{
* This Source Code Form is subject to the terms of the Mozilla Public License,
* v. 2.0. If a copy of the MPL was not distributed with this file, You can
* obtain one at http://mozilla.org/MPL/2.0/
*
* Copyright (C) 2008-2013, Peter Johnson (www.delphidabbler.com).
*
* $Rev$
* $Date$
*
* Various structures. Some are extension of existing structures with added
* functionality.
}
unit UStructs;
interface
uses
// Delphi
Types;
type
{
TRectEx:
Encapsulates a rectangle. Assignment compatible with TRect. Has methods to
manipulate and cast rectangle.
}
TRectEx = packed record
Left, Top, // Coordinates of top left corner of rectangle
Right, Bottom: Longint; // Coordinates of bottom right corner of rectangle
constructor Create(ALeft, ATop, ARight, ABottom: Longint);
{Record constructor. Sets initial field values.
@param ALeft [in] Left position of rectangle.
@param ATop [in] Top position of rectangle.
@param ARight [in] Right position of rectangle.
@param ABottom [in] Bottom position of rectangle.
}
constructor CreateBounds(ALeft, ATop, AWidth, AHeight: Longint); overload;
{Record constructor. Creates rectangle from its bounds.
@param ALeft [in] Left position of rectangle.
@param ATop [in] Top position of rectangle.
@param AWidth [in] Width of rectangle.
@param AHeight [in] Height of rectangle.
}
constructor CreateBounds(ALeft, ATop: Longint; ASize: TSize); overload;
{Record constructor. Creates rectangle from its bounds.
@param ALeft [in] Left position of rectangle.
@param ATop [in] Top position of rectangle.
@param ASize [in] Size of rectangle.
}
class operator Implicit(ARect: TRect): TRectEx;
{Implicit cast of TRect to a TRectEx.
@param ARect [in] TRect to be cast.
@return TRectEx resulting from cast.
}
class operator Implicit(ARect: TRectEx): TRect;
{Implicit cast of TRectEx to a TRect.
@param ARect [in] TRectEx to be cast.
@return TRect resulting from cast.
}
class operator Equal(R1, R2: TRectEx): Boolean;
{Equality test for two TRectEx rectangles.
@param R1 [in] Left hand operand.
@param R2 [in] Right hand operand.
@return True if R1 is the same as R2, False if different.
}
class operator NotEqual(R1, R2: TRectEx): Boolean;
{Inequality test for two TRectEx rectangles.
@param R1 [in] Left hand operand.
@param R2 [in] Right hand operand.
@return True if R1 is different to R2, False if same.
}
function Width: Longint;
{Width of rectangle.
@return Required width.
}
function Height: Longint;
{Height of rectangle.
@return Required height.
}
procedure InflateBy(DeltaX, DeltaY: Longint);
{Inflates or deflates the rectangle.
@param DeltaX [in] Amount to inflate horizontally. Deflated if -ve.
@param DeltaY [in] Amount to inflate vertically. Deflated if -ve.
}
function Inflate(DeltaX, DeltaY: Longint): TRectEx;
{Returns a copy of rectangle, inflated or deflated.
@param DeltaX [in] Amount to inflate horizontally. Deflated if -ve.
@param DeltaY [in] Amount to inflate vertically. Deflated if -ve.
@return Inflated copy of rectangle.
}
procedure OffsetBy(AX, AY: Longint);
{Offsets rectangle in X and Y directions.
@param AX [in] Horizontal offset.
@param AY [in] Vertical offset.
}
function GetTopLeft: TPoint;
{Read accessor for TopLeft property.
@return Co-ordinates of top left of rectangle.
}
procedure SetTopLeft(const Value: TPoint);
{Write accessor for TopLeft property.
@param Value [in] Coordinates of top left.
}
function GetBottomRight: TPoint;
{Read accessor for BottomRight property.
@return Co-ordinates of bottom right of rectangle.
}
procedure SetBottomRight(const Value: TPoint);
{Write accessor for BottomRight property.
@param Value [in] Coordinates of bottom right.
}
function ContainsPoint(const Pt: TPoint): Boolean;
{Checks if a point is contained in the rectangle.
@param Pt [in] Point to be tested.
@return True if point is contained in the rectangle, False if not.
}
function IsEmpty: Boolean;
{Checks if a rectangle is empty. Empty is defined as Right <= Left or
Bottom <= Top.
return True if empty, False if not.
