RCS_Resize

The purpose of this unit is to reszize all components on a form when the form itself is resized.

Usage

The usage is very simple: this is the interface between the using program and the unit:

On every form that needs its components resize add the following:

• Create a variable of the type 'TMyResize':

   var MyResize_: TMyResize;

• Add in the 'Form.Create' event:

   MyResize_ := TMyResize.Create(Self);

• Add in the 'Form.Resize' event:

   MyResize_.Resize(Self);

• Add in the 'Form.destroy' event:

   MyResize_.Free;

The "standard behaviour" is:

The resize unit calculates from the old and the new form Width en hight the horizontal and vertical zoom factors and adapts for all components on the form the height, the width, the left and the top values trough simple multiplication. The resizing is recursive, e.g. a Panel on the form gets resized and also all components on that panel become resized (and repositioned).

Deviations of standard behaviour

For components that need a deviation on the resizing method there is a callback routine available. This routine is called for every component when it is to become resized.

The signature of this routine is:

type TResizeCallbackFunction = function(Control: TControl; VFactor, HFactor: real; L, W, H, T
{$IFDEF FONTRESIZE}
  , S
{$ENDIF}
: integer): boolean;

The routine parameters: Control: the component about to resize; VFactor en HFactor: the zoom factors; L, W, H, T: the original positions and dimensions of the component; S: the original fontsize of the item.

This routine has to return a boolean: false: means the callback routine did NO resizing (this means the standard resizing behaviour will be used); true: means the callback routine DID the resizing (and the standard behaviour is switched off).

The routine itself looks like this (example):

function ResizeCallbackFunction(Control: TControl; VFactor, HFactor: real; L, W, H, T
{$IFDEF FONTRESIZE}
, S
{$ENDIF}
: integer): boolean;
var Tsg: TStringGrid;
begin
  Result := false; // resizing not handled here = default

  if Control.Name = 'StringGrid3' then // special case
  begin
    Result := true; // resizing handled here

    // calculate new values
    W := Trunc(HFactor * W);
    H := Trunc(VFactor * H);
    L := Trunc(HFactor * L);
    T := Trunc(VFactor * T);

    // and use them
    Tsg := Control as TStringGrid;
    Tsg.Left := L;
    Tsg.Top  := T;
    Tsg.DefaultColWidth  := W + 20; // to be sure column 1 is always invisible
    Tsg.DefaultRowHeight := (H div Tsg.RowCount);
    Tsg.Width  := W;
    Tsg.Height := H;
  end;
end;

The callback routine (if any) is activated in the 'Create' call:

MyResize_ := TMyResize.Create(Self, ResizeCallbackFunction);

Compiler directives

The unit uses 2 compilerdirectives: FONTRESIZE: the font of the components is also adapted to the calculated zoomfactors STRINGGRIDRESIZE: Also Stringgrids are resized. The standard behaviour is all rows the same size.

Have fun!