Subversion Repositories or1k

/*

 * Demonstrates loading a binary PPM file and displaying it in a window

 * as a Pixmap.

 */

/* Comment this definition out if you don't want to use server side pixmaps */

/* (it will be slower but will work on device drivers without bitblt) */

#define USE_PIXMAPS

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

#include <nano-X.h>

GR_WINDOW_ID window;    /* ID for output window */

#ifdef USE_PIXMAPS

GR_WINDOW_ID pmap;      /* ID for pixmap */

#endif

GR_GC_ID gc;            /* Graphics context */

int width, height;      /* Size of image */

unsigned char *data;    /* Local copy of image data */

void do_exposure(GR_EVENT_EXPOSURE *event)

{

        /* The window has been exposed so redraw it */

#ifdef USE_PIXMAPS

        GrCopyArea(window, gc, 0, 0, width, height, pmap, 0, 0, MWROP_SRCCOPY);

#else

        GrArea(window, gc, 0, 0, width, height, data, MWPF_RGB);

#endif

}

void errorhandler(GR_EVENT *ep)

{

        printf("Error (%s) code %d id %d", ep->error.name,

                ep->error.code, ep->error.id);

        exit(1);

}

int main(int argc, char *argv[])

{

        unsigned char line[256];

        GR_EVENT event;

        FILE *infile;

        int i, o;

        unsigned char *p;

        if(argc != 2) {

                printf("Usage: demo6 <filename.ppm>\n");

                exit(1);

        }

        if(!(infile = fopen(argv[1], "r"))) {

                printf("Couldn't open \"%s\" for reading: %s\n", argv[1],

                                                strerror(errno));

                exit(2);

        }

        /* Read magic number (P6 = colour, binary encoded PPM file) */

        if(!fgets(line, 256, infile)) goto truncated;

        if(line[0] != 'P' || line[1] != '6') {

                printf("Unsupported PPM type or not a PPM file.\n");

                printf("Please supply a valid P6 format file (colour, with "

                        "binary encoding).\n");

        }

        /* Strip comments */

        do {

                if(!fgets(line, 256, infile)) goto truncated;

        } while(line[0] == '#');

        /* Read width and height */

        sscanf(line, "%i %i", &width, &height);

        /* Read the maximum colour value */

        if(!fgets(line, 256, infile)) goto truncated;

        sscanf(line, "%i", &i);

        if(i != 255) {

                printf("Truecolour mode only is supported\n");

                exit(4);

        }

        /* Calculate how many bytes of image data there is */

        i = width * height * 3;

        /* Calculate how many bytes of data there will be after unpacking */

        o = width * height * 4;

        /* Allocate the space to store the data whilst it's being loaded */

        if(!(data = malloc(o))) {

                printf("Not enough memory to load image\n");

                exit(5);

        }

        /* Read the data in and unpack it to RGBX format */

        /* The lower byte isn't used so we don't set it to anything */

        p = data;

        while(o) {

                if(fread(p, 1, 3, infile) != 3) goto truncated;

                p += 4;

                o -= 4;

        }

        /* We don't need the input file anymore so close it */

        fclose(infile);

        /* Register the error handler */

        GrSetErrorHandler(errorhandler);

        if(GrOpen() < 0) {

                printf("Couldn't connect to Nano-X server\n");

                exit(6);

        }

#ifdef USE_PIXMAPS

        /* Create the pixmap to store the picture in */

        pmap = GrNewPixmap(width, height, NULL);

#endif

        /* Create a graphics context */

        gc = GrNewGC();

#ifdef USE_PIXMAPS

        /* Copy the image data into the pixmap */

        GrArea(pmap, gc, 0, 0, width, height, data, MWPF_RGB);

        /* We can free the image data now because it's stored in the pixmap */

        free(data);

#endif

        /* Create a window to output the image to */

        window = GrNewWindow(GR_ROOT_WINDOW_ID, 0, 0, width, height, 0, 0, 0);

        /* Select expose events so we can redraw the image when necessary */

        GrSelectEvents(window, GR_EVENT_MASK_EXPOSURE |

                                GR_EVENT_MASK_CLOSE_REQ);

        /* Make the window visible */

        GrMapWindow(window);

#ifdef USE_PIXMAPS

        /* Paint the pixmap onto it */

        GrCopyArea(window, gc, 0, 0, width, height, pmap, 0, 0,

                                                        MWROP_SRCCOPY);

#else

        GrArea(window, gc, 0, 0, width, height, data, MWPF_RGB);

#endif

        while(1) {

                GrGetNextEvent(&event);

                switch(event.type) {

                        case GR_EVENT_TYPE_EXPOSURE:

                                do_exposure(&event.exposure);

                                break;

                        case GR_EVENT_TYPE_CLOSE_REQ:

                                GrClose();

                                exit(0);

                }

        }

        return 0;

truncated:

        printf("Error: File appears to be truncated\n");

        exit(3);

}