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Lära Exporting and Importing Canvas Content | Advanced Canvas Features and Practical Projects
Canvas Apps with KonvaJS and JavaScript

bookExporting and Importing Canvas Content

When you want users to save their work or share their creations, you need to export and import the canvas content. In Konva.js, the two main approaches are serialization—to save the canvas state as data—and image exporting to create a visual snapshot.

Serialization involves converting the entire canvas, including all shapes, layers, and their properties, into a format that can be easily stored or transferred. The most common format for this task is JSON. When you serialize a Konva.js stage, you call the stage.toJSON() method, which produces a string representing the complete state of the canvas. This JSON can later be loaded using Konva.Node.create(jsonString, container), fully restoring the canvas to its previous state, including all shapes, positions, and properties.

Exporting the canvas as an image is useful when you want to share or download a visual representation. Konva.js allows you to export the canvas as PNG or JPEG by using the stage.toDataURL() method. This creates a data URL that can be used as the src for an <img> tag or as a download link.

To see how these concepts work in practice, review the following example. You will find an HTML file that demonstrates how to export the current canvas as an image and how to import from a saved JSON string.

index.html

index.html

script.js

script.js

copy
question mark

Which format is commonly used to serialize and restore the state of a Konva.js canvas?

Select the correct answer

Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 4. Kapitel 2

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Suggested prompts:

Can you explain the difference between exporting as JSON and exporting as an image?

How do I use the exported JSON to restore my canvas?

Can you show me how to trigger the export or import actions with buttons?

bookExporting and Importing Canvas Content

Svep för att visa menyn

When you want users to save their work or share their creations, you need to export and import the canvas content. In Konva.js, the two main approaches are serialization—to save the canvas state as data—and image exporting to create a visual snapshot.

Serialization involves converting the entire canvas, including all shapes, layers, and their properties, into a format that can be easily stored or transferred. The most common format for this task is JSON. When you serialize a Konva.js stage, you call the stage.toJSON() method, which produces a string representing the complete state of the canvas. This JSON can later be loaded using Konva.Node.create(jsonString, container), fully restoring the canvas to its previous state, including all shapes, positions, and properties.

Exporting the canvas as an image is useful when you want to share or download a visual representation. Konva.js allows you to export the canvas as PNG or JPEG by using the stage.toDataURL() method. This creates a data URL that can be used as the src for an <img> tag or as a download link.

To see how these concepts work in practice, review the following example. You will find an HTML file that demonstrates how to export the current canvas as an image and how to import from a saved JSON string.

index.html

index.html

script.js

script.js

copy
question mark

Which format is commonly used to serialize and restore the state of a Konva.js canvas?

Select the correct answer

Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 4. Kapitel 2
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