weston/clients/calibrator.c
Rob Bradford bf33b1cced clients: Add a touchscreen calibration tool
This a basic calibration tool designed for "in factory" calibration of a touch
screen. The constants for the calibration functions:

x' = Ax + By + C and
y' = Dx + Ey + F

Are printed on stdout when the calibration is completed.
2012-12-06 15:53:08 -05:00

261 lines
6.5 KiB
C

/*
* Copyright © 2012 Intel Corporation
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting documentation, and
* that the name of the copyright holders not be used in advertising or
* publicity pertaining to distribution of the software without specific,
* written prior permission. The copyright holders make no representations
* about the suitability of this software for any purpose. It is provided "as
* is" without express or implied warranty.
*
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
* OF THIS SOFTWARE.
*/
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <cairo.h>
#include <math.h>
#include <assert.h>
#include <linux/input.h>
#include <wayland-client.h>
#include "window.h"
#include "../shared/matrix.h"
#define ARRAY_LENGTH(a) (sizeof (a) / sizeof (a)[0])
/* Our points for the calibration must be not be on a line */
static const struct {
float x_ratio, y_ratio;
} test_ratios[] = {
{ 0.20, 0.40 },
{ 0.80, 0.60 },
{ 0.40, 0.80 }
};
struct calibrator {
struct tests {
int32_t drawn_x, drawn_y;
int32_t clicked_x, clicked_y;
} tests[ARRAY_LENGTH(test_ratios)];
int current_test;
struct display *display;
struct window *window;
struct widget *widget;
};
/*
* Calibration algorithm:
*
* The equation we want to apply at event time where x' and y' are the
* calibrated co-ordinates.
*
* x' = Ax + By + C
* y' = Dx + Ey + F
*
* For example "zero calibration" would be A=1.0 B=0.0 C=0.0, D=0.0, E=1.0,
* and F=0.0.
*
* With 6 unknowns we need 6 equations to find the constants:
*
* x1' = Ax1 + By1 + C
* y1' = Dx1 + Ey1 + F
* ...
* x3' = Ax3 + By3 + C
* y3' = Dx3 + Ey3 + F
*
* In matrix form:
*
* x1' x1 y1 1 A
* x2' = x2 y2 1 x B
* x3' x3 y3 1 C
*
* So making the matrix M we can find the constants with:
*
* A x1'
* B = M^-1 x x2'
* C x3'
*
* (and similarly for D, E and F)
*
* For the calibration the desired values x, y are the same values at which
* we've drawn at.
*
*/
static void
finish_calibration (struct calibrator *calibrator)
{
struct weston_matrix m;
struct weston_matrix inverse;
struct weston_vector x_calib, y_calib;
int i;
/*
* x1 y1 1 0
* x2 y2 1 0
* x3 y3 1 0
* 0 0 0 1
*/
memset(&m, 0, sizeof(m));
for (i = 0; i < (int)ARRAY_LENGTH(test_ratios); i++) {
m.d[i] = calibrator->tests[i].clicked_x;
m.d[i + 4] = calibrator->tests[i].clicked_y;
m.d[i + 8] = 1;
}
m.d[15] = 1;
weston_matrix_invert(&inverse, &m);
memset(&x_calib, 0, sizeof(x_calib));
memset(&y_calib, 0, sizeof(y_calib));
for (i = 0; i < (int)ARRAY_LENGTH(test_ratios); i++) {
x_calib.f[i] = calibrator->tests[i].drawn_x;
y_calib.f[i] = calibrator->tests[i].drawn_y;
}
/* Multiples into the vector */
weston_matrix_transform(&inverse, &x_calib);
weston_matrix_transform(&inverse, &y_calib);
printf ("Calibration values: %f %f %f %f %f %f\n",
x_calib.f[0], x_calib.f[1], x_calib.f[2],
y_calib.f[0], y_calib.f[1], y_calib.f[2]);
exit(0);
}
static void
button_handler(struct widget *widget,
struct input *input, uint32_t time,
uint32_t button,
enum wl_pointer_button_state state, void *data)
{
struct calibrator *calibrator = data;
int32_t x, y;
if (state == WL_POINTER_BUTTON_STATE_PRESSED && button == BTN_LEFT) {
input_get_position(input, &x, &y);
calibrator->tests[calibrator->current_test].clicked_x = x;
calibrator->tests[calibrator->current_test].clicked_y = y;
calibrator->current_test--;
if (calibrator->current_test < 0)
finish_calibration(calibrator);
}
widget_schedule_redraw(widget);
}
static void
redraw_handler(struct widget *widget, void *data)
{
struct calibrator *calibrator = data;
struct rectangle allocation;
cairo_surface_t *surface;
cairo_t *cr;
int32_t drawn_x, drawn_y;
widget_get_allocation(calibrator->widget, &allocation);
surface = window_get_surface(calibrator->window);
cr = cairo_create(surface);
cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
cairo_set_source_rgba(cr, 1.0, 1.0, 1.0, 1.0);
cairo_paint(cr);
drawn_x = test_ratios[calibrator->current_test].x_ratio * allocation.width;
drawn_y = test_ratios[calibrator->current_test].y_ratio * allocation.height;
calibrator->tests[calibrator->current_test].drawn_x = drawn_x;
calibrator->tests[calibrator->current_test].drawn_y = drawn_y;
cairo_translate(cr, drawn_x, drawn_y);
cairo_set_line_width(cr, 2.0);
cairo_set_source_rgb(cr, 1.0, 0.0, 0.0);
cairo_move_to(cr, 0, -10.0);
cairo_line_to(cr, 0, 10.0);
cairo_stroke(cr);
cairo_move_to(cr, -10.0, 0);
cairo_line_to(cr, 10.0, 0.0);
cairo_stroke(cr);
cairo_destroy(cr);
cairo_surface_destroy(surface);
}
static struct calibrator *
calibrator_create(struct display *display)
{
struct calibrator *calibrator;
calibrator = malloc(sizeof *calibrator);
if (calibrator == NULL)
return NULL;
calibrator->window = window_create(display);
calibrator->widget = window_add_widget(calibrator->window, calibrator);
window_set_title(calibrator->window, "Wayland calibrator");
calibrator->display = display;
calibrator->current_test = ARRAY_LENGTH(test_ratios) - 1;
widget_set_button_handler(calibrator->widget, button_handler);
widget_set_redraw_handler(calibrator->widget, redraw_handler);
window_set_fullscreen(calibrator->window, 1);
return calibrator;
}
static void
calibrator_destroy(struct calibrator *calibrator)
{
widget_destroy(calibrator->widget);
window_destroy(calibrator->window);
free(calibrator);
}
int
main(int argc, char *argv[])
{
struct display *display;
struct calibrator *calibrator;
display = display_create(argc, argv);
if (display == NULL) {
fprintf(stderr, "failed to create display: %m\n");
return -1;
}
calibrator = calibrator_create(display);
if (!calibrator)
return -1;
display_run(display);
calibrator_destroy(calibrator);
display_destroy(display);
return 0;
}