static int blits_intersect_or_touch(mdjvu_image_t image, int32 b1, int32 b2)
{
int32 x1 = mdjvu_image_get_blit_x(image, b1);
int32 x2 = mdjvu_image_get_blit_x(image, b2);
int32 y1 = mdjvu_image_get_blit_y(image, b1);
int32 y2 = mdjvu_image_get_blit_y(image, b2);
mdjvu_bitmap_t bitmap1 = mdjvu_image_get_blit_bitmap(image, b1);
mdjvu_bitmap_t bitmap2 = mdjvu_image_get_blit_bitmap(image, b2);
int32 w1 = mdjvu_bitmap_get_width(bitmap1);
int32 w2 = mdjvu_bitmap_get_width(bitmap2);
int32 h1 = mdjvu_bitmap_get_height(bitmap1);
int32 h2 = mdjvu_bitmap_get_height(bitmap2);
return segments_intersect_or_touch(x1, w1, x2, w2)
&& segments_intersect_or_touch(y1, h1, y2, h2);
}
mdjvu_image_t
mdjvu_split(mdjvu_bitmap_t bitmap, int32 dpi, mdjvu_split_options_t opt)
{
int32 width = mdjvu_bitmap_get_width(bitmap);
int32 height = mdjvu_bitmap_get_height(bitmap);
mdjvu_image_t result = mdjvu_image_create(width, height);
mdjvu_image_enable_suspiciously_big_flags(result);
mdjvu_image_set_resolution(result, dpi);
add_to_image(result, bitmap, dpi, opt, 0, 0, /* big: */ 0);
return result;
}
mdjvu_pattern_t mdjvu_pattern_create(mdjvu_bitmap_t bitmap)
{
int32 w = mdjvu_bitmap_get_width(bitmap);
int32 h = mdjvu_bitmap_get_height(bitmap);
mdjvu_pattern_t pattern;
byte **pixels = mdjvu_create_2d_array(w, h);
mdjvu_bitmap_unpack_all(bitmap, pixels);
pattern = mdjvu_pattern_create_from_array(pixels, w, h);
mdjvu_destroy_2d_array(pixels);
return pattern;
}
MDJVU_IMPLEMENT mdjvu_bitmap_t mdjvu_get_erosion_mask(mdjvu_bitmap_t bmp)
{
int32 w = mdjvu_bitmap_get_width(bmp);
int32 h = mdjvu_bitmap_get_height(bmp);
mdjvu_bitmap_t result = mdjvu_bitmap_create(w, h);
int32 i;
unsigned char *u, *t, *l, *r;
if (h < 3) return result;
u = (unsigned char *) malloc(w); /* upper row */
t = (unsigned char *) malloc(w); /* this row */
l = (unsigned char *) malloc(w); /* lower row */
r = (unsigned char *) malloc(w); /* result */
mdjvu_bitmap_unpack_row_0_or_1(bmp, t, 0);
mdjvu_bitmap_unpack_row_0_or_1(bmp, l, 1);
for (i = 1; i < h - 1; i++)
{
unsigned char *tmp = u;
u = t;
t = l;
l = tmp;
mdjvu_bitmap_unpack_row_0_or_1(bmp, l, i + 1);
get_erosion_candidates_in_a_row(r, u, t, l, w);
mdjvu_bitmap_pack_row(result, r, i);
}
free(u);
free(t);
free(l);
free(r);
return result;
}
MDJVU_IMPLEMENT void mdjvu_smooth(mdjvu_bitmap_t b)
{
int32 w = mdjvu_bitmap_get_width(b);
int32 h = mdjvu_bitmap_get_height(b);
int32 i;
unsigned char *u, *t, *l, *r;
if (h < 3) return;
u = (unsigned char *) calloc(w + 2, 1) + 1; /* upper row */
t = (unsigned char *) calloc(w + 2, 1) + 1; /* this row */
l = (unsigned char *) calloc(w + 2, 1) + 1; /* lower row */
r = (unsigned char *) malloc(w); /* result */
mdjvu_bitmap_unpack_row_0_or_1(b, l, 0);
for (i = 0; i < h; i++)
{
unsigned char *tmp = u;
u = t;
t = l;
l = tmp;
if (i + 1 < h)
mdjvu_bitmap_unpack_row_0_or_1(b, l, i + 1);
else
memset(l, 0, w);
smooth_row(r, u, t, l, w);
mdjvu_bitmap_pack_row(b, r, i);
}
free(u - 1);
free(t - 1);
free(l - 1);
free(r);
}
MDJVU_IMPLEMENT void mdjvu_sort_blits(mdjvu_image_t img)
{
/* We're going to sort only blits with `is_a_letter' flag set. */
int32 char_blit_count = 0;
int32 blit_count, i, j, maxtopchange, ccno;
BlitPassport *bps;
int32 *bottoms, *passport_of_blit;
if (!mdjvu_image_has_not_a_letter_flags(img))
mdjvu_calculate_not_a_letter_flags(img);
/* Count letter blits */
blit_count = mdjvu_image_get_blit_count(img);
for (i = 0; i < blit_count; i++)
{
