Files
8bitMyGoUI/media/tracker.go
T
ZacharyZhang-NY 0e21870b64 Add media components 346-365; input.SlideBase, guarded Pad
An audio player with transport, scrubber and volume; an equalizer and
a visualizer; a playlist; a cassette, cartridge and record that turn
while they play and hold where they stop; piano keys, a step sequencer
and a tracker you can type into; a waveform, a 16:9 video frame, an
image compare, a gallery, a filmstrip, a record button and an FM tuner.

input exports SlideBase, the undrawn rail its sliders share; the
gallery treats exported Bases as building blocks, not components.
pixel's micro font gains '#' for notes like C#4. pixel.Pad and the
slide rail read input only while their base is enabled, so Inert or a
fresh Disabled stops a drag or a key already sent. AGENTS records why
a drawn container keeps the DISABLED description: MyGo paints a
disabled subtree at half opacity.
2026-10-12 06:17:12 -04:00

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package media
import (
"fmt"
"log/slog"
"regexp"
"github.com/egoist/mygo/ui"
"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
)
// Row is one tracker line; no Note is a rest.
type Row struct {
// Note is like "C-4" or "C#4".
Note string
// Instrument is 1–99 and Volume 0–64 under a note.
Instrument, Volume int
}
type TrackerOptions struct {
Disabled bool
}
type TrackerResult struct {
Element *ui.Element
Changed bool
}
var noteForm = regexp.MustCompile(`^[A-G][-#][0-9]$`)
// Tracker edits rows: piano letters write notes, Delete rests.
func Tracker(c *ui.Context, text string, rows []Row, cur *int, o TrackerOptions) TrackerResult {
k := pixel.K(c)
if *cur < 0 || *cur >= len(rows) {
panic(fmt.Sprintf("media: Tracker cursor %d of %d rows", *cur, len(rows)))
}
for i, r := range rows {
if r.Note != "" && (!noteForm.MatchString(r.Note) || r.Instrument < 1 || r.Instrument > 99 || r.Volume < 0 || r.Volume > 64) {
panic(fmt.Sprintf("media: Tracker row %d is %+v", i, r))
}
}
shell, base, st, _ := pixel.Pad(c, text, 1, len(rows), 52, 7, cur, o.Disabled)
res := TrackerResult{Element: shell}
if !base.IsDisabled() {
for _, semi := range played(base) {
write(rows, *cur, cell(semi))
res.Changed = true
slog.Debug("8bit: tracker", "label", text, "row", *cur, "note", rows[*cur].Note)
*cur = min(len(rows)-1, *cur+1)
}
if base.Shortcut(0, ui.KeyDelete) || base.Shortcut(0, ui.KeyBackspace) {
rows[*cur], res.Changed = Row{}, true
slog.Debug("8bit: tracker", "label", text, "row", *cur, "note", "")
}
}
base.Description(line(*cur, rows[*cur]))
at := *cur
shell.Draw(func(p *ui.Painter, r ui.Rect) {
g := k.Canvas(p, r)
g.Rect(0, 0, g.W, g.H, pixel.Well)
for i, row := range rows {
y := i * 7
num, ink := pixel.Faint, pixel.Ink
switch {
case i == at:
g.Rect(0, y, g.W, 7, pixel.Accent)
num, ink = pixel.AccentInk, pixel.AccentInk
case i%4 == 0:
g.Rect(0, y, g.W, 7, pixel.Face)
}
g.Micro(2, y+1, fmt.Sprintf("%02d", i), num, 1)
if row.Note == "" {
g.Micro(14, y+1, "--- .. ..", num, 1)
continue
}
ins, vol := pixel.Info, pixel.Good
if i == at {
ins, vol = ink, ink
}
g.Micro(14, y+1, row.Note, ink, 1)
g.Micro(30, y+1, fmt.Sprintf("%02d", row.Instrument), ins, 1)
g.Micro(42, y+1, fmt.Sprintf("%02d", row.Volume), vol, 1)
}
g.Finish(st)
})
return res
}
// cell is a semitone in tracker form, like "C-4".
func cell(semi int) string {
n := note(semi)
if len(n) == 2 {
return n[:1] + "-" + n[1:]
}
return n
}
// write notes row i; a rest borrows the voice above.
func write(rows []Row, i int, n string) {
if rows[i].Note == "" {
rows[i] = Row{Instrument: 1, Volume: 64}
for j := i - 1; j >= 0; j-- {
if rows[j].Note != "" {
rows[i] = rows[j]
break
}
}
}
rows[i].Note = n
}
// line reads a row aloud: number, note, instrument, volume.
func line(i int, r Row) string {
if r.Note == "" {
return fmt.Sprintf("%02d ---", i)
}
return fmt.Sprintf("%02d %s %02d %02d", i, r.Note, r.Instrument, r.Volume)
}