Commit Graph

404 Commits

Author SHA1 Message Date
Elias Naur c458eb30f0 widget/material: add missing Update calls
Without the updates, the switch and radiobutton would use stale state
for layout.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-12-05 10:40:45 -06:00
Egon Elbre f39245df99 layout: add Background
It's relatively common to create a widget and then add a background to
it. Using layout.Stack causes bunch of heap allocs, which we would like
to avoid whenever we can.

This adds layout.Background which is roughly the same as:

    layout.Stack{Alignment: layout.C}.Layout(gtx,
    	layout.Expanded(background),
    	layout.Stacked(widget)
    )

goos: windows
goarch: amd64
pkg: gioui.org/layout
cpu: AMD Ryzen Threadripper 2950X 16-Core Processor
     │    Stack     │             Background              │
     │    sec/op    │   sec/op     vs base                │
*-32   203.80n ± 1%   83.36n ± 3%  -59.09% (p=0.000 n=10)

     │   Stack    │             Background             │
     │    B/op    │   B/op     vs base                 │
*-32   48.00 ± 0%   0.00 ± 0%  -100.00% (p=0.000 n=10)

     │   Stack    │             Background              │
     │ allocs/op  │ allocs/op   vs base                 │
*-32   2.000 ± 0%   0.000 ± 0%  -100.00% (p=0.000 n=10)

Signed-off-by: Egon Elbre <egonelbre@gmail.com>
2023-11-25 11:50:25 -06:00
Chris Waldon c8801fe233 widget: test update-only editor logic
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-11-10 16:17:56 -05:00
Chris Waldon 3fde0c0061 widget: [API] split text widget Update from Layout
This commit introduces Update(gtx) functions for both Selectable and Editor, allowing their
state to be updated explicitly prior to layout. This completes the transition that allows all
Gio widgets to have their state updated ahead-of-time, ensuring that there is zero frame lag
between an input event and the widget response to that event.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-11-10 14:59:06 -05:00
Egon Elbre 48bd5952b1 widget: optimize processGlyph
processGlyph does not modify the value, so there's no reason to
return the struct.

Signed-off-by: Egon Elbre <egonelbre@gmail.com>
2023-11-09 15:18:46 -05:00
Egon Elbre df8a8789a3 text: [API] reduce size of Glyph.Runes to uint16
This shrinks text.Glyph from 72B to 58B.

  LabelStatic/1000runes-RTL-arabic-32   63.62µ ± 0%   62.05µ ± 0%  -2.47% (p=0.002 n=6)

Signed-off-by: Egon Elbre <egonelbre@gmail.com>
2023-11-09 15:18:46 -05:00
Larry Clapp ae2b1f42b2 widget: Update Selectable key filter
Selectable was using a key event filter copied directly from editor.go,
but it didn't actually process all those keys. Update the filter to only
ask for the keys that Selectable actually uses.

Signed-off-by: Larry Clapp <larry@theclapp.org>
2023-10-15 10:44:39 -04:00
Elias Naur 63fea3d2bd widget: use local random source to avoid deprecated rand.Seed
This change replace the global rand use with a local source, to avoid
the recently deprecated global rand.Seed function. At the same time, the
time-dependent seeds are replaced with static numbers to ensure
reproducible benchmarks numbers.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-10-14 15:45:58 -05:00
Elias Naur c756986d9e gesture: [API] rename gesture state update methods to Update
Change the gesture state update methods to align with the convention.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-10-08 12:37:12 -05:00
Elias Naur d42dae73f0 widget: [API] separate Float state update; remove min, max, invert parameters
This change allows users of Float to determine its state before Layout
by calling Update.

While here, remove the value transformation represented by the min, max,
invert parameters; they're too many arguments for a computation that
may as well be done by the user.

