordinates are relative to the end of the previous
-						-- drawing/character on the same line), so we have to offset all
-						-- future values by the split point. This is handled by bounding the
-						-- first (past) set of drawings with m 0 0 and m #{progressPosition}
-						-- 0.
-						rangeStart -= progressPosition
-						rangeEnd -= progressPosition
 						rect = 'm %g 0 l %g 1 %g 1 %g 0'\format rangeStart, rangeStart, rangeEnd, rangeEnd
 						table.insert barDrawing.future, rect
 					else
-						rangeEnd -= progressPosition
 						rectPast = 'm %g 0 l %g 1 %g 1 %g 0'\format rangeStart, rangeStart, progressPosition, progressPosition
-						rectFuture = 'm %g 0 l %g 1 %g 1 %g 0'\format 0, 0, rangeEnd, rangeEnd
+						rectFuture = 'm %g 0 l %g 1 %g 1 %g 0'\format progressPosition, progressPosition, rangeEnd, rangeEnd
 						table.insert barDrawing.past, rectPast
 						table.insert barDrawing.future, rectFuture
 
-				@line[9] = table.concat( barDrawing.past, ' ' ) .. 'm %g 0'\format progressPosition
-				@line[11] = table.concat barDrawing.future, ' '
+				@line[9] = table.concat barDrawing.past, ' '
+				@line[19] = table.concat barDrawing.future, ' '
 
 				@cacheKey = cacheKey
 				@needsUpdate = true