// -- Adds a run to the CCImage
inline void
CCImage::add_single_run(int y, int x1, int x2, int ccid)
{
int index = runs.hbound();
runs.touch(++index);
Run& run = runs[index];
run.y = y;
run.x1 = x1;
run.x2 = x2;
run.ccid = ccid;
}
int
DjVuPalette::compute_palette(int maxcolors, int minboxsize)
{
if (!hist)
G_THROW( ERR_MSG("DjVuPalette.no_color") );
if (maxcolors<1 || maxcolors>MAXPALETTESIZE)
G_THROW( ERR_MSG("DjVuPalette.many_colors") );
// Paul Heckbert: "Color Image Quantization for Frame Buffer Display",
// SIGGRAPH '82 Proceedings, page 297. (also in ppmquant)
// Collect histogram colors
int sum = 0;
int ncolors = 0;
GTArray<PData> pdata;
{ // extra nesting for windows
for (GPosition p = *hist; p; ++p)
{
pdata.touch(ncolors);
PData &data = pdata[ncolors++];
int k = hist->key(p);
data.p[0] = (k>>16) & 0xff;
data.p[1] = (k>>8) & 0xff;
data.p[2] = (k) & 0xff;
data.w = (*hist)[p];
sum += data.w;
}
}
// Create first box
GList<PBox> boxes;
PBox newbox;
newbox.data = pdata;
newbox.colors = ncolors;
newbox.boxsize = 256;
newbox.sum = sum;
boxes.append(newbox);
// Repeat spliting boxes
while (boxes.size() < maxcolors)
{
// Find suitable box
GPosition p;
for (p=boxes; p; ++p)
if (boxes[p].colors>=2 && boxes[p].boxsize>minboxsize)
break;
if (! p)
break;
// Find box boundaries
PBox &splitbox = boxes[p];
unsigned char pmax[3];
unsigned char pmin[3];
pmax[0] = pmin[0] = splitbox.data->p[0];
pmax[1] = pmin[1] = splitbox.data->p[1];
pmax[2] = pmin[2] = splitbox.data->p[2];
{ // extra nesting for windows
for (int j=1; j<splitbox.colors; j++)
{
pmax[0] = umax(pmax[0], splitbox.data[j].p[0]);
pmax[1] = umax(pmax[1], splitbox.data[j].p[1]);
pmax[2] = umax(pmax[2], splitbox.data[j].p[2]);
pmin[0] = umin(pmin[0], splitbox.data[j].p[0]);
pmin[1] = umin(pmin[1], splitbox.data[j].p[1]);
pmin[2] = umin(pmin[2], splitbox.data[j].p[2]);
}
}
// Determine split direction and sort
int bl = pmax[0]-pmin[0];
int gl = pmax[1]-pmin[1];
int rl = pmax[2]-pmin[2];
splitbox.boxsize = (bl>gl ? (rl>bl ? rl : bl) : (rl>gl ? rl : gl));
if (splitbox.boxsize <= minboxsize)
continue;
if (gl == splitbox.boxsize)
qsort(splitbox.data, splitbox.colors, sizeof(PData), gcomp);
else if (rl == splitbox.boxsize)
qsort(splitbox.data, splitbox.colors, sizeof(PData), rcomp);
else
qsort(splitbox.data, splitbox.colors, sizeof(PData), bcomp);
// Find median
int lowercolors = 0;
int lowersum = 0;
while (lowercolors<splitbox.colors-1 && lowersum+lowersum<splitbox.sum)
lowersum += splitbox.data[lowercolors++].w;
// Compute new boxes
newbox.data = splitbox.data + lowercolors;
newbox.colors = splitbox.colors - lowercolors;
newbox.sum = splitbox.sum - lowersum;
splitbox.colors = lowercolors;
splitbox.sum = lowersum;
// Insert boxes at proper location
GPosition q;
for (q=p; q; ++q)
if (boxes[q].sum < newbox.sum)
break;
boxes.insert_before(q, newbox);
for (q=p; q; ++q)
