bf33b1cced
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.
261 lines
6.5 KiB
C
261 lines
6.5 KiB
C
/*
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* Copyright © 2012 Intel Corporation
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*
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* Permission to use, copy, modify, distribute, and sell this software and its
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* documentation for any purpose is hereby granted without fee, provided that
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* the above copyright notice appear in all copies and that both that copyright
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* notice and this permission notice appear in supporting documentation, and
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* that the name of the copyright holders not be used in advertising or
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* publicity pertaining to distribution of the software without specific,
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* written prior permission. The copyright holders make no representations
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* about the suitability of this software for any purpose. It is provided "as
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* is" without express or implied warranty.
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*
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* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
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* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
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* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
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* OF THIS SOFTWARE.
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*/
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <cairo.h>
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#include <math.h>
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#include <assert.h>
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#include <linux/input.h>
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#include <wayland-client.h>
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#include "window.h"
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#include "../shared/matrix.h"
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#define ARRAY_LENGTH(a) (sizeof (a) / sizeof (a)[0])
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/* Our points for the calibration must be not be on a line */
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static const struct {
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float x_ratio, y_ratio;
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} test_ratios[] = {
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{ 0.20, 0.40 },
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{ 0.80, 0.60 },
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{ 0.40, 0.80 }
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};
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struct calibrator {
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struct tests {
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int32_t drawn_x, drawn_y;
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int32_t clicked_x, clicked_y;
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} tests[ARRAY_LENGTH(test_ratios)];
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int current_test;
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struct display *display;
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struct window *window;
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struct widget *widget;
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};
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/*
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* Calibration algorithm:
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*
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* The equation we want to apply at event time where x' and y' are the
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* calibrated co-ordinates.
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*
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* x' = Ax + By + C
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* y' = Dx + Ey + F
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*
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* For example "zero calibration" would be A=1.0 B=0.0 C=0.0, D=0.0, E=1.0,
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* and F=0.0.
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*
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* With 6 unknowns we need 6 equations to find the constants:
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*
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* x1' = Ax1 + By1 + C
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* y1' = Dx1 + Ey1 + F
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* ...
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* x3' = Ax3 + By3 + C
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* y3' = Dx3 + Ey3 + F
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*
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* In matrix form:
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*
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* x1' x1 y1 1 A
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* x2' = x2 y2 1 x B
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* x3' x3 y3 1 C
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*
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* So making the matrix M we can find the constants with:
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*
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* A x1'
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* B = M^-1 x x2'
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* C x3'
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*
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* (and similarly for D, E and F)
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*
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* For the calibration the desired values x, y are the same values at which
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* we've drawn at.
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*
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*/
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static void
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finish_calibration (struct calibrator *calibrator)
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{
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struct weston_matrix m;
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struct weston_matrix inverse;
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struct weston_vector x_calib, y_calib;
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int i;
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/*
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* x1 y1 1 0
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* x2 y2 1 0
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* x3 y3 1 0
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* 0 0 0 1
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*/
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memset(&m, 0, sizeof(m));
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for (i = 0; i < (int)ARRAY_LENGTH(test_ratios); i++) {
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m.d[i] = calibrator->tests[i].clicked_x;
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m.d[i + 4] = calibrator->tests[i].clicked_y;
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m.d[i + 8] = 1;
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}
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m.d[15] = 1;
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weston_matrix_invert(&inverse, &m);
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memset(&x_calib, 0, sizeof(x_calib));
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memset(&y_calib, 0, sizeof(y_calib));
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for (i = 0; i < (int)ARRAY_LENGTH(test_ratios); i++) {
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x_calib.f[i] = calibrator->tests[i].drawn_x;
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y_calib.f[i] = calibrator->tests[i].drawn_y;
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}
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/* Multiples into the vector */
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weston_matrix_transform(&inverse, &x_calib);
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weston_matrix_transform(&inverse, &y_calib);
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printf ("Calibration values: %f %f %f %f %f %f\n",
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x_calib.f[0], x_calib.f[1], x_calib.f[2],
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y_calib.f[0], y_calib.f[1], y_calib.f[2]);
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exit(0);
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}
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static void
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button_handler(struct widget *widget,
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struct input *input, uint32_t time,
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uint32_t button,
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enum wl_pointer_button_state state, void *data)
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{
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struct calibrator *calibrator = data;
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int32_t x, y;
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if (state == WL_POINTER_BUTTON_STATE_PRESSED && button == BTN_LEFT) {
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input_get_position(input, &x, &y);
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calibrator->tests[calibrator->current_test].clicked_x = x;
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calibrator->tests[calibrator->current_test].clicked_y = y;
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calibrator->current_test--;
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if (calibrator->current_test < 0)
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finish_calibration(calibrator);
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}
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widget_schedule_redraw(widget);
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}
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static void
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redraw_handler(struct widget *widget, void *data)
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{
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struct calibrator *calibrator = data;
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struct rectangle allocation;
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cairo_surface_t *surface;
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cairo_t *cr;
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int32_t drawn_x, drawn_y;
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widget_get_allocation(calibrator->widget, &allocation);
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surface = window_get_surface(calibrator->window);
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cr = cairo_create(surface);
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cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
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cairo_set_source_rgba(cr, 1.0, 1.0, 1.0, 1.0);
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cairo_paint(cr);
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drawn_x = test_ratios[calibrator->current_test].x_ratio * allocation.width;
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drawn_y = test_ratios[calibrator->current_test].y_ratio * allocation.height;
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calibrator->tests[calibrator->current_test].drawn_x = drawn_x;
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calibrator->tests[calibrator->current_test].drawn_y = drawn_y;
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cairo_translate(cr, drawn_x, drawn_y);
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cairo_set_line_width(cr, 2.0);
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cairo_set_source_rgb(cr, 1.0, 0.0, 0.0);
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cairo_move_to(cr, 0, -10.0);
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cairo_line_to(cr, 0, 10.0);
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cairo_stroke(cr);
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cairo_move_to(cr, -10.0, 0);
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cairo_line_to(cr, 10.0, 0.0);
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cairo_stroke(cr);
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cairo_destroy(cr);
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cairo_surface_destroy(surface);
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}
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static struct calibrator *
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calibrator_create(struct display *display)
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{
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struct calibrator *calibrator;
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calibrator = malloc(sizeof *calibrator);
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if (calibrator == NULL)
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return NULL;
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calibrator->window = window_create(display);
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calibrator->widget = window_add_widget(calibrator->window, calibrator);
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window_set_title(calibrator->window, "Wayland calibrator");
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calibrator->display = display;
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calibrator->current_test = ARRAY_LENGTH(test_ratios) - 1;
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widget_set_button_handler(calibrator->widget, button_handler);
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widget_set_redraw_handler(calibrator->widget, redraw_handler);
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window_set_fullscreen(calibrator->window, 1);
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return calibrator;
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}
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static void
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calibrator_destroy(struct calibrator *calibrator)
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{
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widget_destroy(calibrator->widget);
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window_destroy(calibrator->window);
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free(calibrator);
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}
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int
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main(int argc, char *argv[])
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{
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struct display *display;
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struct calibrator *calibrator;
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display = display_create(argc, argv);
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if (display == NULL) {
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fprintf(stderr, "failed to create display: %m\n");
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return -1;
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}
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calibrator = calibrator_create(display);
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if (!calibrator)
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return -1;
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display_run(display);
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calibrator_destroy(calibrator);
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display_destroy(display);
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return 0;
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}
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