modify find contour

src/graphics/image/findContours.js

@@ -6,6 +6,66 @@
 
 define(
     function (require) {
+
+        // 查找的8个方向
+        var DIRECTION = [
+            [1, 0], [1, -1], [0, -1], [-1, -1], [-1, 0], [-1, 1], [0, 1], [1, 1]
+        ];
+
+
+        /**
+         * 查找轮廓边缘点
+         *
+         * @param  {Object}  imageData   图像数据
+         * @param  {Object}  startPoint  起始点
+         * @param  {boolean} isInContour 是否在轮廓内
+         *
+         * @return {Array}               找到的轮廓点集
+         */
+        function findContour(imageData, startPoint, isInContour) {
+            var data = imageData.data;
+            var width = imageData.width;
+            var height = imageData.height;
+            var index = 0; // 当前方向
+            var startIndex; // 当前起始方向
+            var startX = startPoint.x;
+            var startY = startPoint.y;
+            var x = startX;
+            var y = startY;
+            var dx;
+            var dy;
+            var contour = [startPoint];
+            var finded;
+            do {
+                startIndex = index + 3 + 8;
+                finded = false;
+                for (var i = 0; i < 7; i++) {
+                    index = (startIndex - i) % 8;
+                    dx = x + DIRECTION[index][0];
+                    dy = y + DIRECTION[index][1];
+                    // 找到轮廓点
+                    if (!!data[dx + dy * width] === isInContour) {
+                        x = dx;
+                        y = dy;
+                        finded = true;
+                        contour.push({
+                            x: dx,
+                            y: dy
+                        });
+                        break;
+                    }
+                }
+
+                if (!finded) {
+                    throw 'cant\'t find next contour point!';
+                }
+            }
+            while (x !== startX || y !== startY);
+
+            return contour;
+        }
+
+
         /**
          * 查找二值图像轮廓
          *
@@ -19,50 +79,51 @@ define(
             var x;
             var y;
             var line;
+            var prevLine;
             var isInContour = false;
-            var curLineArray = [];
-            var prevLineArray = []; // 记录Y轴有轮廓的起始坐标
             var startPointArray = []; // 记录起始节点
             var point;
 
-            // 查找轮廓坐标
+
+            // 查找外轮廓坐标
             for (y = 0; y < height; y ++) {
                 line = y * width;
                 isInContour = false;
-                curLineArray = [];
                 for (x = 0; x < width; x++) {
+                    // 外轮廓起始点
                     if (!isInContour && data[line + x]) {
-                        if (!point  || (point.x !== x - 1)) {
-                            isInContour = true;
-                            point = {
+                        isInContour = true;
+
+                        prevLine = (y - 1) * width;
+                        if (
+                            // 右侧和上侧无像素
+                            (!data[line + x + 1] && !data[prevLine + x])
+                            // 上一个点
+                            || (!data[prevLine + x] && !data[prevLine + x + 1])
+                        ) {
+                            startPointArray.push({
                                 x: x,
-                                y: y,
-                                isIn: true
-                            };
-                            curLineArray.push(point);
+                                y: y
+                            });
                         }
                     }
                     else if (isInContour && !data[line + x]) {
-                        if (!point  || (point.x !== x - 1)) {
-                            isInContour = false;
-                            point = {
-                                x: x,
-                                y: y,
-                                isIn: false
-                            };
-                            curLineArray.push(point);
-                        }
+                        isInContour = false;
                     }
-
-                    prevLineArray = curLineArray;
-
-
                 }
-
             }
 
+            var contours = [];
+            if (!startPointArray) {
+                return contours;
+            }
+            else {
+                startPointArray.forEach(function (p) {
+                    contours.push(findContour(imageData, p, true));
+                });
+            }
 
-            return pointArray;
+            return contours;
         }
 
         return findContours;