Custom Tab Controls, Tabbed Frame and Tabbed MDI

// History of DotNetTabCtrl.h prior to codeproject article about it
//
// History (Date/Author/Description):
// ----------------------------------
//
// 2002/06/12: Daniel Bowen (DDB)
// - Notifications no longer need to be reflected
// - Draw close button in CDotNetTabCtrlImpl when
//   CTCS_CLOSEBUTTON style is set (draw in PostPaint)
// - Draw scroll buttons in CDotNetTabCtrlImpl when
//   CTCS_SCROLL style is set.
// - Improve drawing.  Override DoPrePaint, DoItemPaint, DoPostPaint
//   instead of being a "client" of custom drawing.  Use the
//   custom draw structure colors, so that you pick up
//   any changes that a client might be doing if they truly are
//   using the custom draw functionality.  Override
//   InitializeDrawStruct to specify the defaults.
// - Move updating of the tab item tool tip RECT updating to
//   "UpdateTabItemTooltipRects" in the base CCustomTabCtrl class.
// - On WM_SETTINGCHANGE, if CTCS_BOLDSELECTEDTAB is set,
//   the bold font wasn't being deleted if one had already been set
//
// 2002/05/13: Daniel Bowen (DDB)
// - Minor updates to avoid level 4 warnings
// - Take out a trace statement in UpdateLayout
//
// 2002/05/09: Daniel Bowen (DDB)
// - Move out of CoolTabCtrls.h into its own file
//   to match how Bjarke has reorganized it.
//   Relevant history also moved.
// - Have the original CDotNetTabCtrl turn into
//   an overrideable CDotNetTabCtrlImpl, and have
//   CDotNetTabCtrl inherit from CDotNetTabCtrlImpl.
// - Minor updates to accomodate changes I made
//   to CCustomTabCtrl (unsigned vs. signed types, etc.).
// - Incorporate suggestsion from Bjarke Viksoe
//   (don't use atlmisc.h types, AtlGetDefaultGuiFont()
//   instead of AtlGetStockFont(DEFAULT_GUI_FONT),
//   UpdateLayout in OnSettingChange, etc.)
//
// 2002/04/26: Daniel Bowen (DDB)
// - CDotNetTabCtrl and CDotNetButtonTabCtrl -
//   Owen Gunter [OwenG@d-graphic.co.uk] pointed out that
//   the tabs were "shifting" when the selection changed
//   (in tab controls that aren't bolding the selected tab).
//   This was due to using "SelMargin" in some recent updates.
//   Now, SelMargin is not used, just "Margin" - and the
//   tabs shouldn't shift like they did.
// - Owen Gunter [OwenG@d-graphic.co.uk] suggested some
//   slight modifications to CDotNetTabCtrl for drawing
//   the tab background on the right side when the tabs
//   are shown on top.  Those modifications are in here now.
//
// 2002/04/22: Daniel Bowen (DDB)
// - Move the Image List and "bold selected tab" stuff to the
//   base "CCustomTabCtrl" class.  In a future revision, I'll
//   probably update the base class to honor these, but for
//   now, its up to the deriving class whether or not to use
//   these things.  Having them there makes it easier to use
//   any CCustomTabCtrl derived class where there's a template
//   parameter for the tab class, and where it might want to
//   use the image list or bold the selected tab.
// - When the tabs are not a subclassed static control,
//   the "GetFont" and "SetFont" calls were going in the bit
//   bucket.  CCustomTabCtrl now has a member variable
//   "CFont m_font", and all the derived classes (with one
//   exception) now use the base class version instead of their own.
//   If a derived class has a bold font, they still declare
//   that themselves.  Because the base class "m_font" is
//   managing the lifetime of the font (i.e., it calls DeleteObject
//   in the destructor), the handler for WM_SETFONT makes
//   a copy of the font instead of "pointing" to it.
//   Typically, no one should be sending us WM_SETFONT.
