twitchapon-anim

colorm.go (13542B)

---

 // 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 affine
 
 import (
 	"image/color"
 	"math"
 )
 
 // ColorMDim is a dimension of a ColorM.
 const ColorMDim = 5
 
 var (
 	colorMIdentityBody = []float32{
 		1, 0, 0, 0,
 		0, 1, 0, 0,
 		0, 0, 1, 0,
 		0, 0, 0, 1,
 	}
 	colorMIdentityTranslate = []float32{
 		0, 0, 0, 0,
 	}
 )
 
 // A ColorM represents a matrix to transform coloring when rendering an image.
 //
 // A ColorM is applied to the source alpha color
 // while an Image's pixels' format is alpha premultiplied.
 // Before applying a matrix, a color is un-multiplied, and after applying the matrix,
 // the color is multiplied again.
 //
 // The nil and initial value is identity.
 type ColorM struct {
 	// When elements is nil, this matrix is identity.
 	// elements are immutable and a new array must be created when updating.
 	body      []float32
 	translate []float32
 }
 
 func clamp(x float32) float32 {
 	if x > 1 {
 		return 1
 	}
 	if x < 0 {
 		return 0
 	}
 	return x
 }
 
 func (c *ColorM) isInited() bool {
 	return c != nil && (c.body != nil || c.translate != nil)
 }
 
 func (c *ColorM) ScaleOnly() bool {
 	if c == nil {
 		return true
 	}
 	if c.body != nil {
 		if c.body[1] != 0 {
 			return false
 		}
 		if c.body[2] != 0 {
 			return false
 		}
 		if c.body[3] != 0 {
 			return false
 		}
 		if c.body[4] != 0 {
 			return false
 		}
 		if c.body[6] != 0 {
 			return false
 		}
 		if c.body[7] != 0 {
 			return false
 		}
 		if c.body[8] != 0 {
 			return false
 		}
 		if c.body[9] != 0 {
 			return false
 		}
 		if c.body[11] != 0 {
 			return false
 		}
 		if c.body[12] != 0 {
 			return false
 		}
 		if c.body[13] != 0 {
 			return false
 		}
 		if c.body[14] != 0 {
 			return false
 		}
 	}
 	if c.translate != nil {
 		for _, e := range c.translate {
 			if e != 0 {
 				return false
 			}
 		}
 	}
 	return true
 }
 
 func (c *ColorM) Apply(clr color.Color) color.Color {
 	if !c.isInited() {
 		return clr
 	}
 	r, g, b, a := clr.RGBA()
 	rf, gf, bf, af := float32(0.0), float32(0.0), float32(0.0), float32(0.0)
 	// Unmultiply alpha
 	if a > 0 {
 		rf = float32(r) / float32(a)
 		gf = float32(g) / float32(a)
 		bf = float32(b) / float32(a)
 		af = float32(a) / 0xffff
 	}
 	eb := c.body
 	if eb == nil {
 		eb = colorMIdentityBody
 	}
 	et := c.translate
 	if et == nil {
 		et = colorMIdentityTranslate
 	}
 	rf2 := eb[0]*rf + eb[4]*gf + eb[8]*bf + eb[12]*af + et[0]
 	gf2 := eb[1]*rf + eb[5]*gf + eb[9]*bf + eb[13]*af + et[1]
 	bf2 := eb[2]*rf + eb[6]*gf + eb[10]*bf + eb[14]*af + et[2]
 	af2 := eb[3]*rf + eb[7]*gf + eb[11]*bf + eb[15]*af + et[3]
 	rf2 = clamp(rf2)
 	gf2 = clamp(gf2)
 	bf2 = clamp(bf2)
 	af2 = clamp(af2)
 	return color.NRGBA64{
 		R: uint16(rf2 * 0xffff),
 		G: uint16(gf2 * 0xffff),
 		B: uint16(bf2 * 0xffff),
 		A: uint16(af2 * 0xffff),
 	}
 }
 
