speedometer with graphic lcd

[MCUprogrammer]

Hello to everyone
I want to make a speedometer with graphic lcd. As long as the button is pressed, the pointer will move within half an arc. Like the system in vehicles. I wrote the arc function to the graphics driver. It works. But how can I move the pointer at an angle? What is the formula for this job? Do I do it using glcd_line or glcd_pixel? How do you think.
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Best Regards...
MCUprogrammer
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Work Hard

[temtronic]

hmm, the last intense graphics I did was 3+ decades ago, on a Model III computer but...
Since you cut the code for the 'arm' of the pointer, you know where the moving 'end' of the arm will be. The 'pointer' is probably 2-3 pixels next to the end of the arm, so you could just turn on those 'nearby' pixels.

[Ttelmah]

You would draw a line from the centre to the angle required on the curve
forming the outside of the shape. Honestly think in terms of using a look-
up table for this. So precalculate the X and Y coordinates of the end
points, perhaps in a spreadsheet on a PC, and store the coordinates in
an array. For something like 100 RPM values, this will be smaller and
enormously faster than trying to do the calculation in the PIC.