//   CFlatTabCtrl is the one deriving class that has its
//   own version of m_font, because it wants to do a
//   SetFont(m_fontBold) - which with the new way of things
//   would cause CCustomTabCtrl::m_font and CFlatTabCtrl::m_fontBold
//   to be the same.
// - More updates for CDotNetTabCtrl and CDotNetButtonTabCtrl
//   to accomodate the current DPI and system metrics.
//   The updates were focused on getting the padding and margin
//   for the active and inactive tabs to be a better match
//   for what VS.Net does under various DPI and font settings.
//   It turned out to be quite difficult to get a pixel-for-pixel
//   match to VS.Net under various font sizes and DPI settings.
//   What's there now is not a perfect match, but its pretty good.
// - Change the logic for CDotNetTabCtrl and CDotNetButtonTabCtrl
//   when they don't get all the real estate their tabs want.
//   When the desired widths of the tabs would be too big for
//   the client area:
//    * First, the inactive tabs are proportionally reduced,
//      and the selected tab is given its desired width
//    * Once the smallest inactive tab would be too small,
//      the inactive tabs are no longer made proportional to
//      their desired size, but are all made the same size.
//      The selected tab is still given its desired width.
//    * Once there's not enough room to show the selected tab
//      at its desired width and all the inactive tabs at
//      the same minimum width, all of the tabs are made
//      the same width (both the selected and inactive tabs)
//   NOTE: This is not the approach VS.Net takes.  VS.Net
//    first gives away the real estate for the widest tabs
//    until all the tabs are the same width.  If you'd rather
//    have that approach, create a new class that inherits
//    from CDotNetTabCtrl/CDotNetButtonTabCtrl and override
//    UpdateLayout with your implementation.
//   
// 2002/04/17: Daniel Bowen (DDB)
// - Owen Gunter [OwenG@d-graphic.co.uk] pointed out that the
//   tab background and font height of CDotNetTabCtrl didn't match
//   what he saw in the tabs under his version of Visual Studio.
//   When I originally chose those, I was running Visual Studio
//   RC1 under Windows XP with the Windows XP theme and the
//   silver color scheme and large fonts.  It wasn't clear to me
//   at the time if the tab background color was dependant on a
//   system color (it didn't seem to be) or if the font was dependant
//   on a system metric (I had changed the caption font and saw
//   it didn't change).
//
//   I've now revisited the issue, and there's now a much better
//   approximation of what Visual Studio.Net is doing.
//   * The tab font is the "ICON" font, which can be retrieved
//     by calling SystemParametersInfo with SPI_GETICONMETRICS.
//     CDotNetTabCtrl and CDotNetButtonTabCtrl now use this
//     font instead of a hardcoded 9 point Tahoma.
//   * The tab background is a "lightened" version of COLOR_BTNFACE.
//     The formula used in CDotNetTabCtrl isn't exactly the same
//     formula that VS.Net uses, but from my experiments, its
//     never more than 1 off for red, green, or blue
//     (with each of these being 0-255)
//   * The "inactive tab" text color is a "darkened" version of
//     COLOR_GRAYTEXT.  Again, the formula is an approximation
//     to what VS.Net is doing, but its seems to be very close.
//   * CDotNetTabCtrl was doing some outlines with a black ben
//     and a white pen.  After some experiments, I found that
//     VS.Net was actually using COLOR_BTNTEXT and COLOR_BTNHIGHLIGHT.
//     I've updated CDotNetTabCtrl to do the same.
//
// 2002/01/30: Daniel Bowen (DDB)
// - Added my version of CDotNetTabCtrl based on Pascal's
//   CDotNetTabCtrl2:
//    * Added support for divider lines between tabs
//    * Closer match to look of tabs used in VS.Net
//    * Support for bolding text of selected tab
// - Added CDotNetButtonTabCtrl (to look like VS.Net
//    view of HTML with the Design/HTML buttons)
//