 func (c *ColorM) UnsafeElements() ([]float32, []float32) {
 	if !c.isInited() {
 		return colorMIdentityBody, colorMIdentityTranslate
 	}
 	eb := c.body
 	if eb == nil {
 		eb = colorMIdentityBody
 	}
 	et := c.translate
 	if et == nil {
 		et = colorMIdentityTranslate
 	}
 	return eb, et
 }
 
 func (c *ColorM) det() float32 {
 	if !c.isInited() {
 		return 1
 	}
 
 	m00 := c.body[0]
 	m01 := c.body[1]
 	m02 := c.body[2]
 	m03 := c.body[3]
 	m10 := c.body[4]
 	m11 := c.body[5]
 	m12 := c.body[6]
 	m13 := c.body[7]
 	m20 := c.body[8]
 	m21 := c.body[9]
 	m22 := c.body[10]
 	m23 := c.body[11]
 	m30 := c.body[12]
 	m31 := c.body[13]
 	m32 := c.body[14]
 	m33 := c.body[15]
 
 	b234234 := m22*m33 - m23*m32
 	b134234 := m21*m33 - m23*m31
 	b124234 := m21*m32 - m22*m31
 	b034234 := m20*m33 - m23*m30
 	b024234 := m20*m32 - m22*m30
 	b014234 := m20*m31 - m21*m30
 
 	return m00*(m11*b234234-m12*b134234+m13*b124234) -
 		m01*(m10*b234234-m12*b034234+m13*b024234) +
 		m02*(m10*b134234-m11*b034234+m13*b014234) -
 		m03*(m10*b124234-m11*b024234+m12*b014234)
 }
 
 // IsInvertible returns a boolean value indicating
 // whether the matrix c is invertible or not.
 func (c *ColorM) IsInvertible() bool {
 	return c.det() != 0
 }
 
 // Invert inverts the matrix.
 // If c is not invertible, Invert panics.
 func (c *ColorM) Invert() *ColorM {
 	if !c.isInited() {
 		return nil
 	}
 
 	det := c.det()
 	if det == 0 {
 		panic("affine: c is not invertible")
 	}
 
 	m00 := c.body[0]
 	m01 := c.body[1]
 	m02 := c.body[2]
 	m03 := c.body[3]
 
 	m10 := c.body[4]
 	m11 := c.body[5]
 	m12 := c.body[6]
 	m13 := c.body[7]
 
 	m20 := c.body[8]
 	m21 := c.body[9]
 	m22 := c.body[10]
 	m23 := c.body[11]
 
 	m30 := c.body[12]
 	m31 := c.body[13]
 	m32 := c.body[14]
 	m33 := c.body[15]
 
 	m40 := c.translate[0]
 	m41 := c.translate[1]
 	m42 := c.translate[2]
 	m43 := c.translate[3]
 
 	a2334 := m32*m43 - m33*m42
 	a1334 := m31*m43 - m33*m41
 	a1234 := m31*m42 - m32*m41
 	a0334 := m30*m43 - m33*m40
 	a0234 := m30*m42 - m32*m40
 	a0134 := m30*m41 - m31*m40
 	a2324 := m22*m43 - m23*m42
 	a1324 := m21*m43 - m23*m41
 	a1224 := m21*m42 - m22*m41
 	a0324 := m20*m43 - m23*m40
 	a0224 := m20*m42 - m22*m40
 	a0124 := m20*m41 - m21*m40
 
