fix(bar): wait for both the new scale and the new width before rebuilding the renderer

commit: 9a0b0c56ad2ea9680125aea77e9459ca4a880bfa
author: brice · 17d ago · 2026-10-05 15:10 UTC
parent: 5b114e9
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

1 file · +33 -6

M internal/bar/bar.go +33 -6


@@ -17,6 +17,7 @@ import (
17	17		"path/filepath"
18	18		"strings"
19	19		"syscall"
	20	+	"time"
20	21
21	22		"github.com/bnema/neferclient"
22	23

@@ -78,9 +79,16 @@ type Bar struct {
78	79		modCh chan struct{}
79	80		cfgPath string
80	81		cfgCh chan config.Config
81		-	Stats Stats
82		-	fatal error
83		-	closed bool
	82	+
	83	+	// settling is true between a scale or size change and the moment both the
	84	+	// new scale and the new logical width have arrived. They come as separate
	85	+	// events, in either order; building a renderer from half of them presents a
	86	+	// buffer of the wrong size, and some compositors keep that size.
	87	+	settling bool
	88	+	settleC <-chan time.Time
	89	+	Stats Stats
	90	+	fatal error
	91	+	closed bool
84	92		}
85	93
86	94		// New builds a bar from a validated config.

@@ -232,6 +240,9 @@ func (b *Bar) Run(ctx context.Context) (err error) {
232	240		b.Stats.ModuleWake++
233	241		case next := <-b.cfgCh:
234	242		b.applyConfig(next)
	243	+	case <-b.settleC:
	244	+	b.settleC, b.settling = nil, false
	245	+	b.reconcile()
235	246		}
236	247		if b.fatal != nil {
237	248		return b.fatal

@@ -315,7 +326,7 @@ func (b *Bar) step() error {
315	326		}
316	327
317	328		func (b *Bar) draw() error {
318		-	if !b.dirty \|\| !b.canPresent \|\| b.rend == nil {
	329	+	if !b.dirty \|\| !b.canPresent \|\| b.rend == nil \|\| b.settling {
319	330		return nil
320	331		}
321	332		ok, err := b.rend.Draw(b.lay.Compose(), b.bg, &b.frame)

@@ -506,6 +517,22 @@ func (b *Bar) shutdown() error {
506	517		return errors.Join(errs...)
507	518		}
508	519
	520	+	// settleDelay is how long the bar waits for the second half of a scale or size
	521	+	// change before it rebuilds.
	522	+	const settleDelay = 60 * time.Millisecond
	523	+
	524	+	// geometryChanged is called when the compositor reports a new scale or size.
	525	+	// The first report builds at once, because there is nothing on screen yet.
	526	+	// Later ones wait for the dust to settle, and nothing is drawn meanwhile.
	527	+	func (b *Bar) geometryChanged() {
	528	+	if b.rend == nil {
	529	+	b.reconcile()
	530	+	return
	531	+	}
	532	+	b.settling = true
	533	+	b.settleC = time.After(settleDelay)
	534	+	}
	535	+
509	536		// Handler methods. Events of a replaced surface are ignored.
510	537
511	538		// Configure marks the surface presentable and rebuilds as needed.

@@ -517,13 +544,13 @@ func (b *Bar) Configure(id neferclient.SurfaceID, _, _ int32) {
517	544		b.canPresent = true
518	545		}
519	546		b.configured = true
520		-	b.reconcile()
	547	+	b.geometryChanged()
521	548		}
522	549
523	550		// Scale follows the monitor's preferred scale.
524	551		func (b *Bar) Scale(id neferclient.SurfaceID, _ float64) {
525	552		if id == b.sid {
526		-	b.reconcile()
	553	+	b.geometryChanged()
527	554		}
528	555		}
529	556


@@ -17,6 +17,7 @@ import (
17		"path/filepath"	17		"path/filepath"
18		"strings"	18		"strings"
19		"syscall"	19		"syscall"
			20	+	"time"
20			21
21		"github.com/bnema/neferclient"	22		"github.com/bnema/neferclient"
22			23

