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linemeter: increase the precision of sine/cos interpolation

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it needs the same time to caclulate then a lower resolution
This commit is contained in:
Gabor Kiss-Vamosi 2020-03-04 16:44:20 +01:00
parent 4e10efd642
commit d79fb70aaa
1 changed files with 7 additions and 7 deletions
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14
src/lv_widgets/lv_linemeter.c
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@ -316,22 +316,22 @@ void lv_linemeter_draw_scale(lv_obj_t * lmeter, const lv_area_t * clip_area, uin
/*In calculation use a larger radius to avoid rounding errors */
lv_coord_t r_out_extra = r_out + LV_DPI;
for(i = 0; i < ext->line_cnt; i++) {
/* `* 16` for extra precision*/
int32_t angle_upscale = (i * ext->scale_angle * 16) / (ext->line_cnt - 1);
int32_t angle_normal = angle_upscale >> 4;
/* `* 256` for extra precision*/
int32_t angle_upscale = (i * ext->scale_angle * 256) / (ext->line_cnt - 1);
int32_t angle_normal = angle_upscale >> 8;
int32_t angle_low = (angle_upscale >> 4);
int32_t angle_low = (angle_upscale >> 8);
int32_t angle_high = angle_low + 1;
int32_t angle_rem = angle_upscale & 0xF;
int32_t angle_rem = angle_upscale & 0xFF;
/*Interpolate sine and cos*/
int32_t sin_low = lv_trigo_sin(angle_low + angle_ofs);
int32_t sin_high = lv_trigo_sin(angle_high + angle_ofs);
int32_t sin_mid = (sin_low * (16 - angle_rem) + sin_high * angle_rem) >> 4;
int32_t sin_mid = (sin_low * (256 - angle_rem) + sin_high * angle_rem) >> 8;
int32_t cos_low = lv_trigo_sin(angle_low + 90 + angle_ofs);
int32_t cos_high = lv_trigo_sin(angle_high + 90 + angle_ofs);
int32_t cos_mid = (cos_low * (16 - angle_rem) + cos_high * angle_rem) >> 4;
int32_t cos_mid = (cos_low * (256 - angle_rem) + cos_high * angle_rem) >> 8;
/*Use the interpolated values to get x and y coordinates*/
int32_t y_out = (int32_t)((int32_t)sin_mid * r_out_extra) >> (LV_TRIGO_SHIFT - 8);