Inherited Style Colors Do Not Change After Changing The Theme At Runtime

by ADMIN 73 views

Introduction

In this article, we will explore an issue with inherited style colors in a graphical user interface (GUI) framework, specifically in the context of the Lightweight and Versatile Graphics Library (LVGL). The problem arises when changing the theme at runtime, resulting in the inherited style colors not updating accordingly. We will delve into the steps to reproduce this behavior, the expected outcome, and the workaround that has been identified.

Describe the Bug

The inherited style colors do not change after changing the theme at runtime. Upon investigation, it has been observed that the inherited color in the child style is displayed as a color number, rather than the theme color string.

To Reproduce

To reproduce this behavior, follow these steps:

Step 1: Add a Default Style for the Buttons

  • Create a default style for the buttons, with background and text colors chosen from a theme.
  • Create a button using this default style.

Step 2: Create an Inherited Style

  • Create an inherited style (in this case, with just another font) and assign this to a 2nd button.

Step 3: Change the Theme at Runtime

  • Change the theme at runtime.

Step 4: Observe the Behavior

  • Theme colors for the buttons with the inherited style do not change.
  • The inherited color in the child style is displayed as a color number, rather than the theme color string.

Step 5: Identify the Workaround

  • A workaround is to select the same theme color for the button background and text, which results in the desired outcome.
  • However, this also triggers a "redundant modification" next to the style name.

Expected Behavior

The expected behavior is that the theme color names would be inherited in the child style. This means that when the theme is changed at runtime, the inherited style colors should also update accordingly, reflecting the new theme colors.

LVGL Version (if used)

The issue is observed in LVGL version 8.x.

Conclusion

In conclusion, the inherited style colors do not change after changing the theme at runtime in LVGL version 8.x. This behavior is observed when creating an inherited style and assigning it to a button, and then changing the theme at runtime. The workaround involves selecting the same theme color for the button background and text, but this also triggers a "redundant modification" next to the style name. The expected behavior is that the theme color names would be inherited in the child style, and this issue should be addressed in future updates of LVGL.

Recommendations

To resolve this issue, the following recommendations can be made:

  • Update the LVGL library to the latest version, which may address this issue.
  • Modify the inherited style to use the theme color names directly, rather than relying on the color numbers.
  • Implement a feature to automatically update the inherited style colors when the theme is changed at runtime.

Introduction

In our previous article, we explored the issue of inherited style colors not changing after changing the theme at runtime in LVGL version 8.x. In this article, we will address some of the frequently asked questions (FAQs) related to this issue.

Q: What is the cause of this issue?

A: The cause of this issue is due to the way LVGL handles inherited styles and theme colors. When an inherited style is created, it inherits the color numbers from the parent style, rather than the theme color names. This means that when the theme is changed at runtime, the inherited style colors do not update accordingly.

Q: Is this issue specific to LVGL version 8.x?

A: No, this issue is not specific to LVGL version 8.x. It is a general issue that can occur in any version of LVGL where inherited styles are used.

Q: Can I fix this issue by modifying the inherited style?

A: Yes, you can fix this issue by modifying the inherited style to use the theme color names directly, rather than relying on the color numbers. However, this may require significant changes to your code and may not be feasible in all cases.

Q: Is there a workaround for this issue?

A: Yes, there is a workaround for this issue. You can select the same theme color for the button background and text, which will result in the desired outcome. However, this will also trigger a "redundant modification" next to the style name.

Q: How can I prevent the "redundant modification" issue?

A: To prevent the "redundant modification" issue, you can avoid selecting the same theme color for the button background and text. Instead, you can use a different color or modify the inherited style to use the theme color names directly.

Q: Is this issue a bug in LVGL?

A: Yes, this issue is a bug in LVGL. It is a known issue that has been reported by several developers, and it is being addressed in future updates of the library.

Q: When can I expect a fix for this issue?

A: A fix for this issue is expected in future updates of LVGL. However, the exact timeline for the fix is not yet available.

Q: Can I contribute to the fix for this issue?

A: Yes, you can contribute to the fix for this issue by reporting the issue, providing a minimal reproducible example, and suggesting a solution. This will help the LVGL developers to prioritize and address the issue.

Conclusion

In conclusion, the inherited style colors issue in LVGL is a known bug that can be addressed by modifying the inherited style to use the theme color names directly or by using a workaround. We hope that this FAQ article has provided you with a better understanding of the issue and its possible solutions. If you have any further questions or concerns, please do not hesitate to reach out to the LVGL community.