WIP Scan line

QT/scan-line/mywindow.cpp

@@ -130,6 +130,7 @@ void MyWindow::on_cleanButton_clicked()
 void MyWindow::czysc()
 {
     shapes.clear();
+    shapes.push_back(Shape());
     DrawShapes();
 }
 
@@ -303,7 +304,40 @@ void MyWindow::DrawShapes(){
             Point p2 = shapes[i].points[0];
             DrawLine(p1.x, p1.y, p2.x, p2.y, img);
         }
+        std::vector<Line> lines;
+        for(int j = 0; j < (int)shapes[i].points.size() - 1; j++){
+            Point p1 = shapes[i].points[j];
+            Point p2 = shapes[i].points[j+1];
+            lines.push_back(Line(p1, p2));
         }
+        for(int y = 0; y < wys; y++){
+            std::vector<int> xs = GetIntersectionsWithY(y, lines);
+            for(int l = 1; l < xs.size(); l+=2){
+                DrawLine(xs[l-1], y, xs[l], y, img);
+            }
+        }
+    }
+}
+
+std::vector<int> MyWindow::GetIntersectionsWithY(int y, std::vector<Line> lines){
+    std::vector<int> res;
+    for(int i = 0; i < lines.size(); i++){
+        Line l = lines[i];
+        if(l.A.x < l.B.x)
+            std::swap(l.A, l.B);
+//        if(l.A.x < l.B.x)
+//            std::swap(l.A, l.B);
+        if((l.A.y < y && l.B.y > y) || (l.A.y > y && l.B.y < y)){
+            float d1 = (y - l.A.y);
+            float d2 = (l.B.y - l.A.y);
+            float dx = (l.B.x - l.A.x);
+            float ratio = d2/d1;
+            int x = l.A.x + dx / ratio;
+            res.push_back(x);
+        }
+    }
+    std::sort(res.begin(), res.end(), std::greater<int>());
+    return res;
 }
 
 void MyWindow::ClearImage(QImage *img){

QT/scan-line/mywindow.h

@@ -147,6 +147,7 @@ private:
     void ClearImage(QImage *img);
     void DrawPixel(QImage *img, int x, int y, QColor color = QColor(255, 255, 255));
     bool FindPoint(int x, int y, int& pt_id, int& shape_id, float radius = FLT_MAX);
+    std::vector<int> GetIntersectionsWithY(int y, std::vector<Line> lines);
 
     // Deklaracje slotow, czyli funkcji wywolywanych
     // po wystapieniu zdarzen zwiazanych z GUI