Chip 2001 September/Chip_2001-09_cd1.bin/zkuste/delphi/kolekce/d123456/DFS.ZIP/DFSLayeredForm.txt

Text File | 2001-06-28 | 11KB | 213 lines

TdfsLayeredForm v1.00 Beta 3

Description:
   A TForm descendent class that provides access to the features of "layered
   windows" which are new in Windows 2000.  Layered windows can be translucent
   (they blend with the things behind them, making it appear as though they are
   "see through"), have transparent sections (areas that do not exist at all
   allowing you to make non-rectangular windows similar to the way SetWindowRgn
   works), or both.  The benefit of using the transparency of a layered window
   vs. SetWindowRgn is that you don't have to construct a region that describes
   the non-rectangular area, you simple paint all the area in one color and
   choose that color as the transparent color.

   NOTE: "Layered windows" were introduced in Windows 2000 and are NOT supported
   on prior versions of Windows (95, 98, NT 4).  There should be no detremental
   effects of using it on a previous OS, the form will simply behave as a
   standard TForm.

Contact Information:
  The lateset version will always be available on the web at:
    http://www.delphifreestuff.com
  If you have any questions, comments or suggestions, please use the Delphi
  Free Stuff Support Forum at:
    http://www.delphifreestuff.com/discus/
  If, for some reason, you can not use the web-based support forum, you can
  email me at [e-mail].  However, the support forum will
  always take precedence over direct email since it provides a resource that
  others can use when they have a problem.  Every message posted to the forum
  is emailed directly to this account, so emailing me directly will not get
  your message to me any faster.  It will only make the message less important
  for me to respond to since only one person (you) is benefiting from it
  instead of everyone interested.  Having said all that, please do email me
  directly if it is regarding something that isn't really support related,
  i.e. just to say thanks (as novel as that idea is).


Installation:
  Delphi 1:
    * Delphi 1 is not supported.

  Delphi 2, C++Builder 1:
    * TdfsLayeredForm has not been tested on, and does not officially support
      Delphi 2 or C++Builder 1.  However, you should be able to simply place
      the files in the directory of your choosing.  There is no component
      involved.

  Delphi 3, 4, 5, C++Builder 3 & 4:
    * Do one of the following:
      + Create a new package by selecting File | New and choosing Package from
        the New tab in the dialog.
      + Open an existing package file.  I suggest you do this if you already
        have a package that you like to use for small, third party components.
        I specifically have a package named "3rdParty.dpk" that I use for
        small components that come from other people.  Or, if you are using
        several of my components, you might create a "DFS.dpk" package and
        use it for all of my DFS components.
    * In the resulting package window, click the Add button.
    * In the Add dialog, on the Add Unit tab, enter the full path name of the
      component's registration unit (the unit that ends with 'Reg.pas', i.e.
      'BrowseDrReg.pas') and click OK.
    * You may want to add the other source files (*.pas) to the package as
      well in the same manner as you did the registration unit.  While this is
      not required, not doing it will cause compiler warnings when the package
      is compiled.  The component will function fine either way, but I
      personally find the warnings very irritating and am not happy until
      every compiler warning and hint is gone.
    * If this package is new, or it has never been installed, click the
      Install button in the package window.  If this package is already
      installed in Delphi, click the Compile button.
      Note that this will NOT add any items to your component palette.
      TdfsDSAForm is not a component, but a TForm descendant class.  So,
      instead of a component palette icon, you will instead have a new "DFS"
      tab added to the Object Repository (File | New).  If you prefer a tab
      name other than "DFS", you can edit the sLayeredFormObjRepositoryPage
      constant in DFSLayeredFormReg.pas and recompile the package.  Note that
      you can use the name of an existing tab ("Forms" for example) to have the
      items added there.

  C++Builder 5 and up:
    * Perform the "Delphi 3 and up, C++Builder 3 and up" steps above, except
      for the last step (Compile or Install).
    * Select the package the component has been added to, and choose
      Project | Edit Option Source to open the package options in the editor.
    * In the entry for PFLAGS, add the "-LUvcl50" option.  For example:
        <PFLAGS value="-$YD -$W -$O -v -JPHNE -M -LUvcl50"/>
    * Perform the final step from above, Compile or Install.
    * For Borland's official word on this situation, open the C++Builder help
      file and search the index for "dsgnintf.dcu" and see the "Compiling
      packages with DsgnIntf" section.

  Delphi 6 and up:
    * Perform the "Delphi 3, 4, 5, C++Builder 3 & 4" steps above, except
      for the last step (Compile or Install).
    * Add the DesignIDE package to the Requires list of the package into which
      the component is being installed.
    * Perform the final step from above, Compile or Install.
    * This is necessary because of changes to the design-time support units
      introduced in Delphi 6.  For complete information, see the Del6New.hlp
      file in your Delphi 6 Help directory.  In the index, search for
      "upgrade issues" and in the resulting list of topics, select the
      "DsgnIntf renamed and related changes" topic.