Remove Float.Pos; it is better to compute its value from the dimensions
returned by Float.Layout.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-10-06 20:04:32 -05:00
Elias Naur 23e44292bb widget: [API] separate state changes from Draggable.Layout to Update
Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-10-06 20:04:32 -05:00
Elias Naur fe85136f99 widget: [API] move Enum state update to Changed, rename it to Update
Similar to an earlier change for other widgets, this change separate
Enum state changes for access earlier than Layout.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-10-06 20:04:32 -05:00
Elias Naur b9837def5c widget: [API] move Decorations state update to Actions
Similar to a previous change for Clickable and Bool this change separates
state changes from Decorations.Layout to Actions so that access may
happen before Layout.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-10-06 20:04:13 -05:00
Elias Naur dc97871122 widget: [API] rename Bool.Changed to Update and move state update to it
Similar to a previous change for Clickable, this change separates Bool
state changes to its renamed method Update. This allows access to
the most recent state before calling Layout.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-10-06 20:03:25 -05:00
Elias Naur 4a4fe5a69b widget: [API] move Clickable state update from Layout to Clicks
Before this change, Clickable state updates would happen in Layout.
However, that is too late in cases where clicks affects layout that
contiains the Clickable.

This change removes state changes from Layout and moves them to Clicks,
to allow users pre-layout access. Note that Layout itself processes
events, which means users can no longer access clicks after Layout.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-10-06 20:03:22 -05:00
Elias Naur 1686874d07 gesture: [API] rename ClickType to ClickKind
"Kind" is the Go idiomatic name for distinguishing structs outside of
the type system.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-10-06 19:11:11 -05:00
Elias Naur 650ccea28d io/pointer: [API] rename PointerEvent.Type to Kind
Kind is the idiomatic field name for distinguishing a struct without
using separate types.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-10-06 19:11:08 -05:00
Elias Naur e1b3928819 io/semantic: [API] replace DisabledOp with EnabledOp
The double-negative DisabledOp is harder to understand than a
straightforward EnabledOp. Note that the absence of an EnabledOp
implies still means that the widget is enabled.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-10-06 18:08:52 -05:00
Veikko Sariola 290b5fe821 widget: click button only if key pressed and released
This commit fixes the non-intuitive behaviour, where hitting return or
space with a button focused, then tabbing to another button and
releasing the key causes the second button to trigger. It feels wrong,
as the "gesture" was never initiated on the second button. The fix makes
widget.Clickable track which key was pressed, in a variable called
pressedKey, and only considers a key release if the released key matches
the pressed key. Finally, if the widget loses focus, pressedKey is
cleared.

Fixes: https://todo.sr.ht/~eliasnaur/gio/525
Signed-off-by: Veikko Sariola <5684185+vsariola@users.noreply.github.com>
2023-08-22 09:07:48 -06:00
Chris Waldon edbf872b44 widget: fix label vertical glyph padding logic
We previously were not handling glyphs that extended vertically beyond the
ascent/descent declared by their font. This is done rarely with text fonts,
but is apparently common among symbol and emoji fonts.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-08-01 09:09:10 +02:00
Chris Waldon fdd102aaf9 widget: simplify and improve cursor position generation
This commit updates the strategy of our cursor positioning index to eliminate
cursor positions *after* trailing whitespace characters on a line. Eliminating
such cursor positions enables us to collapse trailing whitespace visually without
impacting the editability of text (this will be done in a future commit).

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-07-31 12:05:07 +02:00
Chris Waldon 8dc03ed655 text,widget: remove fractional line height
The previous logic kept the y offset of a line as a fractional value
until the last possible moment in an effort to be as true to a fractional
line height as possible (minimize the error), but this interacts pathologically
with multi-line text selections, as the selections may have visibly different
gaps between lines. It's better to always shift lines by a fixed quantity of
whole pixels, even if it is technically less accurate to the desired line height.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-07-31 12:03:18 +02:00
Chris Waldon ddf770b9d5 widget{,/material}: surface line height manipulation
This commit surfaces fields to manipulate the line height of all label and editor
types. It's unfortunate how this spreads through the API, but I don't see a good
way to eliminate that right now.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-07-19 10:05:33 +02:00
Chris Waldon acab582487 widget/material: allow configuring default typeface on theme
This commit introduces the material.Theme.Face field, which will automatically
populate the Font.Typeface in every text widget created using a constructor function
in package material.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-07-19 10:02:18 +02:00
Chris Waldon 43c47f0883 go.*,text,font{,/opentype},app,gpu,widget{,/material}: [API] load system fonts
This commit updates the text package to be able to load system fonts. As a consequence,
application authors may choose to provide no fonts manually, and it's
also possible that the system provides none (WASM, for instance, currently provides no
system fonts). As such, the text stack needed some minor tweaks to handle this case by
displaying blank spaces where text should be rather than crashing when no faces are
available.

