Integrated Polygon Test

Use calculate traingles and the isInPolygon with theese triangles, this is done because of performance reasons

src/Image/IntelliShapedImage.cpp

@@ -35,26 +35,18 @@ void IntelliShapedImage::calculateVisiblity(){
         }
         return;
     }
-    QPoint A = polygonData[0];
     QColor clr;
     for(int y=0; y<imageData.height(); y++){
         for(int x=0; x<imageData.width(); x++){
-            int cutNumeber=0;
-            for(int i=1; i<static_cast<int>(polygonData.size()-1); i++){
-                QPoint B = polygonData[static_cast<size_t>(i)];
-                QPoint C = polygonData[static_cast<size_t>(i+1)];
-                QPoint P(x,y);
-                cutNumeber+=IntelliHelper::isInTriangle(A,B,C,P);
-            }
-            if(cutNumeber%2==0){
-                clr = imageData.pixelColor(x,y);
-                clr.setAlpha(0);
-                imageData.setPixelColor(x,y,clr);
-            }else{
-                clr = imageData.pixelColor(x,y);
+            QPoint ptr(x,y);
+            clr = imageData.pixelColor(x,y);
+            bool isInPolygon = IntelliHelper::isInPolygon(triangles, ptr);
+            if(isInPolygon){
                 clr.setAlpha(std::min(255, clr.alpha()));
-                imageData.setPixelColor(x,y,clr);
+            }else{
+                clr.setAlpha(0);
             }
+            imageData.setPixelColor(x,y,clr);
         }
     }
 }
@@ -79,6 +71,7 @@ void IntelliShapedImage::setPolygon(const std::vector<QPoint>& polygonData){
         for(auto element:polygonData){
             this->polygonData.push_back(QPoint(element.x(), element.y()));
         }
+        triangles = IntelliHelper::calculateTriangles(polygonData);
     }
     calculateVisiblity();
     return;

src/Image/IntelliShapedImage.h

@@ -2,9 +2,13 @@
 #define INTELLISHAPE_H
 
 #include"Image/IntelliRasterImage.h"
+#include<vector>
+#include"IntelliHelper/IntelliHelper.h"
 
 class IntelliShapedImage : public IntelliRasterImage{
     friend IntelliTool;
+private:
+    std::vector<Triangle> triangles;
 protected:
 
     std::vector<QPoint> polygonData;

