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