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;
}
int read_jpeg(FILE *infile) {
struct jpeg_decompress_struct cinfo;
struct my_error_mgr jerr;
int i,y;
JSAMPARRAY buffer; /* Output row buffer */
int row_stride; /* physical row width in output buffer */
cinfo.err = jpeg_std_error(&jerr.pub);
jerr.pub.error_exit = my_error_exit;
if (setjmp(jerr.setjmp_buffer)) {
jpeg_destroy_decompress(&cinfo);
fclose(infile);
return 0;
}
jpeg_create_decompress(&cinfo);
jpeg_stdio_src(&cinfo, infile);
jpeg_read_header(&cinfo, TRUE);
jpeg_start_decompress(&cinfo);
row_stride = cinfo.output_width * cinfo.output_components;
buffer = (*cinfo.mem->alloc_sarray)
((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);
image_maxx = cinfo.output_width;
image_maxy = 0;
while (cinfo.output_scanline < cinfo.output_height) {
jpeg_read_scanlines(&cinfo, buffer, 1);
add_to_image(image_maxy++,buffer[0], image_maxx);
}
jpeg_finish_decompress(&cinfo);
jpeg_destroy_decompress(&cinfo);
return 1;
}
/* 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) */
}
}
}