 	b234234 := m22*m33 - m23*m32
 	b134234 := m21*m33 - m23*m31
 	b124234 := m21*m32 - m22*m31
 	b123234 := m21*a2334 - m22*a1334 + m23*a1234
 	b034234 := m20*m33 - m23*m30
 	b024234 := m20*m32 - m22*m30
 	b023234 := m20*a2334 - m22*a0334 + m23*a0234
 	b014234 := m20*m31 - m21*m30
 	b013234 := m20*a1334 - m21*a0334 + m23*a0134
 	b012234 := m20*a1234 - m21*a0234 + m22*a0134
 	b234134 := m12*m33 - m13*m32
 	b134134 := m11*m33 - m13*m31
 	b124134 := m11*m32 - m12*m31
 	b123134 := m11*a2334 - m12*a1334 + m13*a1234
 	b234124 := m12*m23 - m13*m22
 	b134124 := m11*m23 - m13*m21
 	b124124 := m11*m22 - m12*m21
 	b123124 := m11*a2324 - m12*a1324 + m13*a1224
 	b034134 := m10*m33 - m13*m30
 	b024134 := m10*m32 - m12*m30
 	b023134 := m10*a2334 - m12*a0334 + m13*a0234
 	b034124 := m10*m23 - m13*m20
 	b024124 := m10*m22 - m12*m20
 	b023124 := m10*a2324 - m12*a0324 + m13*a0224
 	b014134 := m10*m31 - m11*m30
 	b013134 := m10*a1334 - m11*a0334 + m13*a0134
 	b014124 := m10*m21 - m11*m20
 	b013124 := m10*a1324 - m11*a0324 + m13*a0124
 	b012134 := m10*a1234 - m11*a0234 + m12*a0134
 	b012124 := m10*a1224 - m11*a0224 + m12*a0124
 
 	m := &ColorM{
 		body:      make([]float32, 16),
 		translate: make([]float32, 4),
 	}
 
 	idet := 1 / det
 
 	m.body[0] = idet * (m11*b234234 - m12*b134234 + m13*b124234)
 	m.body[1] = idet * -(m01*b234234 - m02*b134234 + m03*b124234)
 	m.body[2] = idet * (m01*b234134 - m02*b134134 + m03*b124134)
 	m.body[3] = idet * -(m01*b234124 - m02*b134124 + m03*b124124)
 	m.body[4] = idet * -(m10*b234234 - m12*b034234 + m13*b024234)
 	m.body[5] = idet * (m00*b234234 - m02*b034234 + m03*b024234)
 	m.body[6] = idet * -(m00*b234134 - m02*b034134 + m03*b024134)
 	m.body[7] = idet * (m00*b234124 - m02*b034124 + m03*b024124)
 	m.body[8] = idet * (m10*b134234 - m11*b034234 + m13*b014234)
 	m.body[9] = idet * -(m00*b134234 - m01*b034234 + m03*b014234)
 	m.body[10] = idet * (m00*b134134 - m01*b034134 + m03*b014134)
 	m.body[11] = idet * -(m00*b134124 - m01*b034124 + m03*b014124)
 	m.body[12] = idet * -(m10*b124234 - m11*b024234 + m12*b014234)
 	m.body[13] = idet * (m00*b124234 - m01*b024234 + m02*b014234)
 	m.body[14] = idet * -(m00*b124134 - m01*b024134 + m02*b014134)
 	m.body[15] = idet * (m00*b124124 - m01*b024124 + m02*b014124)
 	m.translate[0] = idet * (m10*b123234 - m11*b023234 + m12*b013234 - m13*b012234)
 	m.translate[1] = idet * -(m00*b123234 - m01*b023234 + m02*b013234 - m03*b012234)
 	m.translate[2] = idet * (m00*b123134 - m01*b023134 + m02*b013134 - m03*b012134)
 	m.translate[3] = idet * -(m00*b123124 - m01*b023124 + m02*b013124 - m03*b012124)
 	return m
 }
 
 // Element returns a value of a matrix at (i, j).
 func (c *ColorM) Element(i, j int) float32 {
 	b, t := c.UnsafeElements()
 	if j < ColorMDim-1 {
 		return b[i+j*(ColorMDim-1)]
 	}
 	return t[i]
 }
 
