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/*
ppedit - A pattern plate editor for Spiro splines.
Copyright (C) 2007 Raph Levien
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA.
*/
#include <stdio.h>
#include <string.h>
#include "zmisc.h"
#include "image.h"
/* An image loaded into memory. */
struct _image {
unsigned char *buf;
int width;
int height;
int rowstride;
};
static image *
load_ppm_file(FILE *f, char **reason)
{
image *result;
char line[256];
int xs, ys;
int depth;
int n;
fseek(f, 0, SEEK_SET);
fgets(line, sizeof(line), f);
do {
fgets(line, sizeof(line), f);
} while (line[0] == '#');
n = sscanf(line, "%d %d", &xs, &ys);
if (n != 2) {
*reason = "Error reading ppmraw size line";
fclose(f);
return NULL;
}
do {
fgets(line, sizeof(line), f);
} while (line[0] == '#');
n = sscanf(line, "%d", &depth);
if (n != 1) {
*reason = "Error reading ppmraw depth line";
fclose(f);
return NULL;
}
result = znew(image, 1);
result->rowstride = 3 * xs;
result->buf = zalloc(ys * result->rowstride);
result->width = xs;
result->height = ys;
fread(result->buf, 1, ys * result->rowstride, f);
fclose(f);
return result;
}
image *
load_image_file(const char *fn, char **reason)
{
FILE *f = fopen(fn, "rb");
unsigned char buf[256];
int n;
if (f == NULL) {
*reason = "Error opening file";
return NULL;
}
n = fread(buf, 1, sizeof(buf), f);
if (n < 4) {
*reason = "Short file";
fclose(f);
return NULL;
}
if (buf[0] != 'P' || buf[1] != '6') {
*reason = "Unrecognized magic";
fclose(f);
return NULL;
}
return load_ppm_file(f, reason);
}
void
free_image(image *im)
{
zfree(im->buf);
zfree(im);
}
void
render_image(image *im, const double affine[6],
unsigned char *buf, int rowstride, int x0, int y0, int x1, int y1)
{
int y;
unsigned char *dest_line = buf;
int src_x0 = x0;
for (y = y0; y < y1; y++) {
int src_y = y;
if (src_y >= 0 && src_y < im->height) {
unsigned char *img_line = im->buf + src_y * im->rowstride;
int left_pad = -src_x0;
int img_run, img_off, right_pad;
if (left_pad > x1 - x0) left_pad = x1 - x0;
if (left_pad > 0) {
memset(dest_line, 255, 3 * left_pad);
} else left_pad = 0;
img_off = src_x0;
if (img_off < 0) img_off = 0;
img_run = x1 - x0 - left_pad;
if (img_run > im->width - img_off) img_run = im->width - img_off;
if (img_run > 0) {
memcpy(dest_line + 3 * left_pad, img_line + 3 * img_off, 3 * img_run);
} else img_run = 0;
right_pad = x1 - x0 - left_pad - img_run;
if (right_pad > 0) {
memset(dest_line + 3 * (left_pad + img_run), 255, 3 * right_pad);
}
} else {
memset(dest_line, 255, rowstride);
}
dest_line += rowstride;
}
}
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