forked from google/gxui
/
scroll_layout.go
155 lines (130 loc) · 3.96 KB
/
scroll_layout.go
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// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package mixins
import (
"github.com/google/gxui"
"github.com/google/gxui/math"
"github.com/google/gxui/mixins/base"
"github.com/google/gxui/mixins/parts"
)
type ScrollLayoutOuter interface {
base.ContainerOuter
}
type ScrollLayout struct {
base.Container
parts.BackgroundBorderPainter
outer ScrollLayoutOuter
theme gxui.Theme
child gxui.Control
scrollOffset math.Point
canScrollX, canScrollY bool
scrollBarX, scrollBarY gxui.ScrollBar
innerSize math.Size
}
func (l *ScrollLayout) Init(outer ScrollLayoutOuter, theme gxui.Theme) {
l.Container.Init(outer, theme)
l.BackgroundBorderPainter.Init(outer)
l.outer = outer
l.theme = theme
l.canScrollX = true
l.canScrollY = true
l.scrollBarX = theme.CreateScrollBar()
l.scrollBarX.SetOrientation(gxui.Horizontal)
l.scrollBarX.OnScroll(func(from, to int) { l.SetScrollOffset(math.Point{X: from, Y: l.scrollOffset.Y}) })
l.scrollBarY = theme.CreateScrollBar()
l.scrollBarY.SetOrientation(gxui.Vertical)
l.scrollBarY.OnScroll(func(from, to int) { l.SetScrollOffset(math.Point{X: l.scrollOffset.X, Y: from}) })
l.AddChild(l.scrollBarX)
l.AddChild(l.scrollBarY)
l.SetMouseEventTarget(true)
// Interface compliance test
_ = gxui.ScrollLayout(l)
}
func (l *ScrollLayout) LayoutChildren() {
s := l.outer.Bounds().Size().Contract(l.Padding())
o := l.Padding().LT()
var sxs, sys math.Size
if l.canScrollX {
sxs = l.scrollBarX.DesiredSize(math.ZeroSize, s)
}
if l.canScrollY {
sys = l.scrollBarY.DesiredSize(math.ZeroSize, s)
}
l.scrollBarX.Layout(math.CreateRect(0, s.H-sxs.H, s.W-sys.W, s.H).Canon().Offset(o))
l.scrollBarY.Layout(math.CreateRect(s.W-sys.W, 0, s.W, s.H-sxs.H).Canon().Offset(o))
l.innerSize = s.Contract(math.Spacing{R: sys.W, B: sxs.H})
if l.child != nil {
max := l.innerSize
if l.canScrollX {
max.W = math.MaxSize.W
}
if l.canScrollY {
max.H = math.MaxSize.H
}
cs := l.child.DesiredSize(math.ZeroSize, max)
l.child.Layout(cs.Rect().Offset(l.scrollOffset.Neg()).Offset(o))
l.scrollBarX.SetScrollLimit(cs.W)
l.scrollBarY.SetScrollLimit(cs.H)
}
l.SetScrollOffset(l.scrollOffset)
}
func (l *ScrollLayout) DesiredSize(min, max math.Size) math.Size {
return max
}
func (l *ScrollLayout) SetScrollOffset(scrollOffset math.Point) bool {
var cs math.Size
if l.child != nil {
cs = l.child.Bounds().Size()
}
s := l.innerSize
scrollOffset = scrollOffset.Min(cs.Sub(s).Point()).Max(math.Point{})
l.scrollBarX.SetVisible(l.canScrollX && cs.W > s.W)
l.scrollBarY.SetVisible(l.canScrollY && cs.H > s.H)
l.scrollBarX.SetScrollPosition(l.scrollOffset.X, l.scrollOffset.X+s.W)
l.scrollBarY.SetScrollPosition(l.scrollOffset.Y, l.scrollOffset.Y+s.H)
if l.scrollOffset != scrollOffset {
l.scrollOffset = scrollOffset
l.Relayout()
return true
}
return false
}
// InputEventHandler override
func (l *ScrollLayout) MouseScroll(ev gxui.MouseEvent) (consume bool) {
if ev.ScrollY == 0 {
return l.InputEventHandler.MouseScroll(ev)
}
switch {
case l.canScrollY:
return l.SetScrollOffset(l.scrollOffset.AddY(-ev.ScrollY))
case l.canScrollX:
return l.SetScrollOffset(l.scrollOffset.AddX(-ev.ScrollY))
default:
return false
}
}
// gxui.ScrollLayout complaince
func (l *ScrollLayout) SetChild(child gxui.Control) {
if l.child != nil {
l.RemoveChild(l.child)
}
l.child = child
if l.child != nil {
l.AddChildAt(0, l.child)
}
}
func (l *ScrollLayout) Child() gxui.Control {
return l.child
}
func (l *ScrollLayout) SetScrollAxis(horizontal, vertical bool) {
if l.canScrollX != horizontal || l.canScrollY != vertical {
l.canScrollX, l.canScrollY = horizontal, vertical
l.scrollBarX.SetVisible(horizontal)
l.scrollBarY.SetVisible(vertical)
l.Relayout()
}
}
func (l *ScrollLayout) ScrollAxis() (horizontal, vertical bool) {
return l.canScrollX, l.canScrollY
}