src/IntelliHelper/IntelliHelper.cpp

@@ -1,2 +1,123 @@
 #include"IntelliHelper.h"
 #include<algorithm>
+#include<queue>
+#include<cmath>
+
+
+std::vector<Triangle> IntelliHelper::calculateTriangles(std::vector<QPoint> polyPoints){
+    //helper for managing the triangle vertices and their state
+    struct TriangleHelper{
+        QPoint vertex;
+        float interiorAngle;
+        int index;
+        bool isTip;
+    };
+
+    //calculates the inner angle of 'point'
+    auto calculateInner = [](QPoint& point, QPoint& prev, QPoint& post){
+        QPoint AP(point.x()-prev.x(), point.y()-prev.y());
+        QPoint BP(point.x()-post.x(), point.y()-post.y());
+
+        float topSclar = AP.x()*BP.x()+AP.y()*BP.y();
+        float absolute = sqrt(pow(AP.x(),2.)+pow(AP.y(),2.))*sqrt(pow(BP.x(),2.)+pow(BP.y(),2.));
+        return acos(topSclar/absolute);
+    };
+
+    //gets the first element of vec for which element.isTip == true holds
+    auto getTip= [](const std::vector<TriangleHelper>& vec){
+        for(auto element:vec){
+            if(element.isTip){
+                return element;
+            }
+        }
+        return vec[0];
+    };
+
+    //get the vertex Index bevor index in relation to the container length
+    auto getPrev = [](int index, int length){
+        return (index-1)>0?(index-1):(length-1);
+    };
+
+    //get the vertex Index after index in relation to the container lenght
+    auto getPost = [](int index, int length){
+        return (index+1)%length;
+    };
+
+    //return if the vertex is a tip
+    auto isTip = [](float angle){
+        return angle<180.f;
+    };
+
+    std::vector<TriangleHelper>  Vertices;
+    std::vector<Triangle> Triangles;
+
+    //set up all vertices and calculate intirior angle
+    for(int i=0; i<static_cast<int>(polyPoints.size()); i++){
+        TriangleHelper helper;
+        int prev = getPrev(i, static_cast<int>(polyPoints.size()));
+        int post = getPost(i, static_cast<int>(polyPoints.size()));
+
+        helper.vertex = polyPoints[static_cast<size_t>(i)];
+        helper.index = i;
+
+        helper.interiorAngle = calculateInner(polyPoints[static_cast<size_t>(i)],
+                                              polyPoints[static_cast<size_t>(prev)],
+                                              polyPoints[static_cast<size_t>(post)]);
+        helper.isTip = isTip(helper.interiorAngle);
+        Vertices.push_back(helper);
+    }
+
+    //search triangles based on the intirior angles of each vertey
+    while(Triangles.size() != polyPoints.size()-2){
+        Triangle tri;
+        TriangleHelper smallest = getTip(Vertices);
+        int prev = getPrev(smallest.index, static_cast<int>(Vertices.size()));
+        int post = getPost(smallest.index, static_cast<int>(Vertices.size()));
+
+        //set triangle and push it
+        tri.A = Vertices[static_cast<size_t>(prev)].vertex;
+        tri.B = Vertices[static_cast<size_t>(smallest.index)].vertex;
+        tri.C = Vertices[static_cast<size_t>(post)].vertex;
+        Triangles.push_back(tri);
+
+        //update Vertice array
+        Vertices.erase(Vertices.begin()+smallest.index);
+        for(size_t i=static_cast<size_t>(smallest.index); i<Vertices.size(); i++){
+            Vertices[i].index-=1;
+        }
+
+        //update post und prev index
+        post = post-1;
+        prev = prev<smallest.index?prev:(prev-1);
+
+        //calcultae neighboors of prev and post to calculate new interior angles
+        int prevOfPrev = getPrev(prev, static_cast<int>(Vertices.size()));
+        int postOfPrev = getPost(prev, static_cast<int>(Vertices.size()));
+
+        int prevOfPost = getPrev(post, static_cast<int>(Vertices.size()));
+        int postOfPost = getPost(post, static_cast<int>(Vertices.size()));
+
+        //update vertices with interior angles
+        //updtae prev
+        Vertices[static_cast<size_t>(prev)].interiorAngle = calculateInner(Vertices[static_cast<size_t>(prev)].vertex,
+                                                                           Vertices[static_cast<size_t>(prevOfPrev)].vertex,
+                                                                           Vertices[static_cast<size_t>(postOfPrev)].vertex);
+        Vertices[static_cast<size_t>(prev)].isTip = isTip(Vertices[static_cast<size_t>(prev)].interiorAngle);
+        //update post
+        Vertices[static_cast<size_t>(post)].interiorAngle = calculateInner(Vertices[static_cast<size_t>(post)].vertex,
+                                                                           Vertices[static_cast<size_t>(prevOfPost)].vertex,
+                                                                           Vertices[static_cast<size_t>(postOfPost)].vertex);
+        Vertices[static_cast<size_t>(post)].isTip = isTip(Vertices[static_cast<size_t>(post)].interiorAngle);
+
+    }
+    return Triangles;
+}
+
+bool IntelliHelper::isInPolygon(std::vector<Triangle> &triangles, QPoint &point){
+    for(auto triangle : triangles){
+        if(IntelliHelper::isInTriangle(triangle.A ,triangle.B, triangle.C, point)){
+            return true;
+        }
+    }
+    return false;
+}

src/IntelliHelper/IntelliHelper.h

@@ -2,17 +2,20 @@
 #define INTELLIHELPER_H
 
 #include<QPoint>
+#include<vector>
+
+struct Triangle{
+    QPoint A,B,C;
+};
+
+namespace IntelliHelper {
 
 
-class IntelliHelper{
-
-public:
-
-    static inline float sign(QPoint& p1, QPoint& p2, QPoint& p3){
+    inline float sign(QPoint& p1, QPoint& p2, QPoint& p3){
         return (p1.x()-p3.x())*(p2.y()-p3.y())-(p2.x()-p3.x())*(p1.y()-p3.y());
     }
 
-    static inline bool isInTriangle(QPoint& A, QPoint& B, QPoint& C, QPoint& P){
+    inline bool isInTriangle(QPoint& A, QPoint& B, QPoint& C, QPoint& P){
         float val1, val2, val3;
         bool neg, pos;
 
@@ -25,6 +28,11 @@ public:
 
         return !(neg && pos);
     }
-};
+
+    std::vector<Triangle> calculateTriangles(std::vector<QPoint> polyPoints);
+
+    bool isInPolygon(std::vector<Triangle> &triangles, QPoint &point);
+
+}
 
 #endif

src/main.cpp

@@ -1,6 +1,8 @@
 #include "GUI/IntelliPhotoGui.h"
 #include <QApplication>
 #include <QDebug>
+#include "IntelliHelper/IntelliHelper.h"
+#include<vector>
 
 int main(int argc, char *argv[]){
     // The main application