The DialogEditorDemo app
The DiagramEditorDemo app
Introduction
So you wanted to add a forms editor to your application? A dialog editor? Something that allows drawing of HTML <div>
s? Here is a feature rich skeleton (!) to get you started. CDiagramEditor
is a package that gives you a basic visual editor intended for vector objects. Although perhaps not sufficient to create a CAD-application, you'll indeed be able to create a dialog editor. The editor itself is derived from CWnd
, with a separate class handling the data, so you'll be able to either use it in a dialog or doc/view application.
Some of the built-in features:
- Full mouse handling. Draw and drag multiple objects, drag draw, and resize single ones.
- Paper size, margin, and grid easily configured.
- Snap to grid, restrain moving and resizing to margin or paper. Or draw outside the paper, if you want.
- Configurable keyboard interface.
- Plug-in popup menu for the editor.
- Unlimited zoom.
- Unlimited undo.
- Support for saving and loading to
CString
s/CStringArray
s.
- For the programming aficionado, the different drawing functions of the editor are virtual, so if you're not satisfied with the look, derive a class and do it yourself.
- Base objects for rectangles and lines, you derive the drawing objects you need from those.
- Support for object-specific popup menus.
- Support for object-specific property dialogs.
And more. Of course, this package is fiendishly difficult to use? No, add an instance of CDiagramEditor
to your app, derive the drawing classes you need, and you have an editor.
I've added two demo applications. The smaller one, DiagramEditorDemo, shows the basics, adding an editor to a dialog application.
DialogEditorDemo is a SDI doc/view application showing how to use the separate data container class, how to plug into the document loading and saving, and using a factory to create the drawing objects, how to add print and print preview, custom background redraw, exporting, and much, much more.
The package consists of the following classes:
CDiagramEditor
- The editor itself.
CDiagramEntityContainer
- A container class for the editor data.
CDiagramEntity
- Base class for the drawing objects.
CDiagramLine
- A CDiagramEntity
-derived class that can be used as a base class for line objects.
CDiagramMenu
- Popup editor menu.
CDiagramPropertyDlg
- Pure virtual base class for object property dialogs.
and a few small help classes.
As it is quite a lot of code, I've added HTML-documentation with an overview of the classes, and a page of How-tos and class details for the bigger classes. The code is commented as well.
History
The beginning of time
Original release.
1/5 2004
Working intensely with the CDiagramEditor
, I've made a few enhancements to the package, mainly to:
- Facilitate deriving from
CDiagramEntityContainer
.
- Make it possible to use the same internal clipboard for several editors.
The second modification is to be able to use CDiagramEditor
in a MDI-application, where you might want to copy and paste objects across editors. It is accomplished by separating out the copy/paste-functionality from CDiagramEntityContainer
and putting it in a class of its own - CDiagramClipboardHandler
.
Especially irritating, while doing these modifications using a MDI-app as the host, was that even though property dialogs were created with the editor as the parent, the parent returned calling GetParent
in the OnOK
-handlers. Thus, the editor was not updated correctly when changes where made to the objects. I had to work around this by adding an explicit redraw-parent to CDiagramPropertyDlg
and adding a new member Redraw
that should be used instead of GetParent()->RedrawWindow()
in derived classes for MDI-applications.
Other than that, I must admit that refactoring is a major hassle in MSVC++ 6.0, something I thought only wimps complained about earlier (have I been lucky in the small amount of refactoring necessary in my life up to this point?).
The documentation is updated accordingly, and the changes are:
CDiagramEditor
SendMessageToObjects
sets the selected-flag to TRUE
- sending the message only to selected objects.
- Made some message mapping functions virtual to allow enhancements in derived classes.
- Added accessors for states to allow access for derived classes.
- Set interact mode to
MODE_NONE
after Ctrl+clicking item (to avoid undesired movement of lines).
- Set scrollbar positions to zero in
Clear
. Earlier, when loading a document, the scrollbars were not reset to 0,0.
- Sending this window as a parent to the property dialog. This is to redraw the editor properly after changes in the dialog in MDI-apps.
- Changed C-style casts to
static_cast
.
- Removed
ShowProperties
-const
-ness.
CDiagramEntityContainer
- Made
RemoveAt
virtual.
- Made several undo- and copy/paste functions virtual. Added array accessors for derived classes. Moved the member function
Find
to the protected
section. All this to simplify deriving from CDiagramEntityContainer
.
- Copy/paste-handling removed to a separate class (
CDiagramClipboardHandler
) to allow several containers to share the same clipboard.
- Changed C-style casts to
static_cast
.
CDiagramEntity
- Changed accessors for
m_type
- SetType
and GetType
- to public
.
- Added colon as a replace-character for saving in
FromString
and GetString
. Earlier, names or titles with embedded colons would have been invalid.
