fixed dependencies

vendor/git.sr.ht/~sbinet/gg/matrix.go

@@ -0,0 +1,92 @@
+// Copyright ©2022 The gg Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package gg
+
+import "math"
+
+type Matrix struct {
+	XX, YX, XY, YY, X0, Y0 float64
+}
+
+func Identity() Matrix {
+	return Matrix{
+		1, 0,
+		0, 1,
+		0, 0,
+	}
+}
+
+func Translate(x, y float64) Matrix {
+	return Matrix{
+		1, 0,
+		0, 1,
+		x, y,
+	}
+}
+
+func Scale(x, y float64) Matrix {
+	return Matrix{
+		x, 0,
+		0, y,
+		0, 0,
+	}
+}
+
+func Rotate(angle float64) Matrix {
+	c := math.Cos(angle)
+	s := math.Sin(angle)
+	return Matrix{
+		c, s,
+		-s, c,
+		0, 0,
+	}
+}
+
+func Shear(x, y float64) Matrix {
+	return Matrix{
+		1, y,
+		x, 1,
+		0, 0,
+	}
+}
+
+func (a Matrix) Multiply(b Matrix) Matrix {
+	return Matrix{
+		a.XX*b.XX + a.YX*b.XY,
+		a.XX*b.YX + a.YX*b.YY,
+		a.XY*b.XX + a.YY*b.XY,
+		a.XY*b.YX + a.YY*b.YY,
+		a.X0*b.XX + a.Y0*b.XY + b.X0,
+		a.X0*b.YX + a.Y0*b.YY + b.Y0,
+	}
+}
+
+func (a Matrix) TransformVector(x, y float64) (tx, ty float64) {
+	tx = a.XX*x + a.XY*y
+	ty = a.YX*x + a.YY*y
+	return
+}
+
+func (a Matrix) TransformPoint(x, y float64) (tx, ty float64) {
+	tx = a.XX*x + a.XY*y + a.X0
+	ty = a.YX*x + a.YY*y + a.Y0
+	return
+}
+
+func (a Matrix) Translate(x, y float64) Matrix {
+	return Translate(x, y).Multiply(a)
+}
+
+func (a Matrix) Scale(x, y float64) Matrix {
+	return Scale(x, y).Multiply(a)
+}
+
+func (a Matrix) Rotate(angle float64) Matrix {
+	return Rotate(angle).Multiply(a)
+}
+
+func (a Matrix) Shear(x, y float64) Matrix {
+	return Shear(x, y).Multiply(a)
+}