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 rebuilds the editor and label types on the common
foundation provided by textView. This enables labels to have
optional state that makes them selectable, and allows the
two widgets to share the code for managing cursor positions,
displaying selections, and soforth. Labels now have an additional
Layout function which can be invoked if they have a Selectable.
It accepts a layout.Widget used to paint their contents. Stateless
labels should still use the old Layout method.
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
This commit provides a new ReadOnly boolean on the editor. If set, the
editor functions as a selectable label. User interaction cannot change
the contents of the editor (though application code can still use the
API).
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
This commit extends the editor to keep track of its own minimum constraint
and to provide that value to the text shaper for the purpose of aligning
text. Without this, the shaper does not know how much of the width of the
editor to use for alignment purposes.
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 fixes the expectations of our ligature iteration tests to
match the new behavior of the text position iterator. Now the cursor
can reach the position after the final glyph on a line, if that glyph
is not a newline.
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
Before this change, an IME text edit would always have its newlines
replaced with spaces. However, for Editors where Submit is enabled
we want newlines to result in SubmitEvents.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
This commit adds a simple linear-history undo/redo mechanism to
widget.Editor bound to Short-(Shift)-Z as well as tests for this
new feature.
Notes on the implementation:
- using a slice to hold the history does mean that we incur
allocations as the user types, but I hope that the Go slice
growth heuristic means that the number of times we pay this
penalty is very small. We also never shrink the slice in this
implementation, which ensures that undoing work and then making
additional modifications is very efficient, but could be framed
as a memory leak.
- this implementation creates a new history element every time
we call replace(). This means that, on desktop, it's essentially
one per rune of input. Users likely want to be able to undo larger
units of change, so a future improvement could be to coalesce
changes so long as the selection doesn't change between them.
- I think it's possible to store only one of the Apply/Reverse
change contents in the history slice, but it's significantly
more complicated. To implement this, you'd need to add a field
indicating if the modification represented a forward or backward
change, and then rewrite the modification's content as you performed
undo/redo operations.For the time being, I'm not sure it's worth
this complexity.
- Future work could introduce a limit to the number of history
entries stored. If we did this, we should also change the
data structure for storing history. Enforcing such a limit
using a simple slice like this would be extremely inefficient.
Perhaps a ring buffer or a linked list would make more sense?
- Applications will likely want to be able to manipulate undo
history in the future. We may wish to export undo() and redo()
from the editor. Applications will also likely want a mechanism
to save the undo history to disk and restore it (implementing
persistent undo). I'm not sure what the most suitable API for
that is yet, so I decided not to try to tackle it yet.
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
The unit.Value is a struct and thus more inconvenient to use than its
underlying float32 type. In addition, most uses don't need a general
value, but rather a specific unit given by the context. This change
replaces unit.Value with two float32 units, Dp and Sp. It also changes
variables and parameters of unit.Value to a specific unit type matching
the context. That is, unit.Dp everywhere except for text sizes which are
in Sp.
Switching to typed float32s has multiple advantages
- They can be constants:
const touchSlop = unit.Dp(16)
- Casting untyped constants is no longer necessary:
insets := layout.UniformInset(16)
- Calculation with values is natural:
func (s ScrollbarStyle) Width() unit.Dp {
return s.Indicator.MinorWidth + s.Track.MinorPadding + s.Track.MinorPadding
}
The main API change is that calls to gtx.Px must be replaced with either
gtx.Dp or gtx.Sp depending on the unit.
Idea by Christophe Meessen.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Prior to this change an editor with no content and a zero minimum
constraint would return itself has having width zero. This
prevented users from being able to see the editor when they
moved focus to it, as it could not display its caret. This
simple change ensures that, at minimum, the editor returns
its dimensions to include the width of a caret.
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
This commit switches gofont.Collection from returning
a collection of fonts using the old text shaper to
using the new harfbuzz-based shaper. The underlying type
of gofont.Collection() has changed, which may break users
who dug into the font data.
References: https://todo.sr.ht/~eliasnaur/gio/146
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
These fields are no longer needed with the new text shaper.
Advances is redundant to the glyph information, and Text
should never be used during layout, as you should
traverse the cluster list instead. This commit also removed
the now-unused string field from the path LRU cache key.
References: https://todo.sr.ht/~eliasnaur/gio/146
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 updates material.Editor and material.Label to support the
new text shaper. This requires breaking their assumption that glyphs
of font data map 1:1 to runes of text data.
