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tomo-old/layouts/basic/horizontal.go

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package basicLayouts
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import "image"
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import "git.tebibyte.media/sashakoshka/tomo/layouts"
import "git.tebibyte.media/sashakoshka/tomo/elements"
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// Horizontal arranges elements horizontally. Elements at the start of the entry
// list will be positioned on the left, and elements at the end of the entry
// list will positioned on the right. All elements have the same height.
type Horizontal struct {
// If Gap is true, a gap will be placed between each element.
Gap bool
// If Pad is true, there will be padding running along the inside of the
// layout's border.
Pad bool
}
// Arrange arranges a list of entries horizontally.
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func (layout Horizontal) Arrange (
entries []layouts.LayoutEntry,
margin int,
bounds image.Rectangle,
) {
if layout.Pad { bounds = bounds.Inset(margin) }
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// get width of expanding elements
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expandingElementWidth := layout.expandingElementWidth (
entries, margin, bounds.Dx())
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// set the size and position of each element
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dot := bounds.Min
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for index, entry := range entries {
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if index > 0 && layout.Gap { dot.X += margin }
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entry.Bounds.Min = dot
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entryWidth := 0
if entry.Expand {
entryWidth = expandingElementWidth
} else {
entryWidth, _ = entry.MinimumSize()
}
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dot.X += entryWidth
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entry.Bounds.Max = entry.Bounds.Min.Add(image.Pt(entryWidth, bounds.Dy()))
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entries[index] = entry
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}
}
// MinimumSize returns the minimum width and height that will be needed to
// arrange the given list of entries.
func (layout Horizontal) MinimumSize (
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entries []layouts.LayoutEntry,
margin int,
) (
width, height int,
) {
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for index, entry := range entries {
entryWidth, entryHeight := entry.MinimumSize()
if entryHeight > height {
height = entryHeight
}
width += entryWidth
if layout.Gap && index > 0 {
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width += margin
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}
}
if layout.Pad {
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width += margin * 2
height += margin * 2
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}
return
}
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// FlexibleHeightFor Returns the minimum height the layout needs to lay out the
// specified elements at the given width, taking into account flexible elements.
func (layout Horizontal) FlexibleHeightFor (
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entries []layouts.LayoutEntry,
margin int,
width int,
) (
height int,
) {
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if layout.Pad { width -= margin * 2 }
// get width of expanding elements
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expandingElementWidth := layout.expandingElementWidth (
entries, margin, width)
x, y := 0, 0
if layout.Pad {
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x += margin
y += margin
}
// set the size and position of each element
for index, entry := range entries {
entryWidth, entryHeight := entry.MinimumSize()
if entry.Expand {
entryWidth = expandingElementWidth
}
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if child, flexible := entry.Element.(elements.Flexible); flexible {
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entryHeight = child.FlexibleHeightFor(entryWidth)
}
if entryHeight > height { height = entryHeight }
x += entryWidth
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if index > 0 && layout.Gap { x += margin }
}
if layout.Pad {
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height += margin * 2
}
return
}
func (layout Horizontal) expandingElementWidth (
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entries []layouts.LayoutEntry,
margin int,
freeSpace int,
) (
width int,
) {
expandingElements := 0
// count the number of expanding elements and the amount of free space
// for them to collectively occupy
for index, entry := range entries {
if entry.Expand {
expandingElements ++
} else {
entryMinWidth, _ := entry.MinimumSize()
freeSpace -= entryMinWidth
}
if index > 0 && layout.Gap {
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freeSpace -= margin
}
}
if expandingElements > 0 {
width = freeSpace / expandingElements
}
return
}