Typst RTL Justify Bug: Overhang With Inline Elements

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Hey guys! Let's dive into a quirky issue in Typst that some users have stumbled upon: unexpected overhang in justified right-to-left (RTL) text, especially when inline elements are involved. If you're working with RTL languages and aiming for that perfect justified alignment, this is something you'll definitely want to know about. We'll break down the problem, look at some examples, and explore potential workarounds. So, buckle up, and let’s get started!

Understanding the Issue

So, what exactly is this overhang issue? Well, in Typst, when you set text to be right-to-left and also justify it, you expect the text to align neatly along both the right and left edges of the paragraph. However, sometimes, when you have inline elements like superscripts or boxes embedded within the text, you might notice that the text overshoots the right edge. This creates a visual imbalance and can be pretty annoying, especially when you're striving for a polished look. The main keyword here is right-to-left text justification, and it's crucial to understand how Typst handles it. When dealing with RTL text, Typst needs to manage the flow of characters from right to left while also ensuring that the text is evenly distributed across the line. This involves complex calculations to adjust spacing and positioning. The unexpected overhang issue arises when inline elements, such as superscripts or custom boxes, disrupt this calculation, causing the text to extend beyond the intended margin. This problem is more than just a cosmetic annoyance; it affects the overall readability and professionalism of documents. Imagine a legal document or a formal letter with misaligned text – it can detract from the message and make the document appear sloppy. Therefore, understanding the root cause and finding effective solutions is essential for anyone working with RTL languages in Typst.

A Closer Look at the Problem

The issue seems to pop up when specific conditions are met. Primarily, it involves RTL text that's set to justify: true and contains inline elements directly attached to words without spaces. Let's break this down:

  1. RTL Text: Obviously, this issue is specific to text that flows from right to left.
  2. Justification: The justify: true setting tells Typst to spread the text out so it aligns on both the left and right margins.
  3. Inline Elements: These are things like superscripts (#super[]), subscripts, or even custom boxes (#box()) that you insert within the text.
  4. No Spaces: The kicker here is that the inline element needs to be connected to a word without an intervening space. For instance, HelloWorld#super[123] is more likely to cause the issue than Hello World #super[123]. The justification algorithm in Typst is designed to distribute spaces evenly across the line to achieve a balanced look. When inline elements are directly attached to words, they disrupt this process. The algorithm might miscalculate the available space, leading to uneven distribution and the dreaded overhang. To further complicate matters, the size and nature of the inline element can also influence the severity of the issue. A larger superscript or a wider box, for example, might exacerbate the problem compared to a smaller element. Therefore, when designing documents with RTL text and inline elements, it's essential to be mindful of these factors and test different scenarios to ensure proper alignment. By understanding the nuances of how Typst handles text justification and inline elements, you can avoid unexpected layout issues and create visually appealing documents.

Example Code

To illustrate, here’s a snippet of Typst code that triggers the issue:

#set text(dir: rtl)
#set par(justify: true)
#set page(paper: "a9", height: auto)

Hello World#super[123] this is some text

In this example, we're setting the text direction to RTL, enabling justification, and then inserting a superscript directly after the word "World" without a space. Running this code in Typst versions 0.13.1 and 0.14-rc1 (as the user reported) shows the overhang on the right edge. This code snippet perfectly highlights the interplay of the key elements contributing to the issue. The #set text(dir: rtl) instruction sets the stage for right-to-left text flow, while #set par(justify: true) invokes the justification algorithm that attempts to distribute the text evenly. The #super[123] element introduces the inline disruption, and the absence of a space between "World" and the superscript exacerbates the problem. By experimenting with variations of this code, you can gain a deeper understanding of how different inline elements and spacing configurations affect the outcome. For instance, replacing #super[123] with a #box(width: 9pt) or adding a space before the superscript can alter the alignment. Such hands-on exploration is invaluable for identifying the specific scenarios that trigger the overhang issue and developing strategies to mitigate it. Moreover, this simple example can serve as a starting point for more complex layouts involving multiple inline elements and varying text lengths. By systematically testing and refining your code, you can ensure consistent and accurate text alignment in your Typst documents.