- Added a redraw parent to the property dialog in
ShowProperties
.
CDiagramPropertyDlg
- Added a redraw parent,
m_redrawWnd
, to redraw the proper window in MDI-applications. Derived classes can now use Redraw
if the editor needs to be updated.
If you are using CDiagramEditor
in an existing project, the things affecting you will be Set interact mode..., Set scrollbar positions..., and Added colon as a replace-character... above. To use the new package, download the source code again and copy the files over the existing ones, and add CDiagramClipboardHandler.cpp and CDiagramClipboardHandler.h to your project.
15/5 2004
Bug fix in the dialog editor demo
The Export
function of the CDiagramEntity
-derived objects in the demo wasn't updated to const
, and so was not called by the export-mechanism.
13/6 2004
This is definitely not an essential update. Mainly, I'm updating the framework because of an upcoming UML-editor, where a few more things have been made virtual
or const
to ease derived editors. Anyhow, on with the list:
Virtual size checks when scrolling
Graham suggested this (see below). Although the scroll position functionality ought to have reported correct values, it's better safe than sorry, so I've included page check in the VScrool
and HScroll
routines - not unnecessarily trying to scroll an editor window with no scroll bars.
Modifications for derived editors
CDiagramEditor
- Added access to
m_subMode
in SetInteractMode
.
- Made
OnObjectCommand
virtual to allow interception in derived classes.
- Made
GetBackgroundColor
const.
- Made
SelectAll
virtual.
CDiagramEntityContainer
- Made
GetAt
virtual.
RemoveAll
, added check to see if there are any items in the object array.
- Made
RemoveAll
access data container objects directly, to avoid chained deletes in derived classes. Applies if a delete
should delete other items automatically.
Who should update the editor code? Anyone experiencing problems while trying to scroll outside the paper area?
8/7 2004
Time for another update! I've added some bug corrections, some enhancements to further assist derived editors, and added some new functionality. The corrections are:
- Corrected a bug in
SetZoom
, where minimum size was not honored (pgrohs).
- Zeroing
m_internalData
after a delete
in SetDiagramEntityContainer
to avoid crashes (pgrohs).
- Corrected bug in alignment-handling in
LeftAlignSelected
et. al. - all, not only selected items where aligned.
- Correction in
VirtualToScreen
, not deducting scrollbar positions any longer (Wolfgang Busch).
- Added
\\newline
as a replace-character to allow newlines in titles and names when saving/loading (Unruled Boy).
Enhancements:
- Made
AddObject
virtual and added the virtual MoveObject
function. This is to allow trapping of added or moved objects in the editor in derived classes (sunmoon9898).
- Made clipboard-functions and
DeleteAllSelected
virtual.
- Added a virtual
GetCursor
function to simplify the addition of customized cursors..
- Coordinate conversion functions made public (Wolfgang Busch).
- Made
Add
and Remove
in the container virtual.
- Added a
GetSelectCount
to the container.
New functionality:
Groups
Suggested by Unruled Boy
The selected objects can now be grouped by right-clicking the editor and selecting Group. Grouped objects can be moved, copied, and pasted as a single unit. By right-clicking and selecting Ungroup, all grouping will be removed for the selected items.
Programmatically, this can be accomplished by calling the public functions CDiagramEditor::Group
and CDiagramEditor::Ungroup
. CDiagramEditor::UpdateGroup( CCmdUI* pCmdUI )
and CDiagramEditor::UpdateUngroup( CCmdUI* pCmdUI )
can be called as command enablers from - for example - the view.
Grouping is implemented as a new attribute in CDiagramEntity
.
Caveat
Old data files for the demo applications based on CDiagramEditor
are no longer compatible with the framework due to the new base attribute. I've considered this an acceptable tradeoff, and hope it is not an inconvenience. Derived works will have to be updated to load/save this attribute, and I've added functionality in CDiagramEntity
to simplify this, LoadFromString
, GetDefaultGetString
, GetHeaderFromString
, and GetDefaultFromString
.
A typical FromString
in a hypothetical CDiagramEntity
-derived class, CSomeEntity
, with an extra CString
attribute. m_someattribute
can now be written as:
BOOL CSomeEntity::FromString( const CString& str )
{
BOOL result = FALSE;
CString data( str );
if( LoadFromString( data ) )
{
CTokenizer tok( data );
CString someattribute;
tok.GetAt( 0, someattribute);
SetSomeAttribute( someattribute );
result = TRUE;
}
return result;
}
where CDiagramEntity::LoadFromString
is used to set the base class attributes, and the rest of the attributes are parsed from the modified input-string.
GetString
can be written as:
CString CSomeEntity::GetString() const
{
str.Format( _T( ",%s;" ),
GetSomeAttribute()
);
str = GetDefaultGetString() + str;
return str;
}
Mouse-wheel support
Suggested by John A. Johnson.
