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tomo-old/layouts/horizontal.go

111 lines
2.7 KiB
Go

package layouts
import "image"
import "golang.org/x/image/math/fixed"
import "git.tebibyte.media/sashakoshka/tomo"
import "git.tebibyte.media/sashakoshka/tomo/artist"
import "git.tebibyte.media/sashakoshka/tomo/fixedutil"
// 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.
func (layout Horizontal) Arrange (
entries []tomo.LayoutEntry,
margin image.Point,
padding artist.Inset,
bounds image.Rectangle,
) {
if layout.Pad { bounds = padding.Apply(bounds) }
// get width of expanding elements
expandingElementWidth := layout.expandingElementWidth (
entries, margin, padding, bounds.Dx())
// set the size and position of each element
dot := fixedutil.Pt(bounds.Min)
for index, entry := range entries {
if index > 0 && layout.Gap { dot.X += fixed.I(margin.X) }
entry.Bounds.Min = fixedutil.FloorPt(dot)
entryWidth := fixed.Int26_6(0)
if entry.Expand {
entryWidth = expandingElementWidth
} else {
min, _ := entry.MinimumSize()
entryWidth = fixed.I(min)
}
dot.X += entryWidth
entry.Bounds.Max = entry.Bounds.Min.Add (
image.Pt(entryWidth.Floor(), bounds.Dy()))
entries[index] = entry
}
}
// MinimumSize returns the minimum width and height that will be needed to
// arrange the given list of entries.
func (layout Horizontal) MinimumSize (
entries []tomo.LayoutEntry,
margin image.Point,
padding artist.Inset,
) (
width, height int,
) {
for index, entry := range entries {
entryWidth, entryHeight := entry.MinimumSize()
if entryHeight > height {
height = entryHeight
}
width += entryWidth
if layout.Gap && index > 0 {
width += margin.X
}
}
if layout.Pad {
width += padding.Horizontal()
height += padding.Vertical()
}
return
}
func (layout Horizontal) expandingElementWidth (
entries []tomo.LayoutEntry,
margin image.Point,
padding artist.Inset,
freeSpace int,
) (
width fixed.Int26_6,
) {
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 {
freeSpace -= margin.X
}
}
if expandingElements > 0 {
width = fixed.I(freeSpace) / fixed.Int26_6(expandingElements)
}
return
}