/*
Copyright (c) 2011 Juan Mellado

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

/*
References:
- "OpenCV: Open Computer Vision Library"
http://sourceforge.net/projects/opencvlibrary/
- "Stack Blur: Fast But Goodlooking"
http://incubator.quasimondo.com/processing/fast_blur_deluxe.php
*/

var CV = CV || {};

CV.Image = function(width, height, data){
        this.width = width || 0;
        this.height = height || 0;
        this.data = data || [];
};

CV.grayscale = function(imageSrc, imageDst){
        var src = imageSrc.data, dst = imageDst.data, len = src.length,
        i = 0, j = 0;
        
        for (; i < len; i += 4){
                dst[j ++] =
                (src[i] * 0.299 + src[i + 1] * 0.587 + src[i + 2] * 0.114 + 0.5) & 0xff;
        }
        
        imageDst.width = imageSrc.width;
        imageDst.height = imageSrc.height;
        
        return imageDst;
};

CV.threshold = function(imageSrc, imageDst, threshold){
        var src = imageSrc.data, dst = imageDst.data,
        len = src.length, tab = [], i;
        
        for (i = 0; i < 256; ++ i){
                tab[i] = i <= threshold? 0: 255;
        }
        
        for (i = 0; i < len; ++ i){
                dst[i] = tab[ src[i] ];
        }
        
        imageDst.width = imageSrc.width;
        imageDst.height = imageSrc.height;
        
        return imageDst;
};

CV.adaptiveThreshold = function(imageSrc, imageDst, kernelSize, threshold){
        var src = imageSrc.data, dst = imageDst.data, len = src.length, tab = [], i;
        
        CV.stackBoxBlur(imageSrc, imageDst, kernelSize);
        
        for (i = 0; i < 768; ++ i){
                tab[i] = (i - 255 <= -threshold)? 255: 0;
        }
        
        for (i = 0; i < len; ++ i){
                dst[i] = tab[ src[i] - dst[i] + 255 ];
        }
        
        imageDst.width = imageSrc.width;
        imageDst.height = imageSrc.height;
        
        return imageDst;
};

CV.otsu = function(imageSrc){
        var src = imageSrc.data, len = src.length, hist = [],
        threshold = 0, sum = 0, sumB = 0, wB = 0, wF = 0, max = 0,
        mu, between, i;
        
        for (i = 0; i < 256; ++ i){
                hist[i] = 0;
        }
        
        for (i = 0; i < len; ++ i){
                hist[ src[i] ] ++;
        }
        
        for (i = 0; i < 256; ++ i){
                sum += hist[i] * i;
        }
        
        for (i = 0; i < 256; ++ i){
                wB += hist[i];
                if (0 !== wB){
                        
                        wF = len - wB;
                        if (0 === wF){
                                break;
                        }
                        
                        sumB += hist[i] * i;
                        
                        mu = (sumB / wB) - ( (sum - sumB) / wF );
                        
                        between = wB * wF * mu * mu;
                        
                        if (between > max){
                                max = between;
                                threshold = i;
                        }
                }
        }
        
        return threshold;
};

CV.stackBoxBlurMult =
[1, 171, 205, 293, 57, 373, 79, 137, 241, 27, 391, 357, 41, 19, 283, 265];

CV.stackBoxBlurShift =
[0, 9, 10, 11, 9, 12, 10, 11, 12, 9, 13, 13, 10, 9, 13, 13];

CV.BlurStack = function(){
        this.color = 0;
        this.next = null;
};

CV.stackBoxBlur = function(imageSrc, imageDst, kernelSize){
        var src = imageSrc.data, dst = imageDst.data,
        height = imageSrc.height, width = imageSrc.width,
        heightMinus1 = height - 1, widthMinus1 = width - 1,
        size = kernelSize + kernelSize + 1, radius = kernelSize + 1,
        mult = CV.stackBoxBlurMult[kernelSize],
        shift = CV.stackBoxBlurShift[kernelSize],
        stack, stackStart, color, sum, pos, start, p, x, y, i;
        
        stack = stackStart = new CV.BlurStack();
        for (i = 1; i < size; ++ i){
                stack = stack.next = new CV.BlurStack();
        }
        stack.next = stackStart;
        
        pos = 0;
        
        for (y = 0; y < height; ++ y){
                start = pos;
                
                color = src[pos];
                sum = radius * color;
                
                stack = stackStart;
                for (i = 0; i < radius; ++ i){
                        stack.color = color;
                        stack = stack.next;
                }
                for (i = 1; i < radius; ++ i){
                        stack.color = src[pos + i];
                        sum += stack.color;
                        stack = stack.next;
                }
                
                stack = stackStart;
                for (x = 0; x < width; ++ x){
                        dst[pos ++] = (sum * mult) >>> shift;
                        
