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tomo-old/layouts/basic/vertical.go

131 lines
3.2 KiB
Go

package basicLayouts
import "image"
import "git.tebibyte.media/sashakoshka/tomo/layouts"
import "git.tebibyte.media/sashakoshka/tomo/elements"
// Vertical arranges elements vertically. Elements at the start of the entry
// list will be positioned at the top, and elements at the end of the entry list
// will positioned at the bottom. All elements have the same width.
type Vertical 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 vertically.
func (layout Vertical) Arrange (
entries []layouts.LayoutEntry,
margin int,
bounds image.Rectangle,
) {
if layout.Pad { bounds = bounds.Inset(margin) }
// count the number of expanding elements and the amount of free space
// for them to collectively occupy, while gathering minimum heights.
freeSpace := bounds.Dy()
minimumHeights := make([]int, len(entries))
expandingElements := 0
for index, entry := range entries {
var entryMinHeight int
if child, flexible := entry.Element.(elements.Flexible); flexible {
entryMinHeight = child.FlexibleHeightFor(bounds.Dx())
} else {
_, entryMinHeight = entry.MinimumSize()
}
minimumHeights[index] = entryMinHeight
if entry.Expand {
expandingElements ++
} else {
freeSpace -= entryMinHeight
}
if index > 0 && layout.Gap {
freeSpace -= margin
}
}
expandingElementHeight := 0
if expandingElements > 0 {
expandingElementHeight = freeSpace / expandingElements
}
// set the size and position of each element
dot := bounds.Min
for index, entry := range entries {
if index > 0 && layout.Gap { dot.Y += margin }
entry.Bounds.Min = dot
entryHeight := 0
if entry.Expand {
entryHeight = expandingElementHeight
} else {
entryHeight = minimumHeights[index]
}
dot.Y += entryHeight
entryBounds := entry.Bounds
entry.Bounds.Max = entryBounds.Min.Add(image.Pt(bounds.Dx(), entryHeight))
entries[index] = entry
}
}
// MinimumSize returns the minimum width and height that will be needed to
// arrange the given list of entries.
func (layout Vertical) MinimumSize (
entries []layouts.LayoutEntry,
margin int,
) (
width, height int,
) {
for index, entry := range entries {
entryWidth, entryHeight := entry.MinimumSize()
if entryWidth > width {
width = entryWidth
}
height += entryHeight
if layout.Gap && index > 0 {
height += margin
}
}
if layout.Pad {
width += margin * 2
height += margin * 2
}
return
}
// 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 Vertical) FlexibleHeightFor (
entries []layouts.LayoutEntry,
margin int,
width int,
) (
height int,
) {
if layout.Pad {
width -= margin * 2
height += margin * 2
}
for index, entry := range entries {
child, flexible := entry.Element.(elements.Flexible)
if flexible {
height += child.FlexibleHeightFor(width)
} else {
_, entryHeight := entry.MinimumSize()
height += entryHeight
}
if layout.Gap && index > 0 {
height += margin
}
}
return
}