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Widget not rendered on window scoll #47
Description
While scrolling on a window, widgets may disappear too early.
A simple example with a colored rectangle:
package main
import (
"image"
"image/color"
"github.com/ebitengine/debugui"
"github.com/hajimehoshi/ebiten/v2"
"github.com/hajimehoshi/ebiten/v2/vector"
)
type Game struct {
ui debugui.DebugUI
}
func (g *Game) Update() error {
_, err := g.ui.Update(func(ctx *debugui.Context) error {
ctx.Window("test", image.Rect(0, 0, 300, 300), func(layout debugui.ContainerLayout) {
ctx.Text("test")
ctx.SetGridLayout(nil, []int{150})
ctx.Loop(5, func(i int) {
ctx.GridCell(func(bounds image.Rectangle) {
ctx.DrawOnlyWidget(func(screen *ebiten.Image) {
col := color.RGBA{R: 255}
vector.FillRect(screen, float32(bounds.Min.X), float32(bounds.Min.Y), float32(bounds.Dx()), float32(bounds.Dy()), col, true)
})
})
})
})
return nil
})
return err
}
func (g *Game) Draw(screen *ebiten.Image) {
g.ui.Draw(screen)
}
func (g *Game) Layout(outsideWidth, outsideHeight int) (screenWidth, screenHeight int) {
return outsideWidth, outsideHeight
}
func main() {
err := ebiten.RunGame(&Game{})
if err != nil {
panic(err)
}
}
Activity
Vmarcelo49 commentedon Dec 29, 2025
The issue is that when DrawOnlyWidget is used inside GridCell, it creates a nested widget that uses the default 18px height instead of the GridCell's 150px height. During scrolling, only the first 18px are "rendered", causing the widget to disappear prematurely as soon as those pixels scroll out of view.
Vmarcelo49 commentedon Dec 29, 2025
I am trying to find a fix for this that does not change either functions signatures.
t-geindre commentedon Dec 30, 2025
I ran the same code with your pullrequest and it fixes the issue 👍
Just to be sure, as far as I understand the API, there is no other way to get the available rect when drawing a widget than putting it in a grid cell to get an
image.Rect?hajimehoshi commentedon Sep 26, 2026
Sorry for my terribly late reply. I'll take a look
debugui: fix DrawOnlyWidget rendering in scrolled grid cells
hajimehoshi commentedon Sep 26, 2026
Confirmed. I'll review the PR
debugui: fix DrawOnlyWidget rendering in scrolled grid cells
debugui: draw DrawOnlyWidget without culling by its layout item
debugui: draw DrawOnlyWidget without culling by its layout item
debugui: draw DrawOnlyWidget without culling by its layout item (#48)
hajimehoshi commentedon Sep 26, 2026
Use
a40c4af6cbb46b4a5df6d1070c2d7fcf6ebaff9auntil I release v0.3.1 a few days later. Thanks,