mdjvu_bitmap_t bmp = mdjvu_image_get_blit_bitmap(img, i);
if (!mdjvu_image_get_not_a_letter_flag(img, bmp))
char_blit_count++;
}
if (char_blit_count < 2) return;
/* Allocate `bps' and `bottoms' arrays */
bps = (BlitPassport *) malloc(char_blit_count * sizeof(BlitPassport));
bottoms = (int32 *) malloc(char_blit_count * sizeof(int32));
/* Fill in `bps' with character blit passports */
j = 0;
for (i = 0; i < blit_count; i++)
{
mdjvu_bitmap_t bmp = mdjvu_image_get_blit_bitmap(img, i);
if (!mdjvu_image_get_not_a_letter_flag(img, bmp))
{
int32 x = bps[j].left = mdjvu_image_get_blit_x(img, i);
int32 y = bps[j].top = mdjvu_image_get_blit_y(img, i);;
bps[j].right = x + mdjvu_bitmap_get_width(bmp) - 1;
bps[j].bottom = y + mdjvu_bitmap_get_height(bmp) - 1;
bps[j].original_index = i;
j++;
}
}
/* Sort the BlitPassports list in top-to-bottom order. */
qsort(bps, char_blit_count, sizeof(BlitPassport),
&compare_top_edges_downward);
/* Subdivide the ccarray list roughly into text lines [LYB] */
/* Determine maximal top deviation */
maxtopchange = mdjvu_image_get_width(img) / 40;
if (maxtopchange < 32) maxtopchange = 32;
/* Loop until processing all ccs */
ccno = 0;
while (ccno < char_blit_count) /* ccno will be increasing constantly */
{
/* Gather first line approximation */
int32 sublist_top = bps[ccno].top;
int32 sublist_bottom = bps[ccno].bottom;
int32 nccno;
/* nccno will be at least ccno + 1,
* or otherwise we're hung.
*/
for (nccno = ccno; nccno < char_blit_count; nccno++)
{
int32 bottom;
if (bps[nccno].top > sublist_bottom) break;
if (bps[nccno].top > sublist_top + maxtopchange) break;
bottom = bps[nccno].bottom;
bottoms[nccno - ccno] = bottom;
if (bottom > sublist_bottom)
sublist_bottom = bottom;
}
/* If more than one candidate cc for the line */
if (nccno > ccno + 1)
{
/* Compute median bottom */
int32 bottom;
qsort(bottoms, nccno - ccno, sizeof(int32),
&compare_integers_reversed);
bottom = bottoms[ (nccno - ccno - 1) / 2 ];
/* Compose final line */
for (nccno = ccno; nccno < char_blit_count; nccno++)
if (bps[nccno].top > bottom)
break;
/* Sort final line */
qsort(bps + ccno, nccno - ccno, sizeof(BlitPassport),
&compare_left_edges_rightward);
}
/* Next line */
ccno = nccno;
}
/* Permute the blits according to `bps' */
passport_of_blit = (int32 *) malloc(blit_count * sizeof(int32));
for (i = 0; i < blit_count; i++)
passport_of_blit[i] = -1;
for (i = 0; i < char_blit_count; i++)
passport_of_blit[bps[i].original_index] = i;
/* We'll maintain that bps[i].original_index points to the same blit */
for (i = 0; i < char_blit_count; i++)
{
int32 blit_to_put_here = bps[i].original_index;
mdjvu_image_exchange_blits(img, blit_to_put_here, i);
if (passport_of_blit[i] != -1)
bps[passport_of_blit[i]].original_index = blit_to_put_here;
passport_of_blit[blit_to_put_here] = passport_of_blit[i];
}
free(passport_of_blit);
free(bps);
free(bottoms);
}
static void add_to_image(mdjvu_image_t image,
mdjvu_bitmap_t bitmap,
int32 dpi,
mdjvu_split_options_t opt,
int32 blit_shift_x,
int32 blit_shift_y,
int big)
{
int32 max_shape_size = opt ? * (int32 *) opt : 0;
int32 width = mdjvu_bitmap_get_width(bitmap);
int32 height = mdjvu_bitmap_get_height(bitmap);
unsigned char **buf, **window_base, **window_buf, **map;
int32 window_shift = 0, y = 0, i;
if (!max_shape_size)
max_shape_size = dpi;
if (max_shape_size > height)
max_shape_size = height;
/* n-th line will be unpacked into buf[n % max_shape_size] + 1.
