Word VBA, Changing the Font Format of Characters in an Equations

Sep 07, 2015 by azurous in Equations

In this article I will explain how you can apply formatting to certain characters in a word equation. Below are some of the things you might want to do:

Change numbers to italic
Change number to bold
Change the font color of certain characters
Replace certain characters
…

Example:

In the figure below numeric characters in the equations have been turned to bold:

Example:

In the example below the Alpha Beta characters have been changed to Red:

All of this can be done using VBA for word.

Formatting characters in an equation is not as simple as apply formatting to the rest of the document. The reason being is that not all characters are recognized by the VBA editor. I have explained more about this topic in the article below:

Word VBA Creating Equations

In order to apply a certain formatting to character in an equation there are several functions that need to be implemented I have explained them in the following sections.

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Contents

Step 1, Get the Unicode Value of Each Character in the Equation:

As a first step we would need a function that returns an array with the unicode values of the characters in the equation. In the article below I have implemented this function:

Word VBA, Get the Unicode Value of Each Character in the Equation

The function receives as input the index of the word equation. It returns an array of long values, which are the unicode values associated with the characters in the equation.

The function declaration can be seen below:

'returns an array of long values. Each index is the 'unicode value of one of the characters in the equation Private Function GetUnicodeValue(ByVal intIndex As Integer) _ As Long() ... End Function

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Step 2, Get the Unicode Value of the Characters to Format:

As mentioned at the start of the article, the VBA editor does not recognize many of the characters used in equations. Therefore we will need to work with their unicode value.

In this step we would need to get the unicode value associated with the characters you wish to format. I have provided a program that does this in the article below:

VBA Get Characters Unicode Value

Example: If we want to change the format of all the numeric characters in the equation we would be looking for characters with a unicode value between [48~57]

Example: If we want to modify operators (+, -, /, *) we would be looking for characters with the unicode values {42, 43, 45, 47}

Example: If we want to modify special characters like ∝, ∇, θ we would be looking for characters with the unicode values {8733, 8711, 952}

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Step 3, Get the Index of the Target Characters in the Equation:

The next would be to find the location of the target characters in the word equation. This can easily be done by comparing the values obtained in Step 1 with the target values in Step 2.

The function below receives as input the array from Step 1 and an array with the values from Step 2. It returns an array with the location the characters have been found:

'Receives as input 2 arrays. Returns matching indexes Private Function GetMatches(ByRef arrUnicodes() As Long, _ ByRef arrTargetValues() As Long) As Long() Dim i As Integer Dim j As Integer Dim K As Integer 'the output array Dim arrOutput() As Long ReDim arrOutput(1 To 1) K = 1 'loops through the first array For i = LBound(arrUnicodes) To UBound(arrUnicodes) 'loops through the second array For j = LBound(arrTargetValues) To UBound(arrTargetValues) 'checks if the arrays are matching If arrTargetValues(j) = arrUnicodes(i) Then ReDim Preserve arrOutput(1 To K) arrOutput(K) = i K = K + 1 End If Next j Next i GetMatches = arrOutput End Function

Example:

Consider the equation below:

The unicode value for the character “a” is 97. The code below returns the index of all the occurrences of the character “a”:

Sub Example1() Dim arrUnicodes() As Long Dim arrTargets(1 To 1) As Long Dim arrMatches() As Long 'unicode value for the character "a" arrTargets(1) = 97 'returns the unicode characters in the equation arrUnicodes = GetUnicodeValue(1) 'returns the matches arrMatches = GetMatches(arrUnicodes, arrTargets) End Sub

The resulting indices are:

Index	Character
6	“a”
21	“a”

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Step 4, Select the Target Characters in the Word Equation:

The next step would be to implement a function that would select the target characters in the word equation. The function below does this. It receives as input the index of the target character and index of the word equation and selects the character in the equation:

'Recieves 2 input parameters. The index of the equation and the 'index of the character to select Sub SelectCharacter(ByVal intCharIndex As Integer, _ ByVal intEquIndex As Integer) 'changes the equation to linearize format OMaths.Item(intEquIndex).Linearize 'select the equation OMaths.Item(intEquIndex).Range.Select 'moves to the start of the equation Selection.MoveLeft unit:=wdCharacter, Count:=1 'move to the index of the character Selection.MoveRight unit:=wdCharacter, Count:=intCharIndex - 1 'selects one character Selection.MoveRight unit:=wdCharacter, Count:=1, Extend:=wdExtend End Sub

Example:

In the example below the 6th character of the first equation will be selected:

Sub Example2() Call SelectCharacter(6, 1) End Sub

Result:

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Example, Change Numeric Values to Bold:

In the example below numeric values in all the equations in the document will be changed to bold:

Sub Example3() Dim i As Integer Dim j As Integer Dim arrTargets(1 To 10) As Long Dim arrCharacterValues() As Long Dim arrMatches() As Long 'character unicode values to format arrTargets(1) = 48 arrTargets(2) = 49 arrTargets(3) = 50 arrTargets(4) = 51 arrTargets(5) = 52 arrTargets(6) = 53 arrTargets(7) = 54 arrTargets(8) = 55 arrTargets(9) = 56 arrTargets(10) = 57 'iterates through the equations in the document For i = 1 To OMaths.Count 'gets the unicode characters in the equation arrCharacterValues = GetUnicodeValue(i) 'gets the index of the matches arrMatches = GetMatches(arrCharacterValues, arrTargets) 'selects and formats For j = LBound(arrMatches) To UBound(arrMatches) Call SelectCharacter(arrMatches(j), i) Selection.Font.Bold = True Next j OMaths.Item(i).BuildUp Next i End Sub

Consider the following equations:

Result:

The lines below create the arrTargets array. The unicode values associate with the numbers 0~9 are being assigned to the array as explained in Step 2. This array is passed as input to the function in Step 3:

arrTargets(1) = 48 arrTargets(2) = 49 arrTargets(3) = 50 arrTargets(4) = 51 arrTargets(5) = 52 arrTargets(6) = 53 arrTargets(7) = 54 arrTargets(8) = 55 arrTargets(9) = 56 arrTargets(10) = 57

The lines below get the unicode values of the characters in the equation. This was explained in Step 1:

'gets the unicode characters in the equation arrCharacterValues = GetUnicodeValue(i)

The line below was explained in Step 3:

'gets the index of the matches arrMatches = GetMatches(arrCharacterValues, arrTargets)

The line below selects the target character in the equation (Step 4):

Call SelectCharacter(arrMatches(j), i)

The line below changes the selected character to bold:

Selection.Font.Bold = True

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Example 2, Change Character Color:

In this example the color of the Alpha and Beta characters will be changed to Red:

Sub Example4() Dim i As Integer Dim j As Integer Dim arrTargets(1 To 10) As Long Dim arrCharacterValues() As Long Dim arrMatches() As Long 'character unicode values to format arrTargets(1) = 945 arrTargets(2) = 946 'iterates through the equations in the document For i = 1 To OMaths.Count 'gets the unicode characters in the equation arrCharacterValues = GetUnicodeValue(i) 'gets the index of the matches arrMatches = GetMatches(arrCharacterValues, arrTargets) 'selects and formats For j = LBound(arrMatches) To UBound(arrMatches) Call SelectCharacter(arrMatches(j), i) Selection.Font.ColorIndex = wdRed Next j OMaths.Item(i).BuildUp Next i End Sub

Result:

You can download the file and code related to this article from the link below:

Format Characters.docm