[Design] Annotation treatment

[shixiedesign]

Annotation is needed on charts for various situations

Design of annotations need to be accessible, standout against data set in chart, but still play the supporting role of helping user to better understand the data set.

Types of annotations include:

• Threshold / max
• Average
• Outliers
• Benchmark line
• Trend lines
• Historical / previous data
• Predictive line

Initial design explorations (NOT APPROVED)