References: https://todo.sr.ht/~eliasnaur/gio/146
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
This commit adds a check that caret coordinates never exceed
the max constraints of the editor.
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
We'd like to re-use the Editor.closestPosition seeking for
segmentIterator.Next; this change extracts the state-less logic
into functions.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
This commit adds a testcase to catch unexpected panics in the
editor's scroll offset logic introduced by using different
setting combinations that affect editor layout. It also fixes
a panic for single-line editors with alignments other than
text.Start.
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
This commit ensures that the edit buffer used by widget.Editor
does not get EOF when trying to read zero bytes from the
underlying buffer, which eliminates a panic when calling
Editor.SelectedText().
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
This change uncovered and fixes a bug in nullLayout.
This is an API change; the methods operated in bytes before.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Needed for efficient implementation of the upcoming IME interface.
Also introduce Editor.replace, seek methods for easier caret navigation
and editing.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
When there were non ASCII characters (for exemple éèàçîï) in a deleted
selection or word, more characters were deleted because there was a
mismatch between runes and bytes in Delete and deleteWord
Fixes: https://todo.sr.ht/~eliasnaur/gio/330
Signed-off-by: Fabien Jansem <fabien@jansem.eu.org>
To make the semantic relation between the editor and its content clear,
the editor clip operation must cover the content. This change adds an
explicit widget argument to editor, and lays it out inside the clip
rect.
This is an API change. Users of Editor.Layout must provide a content
widget.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
For example, ButtonLeft may be the right-most button for a left-handed user.
Rename the button names to match their intended use.
This is an API change. Use the following commands to update your
projects:
$ gofmt -r 'pointer.ButtonLeft -> pointer.ButtonPrimary' -w .
$ gofmt -r 'pointer.ButtonRight -> pointer.ButtonSecondary' -w .
$ gofmt -r 'pointer.ButtonMiddle -> pointer.ButtonTertiary' -w .
Signed-off-by: Elias Naur <mail@eliasnaur.com>
If you created an Editor and immediately SetCaret, it panicked because
e.lines was nil and it looked at e.lines[0].
- Add e.makeValid at the top of SetCaret.
- Add a test case for this situation.
Signed-off-by: Larry Clapp <larry@theclapp.org>
- Allow dragging to be on both horizontal and vertical axes at once.
- Split Editor.caret.pos into caret.start and caret.stop. caret.start is
the old caret.pos, and is both the position of the caret, and also the
start of selected text. caret.end is the end of the selected text.
Start can be after end, e.g. after after Shift-DownArrow.
- Update caret.end after a mouse drag, and various shifted keys
(Shift-UpArrow, Shift-DownArrow, etc).
- Change Shortcut-C to copy only the selected text, not the whole editor
text.
- Add Shortcut-X to copy and delete selected text, and Shortcut-A to
select all text.
- The various Insert/Delete/etc functions now overwrite or delete the
selection, as appropriate.
- Change MoveCaret to accept a distance for selection end, as well.
Change SetCaret to accept a selection end offset.
- Add SelectionLen to get the selection length, Selection to get
selection offsets, SelectedText to get the selected text, and
ClearSelection to clear the selection.
- Add a rudimentary selection unit test, and extend the deleteWord unit
test with some text selection cases.
- Add SelectionColor to material.EditorStyle, which defaults to
Theme.Palette.ContrastBg.
Signed-off-by: Larry Clapp <larry@theclapp.org>
- Move caret from editBuffer.caret to Editor.caret.pos.ofs and related
refactoring. Move other fields in Editor.caret into Editor.caret.pos.
- Refactor several functions to change a position passed into them,
rather than changing e.rr.caret directly.
- Add editBuffer.Seek().
- Remove editBuffer.dump().
- Change Editor.Move to MoveCaret.
- Add Editor.SetCaret.
- Updated tests.
Signed-off-by: Larry Clapp <larry@theclapp.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 adds optional password masking to the Editor. To enable
this feature, set the new Mask field to a non-zero rune. Every rune
in the Editor's contents will be replaced by the mask rune in the
visual display, except for newlines. The actual contents of the
editor can still be accessed with Len, Text, and SetText.
Fixes gio#80
Signed-off-by: tainted-bit <sourcehut@taintedbit.com>
Chris Waldon