1 // Copyright 2016 The TCell Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use file except in compliance with the License. 5 // You may obtain a copy of the license at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package tcell 16 17 import ( 18 "math" 19 20 "github.com/lucasb-eyer/go-colorful" 21 ) 22 23 // FindColor attempts to find a given color, or the best match possible for it, 24 // from the palette given. This is an expensive operation, so results should 25 // be cached by the caller. 26 func FindColor(c Color, palette []Color) Color { 27 match := ColorDefault 28 dist := float64(0) 29 r, g, b := c.RGB() 30 c1 := colorful.Color{ 31 R: float64(r) / 255.0, 32 G: float64(g) / 255.0, 33 B: float64(b) / 255.0, 34 } 35 for _, d := range palette { 36 r, g, b = d.RGB() 37 c2 := colorful.Color{ 38 R: float64(r) / 255.0, 39 G: float64(g) / 255.0, 40 B: float64(b) / 255.0, 41 } 42 // CIE94 is more accurate, but really really expensive. 43 nd := c1.DistanceCIE76(c2) 44 if math.IsNaN(nd) { 45 nd = math.Inf(1) 46 } 47 if match == ColorDefault || nd < dist { 48 match = d 49 dist = nd 50 } 51 } 52 return match 53 } 54