The triangle is where the resistance trend line sloping down (where the price moves up to and either hits it or gets close before dropping below again) meets with the support trend line sloping up (where the price moves down to and either hits it or gets close before bouncing back above again).
The triangle implies that the range between price highs and lows are decreasing until price breaks out either above the resistance trend line or below the support trend line. The breakout either way could be relatively large and could continue for several days or even up to several weeks. The breakout can usually coincide with news about the asset (either good or bad) but doesn't have to.
S - represents support levels
R - represents resistance levels
P - most likely represents profit targets
In my opinion, based on my experience and the Slow Stochastic indicator, I would say that the break would most probably be on the upside.