Скачать или смотреть Creating a Watermark in Flutter with Stack Widget

Discover how to implement a `watermark` in your `Flutter` app using the `Stack widget` while maintaining user interactivity with underlying widgets.
---
This video is based on the question https://stackoverflow.com/q/67084954/ asked by the user 'Rifqi Radifan' ( https://stackoverflow.com/u/15629007/ ) and on the answer https://stackoverflow.com/a/67085062/ provided by the user 'Jim' ( https://stackoverflow.com/u/11276416/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Is it possible to make watermark with stack when the image is over widget and still can interact with the widgets behind?

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Creating a Watermark in Flutter with Stack Widget

When developing applications using Flutter, you may find the need to add a watermark to certain pages. However, a common challenge arises when trying to create a watermark that not only covers the entire screen but also allows user interaction with the widgets located underneath it. Let’s delve into this issue and explore an effective solution.

The Problem at Hand

While using the Stack widget in Flutter provides a straightforward way to stack elements on top of one another, this approach can present a few hurdles:

Full Screen Coverage: The watermark should cover the entire screen, ensuring it is visible in all areas.

Visibility Issues: When attempting to position the watermark behind other widgets, it often gets obscured by those widgets, reducing its visibility. This scenario can occur when using the Positioned widget without proper context.

User Interaction: If the watermark is layered on top, it might obstruct user interaction with the underlying widgets, which is often undesirable.

Example Code: Issues with Watermark

To illustrate these problems, here are two examples of how the watermark implementation might look in code:

Attempting to Position the Watermark Behind Widgets

[[See Video to Reveal this Text or Code Snippet]]

Here, the watermark is positioned behind other widgets, but it may end up being obscured, resulting in a poor visual effect.

Positioning the Watermark on Top of Widgets

[[See Video to Reveal this Text or Code Snippet]]

In this scenario, the watermark is visible but blocks interaction with the widgets beneath it, making it ineffective for user engagement.

A Viable Solution: Leveraging IgnorePointer

To address these challenges, a clever solution is to use the IgnorePointer widget. This widget allows you to create an overlay that doesn't interfere with user interactions on other widgets.

Implementation

Here’s how to implement the IgnorePointer widget to maintain user interactivity while displaying the watermark:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of Key Components

IgnorePointer: This widget is used to wrap the watermark. By setting ignoring to true, it allows touch events to pass through, enabling interaction with the widgets behind it.

Opacity: The watermark’s visibility can be adjusted using the Opacity widget. The opacity level you choose will determine how pronounced the watermark effect will be.

Center and Positioned: Utilizing these widgets ensures that the watermark is appropriately positioned and centered on the screen.

Conclusion

Incorporating a watermark in your Flutter application while maintaining the ability to interact with underlying widgets can be efficiently achieved by using the Stack widget along with IgnorePointer. This method ensures that your watermark remains both aesthetically pleasing and functional.

By following the outlined steps, you can create an engaging user interface that satisfies both design requirements and user experience. Happy coding with Flutter!