static int
_write (int fd,
char *buf, int maxlen, int buflen,
const unsigned char *src, int srclen)
{
if (buflen < 0)
return buflen;
while (srclen) {
int len;
len = buflen + srclen;
if (len > maxlen)
len = maxlen;
len -= buflen;
memcpy (buf + buflen, src, len);
buflen += len;
srclen -= len;
src += len;
if (buflen == maxlen) {
if (! _writen (fd, buf, buflen))
return -1;
buflen = 0;
}
}
return buflen;
}
static const char *
write_ppm (cairo_surface_t *surface, int fd)
{
char buf[4096];
cairo_format_t format;
const char *format_str;
const unsigned char *data;
int len;
int width, height, stride;
int i, j;
data = cairo_image_surface_get_data (surface);
height = cairo_image_surface_get_height (surface);
width = cairo_image_surface_get_width (surface);
stride = cairo_image_surface_get_stride (surface);
format = cairo_image_surface_get_format (surface);
if (format == CAIRO_FORMAT_ARGB32) {
/* see if we can convert to a standard ppm type and trim a few bytes */
const unsigned char *alpha = data;
for (j = height; j--; alpha += stride) {
for (i = 0; i < width; i++) {
if ((*(unsigned int *) (alpha+4*i) & 0xff000000) != 0xff000000)
goto done;
}
}
format = CAIRO_FORMAT_RGB24;
done: ;
}
switch (format) {
case CAIRO_FORMAT_ARGB32:
/* XXX need true alpha for svg */
format_str = "P7";
break;
case CAIRO_FORMAT_RGB24:
format_str = "P6";
break;
case CAIRO_FORMAT_A8:
format_str = "P5";
break;
case CAIRO_FORMAT_A1:
default:
return "unhandled image format";
}
len = sprintf (buf, "%s %d %d 255\n", format_str, width, height);
for (j = 0; j < height; j++) {
const unsigned int *row = (unsigned int *) (data + stride * j);
switch ((int) format) {
case CAIRO_FORMAT_ARGB32:
len = _write (fd,
buf, sizeof (buf), len,
(unsigned char *) row, 4 * width);
break;
case CAIRO_FORMAT_RGB24:
for (i = 0; i < width; i++) {
unsigned char rgb[3];
unsigned int p = *row++;
rgb[0] = (p & 0xff0000) >> 16;
rgb[1] = (p & 0x00ff00) >> 8;
rgb[2] = (p & 0x0000ff) >> 0;
len = _write (fd,
buf, sizeof (buf), len,
rgb, 3);
}
break;
case CAIRO_FORMAT_A8:
len = _write (fd,
buf, sizeof (buf), len,
(unsigned char *) row, width);
break;
}
if (len < 0)
return "write failed";
}
if (len && ! _writen (fd, buf, len))
return "write failed";
return NULL;
}
int
writen(register int fd, register char *ptr, register int nbytes)
{
return _writen(fd, ptr, nbytes, &timeout, 1);
}
