Object-oriented Software in Ada 95

TUI the implementation 347
procedure Mark_Border( The:in out Window;
A_Border:in Attribute;
Pos:in Positive; Ch:in Character ) is
A_Y, A_X : Positive;
begin
case A_Border is
when Top => A_X := Pos; A_Y := 1;
when Bottom => A_X := Pos; A_Y := The.Max_Y+2;
when Left => A_X := 1; A_Y := Pos;
when Right => A_X := The.Max_X+2; A_Y := Pos;
when others => null;
end case;
if A_X return The.Max_Y+2;
when Abs_X => return The.Abs_X;
when Abs_Y => return The.Abs_Y;
when others => return 0;
end case;
end;
Whilst publicly visible, the following procedures are not intended to be used by an application programmer. These
procedures are used by the event loop to allow a window to:
• Clean up before the focus of user input is removed from the window.
• Prepare for the focus of user input to be directed at the window.
The effect of these procedures is to mark the window with a visual indicator of its state.
procedure Switch_Away( The:in out Window ) is
begin
Mark_Border( The, Top, 1, C_Win_Pas );
end Switch_Away;
procedure Switch_To( The:in out Window ) is
begin
Mark_Border( The, Top, 1, C_Win_A );
end Switch_To;
When a user types a character which is not recognized by the system as a switch character it is sent to the
window which has the focus for input. The procedure Send_To receives this character. The procedure is simply
null, because an instance of a Window does not process user input.
© M A Smith - May not be reproduced without permission