Fixing arrow events to draw head

src/data/events/brushes/arrow.py

@@ -1,4 +1,5 @@
 # Python imports
+import math
 
 # Lib imports
 import cairo
@@ -33,12 +34,49 @@ class Arrow(BrushEvent):
 
 
     def process(self, brush: cairo.Context):
-
         brush.set_line_width(self.size)
         brush.set_line_cap(1) # 0 = BUTT, 1 = ROUND, 2 = SQUARE
         brush.set_source_rgba(*self.color)
         brush.set_operator(cairo.OPERATOR_OVER);
 
-        brush.move_to(self.points[0].x, self.points[0].y)
-        brush.line_to(self.points[1].x, self.points[1].y)
+        x1, y1 = self.points[0].x, self.points[0].y
+        x2, y2 = self.points[1].x, self.points[1].y
+
+        # Arrow body
+        brush.move_to(x1, y1)
+        brush.line_to(x2, y2)
+
+        # Arrow head
+        ah1, ay1, \
+        ah2, ay2 = self.get_arrow_head_points(x1, y1, x2, y2)
+
+        brush.move_to(x2, y2)
+        brush.line_to(ah1, ay1)
+        brush.move_to(x2, y2)
+        brush.line_to(ah2, ay2)
+
         brush.stroke()
+
+    def get_arrow_head_points(self, x1, y1, x2, y2, arrow_head_length = 25, arrow_angle = 45):
+        # Convert angle to radians
+        angle_rad = math.radians(arrow_angle)
+
+        # Calculate the angle of the main line
+        line_angle = math.atan2(y2 - y1, x2 - x1)
+
+        # Arrowhead angles (one on each side of the line)
+        angle1 = line_angle + math.pi - angle_rad
+        angle2 = line_angle + math.pi + angle_rad
+
+        # Calculate the two arrowhead points
+        p1 = (
+            x2 + arrow_head_length * math.cos(angle1),
+            y2 + arrow_head_length * math.sin(angle1)
+        )
+
+        p2 = (
+            x2 + arrow_head_length * math.cos(angle2),
+            y2 + arrow_head_length * math.sin(angle2)
+        )
+
+        return *p1, *p2