creating a pause menu in delphi - delphi

Question

Background: I have created a maze game that is playable, however when the maze gets bigger there are more chances to go wrong and takes ages to reach the start of the maze again, I've been told that's really annoying.
Question: I want to create a pause game function that when the user presses the button key a menu pops up that allows the user to be able to either return to main menu or restart the maze.
I have very little knowledge on where to start this in the code as I don't want to mess up anything that has already been added.
I've added the draw maze //creates the maze,
initialise visited and walk // removes the walls of the maze,
Form key down//moves the player
and Timer//collision detection procedures below.
hopefully someone can help?
Many Thanks.
`procedure TfrmMazeDesign.draw_maze(square_size: integer);
var
row, col : integer;
begin
// setup default walls as "WWWW" wall on all four sides.
SetLength(Shapes,height+3, width+3, 2 ) ;
for row := 1 to height do
begin
for col := 1 to width+2 do
begin
Shapes[row,col,0]:= TShape.Create(Self);
Shapes[row,col,0].Parent := Self;
with Shapes[row,col,0] do
begin
Width := 5;
Height := square_size;
Left := 100+ ((col-1) * square_size);
Top := 50+ ((row-1) * square_size);
Brush.Color := RGB(255, 255,25);
Shape := stRectangle;
end;
end;
end;
for row := 1 to height+1 do
begin
for col := 1 to width+1 do
begin
Shapes[row,col,1]:= TShape.Create(Self);
Shapes[row,col,1].Parent := Self;
with Shapes[row,col,1] do
begin
Width := square_size;
Height := 5;
Left := 100+ ((col-1) * square_size);
Top := 50+ ((row-1) * square_size);
Brush.Color := RGB(255, 255,25);
Shape := stRectangle;
end;
end;
end;
end;
procedure TfrmMazeDesign.initialise_visited(var visited: Tvisited);
var
row, col: integer;
begin
for row := 0 to height+2 do
for col := 0 to width+2 do
if (col = 0) or (row = 0) or (row = height+1) or (col= width+2) then
visited[row,col] := True
else
visited[row,col] := False;
end;
procedure TFrmMazeDesign.walk(visited: Tvisited; x: integer; y:integer);
var
xx,yy, counter, ran_direction: integer;
direction: Tstringlist; // 1= Up, 2= right, 3 = down, 4 = left
text: string;
begin
visited[x,y] := True;
direction := TStringlist.Create;
direction.Add('1');
direction.Add('2');
direction.Add('3');
direction.Add('4');
for counter := direction.Count - 1 downto 0 do
direction.Exchange(counter, Random(counter+1));
for counter := 0 to direction.Count-1 do
begin
ran_direction := StrtoInt(direction[counter]);
if ran_direction= 1 then
begin
xx := x-1;
yy := y
end;
if ran_direction = 2 then
begin
xx := x+1;
yy := y
end;
if ran_direction = 3 then
begin
xx := x;
yy := y-1
end;
if ran_direction= 4 then
begin
xx := x;
yy := y+1
end;
if visited[xx,yy] = False then
begin
if xx = x then
shapes[x,Max(yy,y),0].visible := False;
if yy = y then
shapes[Max(xx,x),y,1].visible := False;
walk (visited, xx,yy)
end;
end;
end;
procedure TfrmMazeDesign.FormKeyDown(Sender: TObject; var Key: Word;
Shift: TShiftState);
begin
case Key of
VK_UP:
direction := 1;
VK_DOWN:
direction := 2;
VK_LEFT:
direction := 3;
VK_RIGHT:
direction := 4;
end;
end;
procedure TfrmMazeDesign.FormOpen(Sender: TObject);
var
block_height: integer;
xx,yy: integer;
visited: Tvisited;
monster, monster2: TMonster;
Shape_height : integer;
Shape_Width : integer;
imgfinish_height : integer;
maze_width : integer;
begin
width := frmdifficulty.ScrollBar1.Position;
height := frmdifficulty.ScrollBar1.Position;
maze_width := 650;
block_height := maze_width div width;
Shape_height := round( block_height * 0.5);
imgfinish_height := round(block_height * 0.5);
draw_maze(block_height);
SetLength(visited, height+10, width+10) ;
initialise_visited(visited);
walk(visited,3,3);
ShpUser.height := Shape_height;
ShpUser.Width := Shape_height;
imgfinish.width := Shape_height;
imgfinish.height := shape_height;
ShpUser.Shape := UShapeEditor.frmShape.shpShape.Shape;
ShpUser.Brush.color := UShapeEditor.frmShape.shpShape.Brush.color;
FDateTimeTo := StrToDateTime(FormatDateTime('dd' + FormatSettings.DateSeparator + 'mm' +
FormatSettings.DateSeparator + 'yyyy', Now)); Incsecond(time,120);
Timer1.Enabled := True;
monster := TMonster.Create(Self);
monster.Parent := Self;
monster.SetSizes(width, height, shape_height, 55+ maze_width + 10,665);
monster.start;
monster2 := TMonster.Create(Self);
monster2.Parent := Self;
monster2.SetSizes(width, height, shape_height, 50+ maze_width + 10,565);
monster2.start;
end;
procedure TfrmMazeDesign.Timer1Timer(Sender: TObject);
var IntersectionRect: TRect;
collision, test_collision : boolean;
up : boolean;
right : boolean;
max_width, max_height : integer;
xx, yy : integer ;
aRect1: TRect;
buttonSelected : Integer;
collisionend: boolean;
frmMazeDesign: TfrmMazeDesign;
row, col, hoz_vert : integer;
begin
hoz_vert := 0;
xx := 0;
yy := 0;
case direction of
1:begin //Up
yy := -3;
end;
2: begin //down
yy := + 3;
end;
3: begin //left
xx := -3;
end;
4: begin //right
xx := + 3;
end;
end;
repeat
if hoz_Vert = 0 then begin
max_width := width +3;
max_height := Height+1;
end else begin
max_width := width+2;
max_height := Height+2;
end;
row := 1;
repeat
col := 1;
repeat
aRect1 := Rect(ShpUser.Left+xx, ShpUser.Top+yy, ShpUser.Left+ShpUser.width+xx, ShpUser.top+ ShpUser.Height+yy);
if Shapes[row,col,hoz_vert].visible = True then
collision := IntersectRect(IntersectionRect, aRect1, Shapes[row,col,hoz_vert].BoundsRect) ;
col := col + 1;
until (collision) or (col = max_width);
row := row + 1 ;
until (collision) or (row = max_height);
hoz_vert := hoz_vert +1;
until (collision) or (hoz_vert = 2);
if (collision = False) and (direction <> 0) then begin
ShpUser.Top := ShpUser.Top + yy;
ShpUser.Left := ShpUser.Left + xx;
end;
if IntersectRect(IntersectionRect, imgfinish.BoundsRect, Shpuser.BoundsRect) then
begin
Collisionend := true;
if collisionend = true then
frmfinish.Show;
direction:= 0;
end;`

Answer 1

This is relatively straightforward to add to your program, which is already event driven. In summary you need to do the following:
Add a Boolean flag, perhaps named Paused, set to False when the game starts.
When the user presses the pause button, set the Paused flag to True.
When the user presses the resume button, set the Paused flag to False.
In the time event handler, check the Paused flag before updating the positions. If the Paused flag is True, then simply exit from the timer event handler before doing anything else.