faq.txt

BarMenus230.zip

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                BarMenu Components Frequently Asked Questions
        Copyright (C) 2000-2001 Bluecave Software. All Rights Reserved.
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  This file contains frequently asked questions and answers to those. Before
  asking the Author for help, please read this file completely. If your
  problem is not solved after read this file, you may contact the Author.
  For contact information see Readme.txt.

  FAQ:
   1. How to use separator line item captions?
   2. How to convert existing menus to BarMenus?
   3. How to use OnBeforeDrawBar and OnAfterDrawBar?
   4. I upgraded from version older than 2.0.3 to latest version
      and it gives me error that some properties do not exists.
      What is this all about?
   5. I'm getting "Parameter Incorrect" errors! What is this?
   6. How to use OnMeasureMenuItem and OnDrawMenuItem events of
      TBcCustomDrawModule?
   7. How to create own DrawModule?

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  1.
  Q: How to use separator line item captions?

  A: You make the separator line like before (with "-" character as caption) and
  then the separator line caption you want to have is put to the Hint property
  of the item. If you want to disable the separator line caption, set the
  items Enabled property to False. And of course you need to have the menu
  component ShortLines set True. See the demo application for example.

  Tip: If you want to have separator line as the first item in the menu, you
       need to set the AutoLineReducation on the parent item to maManual.
       Otherwise the item is removed automatically by VCL.

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  2.
  Q: How to convert existing menus to BarMenus?

  A: You need to edit the source code and the dfm source code manually.

  Classes which are compatible:

    TMainMenu - TBcBarMainMenu
    TPopupMenu - TBcBarPopupMenu

    1. Change the menu class to BarMenus class in the source code. Example:

       TForm1 = class(TForm)
         PopupMenu1: TPopupMenu;                    <-- This line
       private
       ...

       Change to:

       TForm1 = class(TForm)
         PopupMenu1: TBcBarPopupMenu;               <-- This line
       private
       ...

    2. Do the same change to the dfm source. Activate the form and press ALT-F12.
       You will now get the form in text format to the editor. Change the
       component's class which you changed in the source code. Example:

       object Form1: TForm1
         object PopupMenu1: TPopupMenu              <-- This line
           AutoLineReduction = maManual
           Images = PopupMenuImages
       ...

       Change to:

       object Form1: TForm1
         object PopupMenu1: TBcBarPopupMenu         <-- This line
           AutoLineReduction = maManual
           Images = PopupMenuImages
       ...

       After that press ALT-F12 again to see the form again. Now the menu
       component has all new properties and features!

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  3.
  Q: How to use OnBeforeDrawBar and OnAfterDrawBar?

  A: As told in the description of these events in the Readme.txt and seen in
     the example Demo project these are fairly easy to use. Here is the example
     code from the Demo project for OnBeforeDrawBar event:

     procedure TForm1.BcBarPopupMenu3BeforeDrawBar(Sender: TObject;
       ACanvas: TCanvas; ARect: TRect; var DefaultDraw: Boolean);
     begin
       DefaultDraw := False; { do not allow default drawing }
       with ACanvas do
       begin
         { fill the whole bar with something }
         Brush.Bitmap := AllocPatternBitmap(clRed, clYellow);
         FillRect(ARect);
         { draw black frame rect around the bar }
         Brush.Color := clBlack;
         FrameRect(ARect);
       end;
     end;

     OnAfterDrawBar event works same way as the OnBeforeDrawBar with exception
     of that the ACanvas contains the bar which has been drawn by the component.
     Also, there is no DefaultDraw parameter in this event. Demo project shows
     code which copies the bar image to the parent forms TImage as "preview":

     procedure TForm1.BcBarPopupMenu1AfterDrawBar(Sender: TObject;
       ACanvas: TCanvas; ARect: TRect);
     begin
       with Image1.Canvas do
       begin
         { empty the image }
         Brush.Color := Form1.Color;
         FillRect(Rect(0, 0, Image1.Width, Image1.Height));
         { copy the menu bar to the image1 }
         CopyRect(ARect, ACanvas, ARect);
       end;
     end;

     You must note that the events are excuted only when the internal bar
     doublebuffer needs refresh. So, if the buffer contants valid bar events
     are not executed. This behavior can be seen in the Demo project. Try
     testing the Enabled check item in the Toolmenu popupmenu.

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  4.
  Q: I upgraded from version older than 2.0.2 to latest version and it gives
     me error that some properties do not exists. What is this all about?

  A: Read the History.txt. Older versions used TBitmaps, but new versions have
     TPicture, which gives much more better support for different file formats
     including .BMP, .ICO, metafiles and other TGraphic supported formats.

     Only solution is to Ignore the errors and reset the BarPicture (old
     BarBitmap) and BarBackPicture (old BarBackBitmap) properties manually.

  A: This has been changed in 2.1.0. Again.. Now the Picture properties are
     TBitmaps by default. This was done to find the cause of the problem
     described in the Question 5. Also now that the TBitmap transparency works
     it's better as TBitmap uses less resources than TPicture.

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  5.
  Q: I'm getting "Parameter Incorrect" errors! What is this? How can I
     fix this?

  A: This has been fixed in version 2.2.0. This bug was in versions 2.0.3 to
     2.1.0. If the system had menu animations enabled the bug appeared.
     "Work-around" by setting the Bar.Visible property to False.

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  6.
  Q: How to use OnMeasureMenuItem and OnDrawMenuItem events of
     TBcCustomDrawModule?

  A: Using these events is very easy. I'd suggest you take a look at the
     Demo project source code for a nice example.

     It is possible to use the OnMeasureItem and OnDrawItem/OnAdvancedDraw
     events of the TMenuItems at the same time. The "global"
     OnMeasureMenuItem and OnDrawMenuItem events are not executed for those
     items.

     If you wish to have the default drawing then set the DefaultDraw to True
     and remember to set it to False if you provide custom drawing.

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  7.
  Q: How to create own DrawModule?

  A: Select: File | New.. | Component.. | and type "TBcBarMenusDrawModule" as
     anchestor class.

     Implement the abstract methods DrawMenuItem and MeasureMenuItem of
     TBcBarMenusDrawModule. See the TBcCustomDrawModule for a very simple
     example.

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