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43 lines
2.5 KiB
Markdown
43 lines
2.5 KiB
Markdown
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---
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title: "FAQ"
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description: "Explore Frequently Asked Questions regarding html2canvas"
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---
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## Why aren't my images rendered?
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html2canvas does not get around content policy restrictions set by your browser. Drawing images that reside outside of
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the [origin](https://developer.mozilla.org/en-US/docs/Web/Security/Same-origin_policy) of the current page [taint the
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canvas](https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image#What_is_a_tainted_canvas) that they are drawn upon. If the canvas gets tainted, it cannot be read anymore. As such, html2canvas implements
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methods to check whether an image would taint the canvas before applying it. If you have set the `allowTaint`
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[option](/configuration) to `false`, it will not draw the image.
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If you wish to load images that reside outside of your pages origin, you can use a [proxy](/proxy) to load the images.
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## Why is the produced canvas empty or cuts off half way through?
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Make sure that `canvas` element doesn't hit [browser limitations](https://stackoverflow.com/questions/6081483/maximum-size-of-a-canvas-element) for the `canvas` size.
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The limitations vary by browser, operating system and system hardware.
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### Chrome
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> Maximum height/width: 32,767 pixels
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> Maximum area: 268,435,456 pixels (e.g., 16,384 x 16,384)
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### Firefox
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> Maximum height/width: 32,767 pixels
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> Maximum area: 472,907,776 pixels (e.g., 22,528 x 20,992)
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### Internet Explorer
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> Maximum height/width: 8,192 pixels
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> Maximum area: N/A
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### iOS
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> The maximum size for a canvas element is 3 megapixels for devices with less than 256 MB RAM and 5 megapixels for devices with greater or equal than 256 MB RAM
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## Why doesn't CSS property X render correctly or only partially?
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As each CSS property needs to be manually coded to render correctly, html2canvas will *never* have full CSS support.
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The library tries to support the most [commonly used CSS properties](/features) to the extent that it can. If some CSS property
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is missing or incomplete and you feel that it should be part of the library, create test cases for it and a new issue for it.
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## How do I get html2canvas to work in a browser extension?
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You shouldn't use html2canvas in a browser extension. Most browsers have native support for capturing screenshots from
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tabs within extensions. Relevant information for [Chrome](https://developer.chrome.com/extensions/tabs#method-captureVisibleTab) and
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[Firefox](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D#drawWindow()).
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