if (boxes[q].sum < splitbox.sum)
break;
boxes.insert_before(q, boxes, p);
}
// Fill palette array
ncolors = 0;
palette.empty();
palette.resize(0,boxes.size()-1);
{ // extra nesting for windows
for (GPosition p=boxes; p; ++p)
{
PBox &box = boxes[p];
// Compute box representative color
float bsum = 0;
float gsum = 0;
float rsum = 0;
for (int j=0; j<box.colors; j++)
{
float w = (float)box.data[j].w;
bsum += box.data[j].p[0] * w;
gsum += box.data[j].p[1] * w;
rsum += box.data[j].p[2] * w;
}
PColor &color = palette[ncolors++];
color.p[0] = (unsigned char) fmin(255, bsum/box.sum);
color.p[1] = (unsigned char) fmin(255, gsum/box.sum);
color.p[2] = (unsigned char) fmin(255, rsum/box.sum);
color.p[3] = ( color.p[0]*BMUL + color.p[1]*GMUL + color.p[2]*RMUL) / SMUL;
}
}
// Save dominant color
PColor dcolor = palette[0];
// Sort palette colors in luminance order
qsort((PColor*)palette, ncolors, sizeof(PColor), lcomp);
// Clear invalid data
colordata.empty();
delete pmap;
pmap = 0;
// Return dominant color
return color_to_index_slow(dcolor.p);
}
// -- Merges small ccs of similar color and splits large ccs
void
CCImage::merge_and_split_ccs(int smallsize, int largesize)
{
int ncc = ccs.size();
int nruns = runs.size();
int splitsize = largesize;
if (ncc <= 0) return;
// Associative map for storing merged ccids
GMap<Grid_x_Color,int> map;
nregularccs = ncc;
// Set the correct ccids for the runs
for (int ccid=0; ccid<ccs.size(); ccid++)
{
CC* cc = &ccs[ccid];
if (cc->nrun <= 0) continue;
Grid_x_Color key;
key.color = cc->color;
int ccheight = cc->bb.height();
int ccwidth = cc->bb.width();
if (ccheight<=smallsize && ccwidth<=smallsize)
{
key.gridi = (cc->bb.ymin+cc->bb.ymax)/splitsize/2;
key.gridj = (cc->bb.xmin+cc->bb.xmax)/splitsize/2;
int newccid = makeccid(key, map, ncc);
for(int runid=cc->frun; runid<cc->frun+cc->nrun; runid++)
runs[runid].ccid = newccid;
}
else if (ccheight>=largesize || ccwidth>=largesize)
{
for(int runid=cc->frun; runid<cc->frun+cc->nrun; runid++)
{
Run *r = & runs[runid];
key.gridi = r->y/splitsize;
key.gridj = r->x1/splitsize;
int gridj_end = r->x2/splitsize;
int gridj_span = gridj_end - key.gridj;
r->ccid = makeccid(key, map, ncc);
if (gridj_span>0)
{
// truncate current run
runs.touch(nruns+gridj_span-1);
r = &runs[runid];
int x = key.gridj*splitsize + splitsize;
int x_end = r->x2;
r->x2 = x-1;
// append additional runs to the runs array
while (++key.gridj < gridj_end)
{
Run& newrun = runs[nruns++];
newrun.y = r->y;
newrun.x1 = x;
x += splitsize;
newrun.x2 = x-1;
newrun.color = key.color;
newrun.ccid = makeccid(key, map, ncc);
}
// append last run to the run array
Run& newrun = runs[nruns++];
newrun.y = r->y;
newrun.x1 = x;
newrun.x2 = x_end;
newrun.color = key.color;
newrun.ccid = makeccid(key, map, ncc);
}
}
}
}
// Recompute cc descriptors
make_ccs_from_ccids();
}
// -- Performs color connected component analysis
void