                        p = x + radius;
                        p = start + (p < widthMinus1? p: widthMinus1);
                        sum -= stack.color - src[p];
                        
                        stack.color = src[p];
                        stack = stack.next;
                }
        }
        
        for (x = 0; x < width; ++ x){
                pos = x;
                start = pos + width;
                
                color = dst[pos];
                sum = radius * color;
                
                stack = stackStart;
                for (i = 0; i < radius; ++ i){
                        stack.color = color;
                        stack = stack.next;
                }
                for (i = 1; i < radius; ++ i){
                        stack.color = dst[start];
                        sum += stack.color;
                        stack = stack.next;
                        
                        start += width;
                }
                
                stack = stackStart;
                for (y = 0; y < height; ++ y){
                        dst[pos] = (sum * mult) >>> shift;
                        
                        p = y + radius;
                        p = x + ( (p < heightMinus1? p: heightMinus1) * width );
                        sum -= stack.color - dst[p];
                        
                        stack.color = dst[p];
                        stack = stack.next;
                        
                        pos += width;
                }
        }
        
        return imageDst;
};

CV.gaussianBlur = function(imageSrc, imageDst, imageMean, kernelSize){
        var kernel = CV.gaussianKernel(kernelSize);
        
        imageDst.width = imageSrc.width;
        imageDst.height = imageSrc.height;
        
        imageMean.width = imageSrc.width;
        imageMean.height = imageSrc.height;
        
        CV.gaussianBlurFilter(imageSrc, imageMean, kernel, true);
        CV.gaussianBlurFilter(imageMean, imageDst, kernel, false);
        
        return imageDst;
};

CV.gaussianBlurFilter = function(imageSrc, imageDst, kernel, horizontal){
        var src = imageSrc.data, dst = imageDst.data,
        height = imageSrc.height, width = imageSrc.width,
        pos = 0, limit = kernel.length >> 1,
        cur, value, i, j, k;
        
        for (i = 0; i < height; ++ i){
                
                for (j = 0; j < width; ++ j){
                        value = 0.0;
                        
                        for (k = -limit; k <= limit; ++ k){
                                
                                if (horizontal){
                                        cur = pos + k;
                                        if (j + k < 0){
                                                cur = pos;
                                        }
                                        else if (j + k >= width){
                                                cur = pos;
                                        }
                                }else{
                                        cur = pos + (k * width);
                                        if (i + k < 0){
                                                cur = pos;
                                        }
                                        else if (i + k >= height){
                                                cur = pos;
                                        }
                                }
                                
                                value += kernel[limit + k] * src[cur];
                        }
                        
                        dst[pos ++] = horizontal? value: (value + 0.5) & 0xff;
                }
        }
        
        return imageDst;
};

CV.gaussianKernel = function(kernelSize){
        var tab =
        [ [1],
        [0.25, 0.5, 0.25],
        [0.0625, 0.25, 0.375, 0.25, 0.0625],
        [0.03125, 0.109375, 0.21875, 0.28125, 0.21875, 0.109375, 0.03125] ],
        kernel = [], center, sigma, scale2X, sum, x, i;
        
        if ( (kernelSize <= 7) && (kernelSize % 2 === 1) ){
                kernel = tab[kernelSize >> 1];
        }else{
                center = (kernelSize - 1.0) * 0.5;
                sigma = 0.8 + (0.3 * (center - 1.0) );
                scale2X = -0.5 / (sigma * sigma);
                sum = 0.0;
                for (i = 0; i < kernelSize; ++ i){
                        x = i - center;
                        sum += kernel[i] = Math.exp(scale2X * x * x);
                }
                sum = 1 / sum;
                for (i = 0; i < kernelSize; ++ i){
                        kernel[i] *= sum;
                }  
        }
        
        return kernel;
};