@@ -78,9 +79,16 @@ type Bar struct {
78		modCh chan struct{}	79		modCh chan struct{}
79		cfgPath string	80		cfgPath string
80		cfgCh chan config.Config	81		cfgCh chan config.Config
81	-	Stats Stats	82	+
82	-	fatal error	83	+	// settling is true between a scale or size change and the moment both the
83	-	closed bool	84	+	// new scale and the new logical width have arrived. They come as separate
			85	+	// events, in either order; building a renderer from half of them presents a
			86	+	// buffer of the wrong size, and some compositors keep that size.
			87	+	settling bool
			88	+	settleC <-chan time.Time
			89	+	Stats Stats
			90	+	fatal error
			91	+	closed bool
84		}	92		}
85			93
86		// New builds a bar from a validated config.	94		// New builds a bar from a validated config.

@@ -232,6 +240,9 @@ func (b *Bar) Run(ctx context.Context) (err error) {
232		b.Stats.ModuleWake++	240		b.Stats.ModuleWake++
233		case next := <-b.cfgCh:	241		case next := <-b.cfgCh:
234		b.applyConfig(next)	242		b.applyConfig(next)
			243	+	case <-b.settleC:
			244	+	b.settleC, b.settling = nil, false
			245	+	b.reconcile()
235		}	246		}
236		if b.fatal != nil {	247		if b.fatal != nil {
237		return b.fatal	248		return b.fatal

@@ -315,7 +326,7 @@ func (b *Bar) step() error {
315		}	326		}
316			327
317		func (b *Bar) draw() error {	328		func (b *Bar) draw() error {
318	-	if !b.dirty \|\| !b.canPresent \|\| b.rend == nil {	329	+	if !b.dirty \|\| !b.canPresent \|\| b.rend == nil \|\| b.settling {
319		return nil	330		return nil
320		}	331		}
321		ok, err := b.rend.Draw(b.lay.Compose(), b.bg, &b.frame)	332		ok, err := b.rend.Draw(b.lay.Compose(), b.bg, &b.frame)

@@ -506,6 +517,22 @@ func (b *Bar) shutdown() error {
506		return errors.Join(errs...)	517		return errors.Join(errs...)
507		}	518		}
508			519
			520	+	// settleDelay is how long the bar waits for the second half of a scale or size
			521	+	// change before it rebuilds.
			522	+	const settleDelay = 60 * time.Millisecond
			523	+
			524	+	// geometryChanged is called when the compositor reports a new scale or size.
			525	+	// The first report builds at once, because there is nothing on screen yet.
			526	+	// Later ones wait for the dust to settle, and nothing is drawn meanwhile.
			527	+	func (b *Bar) geometryChanged() {
			528	+	if b.rend == nil {
			529	+	b.reconcile()
			530	+	return
			531	+	}
			532	+	b.settling = true
			533	+	b.settleC = time.After(settleDelay)
			534	+	}
			535	+
509		// Handler methods. Events of a replaced surface are ignored.	536		// Handler methods. Events of a replaced surface are ignored.
510			537
511		// Configure marks the surface presentable and rebuilds as needed.	538		// Configure marks the surface presentable and rebuilds as needed.

@@ -517,13 +544,13 @@ func (b *Bar) Configure(id neferclient.SurfaceID, _, _ int32) {
517		b.canPresent = true	544		b.canPresent = true
518		}	545		}
519		b.configured = true	546		b.configured = true
520	-	b.reconcile()	547	+	b.geometryChanged()
521		}	548		}
522			549
523		// Scale follows the monitor's preferred scale.	550		// Scale follows the monitor's preferred scale.
524		func (b *Bar) Scale(id neferclient.SurfaceID, _ float64) {	551		func (b *Bar) Scale(id neferclient.SurfaceID, _ float64) {
525		if id == b.sid {	552		if id == b.sid {
526	-	b.reconcile()	553	+	b.geometryChanged()
527		}	554		}
528		}	555		}
529			556