transform clean up
This commit is contained in:
Laurent Le Goff
parent
511954196b
commit
409365e40f
49
transform.go
49
transform.go
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@ -13,11 +13,12 @@ const (
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epsilon = 1e-6
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)
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// Determinant compute the determinant of the matrix
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func (tr MatrixTransform) Determinant() float64 {
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return tr[0]*tr[3] - tr[1]*tr[2]
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}
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// Transform apply the Affine Matrix to points. It modify the points passed in parameter.
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// Transform apply the transformation matrix to points. It modify the points passed in parameter.
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func (tr MatrixTransform) Transform(points []float64) {
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for i, j := 0, 1; j < len(points); i, j = i+2, j+2 {
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x := points[i]
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@ -27,6 +28,7 @@ func (tr MatrixTransform) Transform(points []float64) {
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}
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}
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// TransformPoint apply the transformation matrix to point. It returns the point the transformed point.
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func (tr MatrixTransform) TransformPoint(x, y float64) (xres, yres float64) {
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xres = x*tr[0] + y*tr[2] + tr[4]
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yres = x*tr[1] + y*tr[3] + tr[5]
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@ -40,6 +42,7 @@ func minMax(x, y float64) (min, max float64) {
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return x, y
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}
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// Transform apply the transformation matrix to the rectangle represented by the min and the max point of the rectangle
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func (tr MatrixTransform) TransformRectangle(x0, y0, x2, y2 float64) (nx0, ny0, nx2, ny2 float64) {
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points := []float64{x0, y0, x2, y0, x2, y2, x0, y2}
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tr.Transform(points)
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@ -55,6 +58,7 @@ func (tr MatrixTransform) TransformRectangle(x0, y0, x2, y2 float64) (nx0, ny0,
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return nx0, ny0, nx2, ny2
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}
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// InverseTransform apply the transformation inverse matrix to the rectangle represented by the min and the max point of the rectangle
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func (tr MatrixTransform) InverseTransform(points []float64) {
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d := tr.Determinant() // matrix determinant
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for i, j := 0, 1; j < len(points); i, j = i+2, j+2 {
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@ -65,6 +69,7 @@ func (tr MatrixTransform) InverseTransform(points []float64) {
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}
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}
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// InverseTransformPoint apply the transformation inverse matrix to point. It returns the point the transformed point.
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func (tr MatrixTransform) InverseTransformPoint(x, y float64) (xres, yres float64) {
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d := tr.Determinant() // matrix determinant
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xres = ((x-tr[4])*tr[3] - (y-tr[5])*tr[2]) / d
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@ -72,8 +77,8 @@ func (tr MatrixTransform) InverseTransformPoint(x, y float64) (xres, yres float6
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return xres, yres
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}
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// ******************** Vector transformations ********************
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// VectorTransform apply the transformation matrix to points without using the translation parameter of the affine matrix.
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// It modify the points passed in parameter.
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func (tr MatrixTransform) VectorTransform(points []float64) {
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for i, j := 0, 1; j < len(points); i, j = i+2, j+2 {
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x := points[i]
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@ -83,41 +88,30 @@ func (tr MatrixTransform) VectorTransform(points []float64) {
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}
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}
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// ******************** Transformations creation ********************
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/** Creates an identity transformation. */
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// NewIdentityMatrix creates an identity transformation matrix.
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func NewIdentityMatrix() MatrixTransform {
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return [6]float64{1, 0, 0, 1, 0, 0}
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}
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/**
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* Creates a transformation with a translation, that,
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* transform point1 into point2.
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*/
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// NewTranslationMatrix creates a transformation matrix with a translation tx and ty translation parameter
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func NewTranslationMatrix(tx, ty float64) MatrixTransform {
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return [6]float64{1, 0, 0, 1, tx, ty}
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}
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/**
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* Creates a transformation with a sx, sy scale factor
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*/
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// NewScaleMatrix creates a transformation matrix with a sx, sy scale factor
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func NewScaleMatrix(sx, sy float64) MatrixTransform {
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return [6]float64{sx, 0, 0, sy, 0, 0}
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}
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/**
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* Creates a rotation transformation.
