Support loading TrueType fonts for use in Canvas objects

[ajstarks]

Is your feature request related to a problem? Please describe:

it would be useful to apply an arbitrary font to Text objects rendered on the fyne Canvas

Is it possible to construct a solution with the existing API?

No.

Describe the solution you'd like to see:

Add a field to the fyne/canvas.Text object that points to font resource. The default value can be the sans-serif font used by the current theme.

type Text struct {
    Alignment fyne.TextAlign // The alignment of the text content

    Color     color.Color    // The main text draw colour
    Text      string         // The string content of this Text
    TextSize  int            // Size of the text - if the Canvas scale is 1.0 this will be equivalent to point size
    TextStyle fyne.TextStyle // The style of the text content
    TextFont string          // font name -- points to TTF file in a magic place?
}

[andydotxyz]

I don't think we can rely on magic places, or even filesystem in general if this should work on mobile.
I would propose instead a TextFont fyne.Resource field which means it could be loaded from various different places and passed, already loaded, into the app? That way it could be (recommended?) bundled into the app binary.

It doesn't, however, have the usual font caching or fallback to the latin characters if a lookup fails... I guess that is OK for this purpose though, as the developer has full control over the font they load?

[ajstarks]

Yes, I agree the fyne.Resource is a better choice.

[andydotxyz]

I don't know exactly how this should be done - but as we review text handling in 2.0 it's a good time to discuss

[ajstarks]

Seems good to me

[dosgo]

Does it now support custom font size for widgets? Generally important information in the design may be different in font size and color. If the widget does not support separate font definition, then it cannot be used.

[andydotxyz]

Does it now support custom font size for widgets?

Widgets use the standard size and colours set by the theme. The canvas package provides complete flexibility over what you do as there is no semantic meaning to them.

Generally important information in the design may be different in font size and color.

I agree, but this is controlled by widget APIs, not customisation. For example the Title of a Card or Button.Importance = HighImportance allow this differentiation without breaking the concept of a semantic API styled by the current theme.

[andydotxyz]

Remember, if the standard widgets don't do what you want you can insert your own code or just canvas.Text element - you are not limited to the standard widgets, that is just an easy to use happy-path.

[dosgo]

Thank you very much. Canvas.NewText is really easy to use.