The approach I have chosen, can be described as followed:
- Use multiple paths overlying
- Each path contains only the line segments that are below a certain pressure threshold
- The paths are drawn with alpha value transparency
Disadvantages / potential optimizations:
The alpha value is not been interpolated along the line segment; therefor the steps of the threshold values are visible.
Non-transparent lines resulting from high pressure values now produce the most overlying lines, however, could also be represented by a single one
I wonder whether it is faster
- to draw the whole paths on invalidation or
- store the result in a bitmap and only add the new ones
What do you think of my approach? Any suggestions or comments?