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Desktop Development »
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Custom Controls
Intermediate
Formula EditorBy tbwFormula-editor for editing and exporting mathematical content |
VC6, C++Windows, NT4, Win2K, MFC, VS6, Visual Studio, Dev Posted: 8 Apr 2003 Updated: 15 Apr 2003 Views: 216,150 Bookmarked: 238 times |
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We needed a mathematical formula editor that was able to export the content of the formulas into a programming language (FORTRAN 77 in our case). Therefore we developed a set of classes described below.
Parts of the code are based on the work of
- Chris Maunder (
CGridCtrl,CColourPopup), - Alexander Bischofberger (
CColourPopup), - Matt Weagle (
CFormulaInplaceEdit), - Norm Almond (
CFontCombo), - Shekar Narayanan and S. D. Rajan (
CToolBarBtn), - Keith Rule (
CUndo)
General appearance
The following files and classes are included into the source code :
Core Data Structure
| bintree.cpp, bintree.h | CBinTree |
The binary-tree datastructure. |
| node.cpp, node.h | CNode |
The core node datastructure. |
| nodeentities.cpp, nodeentities.h | see table 1) |
The special node entities. |
| bintreeformat.cpp, bintreeformat.h | CBinTreeFormat, CFormatInfoOb |
Formatting information |
| undo.h | CUndo |
Undo/Redo functions |
Editing and Visualizing
| formuladlg.cpp, formuladlg.h, formuladlg_toolbar.cpp | CFormulaDlg |
A Dialog that holds a CFormulaCtrl and toolbar-buttons supporting formula-editing. The dialog provides Callback-functions which handle the CToolBarBtn notifications |
| formulactrl.cpp, formulactrl.h | CFormulaCtrl |
Custom control that handles keyboard- and mouse-input. |
| formulainplaceedit.cpp, formulainplaceedit.h | CFormulaInPlaceEdit |
Inplace Edit-Control. Behaves like inplace-edit control in CGridCtrl |
| formuladroptarget.cpp, formuladroptarget.h | CFormulaDropTarget |
The drop target for the formula-control |
| matrixdlg.cpp, matrixdlg.h | CMatrixDlg |
A Subdialog for parametrizing matrix dimensions. |
| formulasettingsdialog.cpp, formulasettingsdialog.h | CFormulaSettingsDlg |
Sub dialog supporting the customizing of the formula settings (eg. colours, fonts ...) |
Helper classes
| fontcombobox.cpp, fontcombobox.h | CFontCombo |
A CComboBox derived control supporting fontselection. |
| colourpicker.cpp, colourpicker.h | CColourPicker |
A CButton derived control supporting colour-selection. |
| colourpopup.cpp, colourpopup.h | CColourPopup |
A CWnd derived control supporting colour-selection (used by CColourPicker). |
| toolbarbtn.cpp, toolbarbtn.h | CToolBarBtn |
A CButton derived control supporting the bitmap-based node-entity selections. |
| toolbarbtnctrl.cpp, toolbarbtnctrl.h, toolbardlg.cpp, toolbardlg.h | CToolBarBtnCtrl, CToolBarDlg |
used by CToolBarBtn |
The basic approach of the formula-editor is the representation of mathematical content in a binary-tree data-structure. the extraction of the content is performed by an inorder-traversal through the binary tree.
