In the general case, it isn't possible for us to efficiently find system fonts that
are monospace. Fonts don't advertise being monospace frequently, so the only way to
reliably detect it is to check that all glyphs are the same width. This is expensive,
far too much so to be done on every system font when there may be thousands of them.
Other font resolution systems rely upon the user requesting fonts by their family name.
If you want a monospace font, ask for it by name or use a generic name like 'monospace'.
This will be Gio's approach from here on out.
Existing code relying upon setting Variant="Mono" should instead set Typeface="Go Mono"
(for the Go font) or specify another monospace typeface. The generic face "monospace"
will search for one of a set of known monospace fonts that may be available on the system.
Similarly, smallcaps isn't well advertised and users should rely on requesting all-smallcaps
fonts by typeface. To get the Go smallcaps font, use Typeface="Go Smallcaps".
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
This commit adds back support for loading font collections, which we
lost when switching to the harfbuzz-based shaper last January. In
addition, this commit takes advantage of our new font loading library's
metadata facilities to automatically construct text.FontFaces for all
fonts within a collection. This is significantly more ergonomic for
users, and can be used to load single fonts with automatic metadata
detection as well.
I've exposed a opentype.Face.Font() method that can be used to get the
font metadata for a given face as well, though you have to type assert to
see it:
var myFace text.Face
if asOpentype, ok := myFace.(opentype.Face); ok {
myFont := asOpentype.Font()
}
The one problem with this approach is that the font variant field always
be automatically populated. Mono font detection is supported, but
other variants like SmallCaps are more complicated and may need to be
expressed differently in the future (smallcaps is a feature that any font
file can have, not necessarily a separate font file). See this [0] upstream
issue for details.
Additionally, in order to avoid import cycles, I've moved the declarations
of font attributes to package font. You can fix your code automatically to
refer to the new definitions by running the following:
gofmt -w -r 'text.FontFace -> font.FontFace' .
gofmt -w -r 'text.Variant -> font.Variant' .
gofmt -w -r 'text.Style -> font.Style' .
gofmt -w -r 'text.Typeface -> font.Typeface' .
gofmt -w -r 'text.Font -> font.Font' .
gofmt -w -r 'text.Regular -> font.Regular' .
gofmt -w -r 'text.Italic -> font.Italic' .
gofmt -w -r 'text.Thin -> font.Thin' .
gofmt -w -r 'text.ExtraLight -> font.ExtraLight' .
gofmt -w -r 'text.Light -> font.Light' .
gofmt -w -r 'text.Normal -> font.Normal' .
gofmt -w -r 'text.Medium -> font.Medium' .
gofmt -w -r 'text.SemiBold -> font.SemiBold' .
gofmt -w -r 'text.Bold -> font.Bold' .
gofmt -w -r 'text.ExtraBold -> font.ExtraBold' .
gofmt -w -r 'text.Black -> font.Black' .
gofmt -w -r 'text.Hairline -> font.Thin' .
gofmt -w -r 'text.UltraLight -> font.ExtraLight' .
gofmt -w -r 'text.DemiBold -> font.SemiBold' .
gofmt -w -r 'text.UltraBold -> font.ExtraBold' .
gofmt -w -r 'text.Heavy -> font.Black' .
gofmt -w -r 'text.ExtraBlack -> font.Black+50' .
gofmt -w -r 'text.UltraBlack -> font.ExtraBlack' .
Make sure each affected file imports gioui.org/font.
[0] https://github.com/go-text/typesetting/issues/57
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
Before this change, package font implemented a global font registry,
with the usual problems of package global state.
This change deletes the global registry and introduces the text.Collection
type for representing a list of fonts and their faces. Collection exports
Lookup that finds the closest match and its face.
The existing FontRegistry is renamed to Cache to reflect its new limited
functionality: a cache of shapes and measurements on top of a Collection.
Then, material.NewTheme is changed to take a Collection and initialize
a Cache.
Updates gio#19 because multiple windows require a separate (writable) Cache per
window, while (read-only) Collections may be shared.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Package font holds a singleton text.Shaper for general use. Subpackages
call Register to add fonts to the registry.
The intention is that programs can add a typeface by importing a package:
import _ "gioui.org/font/gofont"
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Chris Waldon