Visual Proof

The user even provided a visual comparison between Typst versions 0.13.1 and 0.14-rc1, clearly showing the overhang. The images speak for themselves, highlighting that this isn't just a minor visual glitch but a noticeable alignment issue. The visual proof provided by the user is crucial for understanding the impact of the overhang issue. A picture is worth a thousand words, and the screenshots vividly demonstrate how the misalignment can detract from the overall appearance of the document. The comparison between Typst versions 0.13.1 and 0.14-rc1 is particularly insightful, as it indicates that the issue persists across different versions of the software. This consistency suggests that the problem might stem from a fundamental aspect of Typst's text layout engine, rather than a temporary bug. By visually inspecting the output in different versions and under varying conditions, developers and users can gain a more nuanced understanding of the problem. For example, one might notice that the severity of the overhang varies depending on the font used, the size of the inline element, or the length of the text. Such observations can provide valuable clues for pinpointing the root cause and developing targeted solutions. Furthermore, visual comparisons can help assess the effectiveness of proposed fixes or workarounds. By comparing the output before and after applying a solution, it's possible to determine whether the issue has been fully resolved or whether further adjustments are needed. In this context, the user's visual evidence serves as a critical reference point for ongoing discussions and efforts to address the RTL text justification problem in Typst.

Why This Happens

The exact cause is likely related to how Typst calculates text justification in RTL contexts when inline elements are present. The justification algorithm might not be correctly accounting for the width and positioning of these elements, leading to the overhang. The core of the problem likely lies in the intricate dance between Typst's text justification algorithm and its handling of inline elements. When Typst justifies text, it aims to distribute the available space evenly between words, creating a visually balanced line. This process involves calculating the width of each word, identifying potential gaps, and adjusting the spacing accordingly. However, when inline elements like superscripts or custom boxes are introduced, the calculation becomes significantly more complex. These elements occupy space within the line, but their dimensions and positioning might not be straightforwardly incorporated into the justification process. For instance, a superscript might extend vertically beyond the normal line height, while a box could have a fixed width that doesn't align with the natural word spacing. In the case of RTL text, the challenges are further amplified. Typst must not only manage the horizontal spacing but also ensure that the text flows correctly from right to left. The presence of inline elements can disrupt this flow, potentially leading to miscalculations in the spacing and positioning. The overhang issue suggests that Typst's current algorithm might not fully account for the impact of inline elements on the justification of RTL text. This could be due to a variety of factors, such as incorrect width calculations, misaligned positioning, or insufficient handling of the interaction between the inline element and the surrounding text. To address the issue effectively, developers might need to delve into the inner workings of Typst's text layout engine and refine the justification algorithm to better accommodate inline elements in RTL contexts. This could involve adjusting the spacing calculations, modifying the positioning logic, or implementing specific rules for handling different types of inline elements.

Potential Workarounds

While a proper fix in Typst is ideal, there are a few workarounds you might try:

  1. Adding Spaces: The simplest workaround is often to add a space between the word and the inline element. This can prevent the justification algorithm from misbehaving.
  2. Adjusting Element Width: If you're using custom boxes, try tweaking their width to see if it resolves the issue.
  3. Manual Kerning: As a last resort, you could manually adjust the spacing using kerning, but this can be tedious for longer documents.

