Undocumented Matlab
  • SERVICES
    • Consulting
    • Development
    • Training
    • Gallery
    • Testimonials
  • PRODUCTS
    • IQML: IQFeed-Matlab connector
    • IB-Matlab: InteractiveBrokers-Matlab connector
    • EODML: EODHistoricalData-Matlab connector
    • Webinars
  • BOOKS
    • Secrets of MATLAB-Java Programming
    • Accelerating MATLAB Performance
    • MATLAB Succinctly
  • ARTICLES
  • ABOUT
    • Policies
  • CONTACT
  • SERVICES
    • Consulting
    • Development
    • Training
    • Gallery
    • Testimonials
  • PRODUCTS
    • IQML: IQFeed-Matlab connector
    • IB-Matlab: InteractiveBrokers-Matlab connector
    • EODML: EODHistoricalData-Matlab connector
    • Webinars
  • BOOKS
    • Secrets of MATLAB-Java Programming
    • Accelerating MATLAB Performance
    • MATLAB Succinctly
  • ARTICLES
  • ABOUT
    • Policies
  • CONTACT

Bold color text in the Command Window

August 8, 2012 2 Comments

A reader comment last week sent me on a short wild goose chase, that had an interesting and useful conclusion. The comment requested a way to display bold text in the Command Window, similarly to the way that we can display colored and underlined text using my cprintf utility.
Since Matlab release 7.13 (R2011b), the Matlab Command Window (CW) has the ability to display bold text. This is used, for example, when displaying the function name in the output of the help function (i.e., help(‘max’) will display the term ‘max’ in bold when displaying the help section). It therefore seemed a reasonable request to add this functionality to cprintf.

Attempt #1: use the underlying Java

I stated out investigating the relevant attributes used by the CW’s underlying Java component to display the text. It turns out that in addition to the three custom attributes used by Matlab in past releases, a fourth attribute called BoldStartTokens was added, which stored the relative position index of the bold text within each text element.
Unfortunately, this attribute contains an array of integer values, that get converted to a simple numeric array in Matlab. This means that unlike the SyntaxTokens attribute, which contains an array of Java String objects that can be modified one at a time (this is used by cprintf), the BoldStartTokens attribute value cannot be modified in a similar manner. Attempting to remove and add the attribute afresh (with modified values) failed due to a javax.swing.text.StateInvariantError: Illegal cast to MutableAttributeSet Java exception.
So unless I find a way to update the BoldStartTokens attribute values from Matlab, this looked like a dead end.

Attempt #2: follow the Matlab trail

My second attempt was to follow the Matlab trail, to see exactly what the help function does internally to format parts of the text as bold. Starting with help‘s m-file (%matlabroot%/toolbox/matlab/helptools/help.m), and step-by-step debugging, I quickly found out that the internal function prepareHelpForDisplay parses the help text and wraps the relevant terms with an HTML <strong> tag to make these terms appear bold.
We can easily use this information ourselves:

>> fprintf('not bold, <strong> bold </strong>\n')
not bold, bold     % the 'bold' term appears bolded

>> fprintf('not bold, <strong> bold </strong>\n') not bold, bold % the 'bold' term appears bolded

Matlab does have an internal limitation, of not allowing hyperlinks and bold formatting together. If both <a> and <strong> tags are present, then only the inner tag set is parsed.

Updating cprintf

Using <strong> is great, but apparently if we use the <strong> tag in cprintf, the output gets messed up – the HTML tag confuses cprintf. So I took the opportunity to update cprintf such that (1) it will not get confused by a <strong> tag, and (2) so that we could use ‘*’ in the style part (input argument #1) to specify bold format:

>> cprintf('*blue', 'this is bold\n')
this is bold     % this text appears bolded-blue

>> cprintf('*blue', 'this is bold\n') this is bold % this text appears bolded-blue

cprintf demo
cprintf demo


The benefit of using cprintf over directly using the <strong> tag is that it works seamlessly on Matlab release 2011a and earlier that do not support the tag (the text is simply not bolded, whereas if we had used <strong> this tag would be displayed onscreen, which is ugly). Moreover, cprintf catches a situation of trying to use both underline and bold formats, and issues a warning. Finally, of course, ‘*’ is more compact and easier to use and maintain than ‘<strong>…</strong>’ …
Please feel free to download cprintf from the File Exchange and read its contents to see how a not-too-large utility can achieve something previously believed to be impossible. And if you find ways to make cprintf better, please do let me know (I don’t mean suggestions for *me* to work on: I mean actual improvements that *you* made to the code).

