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

Aligning uicontrol contents

September 22, 2016 6 Comments

Matlab automatically aligns the text contents of uicontrols: button labels are centered, listbox contents are left-aligned, and table cells align depending on their contents (left-aligned for strings, centered for logical values, and right-aligned for numbers). Unfortunately, the control’s HorizontalAlignment property is generally ignored by uicontrols. So how can we force Matlab buttons (for example) to have right-aligned labels, or for listbox/table cells to be centered? Undocumented Matlab has the answer, yet again…
It turns out that there are at least two distinct ways to set uicontrol alignment, using HTML and using Java. Today I will only discuss the HTML variant.
The HTML method relies on the fact that Matlab uicontrols accept and process HTML strings. This was true ever since Matlab GUI started relying on Java Swing components (which inherently accept HTML labels) over a decade ago. This is expected to remain true even in Matlab’s upcoming web-based GUI system, since Matlab would need to consciously disable HTML in its web components, and I see no reason for MathWorks to do so. In short, HTML parsing of GUI control strings is here to stay for the foreseeable future.

% note: no need to close HTML tags, e.g. </font></html>
uicontrol('Style','list', 'Position',[10,10,70,70], 'String', ...
          {'<html><font color="red">Hello</font></html>', 'world', ...
           '<html><font style="font-family:impact;color:green"><i>What a', ...
           '<html><font color="blue" face="Comic Sans MS">nice day!'});

% note: no need to close HTML tags, e.g. </font></html> uicontrol('Style','list', 'Position',[10,10,70,70], 'String', ... {'<html><font color="red">Hello</font></html>', 'world', ... '<html><font style="font-family:impact;color:green"><i>What a', ... '<html><font color="blue" face="Comic Sans MS">nice day!'});

Listbox with HTML items
Listbox with HTML items

While HTML formatting is generally frowned-upon compared to the alternatives, it provides a very quick and easy way to format text labels in various different manners, including using a combination of font faces, sizes, colors and other aspects (bold, italic, super/sub-script, underline etc.) within a single text label. This is naturally impossible to do with Matlab’s standard properties, but is super-easy with HTML placed in the label’s String property.

Unfortunately, while Java Swing (and therefore Matlab) honors only a [large] sub-set of HTML and CSS. The most important directives are parsed but some others are not, and this is often difficult to debug. Luckily, using HTML and CSS there are often multiple ways to achieve the same visual effect, so if one method fails we can usually find an alternative. Such was the case when a reader asked me why the following seemingly-simple HTML snippet failed to right-align his button label:

hButton.String = '<html><div style="text-align:right">text';

hButton.String = '<html><div style="text-align:right">text';

As I explained in my answer, it’s not Matlab that ignores the CSS align directive but rather the underlying Swing behavior, which snugly fits the text in the center of the button, and of course aligning text within a tight-fitting box has no effect. The workaround that I suggested simply forces Swing to use a non-tightly-fitting boundary box, within which we can indeed align the text:

pxPos = getpixelposition(hButton);
hButton.String = ['<html><div width="' num2str(pxPos(3)-20) 'px" align="right">text'];  % button margins use 20px

pxPos = getpixelposition(hButton); hButton.String = ['<html><div width="' num2str(pxPos(3)-20) 'px" align="right">text']; % button margins use 20px

centered (default) button label   right-aligned button label
Centered (default) and right-aligned button labels

This solution is very easy to set up and maintain, and requires no special knowledge other than a bit of HTML/CSS, which most programmers know in this day and age.
Of course, the solution relies on the actual button size. So, if the button is created with normalized units and changes its size when its parent container is resized, we’d need to set a callback function on the parent (e.g., SizeChangedFcn of a uipanel) to automatically adjust the button’s string based on its updated size. A better solution that would be independent of the button’s pixel-size and would work even when the button is resized needs to use Java.
A related solution for table cells uses a different HTML-based trick: this time, we embed an HTML table cell within the Matlab control’s cell, employing the fact that HTML table cells can easily be aligned. We just need to ensure that the HTML cell is defined to be larger than the actual cell width, so that the alignment fits well. We do this by setting the HTML cell width to 9999 pixels (note that the tr and td HTML tags are necessary, but the table tag is optional):

uitable('Units','norm','Pos',[0,0,0.3,0.3], 'Data', ...
        {'Left', ...
         '<html><tr><td align=center width=9999>Center', ...
         '<html><tr><td align=right  width=9999>Right'});

uitable('Units','norm','Pos',[0,0,0.3,0.3], 'Data', ... {'Left', ... '<html><tr><td align=center width=9999>Center', ... '<html><tr><td align=right width=9999>Right'});

Non-default alignment of uitable cells
Non-default alignment of uitable cells

As noted above, a better solution might be to set the underlying Java component’s alignment properties (or in the case of the uitable, its underlying JTable component’s cellrenderer’s alignment). But in the general case, simple HTML such as above could well be sufficient.

Related posts:

  1. Rich-contents log panel – Matlab listboxes and editboxes can be used to display rich-contents HTML-formatted strings, which is ideal for log panels. ...
  2. Spicing up Matlab uicontrol tooltips – Matlab uicontrol tooltips can be spiced-up using HTML and CSS, including fonts, colors, tables and images...
  3. Additional uicontrol tooltip hacks – Matlab's uicontrol tooltips have several limitations that can be overcome using the control's underlying Java object....
  4. 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....
  5. uicontrol side-effect: removing figure toolbar – Matlab's built-in uicontrol function has a side-effect of removing the figure toolbar. This was undocumented until lately. This article describes the side-effect behavior and how to fix it....
  6. Rich Matlab editbox contents – The Matlab editbox uicontrol does not handle HTML contents as do other uicontrols. In this article I show how this limitation can be removed....
GUI HTML Pure Matlab uicontrol Undocumented feature
Print Print
« Previous
Next »
6 Responses
  1. Les Beckham August 12, 2017 at 06:01 Reply

    Interesting post, as always.