CV.findContours = function(imageSrc, binary){
        var width = imageSrc.width, height = imageSrc.height, contours = [],
        src, deltas, pos, pix, nbd, outer, hole, i, j;
        
        src = CV.binaryBorder(imageSrc, binary);
        
        deltas = CV.neighborhoodDeltas(width + 2);
        
        pos = width + 3;
        nbd = 1;
        
        for (i = 0; i < height; ++ i, pos += 2){
                
                for (j = 0; j < width; ++ j, ++ pos){
                        pix = src[pos];
                        
                        if (0 !== pix){
                                outer = hole = false;
                                
                                if (1 === pix && 0 === src[pos - 1]){
                                        outer = true;
                                }
                                else if (pix >= 1 && 0 === src[pos + 1]){
                                        hole = true;
                                }
                                
                                if (outer || hole){
                                        ++ nbd;
                                        
                                        contours.push( CV.borderFollowing(src, pos, nbd, {x: j, y: i}, hole, deltas) );
                                }
                        }
                }
        }  
        
        return contours;
};

CV.borderFollowing = function(src, pos, nbd, point, hole, deltas){
        var contour = [], pos1, pos3, pos4, s, s_end, s_prev;
        
        contour.hole = hole;
        
        s = s_end = hole? 0: 4;
        do{
                s = (s - 1) & 7;
                pos1 = pos + deltas[s];
                if (src[pos1] !== 0){
                        break;
                }
        }while(s !== s_end);
        
        if (s === s_end){
                src[pos] = -nbd;
                contour.push( {x: point.x, y: point.y} );
                
        }else{
                pos3 = pos;
                s_prev = s ^ 4;
                
                while(true){
                        s_end = s;
                        
                        do{
                                pos4 = pos3 + deltas[++ s];
                        }while(src[pos4] === 0);
                        
                        s &= 7;
                        
                        if ( ( (s - 1) >>> 0) < (s_end >>> 0) ){
                                src[pos3] = -nbd;
                        }
                        else if (src[pos3] === 1){
                                src[pos3] = nbd;
                        }
                        
                        contour.push( {x: point.x, y: point.y} );
                        
                        s_prev = s;
                        
                        point.x += CV.neighborhood[s][0];
                        point.y += CV.neighborhood[s][1];
                        
                        if ( (pos4 === pos) && (pos3 === pos1) ){
                                break;
                        }
                        
                        pos3 = pos4;
                        s = (s + 4) & 7;
                }
        }
        
        return contour;
};

CV.neighborhood = 
[ [1, 0], [1, -1], [0, -1], [-1, -1], [-1, 0], [-1, 1], [0, 1], [1, 1] ];

CV.neighborhoodDeltas = function(width){
        var deltas = [], len = CV.neighborhood.length, i = 0;
        
        for (; i < len; ++ i){
                deltas[i] = CV.neighborhood[i][0] + (CV.neighborhood[i][1] * width);
        }
        
        return deltas.concat(deltas);
};

CV.approxPolyDP = function(contour, epsilon){
        var slice = {start_index: 0, end_index: 0},
        right_slice = {start_index: 0, end_index: 0},
        poly = [], stack = [], len = contour.length,
        pt, start_pt, end_pt, dist, max_dist, le_eps,
        dx, dy, i, j, k;
        
        epsilon *= epsilon;
        
        k = 0;
        
        for (i = 0; i < 3; ++ i){
                max_dist = 0;
                
                k = (k + right_slice.start_index) % len;
                start_pt = contour[k];
                if (++ k === len) {k = 0;}
                
                for (j = 1; j < len; ++ j){
                        pt = contour[k];
                        if (++ k === len) {k = 0;}
                        
                        dx = pt.x - start_pt.x;
                        dy = pt.y - start_pt.y;
                        dist = dx * dx + dy * dy;
                        
                        if (dist > max_dist){
                                max_dist = dist;
                                right_slice.start_index = j;
                        }
                }
        }
        
        if (max_dist <= epsilon){
                poly.push( {x: start_pt.x, y: start_pt.y} );
                
