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refactor transform module

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This commit is contained in:
legoff.laurent 2010-11-26 14:07:49 +00:00
parent ae9b990671
commit 5e6aa57cf2
3 changed files with 48 additions and 72 deletions
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18
draw2d/src/pkg/draw2d/draw2d.go
View file

@ -6,6 +6,7 @@ package draw2d
import (
"exp/draw"
"image"
//"math"
"freetype-go.googlecode.com/hg/freetype/raster"
)
@ -79,28 +80,19 @@ func (gc *GraphicContext) SetMatrixTransform(tr MatrixTransform) {
}
func (gc *GraphicContext) ComposeMatrixTransform(tr MatrixTransform) {
gc.current.tr.Compose(tr)
gc.current.tr = tr.Multiply(gc.current.tr)
}
func (gc *GraphicContext) Rotate(angle float) {
ox, oy := gc.current.path.LastPoint()
tr := NewTranslationMatrix(ox, oy)
tr2 := NewRotationMatrix(angle)
tr1 := tr.GetInverseTransformation()
gc.current.tr.Compose(tr).Compose(tr2).Compose(tr1)
gc.current.tr.Rotate(angle)
}
func (gc *GraphicContext) Translate(tx, ty float) {
tr := NewTranslationMatrix(tx, ty)
gc.current.tr.Compose(tr)
gc.current.tr.Translate(tx, ty)
}
func (gc *GraphicContext) Scale(sx, sy float) {
ox, oy := gc.current.path.LastPoint()
tr := NewTranslationMatrix(ox, oy)
tr2 := NewScaleMatrix(sx, sy)
tr1 := tr.GetInverseTransformation()
gc.current.tr.Compose(tr).Compose(tr2).Compose(tr1)
gc.current.tr.Scale(sx, sy)
}
func (gc *GraphicContext) Clear() {

