static ssize_t sub_read(gp_io *io, void *buf, size_t size)
{
struct sub_io *sub_io = GP_IO_PRIV(io);
if (sub_io->cur > sub_io->end) {
GP_BUG("Current offset (%zi) is after the end (%zi)",
sub_io->cur, sub_io->end);
errno = EINVAL;
return 0;
}
size_t io_size = sub_io->end - sub_io->cur;
size = GP_MIN(size, io_size);
if (size == 0)
return 0;
ssize_t ret = gp_io_read(sub_io->io, buf, size);
if (ret < 0)
return ret;
sub_io->cur += ret;
return ret;
}
/*
* The interlacing consists of 8 pixel high strips. Each pass adds some lines
* into each strip. This function maps y in the gif buffer to real y.
*/
static inline unsigned int interlace_real_y(GifFileType *gf, unsigned int y)
{
const unsigned int h = gf->Image.Height;
unsigned int real_y;
/* Pass 1: Line 0 for each strip */
real_y = 8 * y;
if (real_y < h)
return real_y;
/* Pass 2: Line 4 for each strip */
real_y = 8 * (y - (h - 1)/8 - 1) + 4;
if (real_y < h)
return real_y;
/* Pass 3: Lines 2 and 6 */
real_y = 4 * (y - (h - 1)/4 - 1) + 2;
if (real_y < h)
return real_y;
/* Pass 4: Lines 1, 3, 5, and 7 */
real_y = 2 * (y - h/2 - h%2) + 1;
if (real_y < h)
return real_y;
GP_BUG("real_y > h");
return 0;
}
int GP_WriteJPG(const GP_Context *src, GP_IO *io,
GP_ProgressCallback *callback)
{
struct jpeg_compress_struct cinfo;
GP_PixelType out_pix;
struct my_jpg_err my_err;
struct my_dest_mgr dst;
uint8_t buf[1024];
int err;
GP_DEBUG(1, "Writing JPG Image to I/O (%p)", io);
out_pix = GP_LineConvertible(src->pixel_type, out_pixel_types);
if (out_pix == GP_PIXEL_UNKNOWN) {
GP_DEBUG(1, "Unsupported pixel type %s",
GP_PixelTypeName(src->pixel_type));
errno = ENOSYS;
return 1;
}
if (setjmp(my_err.setjmp_buf)) {
errno = EIO;
return 1;
}
cinfo.err = jpeg_std_error(&my_err.error_mgr);
my_err.error_mgr.error_exit = my_error_exit;
jpeg_create_compress(&cinfo);
init_dest_mgr(&dst, io, buf, sizeof(buf));
cinfo.dest = (void*)&dst;
cinfo.image_width = src->w;
cinfo.image_height = src->h;
switch (out_pix) {
case GP_PIXEL_BGR888:
cinfo.input_components = 3;
cinfo.in_color_space = JCS_RGB;
break;
case GP_PIXEL_G8:
cinfo.input_components = 1;
cinfo.in_color_space = JCS_GRAYSCALE;
break;
default:
GP_BUG("Don't know how to set color_space and compoments");
}
jpeg_set_defaults(&cinfo);
jpeg_start_compress(&cinfo, TRUE);
if (out_pix != src->pixel_type)
err = save_convert(&cinfo, src, out_pix, callback);
else
err = save(&cinfo, src, callback);
if (err) {
jpeg_destroy_compress(&cinfo);
errno = err;
return 1;
}
jpeg_finish_compress(&cinfo);
jpeg_destroy_compress(&cinfo);
GP_ProgressCallbackDone(callback);
return 0;
}
