Is it possible to change the location and the colour of the comment that is displayed on the chart through Comment function or ChartSetString(with CHART_COMMENT)?
By default, it gets displayed in white colour on top left corner.
No, the chart comment feature is fixed to the top left corner, using the foreground color of the chart.
If you want to do anything else, you need to create OBJ_LABEL objects.
To add comments, please log in or register