Design-Time Access to TdfsLayeredForm Properties:
  NOTE:  This information applies only to Delphi 3 and above, and C++Builder 3
         and above.  Previous versions of Delphi and C++Builder do NOT support
         design-time access of TForm descendants.  Sorry.  You can should still
         be able to use this class with those prior versions, you just won't
         have access to the new properties at design-time, only in your code at
         run-time.
  * Create a new application project.
  * Select File | New and choose the "DFS" tab in the Object Repository window.
  * Select the "Layered Form" item and click the OK button.
  * You should now have a new TdfsLayeredForm type form added to the project, and
    when you select it all new properties should be visible in the IDE.


Delphi 2, and C++Builder 1 Notes:
  * Although not officially supported, you may be able to use this class with
    Delphi 2 and/or C++Builder 1 by following these directions.
    The best way to use this form is to add it to your Object Repository.
    Simply open this unit in Delphi, right click on the form and select Add
    To Repository.  Then, when you want a TdfsLayeredForm, you just select it
    from the repository (File | New) and use the "Inherit" option so you
    don't have to see all this code in your form.

    Delphi 1 & 2: If you have existing forms that you want converted to layered
    forms, simply add "DFSLayeredForm" to your "Uses" clause, and change your
    form's ancestor to TdfsLayeredForm.  An example:
       Change:
          TMyForm = class(TForm)
       To:
          TMyForm = class(TdfsLayeredForm)

    C++Builder 1: To convert existing forms, add the DFSLayeredForm.pas file to
      the project (using Project Manager), then open the form's header file and
      add:

       #include "dfslayeredform.hpp"

    above the form class declaration.  Next, change the form's class declaraion:
      Change:
        class TForm1 : public TForm
      To:
        class TForm1 : public TdfsLayeredForm

    And finally, change the form's constructor in the source (.cpp) file:
      Change:
        __fastcall TForm1::TForm1(TComponent* Owner)
          : TForm(Owner)
        {
      To:
        __fastcall TForm1::TForm1(TComponent* Owner)
          : TdfsLayeredForm(Owner)
        {

Documentation:
  * MousePassthrough: boolean
    This property, when set to TRUE, will pass all mouse clicks through to the
    window underneath the TdfsLayeredForm.  Normally, only transparent areas are
    treated in this manner.  You may find this useful if you are doing some sort
    of informational display where the form is very translucent and is not meant
    to be interacted with.  Note that the form will still react to keyboard
    messages when it has focus (i.e. Alt-F4 will close it).
  * Opacity: byte
    This property controls how translucent the form will be.  The allowable
    range is from 0 to 255, where 0 is completely invisible and 255 is
    completely opaque (appears as any other window).
  * UseOpacity: boolean
    Controls whether the form is translucent or not.  When set to TRUE, the
    amount of translucency for the form is controlled by the Opacity property.
  * TransparentColor: TColor
    Defines the color that should be removed from the form.  All visible
    elements on the form of this color will be completely removed, thus allowing
    you to create non-rectangular windows, or non-standard window shapes.  Note
    that this applies only the client area, not the non-client area (i.e. the
    title bar is unaffected).
  * UseTransparentColor: boolean
    Controls whether the form has transparent areas or not.  If set to TRUE,
    all areas on the form that match the color in the TransparentColor property
    will be removed from the form.


Notes:
  * Delphi 6 has added transparency support to TForm (see AlphaBlend,
    AlphaBlendValue, TransparentColor and TransparentColorValue properties).
    I have not investigated these new properties enough to know whether
    I should continue work on this "component" or not.  When I have time
    to review the new D6 stuff, I may decide to drop this component.
  * Transparency means that part of the window does not exist.  If you click
    on a transparent area of the form, that click gets passed through to
    whatever window is underneath it.
  * This component was inspired by an article in Windows Developers Journal.
    I didn't even realize this stuff was in Windows 2000 until I saw it
    discussed in the May 2000 issue.
  * For further reading on the new "layered windows" in Windows 2000, see the
    paper written by Vadim Gorokhovsky and Lou Amadio on Microsoft's site at
    http://msdn.microsoft.com/library/techart/layerwin.htm


Known Issues:
  * There are no known issues at this time.


Revision History:
  Beta 3:  + Updated for Delphi 6 compatibility.  See updated install directions
             above.
  Beta 2:  + Wouldn't run on non-Windows 2000 systems.  I had directly linked to
             the new external API functions instead of dynamically loading them.
             Thanks to Jon Robertson for sending me the fixed code.
           + Updated for C++Builder 5 compatibility.
  1.00:    + Initial release