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math.go
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/
math.go
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// Copyright 2014 Hajime Hoshi
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package internal
import (
"image/color"
"math"
)
func NextPowerOf2Int(x int) int {
x -= 1
x |= (x >> 1)
x |= (x >> 2)
x |= (x >> 4)
x |= (x >> 8)
x |= (x >> 16)
return x + 1
}
func RGBA(clr color.Color) (r, g, b, a float64) {
cr, cg, cb, ca := clr.RGBA()
const max = math.MaxUint16
r = float64(cr) / max
g = float64(cg) / max
b = float64(cb) / max
a = float64(ca) / max
return
}