 // SetElement sets an element at (i, j).
 func (c *ColorM) SetElement(i, j int, element float32) *ColorM {
 	newC := &ColorM{
 		body:      make([]float32, 16),
 		translate: make([]float32, 4),
 	}
 	copy(newC.body, colorMIdentityBody)
 	copy(newC.translate, colorMIdentityTranslate)
 	if c.isInited() {
 		if c.body != nil {
 			copy(newC.body, c.body)
 		}
 		if c.translate != nil {
 			copy(newC.translate, c.translate)
 		}
 	}
 	if j < (ColorMDim - 1) {
 		newC.body[i+j*(ColorMDim-1)] = element
 	} else {
 		newC.translate[i] = element
 	}
 	return newC
 }
 
 func (c *ColorM) Equals(other *ColorM) bool {
 	if !c.isInited() && !other.isInited() {
 		return true
 	}
 
 	lhsb := colorMIdentityBody
 	lhst := colorMIdentityTranslate
 	rhsb := colorMIdentityBody
 	rhst := colorMIdentityTranslate
 	if other.isInited() {
 		if other.body != nil {
 			lhsb = other.body
 		}
 		if other.translate != nil {
 			lhst = other.translate
 		}
 	}
 	if c.isInited() {
 		if c.body != nil {
 			rhsb = c.body
 		}
 		if c.translate != nil {
 			rhst = c.translate
 		}
 	}
 	if &lhsb == &rhsb && &lhst == &rhst {
 		return true
 	}
 
 	for i := range lhsb {
 		if lhsb[i] != rhsb[i] {
 			return false
 		}
 	}
 	for i := range lhst {
 		if lhst[i] != rhst[i] {
 			return false
 		}
 	}
 	return true
 }
 
 // Concat multiplies a color matrix with the other color matrix.
 // This is same as muptiplying the matrix other and the matrix c in this order.
 func (c *ColorM) Concat(other *ColorM) *ColorM {
 	if !c.isInited() {
 		return other
 	}
 	if !other.isInited() {
 		return c
 	}
 
 	lhsb := colorMIdentityBody
 	lhst := colorMIdentityTranslate
 	rhsb := colorMIdentityBody
 	rhst := colorMIdentityTranslate
 	if other.isInited() {
 		if other.body != nil {
 			lhsb = other.body
 		}
 		if other.translate != nil {
 			lhst = other.translate
 		}
 	}
 	if c.isInited() {
 		if c.body != nil {
 			rhsb = c.body
 		}
 		if c.translate != nil {
 			rhst = c.translate
 		}
 	}
 
 	return &ColorM{
 		// TODO: This is a temporary hack to calculate multiply of transposed matrices.
 		// Fix mulSquare implmentation and swap the arguments.
 		body: mulSquare(rhsb, lhsb, ColorMDim-1),
 		translate: []float32{
 			lhsb[0]*rhst[0] + lhsb[4]*rhst[1] + lhsb[8]*rhst[2] + lhsb[12]*rhst[3] + lhst[0],
 			lhsb[1]*rhst[0] + lhsb[5]*rhst[1] + lhsb[9]*rhst[2] + lhsb[13]*rhst[3] + lhst[1],
 			lhsb[2]*rhst[0] + lhsb[6]*rhst[1] + lhsb[10]*rhst[2] + lhsb[14]*rhst[3] + lhst[2],
 			lhsb[3]*rhst[0] + lhsb[7]*rhst[1] + lhsb[11]*rhst[2] + lhsb[15]*rhst[3] + lhst[3],
 		},
 	}
 }
 
 // Add is deprecated.
 func (c *ColorM) Add(other *ColorM) *ColorM {
 	lhsb := colorMIdentityBody
 	lhst := colorMIdentityTranslate
 	rhsb := colorMIdentityBody
 	rhst := colorMIdentityTranslate
 	if other.isInited() {
 		if other.body != nil {
 			lhsb = other.body
 		}
 		if other.translate != nil {
 			lhst = other.translate
 		}
 	}
 	if c.isInited() {
 		if c.body != nil {
 			rhsb = c.body
 		}
 		if c.translate != nil {
 			rhst = c.translate
 		}
 	}
 