Let's explore these workarounds in a bit more detail. Adding a space between the word and the inline element is often the quickest and most effective solution. By inserting a space, you effectively decouple the inline element from the word, allowing Typst's justification algorithm to treat them as separate entities. This can prevent the miscalculations that lead to the overhang issue. However, it's essential to consider the visual impact of adding a space. In some cases, it might create an undesirable gap in the text, especially if the inline element is closely related to the word. Therefore, it's crucial to strike a balance between resolving the overhang and maintaining the overall aesthetic appeal of the document. Adjusting the width of custom boxes is another potential workaround, particularly when the inline element is a fixed-width box. By experimenting with different widths, you might find a value that minimizes the disruption to the justification process. This approach is especially useful when you have control over the dimensions of the inline element. However, it might not be applicable in all scenarios, such as when using superscripts or other elements with inherent size constraints. Manual kerning, the process of adjusting the spacing between individual characters, is a more labor-intensive workaround but can provide fine-grained control over the text layout. By carefully tweaking the spacing, you can compensate for the overhang and achieve a visually pleasing alignment. However, manual kerning is time-consuming and can be challenging to apply consistently across a large document. Therefore, it's best reserved for situations where other workarounds are not feasible or when a high degree of precision is required. Ultimately, the best approach is to use a combination of workarounds tailored to the specific context of your document. By understanding the strengths and limitations of each technique, you can effectively mitigate the overhang issue and create professional-looking Typst documents with RTL text and inline elements.

Status and Next Steps

As of now, this issue seems to be an open bug in Typst. If you encounter this, the workarounds mentioned above can help. Hopefully, the Typst developers will address this in a future release. In the meantime, keep an eye on Typst's issue tracker for updates. The Typst community and development team are generally very responsive to user feedback and bug reports. By actively participating in discussions and providing detailed examples, users can contribute to the resolution of this issue. Reporting specific scenarios, such as the code snippet provided in this discussion, helps developers reproduce the problem and identify the underlying cause. Furthermore, sharing any workarounds or alternative solutions that you discover can benefit the wider community. The more information and insights that are shared, the faster and more effectively the issue can be addressed. In the meantime, staying informed about the status of the bug and any potential fixes or updates is crucial. Regularly checking Typst's issue tracker, discussion forums, and release notes can help you stay abreast of the latest developments. Additionally, consider subscribing to Typst's mailing list or following their social media channels to receive timely notifications about bug fixes and feature updates. By remaining engaged and proactive, you can ensure that you're well-prepared to handle the overhang issue and any other challenges that might arise when working with Typst. Ultimately, the goal is to create a seamless and intuitive typesetting experience for all users, and addressing this RTL text justification bug is a significant step in that direction.

Conclusion

So there you have it, guys! The mystery of the unexpected overhang in justified RTL text with inline elements in Typst. It’s a bit of a niche issue, but if you’re working with RTL languages and need that perfect justification, it’s good to be aware of. Use the workarounds for now, and let’s hope for a proper fix soon! Remember, staying informed and sharing your experiences helps the Typst community grow and improve. Happy typesetting! In conclusion, the unexpected overhang issue in Typst's RTL text justification is a prime example of the complexities involved in typesetting, especially when dealing with different languages and layout requirements. While the issue might seem like a minor visual glitch at first glance, it underscores the importance of meticulous attention to detail in document design. The interplay of RTL text, justification algorithms, and inline elements creates a challenging scenario for any typesetting engine, and Typst is no exception. By understanding the root causes of the problem and exploring potential workarounds, users can mitigate the impact of the issue and create professional-looking documents. The workarounds discussed, such as adding spaces, adjusting element widths, and manual kerning, offer practical solutions for specific situations. However, a more comprehensive fix within Typst itself is the ultimate goal. The active engagement of the Typst community in identifying, reporting, and discussing such issues is crucial for driving the software's evolution. By sharing experiences, providing feedback, and contributing to the development process, users can help ensure that Typst becomes an even more robust and versatile typesetting tool. The hope is that the Typst developers will address this issue in a future release, providing a seamless and intuitive experience for users working with RTL languages. In the meantime, staying informed, utilizing available workarounds, and actively participating in the community are the best ways to navigate this and other typesetting challenges. Happy typesetting, everyone, and let's continue to push the boundaries of what's possible with Typst!