Hi,

I have a problem:

I would like to create a sizeable Form which changes size,position and
fontheight of each component on the Form in the same ratio as the
formsize.

I realized with following Source but if I put a TTabSet on the
Form i will get a GPF.
I anyone have a idea to do it better please help me

Muratore Mario (muratore.ma...@magnet.at)

function Tform1.ChkComponent(component : TComponent) : TControl;
var
  inlist : boolean;
  classname : string[63];
begin
  inlist:= false;
  classname:= TObject(component).classname;
  if classname = 'TGroupBox' then
    begin
      result:= TGroupBox(component);
      inlist:= true;
    end;
  if classname = 'TComboBox' then
    begin
      result:= TComboBox(component);
      inlist:= true;
    end;
  if classname = 'TListBox' then
    begin
      result:= TListBox(component);
      inlist:= true;
    end;
  if classname = 'TRadioButton' then
    begin
      result:= TRadioButton(component);
      inlist:= true;
    end;
  if classname = 'TCheckBox' then
    begin
      result:= TCheckBox(component);
      inlist:= true;
    end;
  if classname = 'TPanel' then
    begin
      result:= TPanel(component);
      inlist:= true;
    end;
  if classname = 'TRadioGroup' then
    begin
      result:= TRadioGroup(component);
      inlist:= true;
    end;
  if classname = 'TMemo' then
    begin
      result:= TMemo(component);
      inlist:= true;
    end;
  if classname = 'TEdit' then
    begin
      result:= TEdit(component);
      inlist:= true;
    end;
  if classname = 'TLabel' then
    begin
      result:= TLabel(component);
      inlist:= true;
    end;
  if classname = 'TButton' then
    begin
      result:= TButton(component);
      inlist:= true;
    end;
  if classname = 'TFileListBox' then
    begin
      result:= TFileListBox(component);
      inlist:= true;
    end;
  if not inlist then
    result:= nil;
end;

procedure Tform1.ChangeSize;
var
  index     : integer;
  factor_x,
  factor_y  : real;
  control   : Tcontrol;

begin
  factor_x:= clientwidth / designwidth;
  factor_y:= clientheight / designheight;
  LockWindowUpdate(handle);
  for index:= componentcount-1 downto 0 do
    begin
      control:= ChkComponent(components[index]);
      if control <> nil then
        with Obj_info^[index], TSizeControl(control) do
          begin
            if Font.Height <> round(schrifthoehe / designheight *
saveheight) then
              schrifthoehe:= round(font.height * designheight /
saveheight);
            Font.Height:= round( factor_y * schrifthoehe);
            width:= round(laenge * factor_x);
            left:= round(x1 * factor_x);
            height:= round(hoehe * factor_y);
            top:= round(y1 * factor_y );
            parentfont:= elternschrift;
          end;
    end;
    with obj_info^[componentcount] do
      begin
        if Font.Height <> round(schrifthoehe / designheight * saveheight)
then
          schrifthoehe:= round(font.height * designheight / saveheight);
        Font.Height:= round( factor_y * schrifthoehe);
      end;
    LockwindowUpdate(0);
    saveheight:= clientheight;
end;

What's TSizeControl?
Casting to TSizeControl without knowing that the control is in fact a
TSizeControl is dangerous. Use is and as.

M.

--
Ettertraktet kaffe, er det ekstra god kaffe?

mailto:martin.lars...@delfi-data.msmail.telemax.no
http://www.delfidata.no/users/~martin

This code snippet (for changing font sizes at runtime) I got from the DKB
won't compile (I realise that now).  It's pretty obvious; TComponent doesn't
have a "font" property!

In article <53sems$...@news.aus.world.net>, mac...@world.net (Peter Macaulay)
wrote:

The following was taken from the delphi knowledge base

P Mac
Melb
-----------------------------------------------------------------------------
FORM DISPLAY WITH DIFFERENT SCREEN RESOLUTIONS

#2032.TIP       From BORLAND

When designing forms, it is sometimes helpful to write the code
so that the screen and all of its objects are displayed at the
same size no matter what the screen resolution is.  Here is
some code to show how that is done:

implementation
const
  ScreenWidth: LongInt = 800; {I designed my form in 800x600 mode.}
  ScreenHeight: LongInt = 600;

{$R *.DFM}

procedure TForm1.FormCreate(Sender: TObject);
begin
  scaled := true;
  if (screen.width <> ScreenWidth) then
  begin
    height := longint(height) * longint(screen.height) div ScreenHeight;
    width := longint(width) * longint(screen.width) div ScreenWidth;

    scaleBy(screen.width, ScreenWidth);
  end;
end;