CCImage::make_ccids_by_analysis()
{
// Sort runs
runs.sort();
// Single Pass Connected Component Analysis (with unodes)
int n;
int p=0;
GTArray<int> umap;
for (n=0; n<=runs.hbound(); n++)
{
int y = runs[n].y;
int x1 = runs[n].x1 - 1;
int x2 = runs[n].x2 + 1;
int color = runs[n].color;
int id = (umap.hbound() + 1);
// iterate over previous line runs
if (p>0) p--;
for(;runs[p].y < y-1;p++);
for(;(runs[p].y < y) && (runs[p].x1 <= x2);p++ )
{
if ( runs[p].x2 >= x1 )
{
if (runs[p].color == color)
{
// previous run touches current run and has same color
int oid = runs[p].ccid;
while (umap[oid] < oid)
oid = umap[oid];
if ((int)id > umap.hbound()) {
id = oid;
} else if (id < oid) {
umap[oid] = id;
} else {
umap[id] = oid;
id = oid;
}
// freshen previous run id
runs[p].ccid = id;
}
// stop if previous run goes past current run
if (runs[p].x2 >= x2)
break;
}
}
// create new entry in umap
runs[n].ccid = id;
if (id > umap.hbound())
{
umap.touch(id);
umap[id] = id;
}
}
// Update umap and ccid
for (n=0; n<=runs.hbound(); n++)
{
Run &run = runs[n];
int ccid = run.ccid;
while (umap[ccid] < ccid)
ccid = umap[ccid];
umap[run.ccid] = ccid;
run.ccid = ccid;
}
}
// -- Merges small ccs and split large ccs
void
CCImage::merge_and_split_ccs()
{
int ncc = ccs.size();
int nruns = runs.size();
int splitsize = largesize;
if (ncc <= 0) return;
// Grid of special components
int gridwidth = (width+splitsize-1)/splitsize;
nregularccs = ncc;
// Set the correct ccids for the runs
for (int ccid=0; ccid<ncc; ccid++)
{
CC* cc = &ccs[ccid];
if (cc->nrun <= 0) continue;
int ccheight = cc->bb.height();
int ccwidth = cc->bb.width();
if (ccheight<=smallsize && ccwidth<=smallsize)
{
int gridi = (cc->bb.ymin+cc->bb.ymax)/splitsize/2;
int gridj = (cc->bb.xmin+cc->bb.xmax)/splitsize/2;
int newccid = ncc + gridi*gridwidth + gridj;
for(int runid=cc->frun; runid<cc->frun+cc->nrun; runid++)
runs[runid].ccid = newccid;
}
else if (ccheight>=largesize || ccwidth>=largesize)
{
for(int runid=cc->frun; runid<cc->frun+cc->nrun; runid++)
{
Run& r = runs[runid];
int y = r.y;
int x_start = r.x1;
int x_end = r.x2;
int gridi = y/splitsize;
int gridj_start = x_start/splitsize;
int gridj_end = x_end/splitsize;
int gridj_span = gridj_end-gridj_start;
int newccid = ncc + gridi*gridwidth + gridj_start;
if (! gridj_span)
{
r.ccid = newccid;
}
else // gridj_span>0
{
// truncate the current run
r.ccid = newccid++;
int x = (gridj_start+1)*splitsize;
r.x2 = x-1;
runs.touch(nruns+gridj_span-1);
// append additional runs to the runs array
for(int gridj=gridj_start+1; gridj<gridj_end; gridj++)
{
Run& newrun = runs[nruns++];
newrun.y = y;
newrun.x1 = x;
x += splitsize;
newrun.x2 = x-1;
newrun.ccid = newccid++;
}
// append last run to the run array
Run& newrun = runs[nruns++];
newrun.y = y;
newrun.x1 = x;
newrun.x2 = x_end;
newrun.ccid = newccid++;
}
}
}
}
// Recompute cc descriptors
make_ccs_from_ccids();
}
