In an earlier post, I mentioned that most Matlab uicontrols support HTML strings. Unfortunately, HTML is not supported in multi-line editbox contents. Today I will show how this limitation can be removed for a multi-line editbox, thereby enabling rich contents (enabling HTML for a single-line editbox needs a different solution).
We first need to get the editbox’s underlying Java object, as explained in my previous article about the findjobj utility. Since a multi-line editbox is contained within a scroll-pane, we need to dig within the scrollpane container to find the actual editable area object:
% Create a multi-line (Max>1) editbox uicontrol hEditbox = uicontrol('style','edit', 'max',5, ...); % Get the Java scroll-pane container reference jScrollPane = findjobj(hEditbox); % List the scroll-pane's contents: >> jScrollPane.list com.mathworks.hg.peer.utils.UIScrollPane[,0,0,100x50,...] javax.swing.JViewport[,1,1,81x48,...] com.mathworks.hg.peer.EditTextPeer$hgTextEditMultiline[,0,0,81x48,...,kit=javax.swing.text.StyledEditorKit@ce05fc,...] com.mathworks.hg.peer.utils.UIScrollPane$1[,82,1,17x48,...] com.sun.java.swing.plaf.windows.WindowsScrollBarUI$WindowsArrowButton[,0,31,17x17,...] com.sun.java.swing.plaf.windows.WindowsScrollBarUI$WindowsArrowButton[,0,0,17x17,...] com.mathworks.hg.peer.utils.UIScrollPane$2[,0,0,0x0,...] com.sun.java.swing.plaf.windows.WindowsScrollBarUI$WindowsArrowButton[,0,0,0x0,...] com.sun.java.swing.plaf.windows.WindowsScrollBarUI$WindowsArrowButton[,0,0,0x0,...]
In this listing, we see that jScrollPane contains a JViewport and two scrollbars (horizontal and vertical), as expected from standard Java scroll-panes. We need the internal hgTextEditMultiline object:
jViewPort = jScrollPane.getViewport; jEditbox = jViewPort.getComponent(0);
The retrieved jEditbox reference, is an object of class com.mathworks.hg.peer.EditTextPeer$hgTextEditMultiline, which indirectly extends the standard javax.swing.JTextPane. The default Matlab implementation of the editbox uicontrol simply enables a multi-line vertical-scrollable text area using the system font. However, the underlying JTextPane object enables many important customizations, including the ability to specify different font attributes (size/color/bold/italic etc.) and paragraph attributes (alignment etc.) for text segments (called style runs) and the ability to embed images, HTML and other controls.
Setting rich contents can be done in several alternative ways. From easiest to hardest:
Setting page URL
Use the setPage(url) method to load a text page from the specified URL (any pre-existing editbox content will be erased). The page contents may be plain text, HTML or RTF. The content type will automatically be determined and the relevant StyledEditorKit and StyledDocument will be chosen for that content. Additional StyledEditorKit content parsers can be registered to handle additional content types. Here’s an example loading an HTML page:
jEditbox.setPage('http://tinyurl.com/c27zpt');
where the URL’s contents are:
<html><body> <img src="images/dukeWaveRed.gif" width="64" height="64"> This is an uneditable <code>JEditorPane</code>, which was <em>initialized</em> with <strong>HTML</strong> text <font size=-2>from</font> a <font size=+2">URL</font>. <p>An editor pane uses specialized editor kits to read, write, display, and edit text of different formats. The Swing text package includes editor kits for plain text, HTML, and RTF. You can also develop custom editor kits for other formats. <script language="JavaScript" src="/js/omi/jsc/s_code_remote.js"></script> </body></html>
Matlab editbox initialized from an HTML webpage URL
Setting the EditorKit and ContentType
Set the requested StyledEditorKit (via setEditorKit()) or ContentType properties and then use setText() to set the text, which should be of the appropriate content type. Note that setting EditorKit or ContentType clears any existing text and left-aligns the contents (hgTextEditMultiline is center aligned by default). Also note that HTML <div>s get their own separate lines and that <html> and <body> opening and closing tags are accepted but unnecessary. For example:
jEditbox.setEditorKit(javax.swing.text.html.HTMLEditorKit); % alternative: jEditbox.setContentType('text/html'); htmlStr = ['<b><div style="font-family:impact;color:green">'... 'Matlab</div></b> GUI is <i>' ... '<font color="red">highly</font></i> customizable']; jEditbox.setText(htmlStr)