Related posts:

  1. cprintf – display formatted color text in the Command Window – cprintf is a utility that utilized undocumented Matlab desktop functionalities to display color and underline-styled formatted text in the Command Window...
  2. Another Command Window text color hack – Matlab's fprintf command has an undocumented hack to display orange-colored text. ...
  3. Command Window text manipulation – Special control characters can be used to format text output in Matlab's Command Window. ...
  4. Changing Matlab's Command Window colors – Matlab's Command Window foreground and background colors can be modified programmatically, using some of Matlab's undocumented internal Java classes. Here's how....
  5. EditorMacro v2 – setting Command Window key-bindings – The EditorMacro utility was extended to support built-in Matlab Editor and Command-Window actions and key-bindings. This post describes the changes and the implementation details....
  6. Changing Matlab's Command Window colors – part 2 – The Matlab Command Window enables a limited degree of inline color customization - this post describes how to use it...
Desktop HTML Java
Print Print
« Previous
Next »
2 Responses
  1. Aurélien Queffurust August 9, 2012 at 00:50 Reply

    Hi Yair,

    Nice article as usual. I had also noticed in Sept. 2011 the new bold syntax for the help
    FYI you can read the answer of Scott Hirsch on my blog :
    http://blog.developpez.com/matlab4geek/p10298/r2011b/startup-accelerator-et-help-en-gras/?page=2

    It is important to say that using the s t r o n g> HTML tag as in your example with fprintf will only work in MATLAB environment.
    In a standalone mode , the DOS command window will display the HTML tags … so my advise would be to use this feature only if the MATLAB code is not expected to be compiled .

    Have a nice day,

    Aurélien

  2. Another Command Window text color hack | Undocumented Matlab January 1, 2014 at 02:42 Reply

    […] using my cprintf utility. I followed this up last year with the relatively new ability to display bold text formatting, using either fprintf or cprintf.A short while ago, Carsten Allefeld (a regular on this blog) […]

  3. Khaled October 30, 2019 at 22:04 Reply

    Hello,
    I found out how Matlab displays bold hyperlinks. It does so by adding an inline style (style=”font-weight:bold”) inside the <a> tag. For example:

    fprintf('nt<a href="matlab:doc sin" style="font-weight:bold" rel="nofollow">sin</a>nn');

    fprintf('nt<a href="matlab:doc sin" style="font-weight:bold" rel="nofollow">sin</a>nn');

Leave a Reply
HTML tags such as <b> or <i> are accepted.
Wrap code fragments inside <pre lang="matlab"> tags, like this:
<pre lang="matlab">
a = magic(3);
disp(sum(a))
</pre>
I reserve the right to edit/delete comments (read the site policies).
Not all comments will be answered. You can always email me (altmany at gmail) for private consulting.

Click here to cancel reply.

Useful links
  •  Email Yair Altman
  •  Subscribe to new posts (feed)
  •  Subscribe to new posts (reader)
  •  Subscribe to comments (feed)
 
Accelerating MATLAB Performance book
Recent Posts

Speeding-up builtin Matlab functions – part 3

Improving graphics interactivity

Interesting Matlab puzzle – analysis

Interesting Matlab puzzle

Undocumented plot marker types

Matlab toolstrip – part 9 (popup figures)

Matlab toolstrip – part 8 (galleries)

Matlab toolstrip – part 7 (selection controls)

Matlab toolstrip – part 6 (complex controls)

Matlab toolstrip – part 5 (icons)

Matlab toolstrip – part 4 (control customization)

Reverting axes controls in figure toolbar

Matlab toolstrip – part 3 (basic customization)

Matlab toolstrip – part 2 (ToolGroup App)

