contours.h

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/*
    Beatmup image and signal processing library
    Copyright (C) 2019, lnstadrum
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
 
#pragma once
#include "../geometry.h"
#include "../bitmap/abstract_bitmap.h"
#include "../bitmap/bitmap_access.h"
#include "../bitmap/mask_bitmap_access.h"
#include "../exception.h"
#include <vector>
#include <mutex>
 
namespace Beatmup {
 
    /**
        A sequence of integer-valued 2D points
    */
    class IntegerContour2D {
    private:
        std::vector<IntPoint> points;
        float
            totalLength,
            lastFragmentLength;
    public:
        IntegerContour2D();
 
        /**
            Adds a new point to the end of the contour. Some points may be skipped to optimize the storage.
            \param x    new point X coordinate
            \param y    new point Y coordinate
        */
        void addPoint(int x, int y);
 
 
        /**
            Removes contour content
        */
        void clear();
 
 
        /**
            \return number of points in the contour.
        */
        int getPointCount() const { return (int)points.size(); };
 
 
        float getLength() const { return totalLength; };
 
 
        /**
            \return a point by its index
        */
        inline IntPoint getPoint(int index) const { return points[index % points.size()]; };
 
        /**
            Discovers an area boundary in a bitmap following a level curve, starting from a given set of points
            \param boundary         vector to put connected components of the detected boundary to
            \param bitmap           the bitmap to discover
            \param border           the starting points
            \param testedPixels     a writer of a binary mask bitmap marking pixels that are already processed
            \param level            the level of the curve
            \returns a vector of all the contours limiting the area
        */
        static void computeBoundary(
            std::vector<IntegerContour2D*>& boundary,
            AbstractBitmap& bitmap,
            std::vector<IntPoint>& border,
            BinaryMaskWriter& testedPixels,
            float level = 0.5f
        );
 
 
        class BadSeedPoint : public Exception {
        public:
            BadSeedPoint() : Exception("Bad seeds: no border points found")
            {}
 
            BadSeedPoint(int x, int y, bool lefttop, bool righttop, bool leftbottom, bool rightbottom):
                Exception("Bad seed (%d,%d), pattern:\n  %d%d\n  %d%d\n", x, y, lefttop, righttop, leftbottom, rightbottom)
            {}
        };
    };
}