| Algorithm | Binary tree | Output |
inorder traversal through a binary treeinorder (node) |
 |
 |
The base class CNode was originally designed as an abstract base class, but it currently provides the standard behaviour of a node. (draw my left child on the left, draw my right child on the right and draw my own content into the middle). If you want to integrate a new node you have to do the following steps:
- Define a new node-type (insert a new unique
NT_*define into the node.h) - Declare a new node-entity in the nodeentities.h (derive it public from
CNode)class CMyNode : public CNode - Implement the methods
virtual void Serialize(CArchive& ar, CBinTree* pTree);virtual void TransformRects(CRect& ,CRect& ,CRect& ,CRect& );virtual CRect GetContentRect(CDC* pDC);virtual void DrawContent(CDC* pDC, CRect rect, DWORD dwSelect); - Insert a new button into a already present ToolbarBtn or build a new ToolbarBtn with your own node
- Handle the ToolBarCtrlSelected Event for your node (in the FormulaDlg_ToolBar.cpp file)
Please have a look on the implementation of the already integrated nodes for further details. Here is a list of them and ther interdependencies:
| Node class | Type | Left Child | Right Child |
| CNode | NT_STANDARD | ||
| CNablaNode | NT_NABLA | NULL | CIndexNode |
| CIndexNode | NT_INDEX | Superscript | Subscript |
| CPartialDerivativeNode | NT_PARTDERIVE | Derivation variable | Content of the derivation |
| CDerivativeNode | NT_DERIVE | Derivation variable | Content of the derivation |
| CPlaceHolderNode | NT_PLACEHOLDER | NULL | CIndexNode |
| CNthRootNode | NT_NTHROOT, NT_ROOT | Content of the root | Basis |
| CPowerToNode | NT_POWERTO | Basis | Exponent |
| CSumNode | NT_SUM | CRangeNode |
Content of the Sum |
| CProdNode | NT_PROD | CRangeNode | Content of the Product |
| CRangeNode | NT_RANGE | Upper Range | Lower Range |
| CIntegrandNode | NT_INTEGRAND | Content of the integral | Integration variable |
| CLimesNode | NT_LIMES | COperatorNode | Content of the limes |
| CBinomialNode | NT_BINOMIAL | Upper | Lower |
| CMatrixNode | NT_MATRIX | CLineNode | NULL |
| CLineNode | NT_LINE | CLineNode | CElementNode |
| CElementNode | NT_ELEMENT | Content of the Matrixelement | CElementNode |
| CValueNode | |||
| CVariableNode | NT_VARIABLE | NULL | CIndexNode |
| CConstantNode | NT_CONSTANT | NULL | CIndexNode |
| CInfinityNode | NT_INFINITY | NULL | CIndexNode |
| CPlanckNode | NT_PLANCK | NULL | CIndexNode |
| CLambdaNode | NT_LAMBDA | NULL | CIndexNode |
| CNumberNode | NT_NUMBER | NULL | CIndexNode |
| CTypedNode | |||
| CFunctionNode | |||
| CUserFuncNode | NT_USERFUNCTION | CBraceNode | NULL |
| CFuncNode | NT_FUNC | CBraceNode | NULL |
| CExtFuncNode | NT_EXTFUNC | CBraceNode | NULL |
| COpNode | |||
| CDivisionNode | NT_DIVISION | Left hand side | Right hand side |
| CEquationNode | NT_EQUATION | Left hand side | Right hand side |
| COperatorNode | NT_OPERATOR | Left hand side | Right hand side |
| CBraceNode | NT_BRACE | Content of the brace | NULL |
| CPoisonNode | NT_POISON | * | * |
| CVectorNode | NT_VECTOR | Content of the Vector | NULL |
| CIntegralNode | NT_INTEGRAL | CRangeNode | CIntegrandNode |
| COverlineNode | NT_OVERLINE | * | * |
| CArrowNode | NT_ARROWS | Left hand side | Right hand side |
| CPlusNode | NT_PLUS | Left hand side | Right hand side |
| CMinusNode | NT_MINUS | Left hand side | Right hand side |
| CTimesNode | NT_TIMES | Left hand side | Right hand side |
| CCrossNode | NT_CROSS | Left hand side | Right hand side |
Please see the implemented TransformRect and DrawContent methods as an example! There are a lot of ways to code them much better. Any suggestions and refinements are welcome.