By handling WM_MOUSEWHEEL
in CDiagramEditor
, the paper can now be scrolled with the mouse wheel. I've thought about making this a bit more flexible. Configurable scroll steps and zoom comes to mind, but this will have to wait. OnMouseWheel
is made virtual to allow personal attempts in this direction :-)
Panning
Suggested by John A. Johnson.
Panning is implemented. By pressing the middle-button, a panning marker is displayed at the point of the cursor. If the mouse is moved, the editor is scrolled in the direction of the cursor. The scroll-amount is relative to the distance between the marker and the current cursor. The cursor changes to imply the current cursor direction. I've used built-in cursors for this, to avoid dependencies on resources.
I checked P J Arends' excellent class for this, CWindowScroller
, and it was indeed possible to plug it in directly in the editor, but as I want to have a completely free license for the CDiagramEditor
, I based the work on MSDN (The Visual Programmer article on panning by George Shepherd and Scot Wingo) instead.
Key functions for this are OnMButtonDown
, SetPanning
, and DrawPanning
.
Zoom to fit
Suggested by John A. Johnson.
This function will set the zoom level so that all objects in the current diagram are visible. The function to call is the public function ZoomToFitScreen
.
Finally, a very big thanks to all those giving feedback (especially those attributed above - but all feedback is welcome) on the framework.
4/8 2004
A handful of minor fixes and additions this time.
- Added scroll wheel mode. By calling
SetScrollWheelMode(WHEEL_SCROLL/WHEEL_ZOOM)
, the scroll wheel will either scroll or zoom.
- Added virtual to more message handlers, among them the scrollbar ones.
- Added virtual to
SetZoom
.
- Added virtual functions to set the scrollbar positions to get one single point where this is made.
- Bug: Checking if the cursor is outside of restraint when placing an item in
OnLButtonDown
.
- Added
ScrollIntoView
commands. The function scrolls the currently selected object(s) into view.
- Bug: Fixed bug with selection markers - virtualization of the mouse coordinates was in discord with the selection marker rectangles (Marc G).
- Added
SelectAll
and UnselectAll
to the container.
28/8 2004
Far too early, here comes, nevertheless, a bug correction round. Once again, a big, fat thanks to you all for the feedback!
CDiagramEditor
: added check for non-normalized rect when hit-testing in OnLButtonDown
, as lines have them.
CDiagramEntity
: setting m_parent
to NULL
in the ctor
(Marc G).
CTokenizer
: changed a char
to TCHAR
to allow UNICODE builds (Enrico Detoma).
25/3 2005
A maintenance update, with a few additions:
- Made
UnselectAll
virtual (Grisha Vinevich).
- Added the minimum step size one pixel in
OnKeyDown
to avoid 0-pixel movement for arrow keys (Graham G Pearson).
- Made
UnselectAll
virtual (Grisha Vinevich).
- Added the
PopUndo
function to pop the latest undo item from the stack.
- Made
IsUndoPossible
const.
- Made
SetParent
/GetParent
public.
as well as a correction to the line-selection mechanism (Graham G Pearson).
15/5 2005
Yet another maintenance update:
- Routing all object selections through a virtual member function to allow customization of the selections (Janiv Ratson).
- Added a Redo-command. This command will undo the last undo. Handlers and enablers as for Undo, but the message handled is, of course,
ID_EDIT_REDO
. Key-mappings to Ctrl+Y (Janiv Ratson).
- Added message mapping for
ID_EDIT_UNDO
(Graham G Pearson).
- Added message mapping for
ID_EDIT_REDO
.
Note: I've only updated the source code for the Download source files-link - not the demo projects. So, make sure you use this download when you incorporate the code into your own project!
23/6 2006
Long overdue, another update:
- Added the
PasteToPosition
function (Janiv Ratson)
- Bug: Corrected bug in
ZoomToFit
(DanMoshe)
- Bug: Corrected bug when resizing several grouped objects with the mouse (obeea)
- Bud: Added dirty-parameter to
SendMessageToObjects
for the dirty handling - not all commands should set the document as changed (Janiv Ratson)
- Bug: Corrected
CDiagramEntityContainer
undo-stack handling to take stack size 0 into consideration (David Hoos)
- Bug: Added the group to the data copied in
CDiagramEntity::Copy
(JeffBean)
- Minor layout changes, and removal of redundant scrollbar handling (Alexey Shalnov)
Note: Once again, I've only updated the source code for the Download source files-link - not the demo projects. So, make sure you use this download when you incorporate the code into your own project!
45 years old, married, three kids.
Started with computers more than 20 years ago on a CBM-64.
Read Theoretical Philosophy at the University of Lund.
Working as a C++ consultant developer.
Science-fiction freak. Enjoy vintage punkrock.