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How can I present text?

The most common way to show text is using a sketchpad or feedback item. These allow you to enter text and other visual stimuli. For a questionnaire-like way to show text, you can use forms.

Note: The text_display plugin has been removed as of OpenSesame 3.0.0, because it was outdated and did not provide any functionality that is not offered by forms and sketchpad items.

Formatting (HTML subset)

You can use a subset of HTML tags, which you can simply insert into your text. You can use these tags everywhere: In sketchpad items, in inline_scripts (provided you use the openexp.canvas class), in forms, etc.

Example:

OpenSesame supports a sub-set of HTML tags:
- <b>Bold face</b>
- <i>Italic</i>
- <u>Underline</u>

In addition, you can pass 'color', 'size', and 'style' as keywords to a 'span' tag:
- <span color="red">Color</span>
- <span size="32">Font size</span>
- <span style="serif">Font style</span>

Finally, you can force newlines with the 'br' tag:
Line 1<br>Line 2

The text above will be rendered as shown in Figure 1. (The exact appearance depends on your default colors, font, etc.)

/pages/manual/stimuli/img/text/form-example.png

Figure 1. Using (a subset of) HTML, you can define the appearance of your text.

Variables and inline Python

You can embed variables in text using the [...] syntax. For example, the following:

The subject number is [subject_nr]

... might evaluate to (for subject 1):

The subject number is 1

You can embed Python code using the [=...] syntax. For example, the following:

The subject number modulo five is [=var.subject_nr % 5]

... might evaluate to (for subject 7)

The subject number modulo five is 2

Fonts

Default fonts

You can select one of the default fonts from the font-selection dialogs (Figure 2). These fonts are included with OpenSesame and your experiment will therefore be fully portable when you use them.

/pages/manual/stimuli/img/text/font-selection-dialog.png

Figure 2. A number of default fonts, which are bundled with OpenSesame, can be selected through the font-selection dialogs.

The fonts have been renamed for clarity, but correspond to the following open-source fonts:

Name in OpenSesame Actual font
sans Droid Sans
serif Droid Serif
mono Droid Sans Mono
chinese-japanese-korean WenQuanYi Micro Hei
arabic Droid Arabic Naskh
hebrew Droid Sans Hebrew
hindi Lohit Hindi

Selecting a custom font through the font-selection dialog

If you select 'other ...' in the font selection dialog, you can select any font that is available on your operating system. If you do this, your experiment is no longer fully portable, and will require that the selected font is installed on the system that you run your experiment on.

Placing a custom font in the file pool

Another way to use a custom font is to put a font file in the file pool. For example, if you place the font file inconsolata.ttf in the file pool, you can use this font in a sketchpad item, like so:

draw textline 0.0 0.0 "This will be inconsolata" font_family="inconsolata"

Note that the font file must be a truetype .ttf file.

Bi-directional text support

By default, all text is rendered from left to right. However, you can enable bi-directional-text support through the 'Bi-directional-text support' checkbox in the general tab:

/pages/manual/stimuli/img/text/bidi.png

Figure 3. .bat lareneg eht hguorht delbane eb nac troppus txet-lanoitcerid-iB

Why do I see squares or question marks when I run my experiment?

If you select the font mono and add a string of, say, Hebrew text to a sketchpad, the user interface will display your text just fine. However, when you run the experiment, you will see a row of squares, and no characters. This happens because the mono font, which is actually 'Droid Sans Mono', does not contain Hebrew characters. The user interface deals with this by falling back to a different font that does contain Hebrew characters. However, the OpenSesame runtime deals with this by showing ... a bunch of squares.

The bottom line is that if you find that characters are missing, you should select a different font that actually contains the characters--even when the characters display fine in the user interface!

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