From b64489be9edbf62a73e6b126bbadaf2c3d7fed9a Mon Sep 17 00:00:00 2001
From: Loic Guegan <manzerbredes@mailbox.org>
Date: Fri, 6 Jan 2023 20:34:14 +0100
Subject: [PATCH] Add code to draw arrows on the board

---
 src/game_tab/left_panel/board/BoardCanvas.cpp | 37 +++++++++++++++++++
 src/game_tab/left_panel/board/BoardCanvas.hpp |  3 ++
 2 files changed, 40 insertions(+)

diff --git a/src/game_tab/left_panel/board/BoardCanvas.cpp b/src/game_tab/left_panel/board/BoardCanvas.cpp
index 7bebe45..119c270 100644
--- a/src/game_tab/left_panel/board/BoardCanvas.cpp
+++ b/src/game_tab/left_panel/board/BoardCanvas.cpp
@@ -1,5 +1,11 @@
 #include "BoardCanvas.hpp"
 
+#define TRANS(PT) { \
+wxPoint2DDouble tmp((PT).x,(PT).y); \
+tmp=rot_m.TransformPoint(tmp); \
+tmp=trans_m.TransformPoint(tmp); \
+(PT).x=tmp.m_x;(PT).y=tmp.m_y;}
+
 wxDEFINE_EVENT(PLAY_MOVE_EVENT, wxCommandEvent);
 
 BoardCanvas::BoardCanvas(wxFrame *parent)
@@ -462,3 +468,34 @@ void BoardCanvas::SetClockTime(short hours, short min, short sec,
     gs.white_time = std::make_tuple(hours, min, sec);
   }
 }
+
+void BoardCanvas::DrawArrow(wxDC &dc, int xsrc, int ysrc, int xdst, int ydst){
+  // Compute arrow length and angle
+  wxPoint vect(xdst-xsrc,ydst-ysrc);
+  double length=sqrt(pow(vect.x,2)+pow(vect.y,2));
+  double angle=acos(vect.x/length);
+
+  // Compute metrics
+  std::uint8_t thickness=50;
+  std::uint8_t tip_height=sqrt(3)/2*thickness;
+  std::uint32_t tail_length=length-tip_height;
+
+  // Setup transform matrix
+  wxAffineMatrix2D rot_m,trans_m;
+  rot_m.Rotate(angle);
+  trans_m.Translate(xsrc,ysrc);
+
+  // Init polygons
+  wxPoint tip[]={wxPoint(tail_length,-thickness/2),wxPoint(tail_length,thickness/2),wxPoint(tail_length+tip_height,0)};
+  wxPoint tail[]={wxPoint(0,-thickness/4),wxPoint(tail_length,-thickness/4),wxPoint(tail_length,thickness/4),wxPoint(0,thickness/4)};
+
+  // Transform points
+  TRANS(tip[0]);TRANS(tip[1]);TRANS(tip[2]);
+  TRANS(tail[0]);TRANS(tail[1]);TRANS(tail[2]);TRANS(tail[3]);
+
+  // Draw
+  dc.SetPen(wxNullPen);
+  dc.SetBrush(wxColour(255,0,0));
+  dc.DrawPolygon(3,tip);
+  dc.DrawPolygon(4,tail);
+}
diff --git a/src/game_tab/left_panel/board/BoardCanvas.hpp b/src/game_tab/left_panel/board/BoardCanvas.hpp
index f53bb8f..ddab72b 100644
--- a/src/game_tab/left_panel/board/BoardCanvas.hpp
+++ b/src/game_tab/left_panel/board/BoardCanvas.hpp
@@ -91,6 +91,9 @@ class BoardCanvas : public wxPanel {
   AnimState adata;
   GameState gs;
 
+  /// @brief Draw an arrow from a source point to a destination point on DC
+  void DrawArrow(wxDC &dc, int xsrc, int ysrc, int xdst, int ydst);
+
 public:
   BoardCanvas(wxFrame *parent);
   BoardCanvas(wxFrame *parent,std::uint32_t square_width, bool frozen);