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*/
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// NewRotationMatrix creates a rotation transformation matrix. angle is in radian
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func NewRotationMatrix(angle float64) MatrixTransform {
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c := math.Cos(angle)
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s := math.Sin(angle)
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return [6]float64{c, s, -s, c, 0, 0}
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}
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/**
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* Creates a transformation, combining a scale and a translation, that transform rectangle1 into rectangle2.
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*/
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func NewMatrixTransform(rectangle1, rectangle2 [4]float64) MatrixTransform {
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// NewMatrixTransform creates a transformation matrix, combining a scale and a translation, that transform rectangle1 into rectangle2.
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func NewMatrixFromRects(rectangle1, rectangle2 [4]float64) MatrixTransform {
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xScale := (rectangle2[2] - rectangle2[0]) / (rectangle1[2] - rectangle1[0])
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yScale := (rectangle2[3] - rectangle2[1]) / (rectangle1[3] - rectangle1[1])
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xOffset := rectangle2[0] - (rectangle1[0] * xScale)
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@ -125,12 +119,8 @@ func NewMatrixTransform(rectangle1, rectangle2 [4]float64) MatrixTransform {
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return [6]float64{xScale, 0, 0, yScale, xOffset, yOffset}
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}
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// ******************** Transformations operations ********************
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/**
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* Returns a transformation that is the inverse of the given transformation.
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*/
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func (tr MatrixTransform) GetInverseTransformation() MatrixTransform {
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// Inverse returns a matrix that is the inverse of the given matrix.
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func (tr MatrixTransform) Inverse() MatrixTransform {
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d := tr.Determinant() // matrix determinant
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return [6]float64{
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tr[3] / d,
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@ -141,6 +131,7 @@ func (tr MatrixTransform) GetInverseTransformation() MatrixTransform {
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(tr[1]*tr[4] - tr[0]*tr[5]) / d}
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}
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// Multiply Compose Matrix tr1 with tr2 returns the resulting matrix
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func (tr1 MatrixTransform) Multiply(tr2 MatrixTransform) MatrixTransform {
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return [6]float64{
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tr1[0]*tr2[0] + tr1[1]*tr2[2],
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@ -151,6 +142,7 @@ func (tr1 MatrixTransform) Multiply(tr2 MatrixTransform) MatrixTransform {
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tr1[5]*tr2[3] + tr1[4]*tr2[1] + tr2[5]}
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}
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// Scale add a scale to the matrix
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func (tr *MatrixTransform) Scale(sx, sy float64) *MatrixTransform {
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tr[0] = sx * tr[0]
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tr[1] = sx * tr[1]
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@ -159,12 +151,14 @@ func (tr *MatrixTransform) Scale(sx, sy float64) *MatrixTransform {
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return tr
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}
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// Translate add a translation to the matrix
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func (tr *MatrixTransform) Translate(tx, ty float64) *MatrixTransform {
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tr[4] = tx*tr[0] + ty*tr[2] + tr[4]
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tr[5] = ty*tr[3] + tx*tr[1] + tr[5]
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return tr
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}
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// Rotate add a rotation to the matrix. angle is in radian
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func (tr *MatrixTransform) Rotate(angle float64) *MatrixTransform {
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c := math.Cos(angle)
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s := math.Sin(angle)
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@ -179,14 +173,17 @@ func (tr *MatrixTransform) Rotate(angle float64) *MatrixTransform {
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return tr
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}
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// GetTranslation
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func (tr MatrixTransform) GetTranslation() (x, y float64) {
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return tr[4], tr[5]
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}
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// GetScaling
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func (tr MatrixTransform) GetScaling() (x, y float64) {
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return tr[0], tr[3]
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}
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// GetScale computes the scale of the matrix
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func (tr MatrixTransform) GetScale() float64 {
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x := 0.707106781*tr[0] + 0.707106781*tr[1]
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y := 0.707106781*tr[2] + 0.707106781*tr[3]
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