I think you have misunderstood the difference between calculating indicators/studies, and drawing the actual image on the screen.
drawing image on the screen is a house keeping process, therefore only one core is used.
Please stay assured, I know the difference between drawing charts (something what I called ''normal charting'') and calculating studies applied to these charts.
The studies' calculation and other processes will be discussed in further questions. All I want to know now is how many cores are used to draw charts of price action. I apologise for confusion that I created with the unscientific term ''normal charting''. I should have been more precise.
Thank you for clarification.
the computer doesn't care what is normal to you.
a chart is a chart.
it can have 100 indicators on it,
or it can have price bars only.
it is a calculation to determine the coordinates and all attributes of those bars.
when all the calculations are done... the information is sent to house keeping and it
in turn draws the IMAGE on the screen.
note that in my post, I refer to drawing the image,
while you refer to as drawing the chart.
don't think of drawing the chart, because it confuses you.
think of it as calculating the coordinates of the bars in the chart.
whether the price bar has a paintbar or an indicator is irrelevant to the computer.
the computer doesn't know the difference, all it knows is, there is a chart, and it has to calculate the coordinates.