MDJVU_IMPLEMENT mdjvu_bitmap_t mdjvu_bitmap_crop
(mdjvu_bitmap_t b, int32 left, int32 top, int32 w, int32 h)
{
if (left == 0 && top == 0 && w == BMP->width && h == BMP->height)
{
return mdjvu_bitmap_clone(b);
}
else
{
mdjvu_bitmap_t result;
int32 i = top, count = h;
unsigned char *buf;
assert(left >= 0);
assert(left + w <= BMP->width);
assert(top >= 0);
assert(top + h <= BMP->height);
result = mdjvu_bitmap_create(w, h);
buf = (unsigned char *) malloc(BMP->width);
while (count--)
{
mdjvu_bitmap_unpack_row(b, buf, i);
mdjvu_bitmap_pack_row(result, buf + left, i - top);
i++;
}
free(buf);
return result;
}
}
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;
}
