mix-blend-mode not rendered

[Cristian-L]

I am trying to use mix-blend-mode on some of the divs to get some nice effects. However, html2canvas does not render it at all. Any suggestions or workarounds, please?

[brcontainer]

Please read this:

https://github.com/niklasvh/html2canvas#browser-compatibility

As each CSS property needs to be manually built to be supported, there are a number of properties that are not yet supported.

I hope it is possible to implement this in the near future :)

[jackuro]

hi cristian have the same issue, did you found any solution?

[brcontainer]

@jackuro see https://github.com/niklasvh/html2canvas#browser-compatibility ;)

[jackuro]

i see it already looks like the render does the image solid forgetin the css mix-blend-mode how can i fix that? its not a browser problem, thank you @brcontainer @niklasvh

[brcontainer]

@jackuro There is no way to fix something that has not been implemented. I really think there is a lack of collaboration in the project, there are many "forks", but few "pullrequests" that are useful. :(

[egfx]

I really wonder if mix-blend-mode is possible. It would be a very welcome addition. Any hints on where to start the implementation?

[MatthijsMud]

CanvasRenderingContext2D has a property that could possibly be used for the desired effect: globalCompositeOperation. All allowed values for mix-blend-mode are valid values for the given property.

Setting the property when the browser doesn't support it, should be no different from the current implementation. In that regard it has a nice fallback. So I expect something akin to the following is all that is needed to implement the feature.

var temp = ctx.globalCompositeOperation;
ctx.globalCompositeOperation = window.getComputedStyle(node).mixBlendMode;

// ...

ctx.globalCompositeOperation = temp;

As to where this piece of code needs to be placed... I have little to no idea, given I'm not all that well versed in the project (yet). It should be before the element and its children are rendered, at which point more properties are likely to be set.

Another issue, pertaining background-blend-mode, can probably be solved in a similar way; the moment the context is restored differs.