        }else{
                slice.start_index = k;
                slice.end_index = (right_slice.start_index += slice.start_index);
                
                right_slice.start_index -= right_slice.start_index >= len? len: 0;
                right_slice.end_index = slice.start_index;
                if (right_slice.end_index < right_slice.start_index){
                        right_slice.end_index += len;
                }
                
                stack.push( {start_index: right_slice.start_index, end_index: right_slice.end_index} );
                stack.push( {start_index: slice.start_index, end_index: slice.end_index} );
        }
        
        while(stack.length !== 0){
                slice = stack.pop();
                
                end_pt = contour[slice.end_index % len];
                start_pt = contour[k = slice.start_index % len];
                if (++ k === len) {k = 0;}
                
                if (slice.end_index <= slice.start_index + 1){
                        le_eps = true;
                        
                }else{
                        max_dist = 0;
                        
                        dx = end_pt.x - start_pt.x;
                        dy = end_pt.y - start_pt.y;
                        
                        for (i = slice.start_index + 1; i < slice.end_index; ++ i){
                                pt = contour[k];
                                if (++ k === len) {k = 0;}
                                
                                dist = Math.abs( (pt.y - start_pt.y) * dx - (pt.x - start_pt.x) * dy);
                                
                                if (dist > max_dist){
                                        max_dist = dist;
                                        right_slice.start_index = i;
                                }
                        }
                        
                        le_eps = max_dist * max_dist <= epsilon * (dx * dx + dy * dy);
                }
                
                if (le_eps){
                        poly.push( {x: start_pt.x, y: start_pt.y} );
                        
                }else{
                        right_slice.end_index = slice.end_index;
                        slice.end_index = right_slice.start_index;
                        
                        stack.push( {start_index: right_slice.start_index, end_index: right_slice.end_index} );
                        stack.push( {start_index: slice.start_index, end_index: slice.end_index} );
                }
        }
        
        return poly;
};

CV.warp = function(imageSrc, imageDst, contour, warpSize){
        var src = imageSrc.data, dst = imageDst.data,
        width = imageSrc.width, height = imageSrc.height,
        pos = 0,
        sx1, sx2, dx1, dx2, sy1, sy2, dy1, dy2, p1, p2, p3, p4,
        m, r, s, t, u, v, w, x, y, i, j;
        
        m = CV.getPerspectiveTransform(contour, warpSize - 1);
        
        r = m[8];
        s = m[2];
        t = m[5];
        
        for (i = 0; i < warpSize; ++ i){
                r += m[7];
                s += m[1];
                t += m[4];
                
                u = r;
                v = s;
                w = t;
                
                for (j = 0; j < warpSize; ++ j){
                        u += m[6];
                        v += m[0];
                        w += m[3];
                        
                        x = v / u;
                        y = w / u;
                        
                        sx1 = x >>> 0;
                        sx2 = (sx1 === width - 1)? sx1: sx1 + 1;
                        dx1 = x - sx1;
                        dx2 = 1.0 - dx1;
                        
                        sy1 = y >>> 0;
                        sy2 = (sy1 === height - 1)? sy1: sy1 + 1;
                        dy1 = y - sy1;
                        dy2 = 1.0 - dy1;
                        
                        p1 = p2 = sy1 * width;
                        p3 = p4 = sy2 * width;
                        
                        dst[pos ++] = 
                        (dy2 * (dx2 * src[p1 + sx1] + dx1 * src[p2 + sx2]) +
                        dy1 * (dx2 * src[p3 + sx1] + dx1 * src[p4 + sx2]) ) & 0xff;
                        
                }
        }
        
        imageDst.width = warpSize;
        imageDst.height = warpSize;
        
        return imageDst;
};

CV.getPerspectiveTransform = function(src, size){
        var rq = CV.square2quad(src);
        
        rq[0] /= size;
        rq[1] /= size;
        rq[3] /= size;
        rq[4] /= size;
        rq[6] /= size;
        rq[7] /= size;
        
        return rq;
};

