韋東山ARM第一期作業(九)觸控式螢幕
阿新 • • 發佈:2019-01-13
文章目錄
01 - 作業所在路徑
ARM裸機1期加強版\原始碼文件圖片\文件圖片\第018課_ADC和觸控式螢幕
02 - 作業描述
- 百度搜索下載tslib庫
- 分析它的較準函式(不需要理解原理)、移植
- tslib還有其他功能,比如判斷連續點之間的距離,如果過大就丟棄。
這可以解決我們程式中出現的問題:畫線時突然有某個點在很遠的距離出現
03 - 作業解答
tslib庫的運算量太大,有大量的浮點數乘除法運算,目前的裸版程式碼不支援,移植沒有問題,只是計算出錯,除法運算庫不夠強大
ts_calibrate.h
#ifndef _TSCALIBRATE_H
#define _TSCALIBRATE_H
typedef struct {
int x[5], xfb[5];
int y[5], yfb[5];
int a[7];
} calibration;
int perform_calibration(calibration *cal);
#endif /* _TSCALIBRATE_H */
ts_calibrate.c
#include "../uart.h"
#include "ts_calibrate.h"
int perform_calibration(calibration * cal)
{
int j;
double n, x, y, x2, y2, xy, z, zx, zy;
double det, a, b, c, e, f, i;
double scaling = 65536.0;
/* Get sums for matrix */
n = x = y = x2 = y2 = xy = 0;
for (j = 0; j < 5; j++) {
n += 1.0;
x += (double)cal->x[j];
y += (double)cal->y[j];
x2 += (double)(cal->x[j]*cal- >x[j]);
y2 += (double)(cal->y[j]*cal->y[j]);
xy += (double)(cal->x[j]*cal->y[j]);
}
/* Get determinant of matrix -- check if determinant is too small */
det = n*(x2*y2 - xy*xy) + x*(xy*y - x*y2) + y*(x*xy - y*x2);
if (det < 0.1 && det > -0.1) {
printf("ts_calibrate: determinant is too small -- %d\n\r", (int)det);
return 0;
}
/* Get elements of inverse matrix */
a = (x2*y2 - xy*xy)/det;
b = (xy*y - x*y2)/det;
c = (x*xy - y*x2)/det;
e = (n*y2 - y*y)/det;
f = (x*y - n*xy)/det;
i = (n*x2 - x*x)/det;
printf("abcefi:%d %d %d %d %d %d \r\n",a,b,c,e,f,i);
/* Get sums for x calibration */
z = zx = zy = 0;
for (j = 0; j < 5; j++) {
z += (double)cal->xfb[j];
zx += (double)(cal->xfb[j]*cal->x[j]);
zy += (double)(cal->xfb[j]*cal->y[j]);
}
/* Now multiply out to get the calibration for framebuffer x coord */
cal->a[0] = (int)((a*z + b*zx + c*zy)*(scaling));
cal->a[1] = (int)((b*z + e*zx + f*zy)*(scaling));
cal->a[2] = (int)((c*z + f*zx + i*zy)*(scaling));
printf("%d %d %d\n\r", (cal->a[0]),
(cal->a[1]),
(cal->a[2]));
/* Get sums for y calibration */
z = zx = zy = 0;
for (j = 0; j < 5; j++) {
z += (double)cal->yfb[j];
zx += (double)(cal->yfb[j]*cal->x[j]);
zy += (double)(cal->yfb[j]*cal->y[j]);
}
/* Now multiply out to get the calibration for framebuffer y coord */
cal->a[3] = (int)((a*z + b*zx + c*zy)*(scaling));
cal->a[4] = (int)((b*z + e*zx + f*zy)*(scaling));
cal->a[5] = (int)((c*z + f*zx + i*zy)*(scaling));
printf("%d %d %d\n\r", (cal->a[3]),
(cal->a[4]),
(cal->a[5]));
/* If we got here, we're OK, so assign scaling to a[6] and return */
cal->a[6] = (int)scaling;
return 1;
}
然後在原來程式碼tslib.c的ts_calibrate()
函式中呼叫
……
if (g_ts_xy_swap)
{
/* 對調所有點的XY座標 */
swap_xy(&(cal.x[0]), &(cal.y[0]));
swap_xy(&(cal.x[1]), &(cal.y[1]));
swap_xy(&(cal.x[2]), &(cal.y[2]));
swap_xy(&(cal.x[3]), &(cal.y[3]));
swap_xy(&(cal.x[4]), &(cal.y[4]));
}
print_cal(&cal);
/* 執行校準 */
perform_calibration(&cal);
//print_cal(&cal); //出錯,計算錯誤
……