Time Bar Chart - A Bar chart where each bar carries a unique volume weight because each specific market/symbol completes a random number of transactions per minute and there are a random number of shares or contracts traded per transaction.
Unbalanced Bar Chart
Tick Bar Chart - A Bar chart where each bar is made up of a fixed number of transactions per bar and still carries a unique volume weight because each specific market/symbol completes a random number of contracts per transaction. (GLOBEX's decision in 2007 to arbitrarily group transactions virtually destroyed the ability to balance this chart type)
Unbalanced Bar Chart
Volume Bar Chart - A Bar chart where each bar is made up of a nearly fixed number of shares or contracts traded per bar but still carries a unique volume weight because unless the volume is capped on each bar there is the potential for contracts or shares can roll over to the next bar based on larger transactions being applied to the chart.
Unbalanced Bar Chart
Constant or Capped Volume Bar Chart - A Bar chart where each bar is made up of a fixed unvarying number of shares or contracts traded per bar.
Balanced Bar Chart
The OP stated they wanted to basically compute a trendline of the form (y - y0) = m (x-x0). They stated wanted to use this to determine box ranges and triangles.
Two 8 EMA's slope envelope alone will not allow the OP to compute their goal.