 	newC := &ColorM{
 		body:      make([]float32, 16),
 		translate: make([]float32, 4),
 	}
 	for i := range lhsb {
 		newC.body[i] = lhsb[i] + rhsb[i]
 	}
 	for i := range lhst {
 		newC.translate[i] = lhst[i] + rhst[i]
 	}
 
 	return newC
 }
 
 // Scale scales the matrix by (r, g, b, a).
 func (c *ColorM) Scale(r, g, b, a float32) *ColorM {
 	if !c.isInited() {
 		return &ColorM{
 			body: []float32{
 				r, 0, 0, 0,
 				0, g, 0, 0,
 				0, 0, b, 0,
 				0, 0, 0, a,
 			},
 		}
 	}
 	eb := make([]float32, len(colorMIdentityBody))
 	if c.body != nil {
 		copy(eb, c.body)
 		for i := 0; i < ColorMDim-1; i++ {
 			eb[i*(ColorMDim-1)] *= r
 			eb[i*(ColorMDim-1)+1] *= g
 			eb[i*(ColorMDim-1)+2] *= b
 			eb[i*(ColorMDim-1)+3] *= a
 		}
 	} else {
 		eb[0] = r
 		eb[5] = g
 		eb[10] = b
 		eb[15] = a
 	}
 
 	et := make([]float32, len(colorMIdentityTranslate))
 	if c.translate != nil {
 		et[0] = c.translate[0] * r
 		et[1] = c.translate[1] * g
 		et[2] = c.translate[2] * b
 		et[3] = c.translate[3] * a
 	}
 
 	return &ColorM{
 		body:      eb,
 		translate: et,
 	}
 }
 
 // Translate translates the matrix by (r, g, b, a).
 func (c *ColorM) Translate(r, g, b, a float32) *ColorM {
 	if !c.isInited() {
 		return &ColorM{
 			translate: []float32{r, g, b, a},
 		}
 	}
 	es := make([]float32, len(colorMIdentityTranslate))
 	if c.translate != nil {
 		copy(es, c.translate)
 	}
 	es[0] += r
 	es[1] += g
 	es[2] += b
 	es[3] += a
 	return &ColorM{
 		body:      c.body,
 		translate: es,
 	}
 }
 
 var (
 	// The YCbCr value ranges are:
 	//   Y:  [ 0   - 1  ]
 	//   Cb: [-0.5 - 0.5]
 	//   Cr: [-0.5 - 0.5]
 
 	rgbToYCbCr = &ColorM{
 		body: []float32{
 			0.2990, -0.1687, 0.5000, 0,
 			0.5870, -0.3313, -0.4187, 0,
 			0.1140, 0.5000, -0.0813, 0,
 			0, 0, 0, 1,
 		},
 	}
 	yCbCrToRgb = &ColorM{
 		body: []float32{
 			1, 1, 1, 0,
 			0, -0.34414, 1.77200, 0,
 			1.40200, -0.71414, 0, 0,
 			0, 0, 0, 1,
 		},
 	}
 )
 
 // ChangeHSV changes HSV (Hue-Saturation-Value) elements.
 // hueTheta is a radian value to ratate hue.
 // saturationScale is a value to scale saturation.
 // valueScale is a value to scale value (a.k.a. brightness).
 //
 // This conversion uses RGB to/from YCrCb conversion.
 func (c *ColorM) ChangeHSV(hueTheta float64, saturationScale float32, valueScale float32) *ColorM {
 	sin, cos := math.Sincos(hueTheta)
 	s32, c32 := float32(sin), float32(cos)
 	c = c.Concat(rgbToYCbCr)
 	c = c.Concat(&ColorM{
 		body: []float32{
 			1, 0, 0, 0,
 			0, c32, s32, 0,
 			0, -s32, c32, 0,
 			0, 0, 0, 1,
 		},
 	})
 	s := saturationScale
 	v := valueScale
 	c = c.Scale(v, s*v, s*v, 1)
 	c = c.Concat(yCbCrToRgb)
 	return c
 }