}
procedure MakeEmpty;
{Makes the rectangle empty.
}
property TopLeft: TPoint read GetTopLeft write SetTopLeft;
{Coordinates of top left corner of rectangle}
property BottomRight: TPoint read GetBottomRight write SetBottomRight;
{Coordinates of bottom right corner of rectangle}
end;
{
TRange:
Encapsulates a range of integers with a method to test wheter a value falls
within the range.
}
TRange = record
Min, Max: Integer; // Minimum and maximum bounds of range
constructor Create(AMin, AMax: Integer);
{Record constructor. Initialises range bounds.
@param AMin [in] Minimum value that falls in range.
@param AMax [in] Maximum value that falls in range.
}
function Contains(const Value: Integer): Boolean;
{Checks if a value is contained in range.
@param Value [in] Value to be tested.
@return True if Value is in range, False otherwise.
}
function Constrain(const Value: Integer): Integer;
{Adjusts the given value to ensure it falls within the range.
@param Value [in] Value to be constrained.
@returns Value is returned unchanged if it falls within the range.
Otherwise Min is returned if Value is less than Min or Max is returned
if Value is greater than max.
}
end;
{
TSelection:
Encapsulates a selection defined by its starting position and its length.
An empty selection has length 0.
}
TSelection = record
public
StartPos: Cardinal; // Start of selection
Length: Cardinal; // Length of selection
constructor Create(AStartPos: Cardinal; ALength: Cardinal = 0);
{Record constructor. Initialises start position and length.
@param AStartPos [in] Start of selection.
@param Length [in] Length of selection. Optional.
}
end;
implementation
uses
// Delphi
Math;
{ TRectEx }
function TRectEx.ContainsPoint(const Pt: TPoint): Boolean;
{Checks if a point is contained in the rectangle.
@param Pt [in] Point to be tested.
@return True if point is contained in the rectangle, False if not.
}
begin
Result := Types.PtInRect(Self, Pt);
end;
constructor TRectEx.Create(ALeft, ATop, ARight, ABottom: Integer);
{Record constructor. Sets initial field values.
@param ALeft [in] Left position of rectangle.
@param ATop [in] Top position of rectangle.
@param ARight [in] Right position of rectangle.
@param ABottom [in] Bottom position of rectangle.
}
begin
Left := ALeft;
Top := ATop;
Right := ARight;
Bottom := ABottom;
end;
constructor TRectEx.CreateBounds(ALeft, ATop, AWidth, AHeight: Integer);
{Record constructor. Creates rectangle from its bounds.
@param ALeft [in] Left position of rectangle.
@param ATop [in] Top position of rectangle.
@param AWidth [in] Width of rectangle.
@param AHeight [in] Height of rectangle.
}
begin
Create(ALeft, ATop, ALeft + AWidth, ATop + AHeight);
end;
constructor TRectEx.CreateBounds(ALeft, ATop: Integer; ASize: TSize);
{Record constructor. Creates rectangle from its bounds.
@param ALeft [in] Left position of rectangle.
@param ATop [in] Top position of rectangle.
@param ASize [in] Size of rectangle.
}
begin
CreateBounds(ALeft, ATop, ASize.cx, ASize.cy);
end;
class operator TRectEx.Equal(R1, R2: TRectEx): Boolean;
{Equality test for two TRectEx rectangles.
@param R1 [in] Left hand operand.
@param R2 [in] Right hand operand.
@return True if R1 is the same as R2, False if different.
}
begin
Result := (R1.Left = R2.Left) and (R1.Top = R2.Top)
and (R1.Right = R2.Right) and (R1.Bottom = R2.Bottom);
end;
function TRectEx.GetBottomRight: TPoint;
{Read accessor for BottomRight property.
@return Co-ordinates of bottom right of rectangle.
}
begin
Result.X := Right;
Result.Y := Bottom;
end;
function TRectEx.GetTopLeft: TPoint;
{Read accessor for TopLeft property.
@return Co-ordinates of top left of rectangle.
}
begin
Result.X := Left;
Result.Y := Top;
end;
function TRectEx.Height: Longint;
{Height of rectangle.
@return Required height.
}
begin
Result := Abs(Bottom - Top);
end;
class operator TRectEx.Implicit(ARect: TRectEx): TRect;
{Implicit cast of TRectEx to a TRect.
