typesetting introduced a cache field that needs to be
properly initialized. Use constructor to avoid the issue.
Signed-off-by: Egon Elbre <egonelbre@gmail.com>
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 updates the internal representation of a font to separate the
threadsafe and non-threadsafe operations in a way that enures font.Faces can
be shared by all text shapers in an application. This should ensure that applications
only need to parse fonts a single time, saving a great deal of memory for
applications that open many windows (which each need a different text shaper).
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>
This commit supports rendering opentype glyphs containing bitmap data instead of
color data. In order to support returning the shaped bitmap glyphs from the Shaper's
Shape() method, it has gained a second return parameter, an op.CallOp. Adding
that CallOp immediately after or immediately before painting the returned path
will display the bitmap glyphs.
The consequences of supporting colored glyphs forced changes upon the widget APIs
for widgets that display text. Previously text always had a fixed paint material,
so we could rely upon the caller setting the material (e.g. adding a paint.ColorOp)
before painting the glyphs and everything would work. Now that we display image-
based glyphs, we end up changing the painting material to an image midway through
displaying text. This is an awkward consequence of how we currently manage the
painting material, and to work around it widgets now accept an op.CallOp that
is expected to set the proper paint material. Text widgets will use that op.CallOp
before painting text (or other paint operations) to ensure that they are painting
with the proper materials.
This, in turn, changed the APIs for laying out widget.Editor, widget.Label, and
widget.Selectable, and eliminated the need for them to accept a callback (the
callback was only really to set the colors). Dropping that callback function
allowed me to consolidate widget.Label to only need one exported Layout method,
and allowed me to unexport the PaintText, PaintCaret, and PaintSelection methods
from widget.Editor and widget.Selectable. Those methods are useless in the public
API now that they don't need to be invoked after applying a color operation.
Callers of the raw text shaper API will need to make the following changes:
- Where before you used:
var ops *op.Ops // Assume we have an operation list.
var shaper *text.Shaper // Assume we have a shaper.
var col color.NRGBA // Assume we have a text color.
var glyphs []text.Glyph // Assume we have already filled a slice of glyphs.
shape := shaper.Shape(glyphs)
paint.FillShape(ops, col, clip.Outline{Path:shape}.Op())
- Now you should do:
shape, call := shaper.Shape(glyphs)
paint.FillShape(ops, col, clip.Outline{Path:shape}.Op())
call.Add(ops)
Callers of the widget.{Label,Selectable,Editor} APIs will need to make the
following changes:
- Where before you used:
var gtx layout.Context // Assume we have an operation list.
var shaper *text.Shaper // Assume we have a shaper.
var textCol color.NRGBA // Assume we have a text color.
var selectCol color.NRGBA // Assume we have a selection color.
var ed widget.Editor // Assume we have an editor.
var sel widget.Selectable // Assume we have a selectable.
// Lay out an editor.
ed.Layout(gtx, shaper, text.Font{}, unit.Sp(30), func(layout.Context) layout.Dimensions {
// Paint the editor.
})
// Lay out a selectable.
sel.Layout(gtx, shaper, text.Font{}, unit.Sp(30), func(layout.Context) layout.Dimensions {
// Paint the selectable.
})
// Lay out an interactive label.
widget.Label{}.LayoutSelectable(gtx, shaper, text.Font{}, unit.Sp(30), "hello", func(layout.Context) layout.Dimensions {
// Paint the label.
})
// Lay out a non-interactive label.
widget.Label{}.Layout(gtx, shaper, text.Font{}, unit.Sp(30), "hello")
- Now you should do:
// Capture setting the text paint material in a macro.
textColMacro := op.Record(gtx.Ops)
paint.ColorOp{Color: textCol}.Add(gtx.Ops)
textMaterial := textColMacro.Stop()
// Capture setting the selection paint material in a macro.
selectColMacro := op.Record(gtx.Ops)
paint.ColorOp{Color: selectCol}.Add(gtx.Ops)
selectMaterial := selectColMacro.Stop()
// Lay out an editor.
ed.Layout(gtx, shaper, text.Font{}, unit.Sp(30), textMaterial, selectMaterial)
// Lay out a selectable.
sel.Layout(gtx, shaper, text.Font{}, unit.Sp(30), textMaterial, selectMaterial)
// Lay out a label (no difference between interactive and non-interactive)
widget.Label{}.Layout(gtx, shaper, text.Font{}, unit.Sp(30), "hello", textMaterial, selectMaterial)
Callers of the material package API do not need to make any changes.
