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imageresizer.go
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/
imageresizer.go
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package valueobject
import (
"github.com/disintegration/gift"
"image"
"math"
)
// Needed by smartcrop
type imagingResizer struct {
p *ImageProcessor
filter gift.Resampling
}
func (r imagingResizer) Resize(img image.Image, width, height uint) image.Image {
// See https://github.com/gohugoio/hugo/issues/7955#issuecomment-861710681
scaleX, scaleY := calcFactorsNfnt(width, height, float64(img.Bounds().Dx()), float64(img.Bounds().Dy()))
if width == 0 {
width = uint(math.Ceil(float64(img.Bounds().Dx()) / scaleX))
}
if height == 0 {
height = uint(math.Ceil(float64(img.Bounds().Dy()) / scaleY))
}
result, _ := r.p.Filter(img, gift.Resize(int(width), int(height), r.filter))
return result
}
// Calculates scaling factors using old and new images dimensions.
// Code borrowed from https://github.com/nfnt/resize/blob/83c6a9932646f83e3267f353373d47347b6036b2/resize.go#L593
func calcFactorsNfnt(width, height uint, oldWidth, oldHeight float64) (scaleX, scaleY float64) {
if width == 0 {
if height == 0 {
scaleX = 1.0
scaleY = 1.0
} else {
scaleY = oldHeight / float64(height)
scaleX = scaleY
}
} else {
scaleX = oldWidth / float64(width)
if height == 0 {
scaleY = scaleX
} else {
scaleY = oldHeight / float64(height)
}
}
return
}