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// Spike: prove that a Plan 9 GUI can be written in Go with nothing but the
// standard library -- no C, no cgo, no libdraw, no window system.
//
// Draws a panel layout and a cursor block that tracks the mouse.
// Button 3 quits; so does the deadline, so a forgotten instance on a VM
// does not sit on /dev/draw forever.
package main
import (
"fmt"
"os"
"time"
"9front/gui/draw"
)
func main() {
if err := run(); err != nil {
fmt.Fprintf(os.Stderr, "spike: %v\n", err)
os.Exit(1)
}
}
func run() error {
d, err := draw.Init("/dev")
if err != nil {
return err
}
defer d.Close()
if d.Screen == nil {
return fmt.Errorf("draw device gave no screen image")
}
scr := d.Screen
r := scr.Rect()
fmt.Fprintf(os.Stderr, "spike: screen %dx%d\n", r.Dx(), r.Dy())
col := map[string]uint32{}
img := map[string]*draw.Image{}
for name, v := range map[string]uint32{
"bg": 0x2B3A42FF,
"panel": 0x3F5765FF,
"accent": 0xBDD4DEFF,
"hot": 0xEFA00BFF,
} {
col[name] = v
if img[name], err = d.Color(v); err != nil {
return err
}
}
// Static layout: a header bar and three panels, laid out by arithmetic
// rather than by hand-placed constants. This is the seam where a real
// layout pass would go.
repaint := func() {
draw.Draw(scr, r, img["bg"], nil, draw.ZP)
hdr := draw.Rect(r.Min.X, r.Min.Y, r.Max.X, r.Min.Y+40)
draw.Draw(scr, hdr, img["accent"], nil, draw.ZP)
const gap = 12
top := r.Min.Y + 40 + gap
w := (r.Dx() - 4*gap) / 3
for i := int32(0); i < 3; i++ {
x := r.Min.X + gap + i*(w+gap)
p := draw.Rect(x, top, x+w, r.Max.Y-gap)
draw.Draw(scr, p, img["panel"], nil, draw.ZP)
}
}
repaint()
d.Flush()
mc, err := draw.OpenMouse("/dev")
if err != nil {
return err
}
defer mc.Close()
deadline := time.After(10 * time.Minute)
cursor := draw.Rect(0, 0, 28, 28)
var last draw.Rectangle
for {
select {
case m, ok := <-mc.C:
if !ok {
return nil
}
if m.Buttons&4 != 0 {
return nil
}
// Damage repair without a full repaint: erase where the
// block was, then draw it where the mouse is now.
if last != (draw.Rectangle{}) {
repaint()
}
now := cursor.Add(draw.Point{X: m.X - 14, Y: m.Y - 14})
draw.Draw(scr, now, img["hot"], nil, draw.ZP)
d.Flush()
last = now
case <-mc.Resize:
r = scr.Rect()
repaint()
d.Flush()
case <-deadline:
return nil
}
}
}
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