append emoji at the text is not showing emoji on the image output.

[emildd]

how to configuration about emoticon support?

[nigeltao]

I'm sorry, but I don't understand the question. Can you re-phrase it?

[emildd]

I want to create text to image with some emojis on the text. like 😎😎😋😊😉😆 how to handle and configuration it?

2017-01-12 12:47 GMT+07:00 Nigel Tao notifications@github.com:

I'm sorry, but I don't understand the question. Can you re-phrase it?

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[nigeltao]

First of all, you will need a font file that contains Emoji images. Even so, I don't think that golang/freetype currently supports such emoji fonts, and probably won't do so any time soon, as it would be a lot of work and I don't have a lot of spare time at the moment.

One reason that it would be a lot of work is that there doesn't appear to be a clear standard for colored or partially transparent glyphs. https://en.wikipedia.org/wiki/OpenType#Color lists three competing approaches, built on PNG, SVG or neither.

[fogleman]

@nigeltao Any pointers on where to look? See the referenced gg issue. We get this error when trying to use an emoji font, such as Apple Color Emoji.ttf:

panic: freetype: unsupported TrueType feature: cmap encoding

That font has a cmap encoding of 4, which isn't one of the supported values in golang/freetype.

I don't know much about TTF. Is this just a matter of parsing a couple more cmap "subtables"?

[nigeltao]

Are you trying to use that Emoji font specifically for its emoji images, or are you just trying to set basic "hello, world" text in a given font that happens to also have (unused) emoji?

If the latter, it's probably just a matter of parsing one more cmap encoding. As per https://www.microsoft.com/typography/otspec/name.htm, Unicode/4 is pretty much the same as Unicode/3. Provided you don't need a new cmap format (not cmap encoding), i.e. you don't need something other than format-4 or format-12, that's probably all you need to do.

I don't have that particular font on my linux computer, but I suspect that the golang.org/x/image/font/sfnt package (a work in progress) will accept "Apple Color Emoji.ttf". Either way, it's probably useful information as to whether the golang.org/x/image/font/sfnt package can handle it, even if github.com/golang/freetype can't.

If the former (which is what the OP bug report is about), then that's a lot more work. Supporting emoji fonts will take much more work than simply tweaking the accepted encodings. For one thing, the API would need to change to work with multi-color glyphs. Even so, as previously mentioned, there are three competing approaches, each needing significant new code:

For Microsoft's take (COLR, CPAL etc tables), look at "Tables Related to Color Fonts" at https://www.microsoft.com/typography/OTSPEC/otff.htm#otttables for the spec.

For Google's take (PNG images), we do already have a image/png decoder, but you'd still need to hook it all up and adding extra dependencies is sad.

For Mozilla/Adobe's take (SVG images), we'd need an SVG decoder, which we don't have and would be a massive amount of work, and even more dependencies.

[antzucaro]

@nigeltao it was for the images (not necessarily the colors).

[fogleman]

Well, emojis would be weird without color.

[antzucaro]

I do it all the time! Here at the top of the screen, for example.

[nigeltao]

I've just pushed a commit that I suspect will let you render black+white (but not color) emoji. I don't know what fonts you're using, so I haven't confirmed that, though.

I'm also leaving this issue open, as I think that the OP refers to color emoji.

[nigeltao]

Note that black-and-whiteness is a property of each font file, not the Go code. It's not like we can take the black-and-white forms of "Apple Color Emoji.ttc", since that font file doesn't supply black-and-white forms, only color forms.

[liudanking]

@nigeltao I am trying to use that Emoji font specifically for its emoji images. The font I am using is NotoColorEmoji.ttf.

I want to confirm that is golang/freetype can handle this case?

[nigeltao]

golang/freetype can not handle this case, for the reasons I said above.

[hpoul]

@nigeltao i was wondering if anything changed in the last 3 years regarding colored emojis? :-) I was able to seamlessly draw back/white emojis, but color fonts (i tried the mentioned NotoColorEmoji) didn't draw anything - It seems there is a sfnt implementation which mentions something about a color glyth, but I couldn't quite find a useful example to draw strings 🤔️

[nigeltao]

Nothing's changed in the last 3 years. My previous comment stands:

If the former (which is what the OP bug report is about), then that's a lot more work. Supporting emoji fonts will take much more work than simply tweaking the accepted encodings. For one thing, the API would need to change to work with multi-color glyphs. Even so, as previously mentioned, there are three competing approaches, each needing significant new code:

As for golang.org/x/image/font/sfnt, it mentions color glyphs only to return an error to say it doesn't implement color glyphs:

// ErrColoredGlyph indicates that the requested glyph is not a monochrome
// vector glyph, such as a colored (bitmap or vector) emoji glyph.
ErrColoredGlyph = errors.New("sfnt: colored glyph")

[lishaoh]

@nigeltao @hpoul how to draw back/white emojis， I couldn't quite find a useful example , can you show me a useful example? thank you !

[hpoul]

@lishaoh I'm pretty clueless, but the best i could come up with was using github.com/AndreKR/multiface and just merging the text font rubik with the [noto emoji font]() (non color version) ..

createFont(fontPath string, emojiFontPath string, size float64)

```go func createFont(fontPath string, emojiFontPath string, size float64) (font.Face, error) { face := new(multiface.Face) opts := &truetype.Options{Size: size, DPI: 96} font1, err := readFont(fontPath) if err != nil { return nil, err } fc := truetype.NewFace(font1, opts) face.AddTruetypeFace(fc, font1) font2, err := readFont(emojiFontPath) if err != nil { return nil, err } fc = truetype.NewFace(font2, opts) face.AddTruetypeFace(fc, font2) return face, nil } ```

And then i used github.com/fogleman/gg to draw the string.. worked for me..

[lishaoh]

@hpoul thank you very much ! I try again

[lishaoh]

@hpoul hi ! I want to know did you define the readFont() function yourself?