    I’m curious why you state that “HTML formatting is generally frowned-upon compared to the alternatives”. By whom? And why?

    Perhaps you can elaborate.

    Thank you

    • Yair Altman August 12, 2017 at 20:37 Reply

      @Les – HTML formatting is more CPU and memory-intensive, while being less powerful, than using Cell Renderers (details). Also, whenever you update an HTML-formatted cell, you’d see the full HTML string as the text in the cell content, which is a bit awkward. Also, if you try to get the values in the table, you’d need to parse out the HTML tags.

      However, there is no dispute that HTML formatting is super-easy to use, and in many cases the drawbacks listed above pale in comparison to the simplicity and usefulness of HTML formatting. So in general I use HTML formatting for most simple formatting, and I only use Cell Renderers for large tables (with numerous formatted cells), when the formatting is not easy to achieve with HTML, and/or when the table cells need to be updated by the user.

  2. Narendra Kintali September 20, 2017 at 19:12 Reply

    Hi sir, I am using uitable for my project, When I am trying to display a array of values. The values are aligned to top, which makes them not visible. So I need to change the height of row in uitable, Please tell me How can I change Height of row in uitable.

    • Yair Altman September 24, 2017 at 10:39 Reply

      @Narendra – you can use the underlying Java table’s setRowHeight() method

      hTable = uitable(...);
      jTable = findjobj(hTable);
      try jTable = jTable.getViewport.getView; catch, end
       
      jTable.setRowHeight(10);    % all rows = 10px
      jTable.setRowHeight(5,12);  % row #6 = 12px

      hTable = uitable(...); jTable = findjobj(hTable); try jTable = jTable.getViewport.getView; catch, end jTable.setRowHeight(10); % all rows = 10px jTable.setRowHeight(5,12); % row #6 = 12px

      • Narendra Kintali September 29, 2017 at 01:36

        sir,

        Its not working. It gives error as “No appropriate method, property, or field ‘setRowHeight’ for class ‘matlab.ui.control.Table’.”

      • Yair Altman September 29, 2017 at 09:19

        These customizations do not work with web-based figures (created with App Designer) – only with tables that are created in non-web figures, using GUIDE or the uitable function.

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 (email)
  •  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
  • Patrick Fitzgerald (1 day 22 hours ago): Just a heads up to anyone else digging around for help related to this: if you assign BackrgoundColor to a pushbutton-style uicontrol, it seems to prevent you from...
  • Vasiliy (17 days 18 hours ago): Hi Yair, i’m trying to use the MonthChooserPanel class. com.mathworks.mwswing.MJUtilit ies.initJIDE; handles.jPanel = com.jidesoft.combobox.MonthCho oserPanel;...
  • DM (17 days 18 hours ago): Hi Yair, I’m trying to use the MonthChooserPanel class. com.mathworks.mwswing.MJUtilit ies.initJIDE; handles.jPanel = com.jidesoft.combobox.MonthCho oserPanel; [handles.hPanel,...
  • Yair Altman (21 days 10 hours ago): @Alex – thanks, but keep in mind that new functions will only work on the recent Matlab releases. If your code needs to work on older Matlab releases, you could revert to...
  • Alex Churchill (21 days 11 hours ago): I was looking up how to do this exact task today. I was about to hold my nose and use the internal controllib function, when I happened to chance across a slightly newer...
  • Sebastian Hölz (27 days 17 hours ago): I have not investigated this in detail, but I think one way to go in new versions of Matlab (>2019b) might be to use listeners to suitable figure properties, e.g. fig =...
  • Prathep (27 days 20 hours ago): Hi Yair, Thanks for your introduction on Matlab Toostrip. Is there any way to add Matlab toolstrip for uifigures as you have done already for figure?
  • Josh (34 days 2 hours ago): Dear Yair, Small typo; you wrote >>Move lines up or down – CTRL + ALT + UP or DOWN allows you to move selected lines up or down but it’s actually ALT+SHIFT then UP/DOWN...
  • Yair Altman (40 days 21 hours ago): You can try to increase the Java heap memory size in the Matlab preferences (General => Java Heap Memory). Any changes to the settings will only take effect after restarting...
  • Thomas (40 days 22 hours ago): Hello, thanks for sharing! I currently receive the following memory error message when using savezip with a big object (Matlab R2020b, Windows 10). Error using...
  • Yair Altman (44 days 6 hours ago): Yerlan – either use menuItem1.setEnabled(0) or set(menuItem1,'Enabled',0)
  • Manzn (44 days 8 hours ago): Thank you man! you saved me, when there was no more light 😀
  • Yerlan (45 days 13 hours ago): Hello Mr. Altman, how can I disable menu items in the context menu? E.g. when I am trying to do this: menuItems = jmenu.getSubElements; menuItem1 = menuItems(1);...
  • Yair Altman (46 days 5 hours ago): Thanks for the note Eric – you forgot the crucial call to jTable.setLabelTable(labelTabl e) – I added it into your code snippet above.
  • Erik (47 days 17 hours ago): Thank you for this — I don’t know if this has been mentioned anywhere else before, but it could be useful to mention how to add custom labels to a jslider. I did the...
Contact us
Undocumented Matlab © 2009 - Yair Altman
Scroll to top