CV.square2quad = function(src){
        var sq = [], px, py, dx1, dx2, dy1, dy2, den;
        
        px = src[0].x - src[1].x + src[2].x - src[3].x;
        py = src[0].y - src[1].y + src[2].y - src[3].y;
        
        if (0 === px && 0 === py){
                sq[0] = src[1].x - src[0].x;
                sq[1] = src[2].x - src[1].x;
                sq[2] = src[0].x;
                sq[3] = src[1].y - src[0].y;
                sq[4] = src[2].y - src[1].y;
                sq[5] = src[0].y;
                sq[6] = 0;
                sq[7] = 0;
                sq[8] = 1;
                
        }else{
                dx1 = src[1].x - src[2].x;
                dx2 = src[3].x - src[2].x;
                dy1 = src[1].y - src[2].y;
                dy2 = src[3].y - src[2].y;
                den = dx1 * dy2 - dx2 * dy1;
                
                sq[6] = (px * dy2 - dx2 * py) / den;
                sq[7] = (dx1 * py - px * dy1) / den;
                sq[8] = 1;
                sq[0] = src[1].x - src[0].x + sq[6] * src[1].x;
                sq[1] = src[3].x - src[0].x + sq[7] * src[3].x;
                sq[2] = src[0].x;
                sq[3] = src[1].y - src[0].y + sq[6] * src[1].y;
                sq[4] = src[3].y - src[0].y + sq[7] * src[3].y;
                sq[5] = src[0].y;
        }
        
        return sq;
};

CV.isContourConvex = function(contour){
        var orientation = 0, convex = true,
        len = contour.length, i = 0, j = 0,
        cur_pt, prev_pt, dxdy0, dydx0, dx0, dy0, dx, dy;
        
        prev_pt = contour[len - 1];
        cur_pt = contour[0];
        
        dx0 = cur_pt.x - prev_pt.x;
        dy0 = cur_pt.y - prev_pt.y;
        
        for (; i < len; ++ i){
                if (++ j === len) {j = 0;}
                
                prev_pt = cur_pt;
                cur_pt = contour[j];
                
                dx = cur_pt.x - prev_pt.x;
                dy = cur_pt.y - prev_pt.y;
                dxdy0 = dx * dy0;
                dydx0 = dy * dx0;
                
                orientation |= dydx0 > dxdy0? 1: (dydx0 < dxdy0? 2: 3);
                
                if (3 === orientation){
                        convex = false;
                        break;
                }
                
                dx0 = dx;
                dy0 = dy;
        }
        
        return convex;
};

CV.perimeter = function(poly){
        var len = poly.length, i = 0, j = len - 1,
        p = 0.0, dx, dy;
        
        for (; i < len; j = i ++){
                dx = poly[i].x - poly[j].x;
                dy = poly[i].y - poly[j].y;
                
                p += Math.sqrt(dx * dx + dy * dy) ;
        }
        
        return p;
};

CV.minEdgeLength = function(poly){
        var len = poly.length, i = 0, j = len - 1, 
        min = Infinity, d, dx, dy;
        
        for (; i < len; j = i ++){
                dx = poly[i].x - poly[j].x;
                dy = poly[i].y - poly[j].y;
                
                d = dx * dx + dy * dy;
                
                if (d < min){
                        min = d;
                }
        }
        
        return Math.sqrt(min);
};

CV.countNonZero = function(imageSrc, square){
        var src = imageSrc.data, height = square.height, width = square.width,
        pos = square.x + (square.y * imageSrc.width),
        span = imageSrc.width - width,
        nz = 0, i, j;
        
        for (i = 0; i < height; ++ i){
                
                for (j = 0; j < width; ++ j){
                        
                        if ( 0 !== src[pos ++] ){
                                ++ nz;
                        }
                }
                
                pos += span;
        }
        
        return nz;
};

CV.binaryBorder = function(imageSrc, dst){
        var src = imageSrc.data, height = imageSrc.height, width = imageSrc.width,
        posSrc = 0, posDst = 0, i, j;
        
        for (j = -2; j < width; ++ j){
                dst[posDst ++] = 0;
        }
        
        for (i = 0; i < height; ++ i){
                dst[posDst ++] = 0;
                
                for (j = 0; j < width; ++ j){
                        dst[posDst ++] = (0 === src[posSrc ++]? 0: 1);
                }
                
                dst[posDst ++] = 0;
        }
        
        for (j = -2; j < width; ++ j){
                dst[posDst ++] = 0;
        }
        
        return dst;
};