If you want to use this code in your project you only have to import the classes and to call the DoModal-method of the FormulaDlg.Please be careful with the resources. The resources for the toolbar of the formula-dialog are included via compiletime-directives (resource includes-submenu in the view -menu of the developer-studio)
#include "mathsym.h" #include "mathsym.rc"
#include "FormulaDlg.h" void CMainFrame::OnFormula() { CFormulaDlg FormulaDlg; FormulaDlg.DoModal(); }
The core-classes with there attributes and methods look as follow:
CBinTree
CNode* m_pRootNode |
The rootnode of the tree. |
CNode* m_pSelectNode |
The selected node. |
DWORD m_dwSelectType |
The node-selection type (one of NS_*, see node.h). |
CString m_strName |
The name of the tree. |
CNode* CreateTree(CString strType) |
Creates a tree with a root node of type strType. |
CNode* GetRootNode() |
Returns the root node. |
void SetRootNode(CNode* pNode) |
Sets the root node. |
void SetName(CString) |
Sets the Name of the Bintree. |
CString GetName() |
Returns the name of the Bintree. |
void SelectNode(CNode* pNode, DWORD dwSelectType) |
Selects the node pNode with nodeselectiontype dwSelectType. |
CNode* GetSelectedNode() |
Returns the selected node. |
void SetNodeSelectionType(DWORD dwSelectType) |
Sets the nodeselectiontype for the tree. |
void GetNodeSelectionType(DWORD dwSelectType) |
Returns the nodeselectiontype for the tree. |
void ResetTree() |
Resets the tree and delete all nodes. |
CNode* GetParent(CNode* pNode) |
Returns the parent of node pNode. |
CNode* CreateNode(CString strType) |
Creates a node of type strType. |
CNode* ReplaceNode(CNode*, CString) |
Some handy functions for rearrangement of the tree. |
void DrawTree(CDC* pDC, CRect rect) |
Draws the tree on a dc. |
CRect GetRect(CDC* pDC) |
Returns the destination-rect of the tree. |
CNode* GetNodeFromPoint(CDC*, CRect&, CPoint) |
Returns a node that draws itself into a rect (resultRect) that contains point. |
void ReformatNodes(CBinTreeFormat* pFormat=NULL) |
Reformat the tree with a special formatter. |
void SortPreOrder(CNode* pOldNode) |
Sorting the tree in associative order (currently not used). |
BOOL WriteDIB(CString strFile) |
Writes the binary-tree content into a dib. |
BOOL PrintDDB(CDC* pDC) |
Prints the binary-tree content into a DC. |
CString CBinTree::WriteFormula(int nLanguageType) |
Write the binary-tree content into a CString. |
virtual void DeleteContents() |
Resets the tree and delete all nodes (from CUndo). |
void DeleteNode(CNode* pNode) |
Deletes a node. |
CNode* CloneNode(CNode* pNode, BOOLbCloneSubTree) |
Clones a node with or without its subtree. |
CNode
CNode* m_pParent |
Pointer to parent. |
CNode* m_pLeftChild |
Pointer to left child. |
CNode* m_pRightChild |
Pointer to right child. |
int m_nAssociativityLevel |
assoicativity level for mathematical analysis |
DWORD m_dwEditMode |
edit mode of the node (one of the NE_* defines) |
int m_nSubLevel |
sublevel (subscript, sub-subscript ...) |
int m_nSubLevelLeftInc |
the increments of the sublevel for the children |
CString m_strNodeType |
node type (one of the NT_* defines) |
CString m_strShortCut |
the shortcut of the node (sin for sinus) |
CString m_strName |
the name of the node (sinus for sinus) |
COLORREF m_crColor |
color of the node (modified by the formatter class) |
LOGFONT m_lf |
LOGFONT node (modified by the formatter class) |
CStringArray m_saKeyWord |
Keywords are stored in a Stringarray (Use the define LT_* to access) |
CRect m_NodeRect |
the destination rectangle for the ouput |
int m_nBaseLine |
the baseline of the node (with childs ) // e.g. the division line for the CDivisionNode |
CString GetNodeType() |
Returns the node type |
void SetParentDirect(CNode* pNode) |
Sets the parent node directly |
CNode* GetParentDirect() |
Returns the parent node |
void SetLeftChild(CNode* pNode) |