Internally, we are dropping the old method of choosing faces and instead relying solely
on the new font matching logic in go-text. I chose to do this because maintaining two
different sets of logic with a hierarchical relationship proved to be really complex,
and also the go-text logic seems to produce higher-quality choices.

The breaking API change from this commit is the new way of constructing a text shaper
using text.ShaperOptions. Providing no options will result in a shaper that uses solely
system fonts. The various options can be used to disable system font loading and to
provide an already-parsed collection of fonts as per Gio's old API.

The material.NewTheme function now accepts no arguments instead of a font collection.
Users wanting to provide a collection can simply provide a new shaper configured how
they would like:

    theme := material.NewTheme()
	theme.Shaper = text.NewShaper(text.NoSystemFonts(), text.WithCollection(gofont.Regular()))

This commit touches many packages to fix up their construction of text shapers, mostly in
test code. The changes to the tests in package widget deserve special note:
Changing our font resolution logic caused the tofu characters within the
test strings to use a different font's tofu. This isn't a problem, but shifted
the layout of the shaped text a little bit. I've updated the numbers to expect
the new glyph positions.

Fixes: https://todo.sr.ht/~eliasnaur/gio/309
Fixes: https://todo.sr.ht/~eliasnaur/gio/184
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-07-19 10:01:51 +02:00
Chris Waldon 6ea4119a3c text,widget: [API] implement consistent, controllable line height
This commit ensures that any given paragraph of text shaped by Gio will use a single
internal line height. This line height is determined (by default) by the text size,
rather than the fonts involved. This is a breaking change, as previously we would
blindly use the largest line height of any font in a line for that line, leading to
lines within the same paragraph with extremely uneven spacing. This commit also
updates some test expectations in package widget.

I thought pretty hard about how to implement line spacing, and consulted a few sources:

[0] https://www.figma.com/blog/line-height-changes/
[1] https://practicaltypography.com/line-spacing.html
[2] https://developer.mozilla.org/en-US/docs/Web/CSS/line-height

There is no single, universal way to think about line spacing. Fonts internally specify
a line height as the sum of their ascent, descent, and gap, but the line height of two
fonts at the same pixel size (say 20 Sp) can vary wildy (especially across writing systems).
There are two strategies we could pursue to establish the line height of a paragraph of text:

- derive the line height from the fonts involved (our old behavior, and the behavior of
  many word processors)
- derive the line height from the requested text size provided by the user (the behavior of the
  web).

The challenge with the first option is that for a given piece of text in the UI, there can
be a silly number of fonts involved. If a label dispays user-generated content, the user can
put an emoji in it, and emoji fonts have different line heights from latin ones. This can cause
unexpected and nasty layout shift. Gio would previously do exactly this, on a line-by-line basis,
resulting in unevenly spaced lines within a paragraph depending on which fonts were used on
which lines. Choosing one of the fonts and enforcing its line height would make things consistent,
but it isn't clear how to choose that canonical font. There is no 1:1 mapping between the input
text.Font provided in the shaping parameters and a single font.Face. Instead, that mapping depends
upon the runes being shaped.

I think the only sane way to implement the first option would be to synthesize some text in the
provided system.Locale (mapping the language to a script and then generating a rune from that
script), shape that single rune, and then enforce the line height of the resulting face on the
entire paragraph. This would require doing a fair bit more work per paragraph than Gio does today,
so I've opted not to do it.

Instead, the second option allows us to choose a line height based on the size of the text that
the user wants to display. While this can potentially interact poorly with unusually tall fonts,
it means that text will always have a consistent line height.

I've provided two knobs to control line height:

- text.Parameters.LineHeight lets you set a specific height in pixels with a default value of
  text.Parameters.PxPerEm.
- text.Parameters.LineHeightScale applies a scaling factor to the LineHeight, allowing you to
  easily space out text without hard-coding a specific pixel size. The default value here
  (drawn from the recommendations of [1]) is 1.2, which looks pretty good across many fonts.

I've chosen this two-value API because many users will want to set one or the other value. I
considered instead a single value field and a "mode" that would specify how it was used, but
that felt uglier. Also, you *can* set both of these two fields and get predictable results.

