Add arrow functionality

src/capture/screenshot.cpp

@@ -156,6 +156,32 @@ QPixmap Screenshot::paintBaseModifications(
     return m_modifiedScreenshot;
 }
 
+QPainterPath getArrowHead(QPoint p1, QPoint p2) {
+    QLineF body(p1, p2);
+    int originalLength = body.length();
+    body.setLength(10);
+    // move across the line up to the head
+    //QPointF  = ;
+    QLineF temp(QPoint(0,0), p2-p1);
+    temp.setLength(originalLength-20);
+    QPointF bottonTranslation(temp.p2());
+
+    // generates the transformation to center the head of the arrow
+    body.setAngle(body.angle()+90);
+    QPointF temp2 = p1-body.p2();
+    QPointF centerTranslation((temp2.x()/2), (temp2.y()/2));
+
+    body.translate(bottonTranslation);
+    body.translate(centerTranslation);
+
+    QPainterPath path;
+    path.moveTo(p2);
+    path.lineTo(body.p1());
+    path.lineTo(body.p2());
+    path.lineTo(p2);
+    return path;
+}
+
 // paintInPainter is an aux method to prevent duplicated code, it draws the
 // passed modification to the painter.
 void Screenshot::paintInPainter(QPainter &painter,
@@ -165,8 +191,8 @@ void Screenshot::paintInPainter(QPainter &painter,
     switch (modification.getType()) {
     case Button::Type::arrow:
         painter.drawLine(points[0], points[1]);
-        // TODO
-
+        painter.fillPath(getArrowHead(points[0], points[1]),
+                QBrush(modification.getColor()));
         break;
     case Button::Type::circle:
         painter.drawEllipse(QRect(points[0], points[1]));
@@ -189,7 +215,6 @@ void Screenshot::paintInPainter(QPainter &painter,
     default:
         break;
     }
-
 }
 
 void Screenshot::uploadToImgur(QNetworkAccessManager *accessManager,