Then, you will want to have something that checks to see that
the font sizes are OK.  Before you change the font's size, you
would need to ensure the object actually has a font property.  
This can be done as follows:

uses typinfo;

var
  i: integer;
begin
  for i := componentCount - 1 downtto 0 do
    with components[i] do
    begin
      if GetPropInfo(ClassInfo, 'font') <> nil  then
        font.size := (NewFormWidth DIV OldFormWidth) * font.size;
    end;
end;

Note:  The following are issue to bear in mind when scaling
Delphi applications (forms) on different screen resolutions:

  * Decide early on in the form design stage whether you're
going to allow the form to be scaled or not.  The advantage of
not scaling is that nothing changes at runtime.  The
disadvantage of not scaling is that nothing changes at runtime
(your form may be far too small or too large to read on some
systems if it is not scaled).

  * If you're NOT going to scale the form, set Scaled to False.

  * Otherwise, set the Form's Scaled property to True.

  * Set AutoScroll to False.  AutoScroll = True means 'don't
change the form's frame size at runtime' which doesn't look
good when the  form's contents do change size.

  * Set the form's font to a scaleable TruueType font, like

Arial.   MS San Serif is an ok alternate, but remember that it
is still a  bitmapped font.  Only Arial will give you a font
within a pixel of the desired height.  NOTE: If the font used
in an application is not installed on the target computer, then
Windows will select an  alternative font within the same font
family to use instead.  This font may not match the same size
of the original font any may cause problems.

  * Set the form's Position property to something other than
poDesigned.  poDesigned leaves the form where you left it at
design time, which for me always winds up way off to the left
on my 1280x1024 screen -  and completely off the 640x480 screen.

  * Don't crowd controls on the form - leave at least 4 pixels

between  controls, so that a one pixel change in border
locations (due to  scaling) won't show up as ugly overlapping
controls.

  * For single line labels that are alLeft or alRight aligned,
set AutoSize to True.  OOtherwise, set AutoSize to False.

  * Make sure there is enough blank space in a label component
to allow for font width changes - a blank space that is 25% of
the length of the current string display length is a little too
much, but safe. (You'll need at least 30% expansion space for
string labels if you  plan to translate your app into other
languages) If AutoSize is  False, make sure you actually set
the label width appropriately.  If AutoSize is True, make sure

there is enough room for the label  to grow on its own.

  * In multi-line, word-wrapped labels, leave at least one line
of blank space at the bottom.  You'll need this to catch the
overflow when the text wraps differently when the font width
changes with scaling. Don't assume that because you're using
large fonts, you don't have to allow for text overflow -
somebody else's large  fonts may be larger than yours!

  * Be careful about opening a project in the IDE at different
resolutions.  The  form's PixelsPerInch property will be
modified as soon as the form is opened, and will be saved to
the DFM if you save the project. It's best to test the app by
running it standalone, and edit the form at only one

resolution. Editing at varying resolutions and font sizes
invites component drift  and sizing problems.

  * Speaking of component drift, don't rescale a form multiple
times, at design time or a runtime.  Each rescaling introduces
roundoff errors which accumulate very quickly since coordinates
are  strictly integral.  As fractional amounts are truncated
off control's origins and sizes with each successive
rescaling,  the controls will appear to creep northwest and get
smaller. If you want to allow your users to rescale the form
any number  of times, start with a freshly loaded/created form
before each  scaling, so that scaling errors do not accumulate.

  * Don't change the PixelsPerInch property of the form, period.

  * In general, it is not  necessary to design forms at any
particular resolution, but it is crucial that you review their
appearance at 640x480 with small fonts and large, and at a
high-resolution with small fonts and large before releasing
your app.  This should be  part of your regular system
compatibility testing checklist.

  * Pay close attention to any components that are essentially  
single-line TMemos - things like TDBLookupCombo.  The Windows  
multi-line edit control always shows only whole lines of text
-  if the control is too short for its font, a TMemo will show  
nothing at all (a TEdit will show clipped text). For such  

components, it's better to make them a few pixels too large
than to be one pixel too small and show not text at all.

  * Keep in mind that all scaling is proportional to the
difference  in the font height between runtime and design time,
NOT the pixel resolution or screen size.  Remember also that
the origins of your controls will be changed when thhe form is
scaled - you can't very well make components bigger without
also moving them over a bit.