HTML contents in a Matlab editbox
Let’s show another usage example, of an event log file, spiced with icons and colored text based on event severity. First, define the logging utility function (the icon filenames may need to be changed based on your Matlab release):
function logMessage(jEditbox,text,severity) % Ensure we have an HTML-ready editbox HTMLclassname = 'javax.swing.text.html.HTMLEditorKit'; if ~isa(jEditbox.getEditorKit,HTMLclassname) jEditbox.setContentType('text/html'); end % Parse the severity and prepare the HTML message segment if nargin<3, severity='info'; end switch lower(severity(1)) case 'i', icon = 'greenarrowicon.gif'; color='gray'; case 'w', icon = 'demoicon.gif'; color='black'; otherwise, icon = 'warning.gif'; color='red'; end icon = fullfile(matlabroot,'toolbox/matlab/icons',icon); iconTxt =['<img src="file:///',icon,'" height=16 width=16>']; msgTxt = [' <font color=',color,'>',text,'</font>']; newText = [iconTxt,msgTxt]; endPosition = jEditbox.getDocument.getLength; if endPosition>0, newText=['<br/>' newText]; end % Place the HTML message segment at the bottom of the editbox currentHTML = char(jEditbox.getText); jEditbox.setText(strrep(currentHTML,'</body>',newText)); endPosition = jEditbox.getDocument.getLength; jEditbox.setCaretPosition(endPosition); % end of content end
Now, let’s use this logging utility function to log some messages:
logMessage(jEditbox, 'a regular info message...'); logMessage(jEditbox, 'a warning message...', 'warn'); logMessage(jEditbox, 'an error message!!!', 'error'); logMessage(jEditbox, 'a regular message again...', 'info');
Rich editbox contents (a log file)
HTML editboxes are normally editable, images included. In actual applications, we may wish to prevent editing the display log. To do this, simply call jEditbox.setEditable(false).
Setting a hyperlink handler is easy: first we need to ensure that we’re using an HTML content-type document. Next, set the editbox to be uneditable (hyperlinks display correctly when the editbox is editable, but are unclickable), using jEditbox.setEditable(false). Finally, set the callback function in the editbox’s HyperlinkUpdateCallback property:
jEditbox.setContentType('text/html'); jEditbox.setText('link: <a href= "http://UndocumentedMatlab.com">UndocumentedMatlab.com</a>'); jEditbox.setEditable(false); hjEditbox = handle(jEditbox,'CallbackProperties'); set(hjEditbox,'HyperlinkUpdateCallback',@linkCallbackFcn); function linkCallbackFcn(src,eventData) url = eventData.getURL; % a java.net.URL object description = eventData.getDescription; % URL string jEditbox = eventData.getSource; switch char(eventData.getEventType) case char(eventData.getEventType.ENTERED) disp('link hover enter'); case char(eventData.getEventType.EXITED) disp('link hover exit'); case char(eventData.getEventType.ACTIVATED) jEditbox.setPage(url); end end
Hyperlink in editbox
Setting the style runs programmatically
Setting the styles programmatically, one style run after another, can be done via the text-pane’s Document property object. Individual character ranges can be set using the Document’s setCharacterAttributes method, or entire style runs can be inserted via insertString. Attributes are updated using the static methods available in javax.swing.text.StyleConstants. These methods include setting character attributes (font/size/bold/italic/strike-through/underline/subscript/superscript and foreground/background colors), paragraph attributes (indentation/spacing/tab-stops/bidi), image icons and any Swing Component (buttons etc.). Here is the end result:
Rich editbox contents: images, controls & font styles
Note that if a styled multi-line editbox is converted to a single-line editbox (by setting hEditbox’s Max property to 1), it loses all style information, embedded images and components. Returning to multi-line mode will therefore show only the plain-text.
Related posts:
- Customizing listbox & editbox scrollbars Matlab listbox and multi-line editbox uicontrols have pre-configured scrollbars. This article shows how they can be customized....
- Customizing help popup contents The built-in HelpPopup, available since Matlab R2007b, has a back-door that enables displaying arbitrary text, HTML and URL web-pages....