I'd like to revisit using the line height of the chosen fonts in the future, but it seems a
little too complex to be worthwhile right now. An interesting option would be making the
select-a-face-using-locale strategy described above an opt-in feature, though some users
might instead want to just use the tallest line height among fonts in use. Something like
this Android API might be appropriate:

[3] https://learn.microsoft.com/en-us/dotnet/api/android.widget.textview.fallbacklinespacing?view=xamarin-android-sdk-13

I'd like to thank Dominik Honnef for some good discussion around this feature, and for pointing
me to some good sources on the subject.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-07-17 22:33:02 +02:00
Chris Waldon cc2d2c0abf widget/material: use offsetlast in scroll position calculations
This commit updates the logic that computes scroll viewport coordinates to correctly
consume layout.Position.OffsetLast, which was previously ignored. The impact of ignoring
that field was that dragging on a scroll indicator could sometimes fail to reach the
end of the list.

I've updated the logic to consume that field, which increased the amount of visual
jitter in the position of the scrollbar. I then also added a mechanism for smoothing
the jitter by using both methods of deriving the viewport and synthesizing a viewport
from both.

This new strategy exhibits a lower standard deviation than the other options on each of:

- the length of the scroll indicator
- the change in the start coordinate of the viewport when scrolling smoothly
- the change in the end coordinate of the viewport when scrolling smoothly

Fixes: https://todo.sr.ht/~eliasnaur/gio/504
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-07-01 09:05:06 +02:00
Chris Waldon 90e57c2b18 widget: add method to acquire label shaping metadata
There are many times when an application wants to know metadata about shaped text without
allocating a stateful text widget such as widget.Selectable. This commit introduces widget.TextInfo
and adds an extra LayoutDetailed method to widget.Label returning this struct. Currently
the struct only provides the information necessary to determine whether the text was truncated
(useful for deciding whether a tooltip makes sense), but it can be expanded to include text metrics
in the future for applications which require those.

In the future other text widgets may surface methods of acquiring widget.TextInfos, but the critical
gap in the API is that we can't currently determine whether a stateless label was truncated, so
I'm starting here.

I considered making Label.Layout() always return this, but I didn't want to introduce a breaking
API change yet. I have some other thoughts I want to explore about the label API which might
trigger breaking changes (moving parameters into fields).

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-06-19 16:17:10 +02:00
Chris Waldon c6e4eecf21 go.*,text,widget{,/material}: enable configurable line wrapping within words
This commit enables consumers of the text shaper to select a policy for how
line breaking candidates will be chosen. The new default policy can break lines
within "words" (UAX#14 segments) when words do not fit by themselves on a line.
This ensures that text does not horizontally overflow its bounding box unless
the available width is insufficient to display a single UAX#29 grapheme cluster.

Fixes: https://todo.sr.ht/~eliasnaur/gio/467
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-06-07 16:41:14 -06:00
Elias Naur a252394356 widget: update Editor.Delete documentation to refer to graphemes
Signed-off-by: Elias Naur <mail@eliasnaur.com>
2023-06-07 11:29:36 -06:00
Chris Waldon 816bda7ac7 widget: update textIterator docs for accuracy
The previous docs claimed that failing to set a textMaterial would result in
invisible glyphs when in reality it results in using whatever the current paint
material is. This could be the paint material from before laying out the glyphs,
or it could be the material for a bitmap glyph. As such, it's better to say that
the color is undefined.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-04-27 07:34:31 -06:00
Chris Waldon a7c9ca99f3 widget/material: make ScrollBarStyle.MajorMinLen default to FingerSize
Egon pointed out that the current default is unusable on touch screens in Slack, so this
change should hopefully ensure the indicator is interactable on touch devices.

I considered expanding the minor axis dimensions as well, but I don't know what value to
use. The 38DP default would be enormous on non-mobile displays if we made that the default
width.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-04-18 16:40:39 -06:00
Chris Waldon f77bf9a42c font/opentype: [API] support font collection loading
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>
2023-04-18 16:22:48 -06:00
Chris Waldon 73787b8478 text,widget: minimize loss of positional precision in shaping
This commit combs through the logic of computing glyph sizes and positions,
attempting to remove all unnecessary rounding and truncation. This is in
an effort to help text display consistently when different-length strings
are displayed near one another.

