func runLevelsOnChannel(cmd *Command, args []string, img image.Image,
ch levels.Channel) image.Image {
if levelsAuto {
img = levels.Auto(img, ch)
} else if levelsAutoBlack {
img = levels.AutoBlack(img, ch)
} else if levelsAutoWhite {
img = levels.AutoWhite(img, ch)
} else if utils.FlagVisited("black", cmd.Flag) {
img = levels.SetBlack(img, ch, levelsBlack)
} else if utils.FlagVisited("white", cmd.Flag) {
img = levels.SetWhite(img, ch, levelsWhite)
} else if utils.FlagVisited("curve", cmd.Flag) {
img = levels.SetCurve(img, ch, levels.ParseCurveString(levelsCurve))
}
return img
}
func runChannel(cmd *Command, args []string) {
i := utils.ReadStdin()
var adj utils.Adjuster
if utils.FlagVisited("by", cmd.Flag) {
adj = utils.Adder(channelBy)
} else {
adj = utils.Multiplier(channelRatio)
}
if !(channelRed || channelGreen || channelBlue || channelHue ||
channelSaturation || channelLightness || channelBrightness || channelAlpha) {
channelRed = true
channelGreen = true
channelBlue = true
}
if channelRed {
i = channel.Red(i, adj)
}
if channelGreen {
i = channel.Green(i, adj)
}
if channelBlue {
i = channel.Blue(i, adj)
}
if channelHue {
i = channel.Hue(i, adj)
}
if channelSaturation {
i = channel.Saturation(i, adj)
}
if channelLightness {
i = channel.Lightness(i, adj)
}
if channelBrightness {
i = channel.Brightness(i, adj)
}
if channelAlpha {
i = channel.Alpha(i, adj)
}
utils.WriteStdout(i)
}