96
draw2d/src/pkg/draw2d/transform.go
View file

@ -9,36 +9,19 @@ const (
epsilon = 1e-6
)
func (tr MatrixTransform) TransformX(x, y float) float {
return x*tr[0] + y*tr[2] + tr[4]
}
func (tr MatrixTransform) TransformY(x, y float) float {
return x*tr[1] + y*tr[3] + tr[5]
}
func (tr MatrixTransform) Determinant() float {
return tr[0]*tr[3] - tr[1]*tr[2]
}
func (tr MatrixTransform) InverseTransformX(x, y float) float {
return ((x-tr[4])*tr[3] - (y-tr[5])*tr[2]) / tr.Determinant()
}
func (tr MatrixTransform) InverseTransformY(x, y float) float {
return ((y-tr[5])*tr[0] - (x-tr[4])*tr[1]) / tr.Determinant()
}
func (tr MatrixTransform) Transform(points ...*float) {
for i, j := 0, 1; j < len(points); i, j = i+2, j+2 {
x := *points[i]
y := *points[j]
*points[i] = tr.TransformX(x, y)
*points[j] = tr.TransformY(x, y)
*points[i] = x*tr[0] + y*tr[2] + tr[4]
*points[j] = x*tr[1] + y*tr[3] + tr[5]
}
}
func (tr MatrixTransform) InverseTransform(points ...*float) {
d := tr.Determinant() // matrix determinant
for i, j := 0, 1; j < len(points); i, j = i+2, j+2 {
@ -51,30 +34,12 @@ func (tr MatrixTransform) InverseTransform(points ...*float) {
// ******************** Vector transformations ********************
func (tr MatrixTransform) VectorTransformX(x, y float) float {
return x*tr[0] + y*tr[2]
}
func (tr MatrixTransform) VectorTransformY(x, y float) float {
return x*tr[1] + y*tr[3]
}
func (tr MatrixTransform) VectorInverseTransformX(x, y float) float {
d := tr.Determinant() // matrix determinant
return (x*tr[3] - y*tr[2]) / d
}
func (tr MatrixTransform) VectorInverseTransformY(x, y float) float {
d := tr.Determinant() // matrix determinant
return (y*tr[0] - x*tr[1]) / d
}
func (tr MatrixTransform) VectorTransform(points ...*float) {
for i, j := 0, 1; j < len(points); i, j = i+2, j+2 {
x := *points[i]
y := *points[j]
*points[i] = tr.VectorTransformX(x, y)
*points[j] = tr.VectorTransformY(x, y)
*points[i] = x*tr[0] + y*tr[2]
*points[j] = x*tr[1] + y*tr[3]
}
}
@ -112,7 +77,7 @@ func NewRotationMatrix(angle float) MatrixTransform {
/**
* Creates a transformation, combining a scale and a translation, that transform rectangle1 into rectangle2.
*/
func NewMatrixTransform(rectangle1 [4]float, rectangle2 [4]float) MatrixTransform {
func NewMatrixTransform(rectangle1, rectangle2 [4]float) MatrixTransform {
xScale := (rectangle2[2] - rectangle2[0]) / (rectangle1[2] - rectangle1[0])
yScale := (rectangle2[3] - rectangle2[1]) / (rectangle1[3] - rectangle1[1])
xOffset := rectangle2[0] - (rectangle1[0] * xScale)
@ -136,15 +101,8 @@ func (tr MatrixTransform) GetInverseTransformation() MatrixTransform {
(tr[1]*tr[4] - tr[0]*tr[5]) / d}
}
/**
* Returns a transformation that is the composition (tr2 o tr1) of the given
* transformations tr2 and tr1.
* For given point (x, y), the composed transformation is defined by the
* equation:
* (tr2 o tr1)(x, y) = tr2(tr1(x, y))
*/
func (tr1 MatrixTransform) GetComposedTransformation(tr2 MatrixTransform) MatrixTransform {
func (tr1 MatrixTransform) Multiply(tr2 MatrixTransform) MatrixTransform {
return [6]float{
tr1[0]*tr2[0] + tr1[1]*tr2[2],
tr1[1]*tr2[3] + tr1[0]*tr2[1],
@ -154,14 +112,40 @@ func (tr1 MatrixTransform) GetComposedTransformation(tr2 MatrixTransform) Matrix
tr1[5]*tr2[3] + tr1[4]*tr2[1] + tr2[5]}
}
func (tr1 *MatrixTransform) Compose(tr2 MatrixTransform) (*MatrixTransform){
tr1[0] = tr2[0]*tr1[0] + tr2[1]*tr1[2]
tr1[1] = tr2[1]*tr1[3] + tr2[0]*tr1[1]
tr1[2] = tr2[2]*tr1[0] + tr2[3]*tr1[2]
tr1[3] = tr2[3]*tr1[3] + tr2[2]*tr1[1]
tr1[4] = tr2[4]*tr1[0] + tr2[5]*tr1[2] + tr1[4]
tr1[5] = tr2[5]*tr1[3] + tr2[4]*tr1[1] + tr1[5]
return tr1
func (tr *MatrixTransform) Scale(sx, sy float) (*MatrixTransform){
tr[0] = tr[0]*sx;
tr[1] = tr[1]*sx;
tr[4] = tr[4]*sx;
tr[2] = tr[2]*sy;
tr[3] = tr[3]*sy;
tr[5] = tr[5]*sy;
return tr;
}
func (tr *MatrixTransform) Translate(tx, ty float) (*MatrixTransform){
tr[4] = tr[4] + tx
tr[5] = tr[5] + ty
return tr;
}
func (tr *MatrixTransform) Rotate(angle float) (*MatrixTransform){
ca := cos(angle);
sa := sin(angle);
t0 := tr[0] * ca - tr[1] * sa;
t2 := tr[1] * ca - tr[3] * sa;
t4 := tr[4] * ca - tr[5] * sa;
tr[1] = tr[0] * sa + tr[1] * ca;
tr[3] = tr[2] * sa + tr[3] * ca;
tr[5] = tr[4] * sa + tr[5] * ca;
tr[0] = t0;
tr[2] = t2;
tr[4] = t4;
return tr;
}
func (tr MatrixTransform) GetTranslation() (x, y float) {
return tr[4], tr[5]
}
// ******************** Testing ********************