The specific problem prompting this change was end-aligned text stacked in
rows with a common suffix. If the rows displayed different values, they
would shape such that those final glyphs were at different fractional x
coordinates, and then they would be aligned with rounding that could display
them at different x positions in spite of the fact that both suffixes are
the same glyphs.

By removing rounding from Alignment.Align, the largest problem is fixed, but
I'm also removing other unnecessary loss of precision that can circumstantially
contribute to this sort of visual issue.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-04-05 11:32:35 -06:00
Chris Waldon e768fe347a widget/material: export LabelStyle.Shaper and document fields
We panic when someone constructs a literal LabelStyle because they cannot possibly
populate the shaper field. The resulting error is cryptic, and unusual within Gio
because most style types are safe to construct literally. This commit enables
creating literal LabelStyles by exporting the Shaper field, and also documents
the purposes of all of the fields.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-04-01 07:50:47 -06:00
Chris Waldon 7e8c10927b text,widget{,/material}: [API] move all shaping parameters into text.Parameters
This commit moves the min/max width of shaped text and the text's Locale into
text.Parameters. They were previously passed as separate function parameters to
the shaper, but this made little sense and added visual noise. This is a breaking
change, but only if you previously invoked the shaping API directly.

Callers of text.(*Shaper).LayoutString should change:

    shaper.LayoutString(params, minWidth, maxWidth, locale, "string")

to

    params.MinWidth=minWidth
    params.MaxWidth=maxWidth
    params.Locale=locale
    shaper.LayoutString(params, "string")

Callers of text.(*Shaper).Layout should do likewise.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-03-28 09:25:35 -06:00
Chris Waldon 9d0a53fc9f widget{,/material}: [API] split interactive and non-interactive text widgets
This commit separates the types for interactive and non-interactive text within
package widget. widget.Selectable is used for all interactive text. widget.Label
is used for all non-interactive text. There is no longer a field on widget.Label
to provide it with a Selectable. If you want selectable text and are not relying
upon the material pacakge API, you need to create widget.Selectables instead of
widget.Labels. The material package's LabelStyle API is unchanged.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-03-28 09:25:33 -06:00
Chris Waldon 5e6e1217da widget: expose truncation status of Selectable
This commit adds an exported method to enable widgets to detect
when the text displayed by a Selectable has been truncated. This
can be used to implement proper show-full-text-in-an-overlay
behavior in a parent widget. I haven't attempted to implement
that in core yet, as it is a complex feature involving animation
and pointer interaction.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-03-28 09:25:31 -06:00
Chris Waldon 959f5889a1 go.*,text,widget{,/material}: implement text truncators
This commit adds support for the idea of a text "Truncator", a string
that is shown at the end of truncated text to indicate that it has been
shortened because it would not fit within the requested number of lines.

When specifying a maximum number of lines, a truncator symbol is always
used. If the user does not provide one, the rune `…` is used. This
requirement results in a better user experience and significantly simpler
code, as we can rely upon the presence of one or more truncator glyphs in
the output glyph stream when truncation has occurred.

When interacting with truncated text, the truncator glyphs all act as
a single, indivisible unit. They can be selected or not, and if selected
they act as the entire contents of the truncated portion of the text.
This means that copying all of a truncated label will copy the entire
label text content, with the truncator symbol not appearing at all.

Concretely, the exposed text API now accepts a Truncator string in
text.Parameters, and there is a new glyph flag FlagTruncator which indicates
that the glyph is part of the truncator run. The truncator run will only
have a single FlagClusterBreak (even if the run would usually have many),
and the glyph with both FlagClusterBreak and FlagTruncator will have the
quantity of truncated runes in its Runes field. This necessitated increasing
the size of the Runes field from a byte to an int, as it's theoretically possible
for quite a lot of text to be truncated.

This commit necessarily bumps our go-text/typesetting dependency to the version
exposing truncation in the exported API.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-03-28 09:25:28 -06:00
Chris Waldon 5c54268d40 widget: [API] implement UAX#29 grapheme clustering in text widgets
This commit teaches the text widgets how to position their cursor according to
grapheme cluster boundaries rather than rune boundaries. While this is more work,
the results better match the expectations of users. A "grapheme cluster" is a
user-perceived character that may be composed of arbitrarily many runes.

