quagga
Version:
An advanced barcode-scanner written in JavaScript
196 lines (185 loc) • 7.75 kB
JavaScript
import Tracer from './tracer';
/**
* http://www.codeproject.com/Tips/407172/Connected-Component-Labeling-and-Vectorization
*/
var Rasterizer = {
createContour2D: function() {
return {
dir: null,
index: null,
firstVertex: null,
insideContours: null,
nextpeer: null,
prevpeer: null
};
},
CONTOUR_DIR: {
CW_DIR: 0,
CCW_DIR: 1,
UNKNOWN_DIR: 2
},
DIR: {
OUTSIDE_EDGE: -32767,
INSIDE_EDGE: -32766
},
create: function(imageWrapper, labelWrapper) {
var imageData = imageWrapper.data,
labelData = labelWrapper.data,
width = imageWrapper.size.x,
height = imageWrapper.size.y,
tracer = Tracer.create(imageWrapper, labelWrapper);
return {
rasterize: function(depthlabel) {
var color,
bc,
lc,
labelindex,
cx,
cy,
colorMap = [],
vertex,
p,
cc,
sc,
pos,
connectedCount = 0,
i;
for ( i = 0; i < 400; i++) {
colorMap[i] = 0;
}
colorMap[0] = imageData[0];
cc = null;
for ( cy = 1; cy < height - 1; cy++) {
labelindex = 0;
bc = colorMap[0];
for ( cx = 1; cx < width - 1; cx++) {
pos = cy * width + cx;
if (labelData[pos] === 0) {
color = imageData[pos];
if (color !== bc) {
if (labelindex === 0) {
lc = connectedCount + 1;
colorMap[lc] = color;
bc = color;
vertex = tracer.contourTracing(cy, cx, lc, color, Rasterizer.DIR.OUTSIDE_EDGE);
if (vertex !== null) {
connectedCount++;
labelindex = lc;
p = Rasterizer.createContour2D();
p.dir = Rasterizer.CONTOUR_DIR.CW_DIR;
p.index = labelindex;
p.firstVertex = vertex;
p.nextpeer = cc;
p.insideContours = null;
if (cc !== null) {
cc.prevpeer = p;
}
cc = p;
}
} else {
vertex = tracer
.contourTracing(cy, cx, Rasterizer.DIR.INSIDE_EDGE, color, labelindex);
if (vertex !== null) {
p = Rasterizer.createContour2D();
p.firstVertex = vertex;
p.insideContours = null;
if (depthlabel === 0) {
p.dir = Rasterizer.CONTOUR_DIR.CCW_DIR;
} else {
p.dir = Rasterizer.CONTOUR_DIR.CW_DIR;
}
p.index = depthlabel;
sc = cc;
while ((sc !== null) && sc.index !== labelindex) {
sc = sc.nextpeer;
}
if (sc !== null) {
p.nextpeer = sc.insideContours;
if (sc.insideContours !== null) {
sc.insideContours.prevpeer = p;
}
sc.insideContours = p;
}
}
}
} else {
labelData[pos] = labelindex;
}
} else if (labelData[pos] === Rasterizer.DIR.OUTSIDE_EDGE
|| labelData[pos] === Rasterizer.DIR.INSIDE_EDGE) {
labelindex = 0;
if (labelData[pos] === Rasterizer.DIR.INSIDE_EDGE) {
bc = imageData[pos];
} else {
bc = colorMap[0];
}
} else {
labelindex = labelData[pos];
bc = colorMap[labelindex];
}
}
}
sc = cc;
while (sc !== null) {
sc.index = depthlabel;
sc = sc.nextpeer;
}
return {
cc: cc,
count: connectedCount
};
},
debug: {
drawContour: function(canvas, firstContour) {
var ctx = canvas.getContext("2d"),
pq = firstContour,
iq,
q,
p;
ctx.strokeStyle = "red";
ctx.fillStyle = "red";
ctx.lineWidth = 1;
if (pq !== null) {
iq = pq.insideContours;
} else {
iq = null;
}
while (pq !== null) {
if (iq !== null) {
q = iq;
iq = iq.nextpeer;
} else {
q = pq;
pq = pq.nextpeer;
if (pq !== null) {
iq = pq.insideContours;
} else {
iq = null;
}
}
switch (q.dir) {
case Rasterizer.CONTOUR_DIR.CW_DIR:
ctx.strokeStyle = "red";
break;
case Rasterizer.CONTOUR_DIR.CCW_DIR:
ctx.strokeStyle = "blue";
break;
case Rasterizer.CONTOUR_DIR.UNKNOWN_DIR:
ctx.strokeStyle = "green";
break;
}
p = q.firstVertex;
ctx.beginPath();
ctx.moveTo(p.x, p.y);
do {
p = p.next;
ctx.lineTo(p.x, p.y);
} while (p !== q.firstVertex);
ctx.stroke();
}
}
}
};
}
};
export default Rasterizer;