67 lines
1.5 KiB
Go
67 lines
1.5 KiB
Go
package geom
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// RectangleF is defined by two points, the minimum and maximum (floating point).
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// Tries to use the same interface as the image.Rectangle but uses float64 instead of int.
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type RectangleF struct {
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Min, Max PointF
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}
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// RectF is a shorthand function to create a rectangle.
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func RectF(x0, y0, x1, y1 float64) RectangleF {
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if x0 > x1 {
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x0, x1 = x1, x0
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}
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if y0 > y1 {
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y0, y1 = y1, y0
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}
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return RectangleF{PtF(x0, y0), PtF(x1, y1)}
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}
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// Add translates rectangle r by point p.
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func (r RectangleF) Add(p PointF) RectangleF {
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return RectangleF{
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PointF{r.Min.X + p.X, r.Min.Y + p.Y},
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PointF{r.Max.X + p.X, r.Max.Y + p.Y},
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}
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}
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// Center returns the center of the rectangle.
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func (r RectangleF) Center() PointF {
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return PointF{r.Min.X + .5*(r.Max.X-r.Min.X), r.Min.Y + .5*(r.Max.Y-r.Min.Y)}
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}
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// Dx returns the width of r.
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func (r RectangleF) Dx() float64 {
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return r.Max.X - r.Min.X
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}
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// Dy returns the height of r.
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func (r RectangleF) Dy() float64 {
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return r.Max.Y - r.Min.Y
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}
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// Inset returns the rectangle r inset by n. The resulting rectangle will never have
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// a negative size.
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func (r RectangleF) Inset(n float64) RectangleF {
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if r.Dx() < 2*n {
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r.Min.X = (r.Min.X + r.Max.X) / 2
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r.Max.X = r.Min.X
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} else {
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r.Min.X += n
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r.Max.X -= n
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}
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if r.Dy() < 2*n {
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r.Min.Y = (r.Min.Y + r.Max.Y) / 2
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r.Max.Y = r.Min.Y
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} else {
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r.Min.Y += n
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r.Max.Y -= n
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}
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return r
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}
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// Size returns the size of the rectangle.
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func (r RectangleF) Size() PointF {
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return PointF{r.Max.X - r.Min.X, r.Max.Y - r.Min.Y}
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}
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