I chose to implement this within widgets for two reasons:

- grapheme cluster boundaries would be extremely difficult to encode within the
glyph stream returned by the text shaper
- not all text needs to be segmented, only text that can be interacted with

All mutation operations exposed by widget.Editor now work in terms of grapheme
clusters instead of runes.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-03-28 09:25:25 -06:00
Chris Waldon 36e768e716 widget: make glyphIndex reusable
This commit allows the glyph index type to be reset and reused, preventing the
reallocation of numerous buffers when indexing glyphs.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-03-28 09:25:24 -06:00
Chris Waldon 3bdbcab874 go.*,widget: add initial emoji rendering benchmarks
This commit upgrades our version of eliasnaur.com/font to include a color
emoji font and uses that to benchmark displaying large quantities of emoji.
As expected, this is very slow when the strings change frequently, and uses
silly amounts of memory. Future commits will work to improve this.

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-03-28 09:25:18 -06:00
Chris Waldon 6ab3ff40a6 font/opentype,text,widget{,/material}: [API] support bitmap glyph rendering
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>
2023-03-28 09:25:15 -06:00
Dominik Honnef 51b11486c5 widget: [API] correct default scaling of images
When no scale factor is set, scale by 1.0, mapping one image pixel to
one device-independent pixel. This matches the behavior of CSS and other
frameworks.

The old code attempted to convert to Dp while taking the image's DPI
into account. This was wrong in two ways:

- It assumed that the default display DPI is 160, but this is only true
  for Android. Other platforms use 96, 162, or leave it undefined. Thus
  image.Layout's idea of a dp didn't match that of Gio on most
  platforms.

- It tried to account for image DPI, and assumed a default of 72. This
  was wrong in that DPI in images is merely metadata meant for printing,
  not display. The vast majority of software such as image viewers and
  image editors do not take DPI into account, mapping one image pixel
  either to one physical pixel or to one device-independent pixel. That
  is, users would expect their images to either display 1 to 1, or scaled
  based on PxPerDp, but not scaled based on the image's DPI.

We default to a scale of 1 to stay consistent with other parts of Gio
that scale by default. Users who don't want any scaling can continue to
set the scale to the inverse of PxPerDp.

While we're here we clarify the documentation of the Scale field.

This change is backwards incompatible for users that relied on the
default scale.

Signed-off-by: Dominik Honnef <dominik@honnef.co>
2023-03-23 17:06:43 -06:00
Chris Waldon b09ef80d9f widget: ensure proper modifiers on key events
This commit extends the key event handling for text widgets to always check for
appropriate modifier keys. Previously this wasn't necessary, as the text widgets
would only ever receive key events it registered for, but now it may be the top-level
key event handler and thus receive all key events that aren't handled elsewhere.

Fixes: https://todo.sr.ht/~eliasnaur/gio/487
Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
2023-03-23 16:57:52 -06:00
Serhat Sevki Dincer 35a8231963 text,widget: remove ineffective assignments
Signed-off-by: Serhat Sevki Dincer <jfcgauss@gmail.com>
2023-03-23 16:37:46 -06:00
Dominik Honnef 5f818bc5e7 widget/material: use more efficient way of scrolling lists
Signed-off-by: Dominik Honnef <dominik@honnef.co>
2023-02-23 18:43:50 -06:00
Gordon Klaus db6b4de0f7 widget/material: [API] move widget.Float.{Axis,Invert} into material.SliderStyle
Signed-off-by: Gordon Klaus <gordon.klaus@gmail.com>
2023-01-27 21:04:32 -06:00
Gordon Klaus 22aa00f476 widget/material: add Float.Invert
Setting Float.Invert=true not only inverts the order of values (which was already easily done by swapping min and max), it also draws the widget inverted so that the track is darkened on the opposite side from usual.

This patch also fixes a bug wherein a vertical slider was drawn inverted by default.

Signed-off-by: Gordon Klaus <gordon.klaus@gmail.com>
2023-01-27 21:04:01 -06:00
Larry Clapp e0cf570339 widget: add a Focus() method to widget.Clickable
Signed-off-by: Larry Clapp <larry@theclapp.org>
2023-01-18 16:28:18 -06:00