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
This commit upgrades our go-text version to the latest one which internalizes
harfbuzz and supports text truncators. This allows us to drop our dependency
upon Benoit's textlayout package.
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
This commit restructures the entire text shaping stack to enable lines of shaped text to
have non-homogeneous properties like which font face they belong to and which direction
a segment of text is going.
The text package now provides a concrete type text.Shaper which can be used to convert
strings into sequences of renderable text.Glyphs. At a high level, the API is used
like this:
// Prepare some fonts.
var collection []text.FontFace
// Make a shaper with those fonts loaded.
shaper := text.NewShaper(collection)
// Shape a string.
shaper.LayoutString(text.Parameters{
PxPerEm: fixed.I(12),
}, 0, 100, system.Locale{}, "Hello")
// Iterate the glyphs from that string.
for glyph, ok := shaper.NextGlyph(); ok; glyph, ok = shaper.NextGlyph() {
// Convert the glyph data into a path. In real uses, convert batches of glyphs
// rather than single glyphs to reduce the number of individual paths and offsets
// required to display your text.
shape := shaper.Shape([]text.Glyph{glyph})
// Offset the glyph to the position it declares within its fields. This will
// automatically handle correct bidirectional text glyph positioning.
offset := op.Offset(image.Pt(glyph.X.Floor(), int(glyph.Y))).Push(gtx.Ops)
// Create a clip area from the shape of the glyph.
area := clip.Outline{Path: shape}.Push(gtx.Ops)
// Paint whatever the current color is within the glyph's shape.
paint.PaintOp{}.Add(gtx.Ops)
area.Pop()
offset.Pop()
}
This API will transparently handle both font fallback (choosing appropriate fonts
from those loaded when the primary font doesn't contain a required glyph) and
bidirectional text (mixed left-to-right and right-to-left text). Glyphs are
iterated in order of the input runes, not their visual order, but proper use
of the provided offsets will ensure that text always displays correctly.
Thanks to Elias Naur for suggesting this glyph iterator strategy. It let us cut
through a lot of accumulated complexity from trying to match our old text APIs,
meaning that this change actually is a net negative change in lines of code.
This commit consumes the upstream github.com/go-text/typesetting/shaping API
now that my prior work is merged there, removing the need for the font/opentype/internal
package entirely.
As part of my efforts, I fuzzed both the low-level text shaping stack and the
editor widget extensively. I've committed regression tests found that way into
the appropriate testdata files to ensure the fuzzer re-checks them.
Fixes: https://todo.sr.ht/~eliasnaur/gio/425
Fixes: https://todo.sr.ht/~eliasnaur/gio/211
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
This commit replaces the previous opentype.Font with
an implementation that uses the new text shaper. In
order to keep the implementation simple, support for
opentype font collections was dropped. It should be
possible to re-add this support after some changes
to the text shaper's line wrapping algorithm.
To expand on the above, doing proper font fallback with
harfbuzz will require splitting the input text on font
glyph support boundaries, changing the input from a
simple shaping.Input to []shaping.Input with each input
matched against the font that supports its language.
The line wrapping then needs to be able to properly
consume that slice. Since the line wrapping algorithm is
really complex, I'm hoping to defer that modification
until this simple version is accepted.
References: https://todo.sr.ht/~eliasnaur/gio/146
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
This commit introduces a new text shaping infrastructure
powered by Benoit Kugler's Go source-port of harfbuzz.
This shaper can properly display complex scripts and RTL
text. This commit changes the signature of the text.Shaper
function, which is a breaking API change.
The new functionality is available via opentype.ParseHarfbuzz,
which configures a text.Shaper leveraging the new backend.
References: https://todo.sr.ht/~eliasnaur/gio/146
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
With this change, the Shape function returns a clip.PathSpec
instead of a clip.Outline op. It is then possible to create
a clip.Outline or clip.Stroke op to fill the text path or
draw its stroke.