Sets the left child (and sets left child's new parent as this) |
CNode* GetLeftChild() |
Returns the left child |
void SetRightChild(CNode* pNode) |
Sets the right child (and sets right child's new parent as this) |
CNode* GetRightChild() |
Returns the right child |
void SetName(CString strName) |
Sets the name of the node |
CString GetName() |
Returns the name of the node |
void SetShortCut(CString strShortCut) |
Sets the shortcut of the node (used for rendering) |
<CODE><CODE>CString GetShortCut() |
Returns the shortcut of the node |
void SetEditMode(DWORD dwEditMode) |
Sets the edit mode of the node (Combination of NE_ defines) |
DWORD GetEditMode() |
Returns the edit mode of the node |
void SetItalic(BOOL bItalic) |
Sets the italic attribute in the LOGFONT structure |
BOOL GetItalic() |
Returns the italic attribute in the LOGFONT structure |
void SetBold(BOOL bBold) |
Sets the lfWeight-value of the LOGFONT structure (FW_BOLD for bBold==TRUE and FW_NORMAL for bBold==FALSE) |
BOOL GetBold() |
Returns the weight of LOGFONT structure (TRUE for lfWeight==FW_BOLD and FALSE for bBold==FW_NORMAL) |
void SetColor(COLORREF crColor) |
Sets the RGB colour of the node |
COLORREF GetColor() |
Returns the RGB colour of the node |
void SetSubLevel(int nSubLevel) |
Sets the sublevel of the node |
int GetSubLevel() |
Returns the sublevel of the node |
int GetSubLevelLeftInc() |
Returns the sublevel-increment of the left children |
int GetSubLevelRightInc() |
Returns the sublevel-increment of the right children |
void SetFaceName(CString strFaceName) |
Sets the facename in the LOGFONT structure |
CString GetFaceName() |
Returns the facename of the LOGFONT structure as a CString |
virtual int GetAssociativityLevel() |
Returns the Associativity Level of the node (for symbolical postprocessing, currently not used) |
virtual BOOL IsNodeLeaf() |
Returns TRUE if the node has no valid left and right child |
virtual void DrawNode(CDC*, CRect&, |
drawing functions |
CNode* FindParentPraeorder(CNode* pSearchNode) |
searching praeorder for the parent of a given node |
virtual void Serialize(CArchive& ar, |
function to overload by subentities |
virtual void TransformRects(CRect&, CRect&, |
standardimplementation (default behaviour) |
virtual CString WriteNode(int nLanguageType) |
Output of the formula in the language LT_* |
LOGFONT* GetLogFont() |
Returns a pointer to the LOGFONT structure m_lf |
Features
The formula-control has got the following additional features:
- Copy, cut and paste (currently you are allowed to paste into placeholder-nodes only )
- Drag & Drop (currently you are allowed to drop onto placeholder-nodes only)
- Export into a Bitmap
- Printing and Print-Preview is realized via DDB
- Sourcecode export (currently only FORTRAN 77 is implemented)
How to use...
Select an equation-node from the equation-toolbar-button. Then you get an equation with placeholders on the left and on the right side. By moving the mouse over the equation the nodes are highlited. Select a placeholder with a single left-mouseclick. Now you can overwrite the placeholder with any node you want. By selecting a node with a double-click, the whole subtree of the node is selcted (e.g select the = from an equation with a doubleclick and either the left and the right side of the equation are selected). If you select a variable-node, a constant-node, a number-node or a userfunction-node you get into the editing by another left-mouseclick.
History
for detailed information please have a look on the file-header-commentsVersion 1.0.0.1 - 15-Apr-2003
- Reduced Flickering (Scrolling and Updating)
- Drag&Drop refined
- Modified
FormulaInPlaceEdit - Added WMF export
CRangeNoderefined
First Version
Environment:
Windows NT 4.0 Service Pack 6
MFC Version: 6.0
Service Pack: 5
DataPool engineering
Essener Str. 99
D-46047 Oberhausen
Internet: www.dp-e.de
thorsten.wack@dp-e.de
