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xgb-window: add comparison with correct blending

This commit is contained in:
Přemysl Eric Janouch 2018-08-21 20:45:25 +02:00
parent 0f7fcca7ce
commit 44b01ccb17
Signed by: p
GPG Key ID: A0420B94F92B9493
1 changed files with 27 additions and 4 deletions
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31
prototypes/xgb-window.go
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@ -4,6 +4,7 @@ import (
"github.com/BurntSushi/xgb"
"github.com/BurntSushi/xgb/xproto"
"log"
"math"
"math/rand"
)
@ -73,6 +74,17 @@ func main() {
_ = xproto.CreateGC(X, cid, xproto.Drawable(wid),
xproto.GcGraphicsExposures, []uint32{0})
blend := func(a, b uint32, ratio, gamma float64) uint32 {
iratio := 1 - ratio
fa := math.Pow(float64(a)/255, gamma)
fb := math.Pow(float64(b)/255, gamma)
return uint32(math.Pow(ratio*fa+iratio*fb, 1/gamma)*255) & 0xff
}
// TODO: We could show some text just like we intend to with xgb-xrender.go.
var w, h uint16
var start, end uint32 = 0xabcdef, 0x32ab54
gradient := func() {
@ -86,17 +98,28 @@ func main() {
for y := low; y < high; y++ {
ratio := float64(y-low) / (float64(high) - float64(low))
iratio := 1 - ratio
rR := uint32(ratio*float64(ra)+iratio*float64(rb)) & 0xff
gG := uint32(ratio*float64(ga)+iratio*float64(gb)) & 0xff
bB := uint32(ratio*float64(ba)+iratio*float64(bb)) & 0xff
rR := blend(ra, rb, ratio, 2.2)
gG := blend(ga, gb, ratio, 2.2)
bB := blend(ba, bb, ratio, 2.2)
_ = xproto.ChangeGC(X, cid, xproto.GcForeground,
[]uint32{0xff000000 | rR<<16 | gG<<8 | bB})
_ = xproto.PolyLine(X, xproto.CoordModeOrigin, xproto.Drawable(wid),
cid, []xproto.Point{
{X: 50, Y: int16(y)},
{X: int16(w / 2), Y: int16(y)},
})
rR = blend(ra, rb, ratio, 1)
gG = blend(ga, gb, ratio, 1)
bB = blend(ba, bb, ratio, 1)
_ = xproto.ChangeGC(X, cid, xproto.GcForeground,
[]uint32{0xff000000 | rR<<16 | gG<<8 | bB})
_ = xproto.PolyLine(X, xproto.CoordModeOrigin, xproto.Drawable(wid),
cid, []xproto.Point{
{X: int16(w / 2), Y: int16(y)},
{X: int16(w - 50), Y: int16(y)},
})
}