- Setting line position in an edit-box uicontrol Matlab uicontrols have many useful features that are only available via Java. Here's how to access them....
- Customizing Matlab labels Matlab's text uicontrol is not very customizable, and does not support HTML or Tex formatting. This article shows how to display HTML labels in Matlab and some undocumented customizations...
- GUI integrated HTML panel Simple HTML can be presented in a Java component integrated in Matlab GUI, without requiring the heavy browser control....
- FindJObj – find a Matlab component’s underlying Java object The FindJObj utility can be used to access and display the internal components of Matlab controls and containers. This article explains its uses and inner mechanism....
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Thanks.
Can you please explain how I can read from the editbox this information – for example what is the color of the first word in the third line?
I have problems understanding that part or retreiving information.
@Amichay – if you use style runs then you can try to use getCharacterAttributes(); if you use HTML you don’t have an easy solution AFAIK, but if you are in control of the data that is placed in the editbox then you can keep meta-data information stored where it can later be retrieved (for example, in the control’s appdata).
Yair,
I actually want to get (by copy paste) a text with colored text (such for example as some editros like matlab m-file editor) into the editbox (or if you can suggest something better) and process the text also according to the text color. Can you suggest what to do?
@Amichay – when you copy a styled Matlab text, it gets copied as Rich-Text Formatted (RTF) data. Some applications, like MS Word, automatically know how to use RTF data when you paste sch contents into them. If you need to paste into your own application, you need to create a dedicated RTF-sensitive CCP drop target. This is a very technical issue that is well outside the boundaries of this comment (or blog). You can start here.
Hello,
first I would like to thank you for the usefull information I found in your blog. And now to my question: Do you know an easy way to have a matlab editor like features (syntax highliting, smart indent, …) in an editable multiline text box?
Thank you!
Best regards
Youlian
@Youlian – Yes it is possible. Here’s a short code snippet demonstrating this (I will provide more details and other possibilities in an article sometime in the upcoming weeks):
SyntaxTextPane panel (Matlab MIME type)
Hello Yair,
thank you very much for your fast response. The code you posted worked quite well, with one exception, which is probably Matlab version dependent. The statement:
codeType = com.mathworks.widgets.text.mcode.MLanguage.M_MIME_TYPE;
led in Matlab 2008b to the following Matlab error:
??? Undefined variable “com” or class
“com.mathworks.widgets.text.mcode.MLanguage.M_MIME_TYPE”.
Instead of it I used:
codeType = com.mathworks.widgets.SyntaxTextPane.M_MIME_TYPE;
I tested it in Matlab 7.1, 2006b, 2007a and 2008b and it worked well.
Thank you very much once again!
Best regards
Youlian
@Youlian and any other reader interested in syntax highlighting – I posted an expanded article about this topic in http://undocumentedmatlab.com/blog/syntax-highlighted-labels-panels/
Hello,
it’s possible to set this property (Matlab Syntax) in a uicontrol type text?
thanks.
Thank you!
Best regards
Camilo
Regular Matlab uicontrols do not support syntax hiliting – you need to use one of the controls I mentioned in http://undocumentedmatlab.com/blog/syntax-highlighted-labels-panels/
Hi
Thank you very much for the useful info. In my GUI, I first read a long string from an editbox (multiple lines) and then I’d like to change the font color of a portion of this text and display it in the same editbox. I’m not familiar with HTML coding but that’s what I did using your example above:
the formatted string is displayed in the editbox however, it is no longer divided nicely between multiple lines! There is a very long first line where most of the string is out of the right margin. I was wondering is there is another setting that I need to tune for this to be properly displayed?
I appreciate your help, Noushin
@Noushin – of course; HTML is not multi-line by default, as you will notice if you prepare a multi-line HTML file and load it in your browser. To separate lines, you can use the HTML <p> or <br> tags. The W3Schools website is a good reference & tutorial for HTML and related technologies.
Nice article with useful information. But i have problem. I try overline text, but it doesnt work.
Is there any change, how to make overline text ?
Thank you for answer
htmlStr contains, but it doesnt show: *div style=”text-decoration: overline”+text*/div+….* means
@Jorge – unfortunately, not all CSS style formattings are supported