Matlab toolstrip – part 1

Categories
  • Desktop (45)
  • Figure window (59)
  • Guest bloggers (65)
  • GUI (165)
  • Handle graphics (84)
  • Hidden property (42)
  • Icons (15)
  • Java (174)
  • Listeners (22)
  • Memory (16)
  • Mex (13)
  • Presumed future risk (394)
    • High risk of breaking in future versions (100)
    • Low risk of breaking in future versions (160)
    • Medium risk of breaking in future versions (136)
  • Public presentation (6)
  • Semi-documented feature (10)
  • Semi-documented function (35)
  • Stock Matlab function (140)
  • Toolbox (10)
  • UI controls (52)
  • Uncategorized (13)
  • Undocumented feature (217)
  • Undocumented function (37)
Tags
ActiveX (6) AppDesigner (9) Callbacks (31) Compiler (10) Desktop (38) Donn Shull (10) Editor (8) Figure (19) FindJObj (27) GUI (141) GUIDE (8) Handle graphics (78) HG2 (34) Hidden property (51) HTML (26) Icons (9) Internal component (39) Java (178) JavaFrame (20) JIDE (19) JMI (8) Listener (17) Malcolm Lidierth (8) MCOS (11) Memory (13) Menubar (9) Mex (14) Optical illusion (11) Performance (78) Profiler (9) Pure Matlab (187) schema (7) schema.class (8) schema.prop (18) Semi-documented feature (6) Semi-documented function (33) Toolbar (14) Toolstrip (13) uicontrol (37) uifigure (8) UIInspect (12) uitools (20) Undocumented feature (187) Undocumented function (37) Undocumented property (20)
Recent Comments
  • Sunham (2 days 23 hours ago): This is an old article, but the issue persists even in 2023. 2023a: z = mat2cell(1:1e6,1,repmat(1,1,1e 6)); f = @() cellfun(‘isempty’, z); g = @() cellfun(@isempty,z);...
  • Yair Altman (12 days 14 hours ago): Robot only runs when you tell it to run a command such as keyPress. If you don’t tell it to run a command, it uses no CPU, so there’s no need to remove the Robot...
  • Eric (13 days 1 hour ago): Hey @Kevin, can you share your code about create group of figures in the AppContainer? The container of multiples uifigures could be an amazing improvement over AppDesigner and its...
  • Elsa Smith (13 days 16 hours ago): I recently used java.awt.Robot to perform GUI testing on MATLAB and found it to be an extremely easy and useful way to control mouse movements.
  • Elsa Smith (13 days 16 hours ago): I’m suspecting that the slow performance of my GUI may be due to the use of java.awt.Robot. Is there a way to cancel/stop/remove the robot after it has been created, or is...
  • Michelle Kline (14 days 9 hours ago): *edit* tip about fopen(), not about fwrite(). ‘Wb’ vs. ‘wb’
  • Michelle Kline (14 days 9 hours ago): Thank you, Yair! With this previously-unknown-to-me tip about fwrite() performance, you have saved me literally hours of processing time. Michelle Kline Department of...
  • Alessandro Beda (26 days 21 hours ago): I found what I think is a bug related to this (tested in R2022 and R2023a). If I add a “ButtonDownFcn” to the plots (see example below), then the modified...
  • Nicholas (28 days 11 hours ago): Yair, Changing the desktop help options did not solve the issue. Though, it’s unclear how I could change these options in the Runtime, if that’s what you meant? I should...
  • Yair Altman (32 days 7 hours ago): @Francisco – this is one of those cases where you should ask MathWorks support. After all, you’re trying to use a supported Matlab functionality when you encountered...
  • Francisco Campos (32 days 18 hours ago): Hello, thanks for all your work that has been immensely useful for those working in the Matlab environment. I have been trying to replace matlabcontrol with the official...
  • Yair Altman (36 days 19 hours ago): Kei – this is possible, I believe that I saw this ability somewhere, a few years ago. I don’t remember exactly where, it will require a bit of research, but...
  • Kei (36 days 22 hours ago): Hello Yair Thank you for this great article. I would like to freeze first two columns in uitable. Do you know if such option is available? Since looks like this option is not available...
  • Andrés Aguilar (40 days 9 hours ago): Hello, has anyone tried to change the language of the DateComboBox? For example English -> French ————&# 8212;—- January -> Janvier April...
  • Yair Altman (49 days 7 hours ago): I posted my treeTable utility 10 years ago for anyone to use freely, on an as-is basis, without any warranty, updates or support. If you need any customization or assistance...
Contact us
Captcha image for Custom Contact Forms plugin. You must type the numbers shown in the image
Undocumented Matlab © 2009 - Yair Altman
This website and Octahedron Ltd. are not affiliated with The MathWorks Inc.; MATLAB® is a registered trademark of The MathWorks Inc.
Scroll to top