forked from Mirrors/bubbletea
172 lines
3.0 KiB
Go
172 lines
3.0 KiB
Go
package viewport
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import (
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"strings"
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"github.com/charmbracelet/boba"
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)
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// MODEL
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type Model struct {
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Err error
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Width int
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Height int
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Y int
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lines []string
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}
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// Scrollpercent returns the amount scrolled as a float between 0 and 1
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func (m Model) ScrollPercent() float64 {
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if m.Height >= len(m.lines) {
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return 1.0
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}
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y := float64(m.Y)
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h := float64(m.Height)
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t := float64(len(m.lines))
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return y / (t - h)
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}
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// SetContent set the pager's text content
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func (m *Model) SetContent(s string) {
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s = strings.Replace(s, "\r\n", "\n", -1) // normalize line endings
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m.lines = strings.Split(s, "\n")
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}
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// NewModel creates a new pager model. Pass the dimensions of the pager.
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func NewModel(width, height int) Model {
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return Model{
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Width: width,
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Height: height,
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}
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}
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// ViewDown moves the view down by the number of lines in the viewport.
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// Basically, "page down."
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func (m *Model) ViewDown() {
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m.Y = min(len(m.lines)-m.Height, m.Y+m.Height)
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}
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// ViewUp moves the view up by one height of the viewport. Basically, "page up."
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func (m *Model) ViewUp() {
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m.Y = max(0, m.Y-m.Height)
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}
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// HalfViewUp moves the view up by half the height of the viewport
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func (m *Model) HalfViewUp() {
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m.Y = max(0, m.Y-m.Height/2)
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}
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// HalfViewDown moves the view down by half the height of the viewport
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func (m *Model) HalfViewDown() {
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m.Y = min(len(m.lines)-m.Height, m.Y+m.Height/2)
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}
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// LineDown moves the view up by the given number of lines.
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func (m *Model) LineDown(n int) {
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m.Y = min(len(m.lines)-m.Height, m.Y+n)
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}
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// LineDown moves the view down by the given number of lines.
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func (m *Model) LineUp(n int) {
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m.Y = max(0, m.Y-n)
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}
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// UPDATE
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// Update runs the update loop with default keybindings. To define your own
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// keybindings use the methods on Model.
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func Update(msg boba.Msg, m Model) (Model, boba.Cmd) {
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switch msg := msg.(type) {
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case boba.KeyMsg:
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switch msg.String() {
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// Down one page
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case "pgdown":
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fallthrough
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case " ": // spacebar
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fallthrough
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case "f":
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m.ViewDown()
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return m, nil
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// Up one page
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case "pgup":
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fallthrough
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case "b":
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m.ViewUp()
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return m, nil
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// Down half page
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case "d":
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m.HalfViewDown()
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return m, nil
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// Up half page
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case "u":
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m.HalfViewUp()
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return m, nil
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// Down one line
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case "down":
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fallthrough
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case "j":
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m.LineDown(1)
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return m, nil
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// Up one line
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case "up":
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fallthrough
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case "k":
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m.LineUp(1)
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return m, nil
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}
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}
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return m, nil
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}
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// VIEW
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// View renders the viewport into a string
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func View(m Model) string {
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if m.Err != nil {
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return m.Err.Error()
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}
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var lines []string
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if len(m.lines) > 0 {
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top := max(0, m.Y)
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bottom := min(len(m.lines), m.Y+m.Height)
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lines = m.lines[top:bottom]
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}
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// Fill empty space with newlines
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extraLines := ""
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if len(lines) < m.Height {
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extraLines = strings.Repeat("\n", m.Height-len(lines))
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}
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return strings.Join(lines, "\n") + extraLines
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}
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// ETC
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func min(a, b int) int {
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if a < b {
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return a
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}
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return b
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}
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func max(a, b int) int {
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if a > b {
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return a
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}
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return b
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}
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