图像色彩调整

色彩空间转换

色彩空间的介绍可以在 基本概念 中看到。

func (r *ImageRef) ToColorSpace(interpretation Interpretation) error

其中 Interpretation 的可选项有如下：

// Interpretation enum
const (
	InterpretationError     Interpretation = C.VIPS_INTERPRETATION_ERROR
	InterpretationMultiband Interpretation = C.VIPS_INTERPRETATION_MULTIBAND
	InterpretationBW        Interpretation = C.VIPS_INTERPRETATION_B_W
	InterpretationHistogram Interpretation = C.VIPS_INTERPRETATION_HISTOGRAM
	InterpretationXYZ       Interpretation = C.VIPS_INTERPRETATION_XYZ
	InterpretationLAB       Interpretation = C.VIPS_INTERPRETATION_LAB
	InterpretationCMYK      Interpretation = C.VIPS_INTERPRETATION_CMYK
	InterpretationLABQ      Interpretation = C.VIPS_INTERPRETATION_LABQ
	InterpretationRGB       Interpretation = C.VIPS_INTERPRETATION_RGB
	InterpretationRGB16     Interpretation = C.VIPS_INTERPRETATION_RGB16
	InterpretationCMC       Interpretation = C.VIPS_INTERPRETATION_CMC
	InterpretationLCH       Interpretation = C.VIPS_INTERPRETATION_LCH
	InterpretationLABS      Interpretation = C.VIPS_INTERPRETATION_LABS
	InterpretationSRGB      Interpretation = C.VIPS_INTERPRETATION_sRGB
	InterpretationYXY       Interpretation = C.VIPS_INTERPRETATION_YXY
	InterpretationFourier   Interpretation = C.VIPS_INTERPRETATION_FOURIER
	InterpretationGrey16    Interpretation = C.VIPS_INTERPRETATION_GREY16
	InterpretationMatrix    Interpretation = C.VIPS_INTERPRETATION_MATRIX
	InterpretationScRGB     Interpretation = C.VIPS_INTERPRETATION_scRGB
	InterpretationHSV       Interpretation = C.VIPS_INTERPRETATION_HSV
)

例子：

img.ToColorSpace(vips.InterpretationSRGB)

调整亮度、饱和度，色相

func (r *ImageRef) Modulate(brightness, saturation, hue float64) error

这个函数如传入参数，可以同时调整图片的亮度，饱和度和色相，brightness 和 saturation 保持为 1 表示不变，hue 色相的调整稍微复杂一些，是一个角度，如果传入 0 表示不变，所以：

当我们仅调节图片亮度时，应该传入 brightness ，保持 saturation 是 1 ，hue 是 0，例如：

img.Modulate(1.5, 1, 0)

原图	调整亮度后

当我们仅调节图片饱和度时，应该保持 brightness 是 1 ，仅传入 saturation ，hue 是 0，例如：

TODO

当我们仅调节图片色相时，应该保持 brightness 是 1，brightness 是 1，仅传入 hue ，例如：

TODO