How can I draw a background grid only when resize or zoom, and draw the audio-signal or fft result over it with high frame rate. In my pure objectiveC app I could solve this with CALayer. Draw some layer (grid, ruler) only when resize, one layer for current time and other text informations in higher frame rate, and the audio signal as fast as possible.
My very old Application Sonifyer with CALayer. Video: Sonifyer, Sonification of Tohoku Earthquake