@param ARect [in] TRectEx to be cast.
@return TRect resulting from cast.
}
begin
Result.Left := ARect.Left;
Result.Top := ARect.Top;
Result.Right := ARect.Right;
Result.Bottom := ARect.Bottom;
end;
class operator TRectEx.Implicit(ARect: TRect): TRectEx;
{Implicit cast of TRect to a TRectEx.
@param ARect [in] TRect to be cast.
@return TRectEx resulting from cast.
}
begin
Result.Left := ARect.Left;
Result.Top := ARect.Top;
Result.Right := ARect.Right;
Result.Bottom := ARect.Bottom;
end;
function TRectEx.Inflate(DeltaX, DeltaY: Integer): TRectEx;
{Returns a copy of rectangle, inflated or deflated.
@param DeltaX [in] Amount to inflate horizontally. Deflated if -ve.
@param DeltaY [in] Amount to inflate vertically. Deflated if -ve.
@return Inflated copy of rectangle.
}
begin
Result := Self;
Result.InflateBy(DeltaX, DeltaY);
end;
procedure TRectEx.InflateBy(DeltaX, DeltaY: Integer);
{Inflates or deflates the rectangle.
@param DeltaX [in] Amount to inflate horizontally. Deflated if -ve.
@param DeltaY [in] Amount to inflate vertically. Deflated if -ve.
}
begin
Dec(Left, DeltaX);
Inc(Right, DeltaX);
Dec(Top, DeltaY);
Inc(Bottom, DeltaY);
end;
function TRectEx.IsEmpty: Boolean;
{Checks if a rectangle is empty. Empty is defined as Right <= Left or
Bottom <= Top.
return True if empty, False if not.
}
begin
Result := Types.IsRectEmpty(Self);
end;
procedure TRectEx.MakeEmpty;
{Makes the rectangle empty.
}
begin
Left := 0;
Top := 0;
Right := 0;
Bottom := 0;
end;
class operator TRectEx.NotEqual(R1, R2: TRectEx): Boolean;
{Inequality test for two TRectEx rectangles.
@param R1 [in] Left hand operand.
@param R2 [in] Right hand operand.
@return True if R1 is different to R2, False if same.
}
begin
Result := not (R1 = R2);
end;
procedure TRectEx.OffsetBy(AX, AY: Integer);
{Offsets rectangle in X and Y directions.
@param AX [in] Horizontal offset.
@param AY [in] Vertical offset.
}
begin
Inc(Left, AX);
Inc(Right, AX);
Inc(Top, AY);
Inc(Bottom, AY);
end;
procedure TRectEx.SetBottomRight(const Value: TPoint);
{Write accessor for BottomRight property.
@param Value [in] Coordinates of bottom right.
}
begin
Right := Value.X;
Bottom := Value.Y;
end;
procedure TRectEx.SetTopLeft(const Value: TPoint);
{Write accessor for TopLeft property.
@param Value [in] Coordinates of top left.
}
begin
Left := Value.X;
Top := Value.Y;
end;
function TRectEx.Width: Longint;
{Width of rectangle.
@return Required width.
}
begin
Result := Abs(Right - Left);
end;
{ TRange }
function TRange.Constrain(const Value: Integer): Integer;
{Adjusts the given value to ensure it falls within the range.
@param Value [in] Value to be constrained.
@returns Value is returned unchanged if it falls within the range. Otherwise
Min is returned if Value is less than Min or Max is returned if Value is
greater than max.
}
begin
if Value < Min then
Exit(Min);
if Value > Max then
Exit(Max);
Result := Value;
end;
function TRange.Contains(const Value: Integer): Boolean;
{Checks if a value is contained in range.
@param Value [in] Value to be tested.
@return True if Value is in range, False otherwise.
}
begin
Result := Math.InRange(Value, Min, Max);
end;
constructor TRange.Create(AMin, AMax: Integer);
{Record constructor. Initialises range bounds.
@param AMin [in] Minimum value that falls in range.
@param AMax [in] Maximum value that falls in range.
}
begin
Min := AMin;
Max := AMax;
end;
{ TSelection }
constructor TSelection.Create(AStartPos, ALength: Cardinal);
{Record constructor. Initialises start position and length.
@param AStartPos [in] Start of selection.
@param Length [in] Length of selection. Optional.
}
begin
StartPos := AStartPos;
Length := ALength;
end;
end.
