gomuks/ui/widget/color.go

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// gomuks - A terminal Matrix client written in Go.
// Copyright (C) 2018 Tulir Asokan
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package widget
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import (
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"fmt"
"hash/fnv"
"sort"
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"github.com/gdamore/tcell"
)
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var colorNames []string
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// init initializes the colorNames array.
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func init() {
colorNames = make([]string, len(tcell.ColorNames))
i := 0
for name, _ := range tcell.ColorNames {
colorNames[i] = name
i++
}
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// In order to have consistent coloring between restarts, we need to sort the array.
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sort.Sort(sort.StringSlice(colorNames))
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}
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// GetHashColorName gets a color name for the given string based on its FNV-1 hash.
//
// The array of possible color names are the alphabetically ordered color
// names specified in tcell.ColorNames.
//
// The algorithm to get the color is as follows:
// colorNames[ FNV1(string) % len(colorNames) ]
//
// With the exception of the three special cases:
// --> = green
// <-- = red
// --- = yellow
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func GetHashColorName(s string) string {
switch s {
case "-->":
return "green"
case "<--":
return "red"
case "---":
return "yellow"
default:
h := fnv.New32a()
h.Write([]byte(s))
return colorNames[int(h.Sum32())%len(colorNames)]
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}
}
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// GetHashColor gets the tcell Color value for the given string.
//
// GetHashColor calls GetHashColorName() and gets the Color value from the tcell.ColorNames map.
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func GetHashColor(s string) tcell.Color {
return tcell.ColorNames[GetHashColorName(s)]
}
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// AddHashColor adds tview color tags to the given string.
// The color added is the color returned by GetHashColorName().
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func AddHashColor(s string) string {
return fmt.Sprintf("[%s]%s[white]", GetHashColorName(s), s)
}