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Showimage

A simple example that loads an image and shows it in X11 window.

// SPDX-License-Identifier: GPL-2.1-or-later
/*
 * Copyright (C) 2009-2013 Cyril Hrubis <metan@ucw.cz>
 */

/*

  Simple example that shows X11 window with image.

 */

#include <stdio.h>
#include <errno.h>
#include <string.h>

#include <gfxprim.h>

int main(int argc, char *argv[])
{
        gp_backend *backend;
        gp_pixmap *image;

        if (argc != 2) {
                fprintf(stderr, "Takes image as an argument\n");
                return 1;
        }

        /* Load image */
        image = gp_load_image(argv[1], NULL);

        if (!image) {
                fprintf(stderr, "Failed to load bitmap: %s\n", strerror(errno));
                return 1;
        }

        /* Initalize backend */
        backend = gp_x11_init(NULL, 0, 0, image->w, image->h, argv[1], 0);

        if (!backend) {
                fprintf(stderr, "Failed to initalize backend\n");
                return 1;
        }

        /* Blit image into the window and show it */
        gp_blit(image, 0, 0, image->w, image->h, backend->pixmap, 0, 0);
        gp_backend_flip(backend);

        /* Wait for events  */
        for (;;) {
                gp_event ev;

                gp_backend_wait_event(backend, &ev);

                if (ev.type == GP_EV_KEY && ev.val == GP_KEY_Q) {
                        gp_backend_exit(backend);
                        return 0;
                }

                if (ev.type == GP_EV_SYS && ev.code == GP_EV_SYS_RESIZE) {
                        int cx, cy;

                        gp_backend_resize_ack(backend);

                        cx = ((int)backend->pixmap->w - (int)image->w) / 2;
                        cy = ((int)backend->pixmap->h - (int)image->h) / 2;

                        gp_fill(backend->pixmap, 0);
                        gp_blit_clipped(image, 0, 0, image->w, image->h, backend->pixmap, cx, cy);
                        gp_backend_flip(backend);
                }
        }

        return 0;
}