* ( +1 is to make the left margin)
* buf[max_shape_size] will always be blank.
*
* window_base[window_shift - 1]
* points to buf[max_shape_size] + 1 (blank line) - top margin
* window_base[window_shift + max_shape_size]
* points to buf[max_shape_size] + 1 (blank line) - bottom margin
* window_base[window_shift + i]
* points to buf[(window_shift + i) % max_shape_size] + 1.
*/
/* map has the right margin of 1 */
map = mdjvu_create_2d_array(width + 1, max_shape_size);
/* buf has left, right and bottom margins of 1 */
buf = mdjvu_create_2d_array(width + 2, max_shape_size + 1);
window_buf = (unsigned char **)
malloc(2 * (max_shape_size + 2) * sizeof(unsigned char *));
window_base = window_buf + 1;
/* Unpack initial portion of the bitmap; bind the window to the buffer */
for (i = 0; i < max_shape_size; i++)
{
window_base[i] = window_base[max_shape_size + i] = buf[i] + 1;
mdjvu_bitmap_unpack_row(bitmap, buf[i] + 1, i);
}
/* Setup top and bottom white margins */
window_base[-1] =
window_base[2 * max_shape_size - 1] =
buf[max_shape_size] + 1;
/* The "window moving" loop.
* We're moving a (width x max_shape_size) window through the image.
*/
while(1)
{
/* Extract some shapes from the window
* (shapes touching the topmost row will be affected).
*/
unsigned char *top_margin_save = /* make the top margin */
window_base[window_shift - 1]; /* (save what was there) */
unsigned char *bot_margin_save = /* same with the bottom margin */
window_base[window_shift + max_shape_size];
int32 old_window_shift;
window_base[window_shift - 1] = buf[max_shape_size] + 1; /* clear them */
window_base[window_shift + max_shape_size] = buf[max_shape_size] + 1;
process_row(window_base + window_shift, map,
/* index of a row to process: */ 0,
width, max_shape_size, image, 0, y, max_shape_size,
blit_shift_x, blit_shift_y, dpi, opt, big);
window_base[window_shift - 1] = top_margin_save; /* restore margins */
window_base[window_shift + max_shape_size] = bot_margin_save;
/* Shift the window */
y++;
old_window_shift = window_shift;
window_shift = y % max_shape_size;
if (y + max_shape_size > height)
break;
/* Unpack a new row into the bottom window row */
mdjvu_bitmap_unpack_row(bitmap, buf[old_window_shift] + 1,
y + max_shape_size - 1);
}
/* Process the last window fully */
for (i = 0; y + i < height; i++)
{
process_row(window_base + window_shift, map,
/* index of a row to process: */ i,
width, max_shape_size, image, 0, y, max_shape_size,
blit_shift_x, blit_shift_y, dpi, opt, big);
}
/* Clean up */
free(window_buf);
mdjvu_destroy_2d_array(map);
mdjvu_destroy_2d_array(buf);
}
/* Margins (1 pixel) from each side are required. */
static void process_row(unsigned char **pixels, unsigned char **map,
int32 y, int32 w, int32 h,
mdjvu_image_t image, int32 shift_x, int32 shift_y,
int32 max_shape_width,
int32 blit_shift_x, int32 blit_shift_y,
int32 dpi, mdjvu_split_options_t opt,
int big)
{
unsigned char *row = pixels[y];
int32 i;
for (i = 0; i < w; i++)
{
if (row[i])
{
int32 min_x, max_x, min_y, max_y, shape_width;
/* extract the contour */
mdjvu_bitmap_t bitmap;
walk_around_a_black_contour(pixels, map, i, y,
&min_x, &max_x, &min_y, &max_y);
bitmap = interpret_runs(min_x, max_x,
min_y, max_y,
map, pixels);
shape_width = mdjvu_bitmap_get_width(bitmap);
assert(shape_width == max_x - min_x + 1);
assert(mdjvu_bitmap_get_height(bitmap) == max_y - min_y + 1);
if (shape_width <= max_shape_width)
{
mdjvu_image_add_bitmap(image, bitmap);
mdjvu_image_add_blit(image, shift_x + min_x + blit_shift_x,
y + shift_y + blit_shift_y, bitmap);
mdjvu_image_set_suspiciously_big_flag(image, bitmap, big);
}
else
{
/* further split the bitmap */
int32 number_of_chunks = (shape_width + max_shape_width - 1)
/
max_shape_width;
int32 j;
int32 shape_height = mdjvu_bitmap_get_height(bitmap);
for (j = 0; j < number_of_chunks; j++)
{
int32 chunk_x = shape_width * j / number_of_chunks;
mdjvu_bitmap_t chunk = mdjvu_bitmap_crop(bitmap,
chunk_x, 0,
shape_width * (j+1) / number_of_chunks - chunk_x,
shape_height
);
/* After splitting, some white margins may be left,
* or the bitmap may lose connectivity.
