etk/frame.go

146 lines
3.2 KiB
Go

package etk
import (
"image"
)
// Frame is a widget container. All children are displayed at once. Children are
// not repositioned by default. Repositioning may be enabled via SetPositionChildren.
type Frame struct {
*Box
padding int
positionChildren bool
maxWidth int
maxHeight int
horizontal Alignment
vertical Alignment
}
// NewFrame returns a new Frame widget.
func NewFrame(w ...Widget) *Frame {
f := &Frame{
Box: NewBox(),
}
f.AddChild(w...)
return f
}
// SetPadding sets the amount of padding around widgets in the frame.
func (f *Frame) SetPadding(padding int) {
f.Lock()
defer f.Unlock()
f.padding = padding
f.repositionAll()
}
// SetRect sets the position and size of the widget.
func (f *Frame) SetRect(r image.Rectangle) {
f.Lock()
defer f.Unlock()
f.rect = r
f.repositionAll()
}
// SetPositionChildren sets a flag that determines whether child widgets are
// repositioned when the Frame is repositioned.
func (f *Frame) SetPositionChildren(position bool) {
f.Lock()
defer f.Unlock()
f.positionChildren = position
f.repositionAll()
}
// SetMaxWidth sets the maximum width of widgets within the frame. This will
// only have an effect after SetPositionChildren(true) is called. 0 to disable.
func (f *Frame) SetMaxWidth(w int) {
f.Lock()
defer f.Unlock()
f.maxWidth = w
f.repositionAll()
}
// SetMaxHeight sets the maximum height of widgets within the frame. This will
// only have an effect after SetPositionChildren(true) is called. 0 to disable.
func (f *Frame) SetMaxHeight(h int) {
f.Lock()
defer f.Unlock()
f.maxHeight = h
f.repositionAll()
}
// SetHorizontal sets the horizontal alignment of widgets within the Frame. This
// will only have an effect when a max width is set and there is extra space.
func (f *Frame) SetHorizontal(h Alignment) {
f.Lock()
defer f.Unlock()
f.horizontal = h
}
// SetVertical sets the vertical alignment ofwidgets within the Frame. This
// will only have an effect when a max height is set and there is extra space.
func (f *Frame) SetVertical(v Alignment) {
f.Lock()
defer f.Unlock()
f.vertical = v
}
// AddChild adds a child to the widget.
func (f *Frame) AddChild(w ...Widget) {
f.Lock()
defer f.Unlock()
f.children = append(f.children, w...)
if !f.positionChildren {
return
}
for _, child := range w {
f.repositionChild(child)
}
}
func (f *Frame) repositionChild(w Widget) {
r := f.rect
if f.maxWidth > 0 {
if r.Dx() > f.maxWidth {
r.Max.X = r.Min.X + f.maxWidth
}
if f.horizontal == AlignCenter {
extraSpace := f.rect.Dx() - r.Dx()
if extraSpace > 0 {
r = image.Rectangle{image.Point{f.rect.Min.X + extraSpace/2, r.Min.Y}, image.Point{f.rect.Max.X - extraSpace/2, r.Max.Y}}
}
}
// TODO Handle AlignEnd
}
if f.maxHeight > 0 {
if r.Dy() > f.maxHeight {
r.Max.Y = r.Min.Y + f.maxHeight
}
if f.vertical == AlignCenter {
extraSpace := f.rect.Dy() - r.Dy()
if extraSpace > 0 {
r = image.Rectangle{image.Point{r.Min.X, f.rect.Min.Y + extraSpace/2}, image.Point{r.Max.X, f.rect.Max.Y - extraSpace/2}}
}
}
// TODO Handle AlignEnd
}
r = r.Inset(f.padding)
w.SetRect(r)
}
func (f *Frame) repositionAll() {
if !f.positionChildren {
return
}
for _, w := range f.children {
f.repositionChild(w)
}
}