Signed-off-by: Christophe Meessen <meessen@cppm.in2p3.fr>
This change avoids a macro wrapping every text shape, and prepares text
shaping for scoped clip operations.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
This CL introduces 2 new path builders:
- Outline which takes a PathSpec to be outlined
- Stroke which takes a PathSpec and a stroke style, to stroke a path.
typically, code like this:
var p clip.Path
...
p.Outline().Add(o)
should be replaced with:
var p clip.Path
...
clip.Outline{Path: p.End()}.Op().Add(o)
similarly, stroking should be modified from:
var p clip.Path
...
p.Stroke(width, clip.StrokeStyle{...}).Add(o)
to:
var p clip.Path
...
clip.Stroke{Path: p.End(), Style: clip.StrokeStyle{Width:...}}.Op().Add(o)
here are tentative 'rf' scripts (see rsc.io/rf for more details):
```
ex {
import "gioui.org/op";
import "gioui.org/op/clip";
var p clip.Path;
var o *op.Ops;
p.Outline().Add(o) -> clip.Outline{Path:p.End()}.Op().Add(o);
}
ex {
import "gioui.org/op";
import "gioui.org/op/clip";
var o *op.Ops;
var p clip.Path;
var sty clip.StrokeStyle;
var width float32;
p.Stroke(width, sty).Add(o) -> \
clip.Stroke{ \
Path:p.End(), \
Style: clip.StrokeStyle{ \
Width: width, \
}}.Op().Add(o);
}
```
Signed-off-by: Sebastien Binet <s@sbinet.org>
Commit https://gioui.org/commit/b331407e81456 added text layout and shaping
based on io.Reader and changed Editor to use it. Unfortunately, as ~inkeliz
discovered, caching of shapes were also lost.
~inkeliz suggested fix,
https://lists.sr.ht/~eliasnaur/gio-patches/patches/15059
adds caching of shapes to Editor to regain lost performance.
This change repairs the cache to work on io.Reader API, in hope that the
already complicated Editor won't need additional caching.
Before this change, text layouts were represented as a slice of (rune, advance)
pairs. Unfortunately, this representation doesn't lend itself to caching of
shaping results, so change the representation of a line of text to be a pair
of text and advances:
package text
type Layout {
Text string
Advances []fixed.Int26_6
}
The Text field can then be used in a cache key, assuming Advances is
consistent with it.
The end result is that the two shaper variants of text.Shaper is reduced to
just one, and the Len field field of text.Line is no longer needed.
The changed representation adds a bit of extra work to package opentype.
Cleaning that up is left as a future TODO.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
This change allows font collection files (extensions .ttc or .otc)
to be used as a text.Face. These files contain an ordered list of
SFNT fonts, each supporting a maximum of 2^16 glyphs. When used as
a text.Face, each rune in the string to layout or render will be
assigned to the first font with a glyph for that rune, or to the
replacement character from the first font in the file otherwise.
With this change, it is possible to support multiple unicode planes
in a single text.Face by using a Collection with more than one
internal SFNT file. For example, it is now possible to display
characters from the basic multilingual plane and emoji in a single
widget.Label by loading an appropriate OTC file.
Fixes gio#104
Signed-off-by: tainted-bit <sourcehut@taintedbit.com>
Implementations of text.Face are reused across multiple windows for efficiency.
Make the opentype implementation safe for concurrent use and document it.
Updates gio#104
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Converting
macro := op.Record(ops)
...
macro.Stop()
macro.Add()
to
macro := op.Record(ops)
...
call := macro.Stop()
call.Add(ops)
Which is more general (call.Add can take a different ops than the op.Record
that started it), and enforced the order between Stop and the subsequent Add.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
First, replace LayoutOptions with an explicit maximum width parameter. The
single-field option struct doesn't carry its weight, and I don't think we'll
see more global layout options in the future. Rather, I expect options to cover
spans of text or be part of a Font.
Second, replace the unit.Converter with an scaled text size. It's simpler and
allow the Editor and similar widgets to easily detect whether their cached
layouts are stale. Package text no longer depends on package unit, which is
now dealt with at the widget-level only.
Finally, remove the Size field from Font. It was a design mistake: a Font is
assumed to cover all sizes, as evidenced by the FontRegistry disregarding
Size when looking up fonts.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
In preparation for using Shaper with an io.Reader, rework the API to not refer
to strings. In particular, introduce Glyph for holding the rune in addition to
the advance. For fast traversing of the underlying text, add Len to Line with
the UTF8 length.
Layout is a useless wrapper around []Line; remove it while we're
here.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
MacroOp is about to lose the ability to run a different operation list
than the one it was recorded on. Text shape caches rely on that property,
and must use the new CallOp operation added for purpose.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Opentype parsing, layout and shaping will be used by subpackages to package
font. Move the opentype package accordingly.
Remove the Must helper function; programs will no longer use the opentype
package in the normal case.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Egon Elbre