* Apply the algorithm recursively to the chunk.
*/
add_to_image(image, chunk, dpi, opt,
shift_x + chunk_x + min_x + blit_shift_x,
y + shift_y + blit_shift_y, /* big: */ 1);
mdjvu_bitmap_destroy(chunk);
}
mdjvu_bitmap_destroy(bitmap);
} /* if (shape_width <= max_shape_width) */
}
}
}
MDJVU_IMPLEMENT mdjvu_bitmap_t mdjvu_average(mdjvu_bitmap_t *bitmaps,
int32 n,
int32 *cx, int32 *cy)
{
int32 i;
int32 min_x = 0, min_y = 0, max_x_plus_1 = 0, max_y_plus_1 = 0;
int32 *buf;
int32 buf_w, buf_h;
unsigned char *row;
int32 tmp_x, tmp_y;
int32 threshold = n / 2;
mdjvu_bitmap_t result;
if (n == 1)
{
return mdjvu_bitmap_clone(bitmaps[0]);
}
for (i = 0; i < n; i++)
{
int32 w = mdjvu_bitmap_get_width(bitmaps[i]);
int32 h = mdjvu_bitmap_get_height(bitmaps[i]);
int32 ncx = cx[i] / MDJVU_CENTER_QUANT;
int32 ncy = cy[i] / MDJVU_CENTER_QUANT;
assert(ncx >= 0 && ncx < w);
assert(ncy >= 0 && ncy < h);
if (-ncx < min_x) min_x = -ncx;
if (-ncy < min_y) min_y = -ncy;
if (w-ncx > max_x_plus_1) max_x_plus_1 = w-ncx;
if (h-ncy > max_y_plus_1) max_y_plus_1 = h-ncy;
}
buf_w = max_x_plus_1 - min_x;
buf_h = max_y_plus_1 - min_y;
buf = (int32 *) calloc(buf_w * buf_h, sizeof(int32));
row = (unsigned char *) malloc(buf_w);
/* Now adding the bitmaps to the buffer */
for (i = 0; i < n; i++)
{
int32 w = mdjvu_bitmap_get_width(bitmaps[i]);
int32 h = mdjvu_bitmap_get_height(bitmaps[i]);
int32 sx = min_x + cx[i] / MDJVU_CENTER_QUANT, sy = min_y + cy[i] / MDJVU_CENTER_QUANT;
int32 x, y;
for (y = 0; y < h; y++)
{
int32 *buf_row = buf + buf_w * (y - sy);
mdjvu_bitmap_unpack_row(bitmaps[i], row, y);
for (x = 0; x < w; x++)
{
if (row[x])
buf_row[x - sx]++;
}
}
}
result = mdjvu_bitmap_create(buf_w, buf_h);
for (i = 0; i < buf_h; i++)
{
int32 j;
for (j = 0; j < buf_w; j++)
{
row[j] = ( buf[i * buf_w + j] > threshold ? 1 : 0 );
}
mdjvu_bitmap_pack_row(result, row, i);
}
mdjvu_bitmap_remove_margins(result, &tmp_x, &tmp_y);
free(row);
free(buf);
return result;
}