Providing additional fonts for Svg.Skia about svg.skia HOT 7 CLOSED

@JonathanDDuncan It is doable (for my application, I have done it). But it's not simple.

Essentially you'll need to create a separate utility class that parses the SVG file (or whatever other file contains your in-line styles), finds places where "@font-face { whatever}" appears in it, and where it finds src: url('...') it reads that source data and constructs an SKTypeFace from it, and adds it to a Dictionary<string,SKTypeFace>, that lets you obtain the typeface you want, based on its font-family name.

Then you define a 'provider' class that implements ITypeFaceProvider, and in your code you construct an instance of your provider class., and register it by calling SKSvgSettings.s_typefaceProviders.Insert(0, myProviderInstance).

Your provider class has to implement a method FromFamilyName(string name, SKFontStyleWeight wt, SKFontStyleWidth dw, SKFontStyleSlant sl) which will use 'name' to do a look up the SKTypeface in your Dictionary<string,SKTypeFace>, and will then do whatever messing about is necessary to apply weight, width and slant, and will then finally return the SKTypeFace that it found in the dictionary.

I hope that makes sense, and is helpful. I can't quickly post a working implementation, because my implementation of this logic has to achieve a bunch of other things on the side, and is rather entangled with several thousand lines of code for doing other things. But if I can help more, please let me know,

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I did not run into this problem. We can come up with some solution together. No need for making forked version. I just have to figure out how to make the library plug-able.

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@jrc14 I will add interface in next release:

public interface ITypefaceProvider
{
    SKTypeface? FromFamilyName(string fontFamily, SKFontStyleWeight fontWeight, SKFontStyleWidth fontWidth, SKFontStyleSlant fontStyle);
}

You can implement your own typeface provider and add to SvgTextExtensions.s_typefaceProviders.

Change is already in master branch cb51079

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Thank you - that looks good!

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@wieslawsoltes
For the following example, how would I use ITypefaceProvider
public void SVGtoPNG(string id, string svg) { using (var skSVG = new SKSvg()) { if (skSVG.FromSvg(svg) != null) { using (var stream = File.OpenWrite(@"image.png"))) { skSVG.Picture.ToImage(stream, SKColors.Empty, SKEncodedImageFormat.Png, 100, 1f, 1f, SKColorType.Rgba8888, SKAlphaType.Premul); } } } }

We are using embeded fonts in our SVGs like this.
`
<style>

   @font-face {
                    font-family: Fontania;
                    src: url('data:application/font-woff;base64,d09GRgABAAAA....ysKzC/wZ21h')
                }

</style>

`

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@wieslawsoltes
For the following example, how would I use ITypefaceProvider
public void SVGtoPNG(string id, string svg) { using (var skSVG = new SKSvg()) { if (skSVG.FromSvg(svg) != null) { using (var stream = File.OpenWrite(@"image.png"))) { skSVG.Picture.ToImage(stream, SKColors.Empty, SKEncodedImageFormat.Png, 100, 1f, 1f, SKColorType.Rgba8888, SKAlphaType.Premul); } } } }

We are using embeded fonts in our SVGs like this.
`

<style> ``` @font-face { font-family: Fontania; src: url('data:application/font-woff;base64,d09GRgABAAAA....ysKzC/wZ21h') } </style>

`

This is not supported.

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@wieslawsoltes Thanks for your prompt response

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