2018-01-11 17:14:52 +02:00
|
|
|
package caire
|
|
|
|
|
|
|
|
|
|
import (
|
|
|
|
|
"image"
|
2018-01-15 10:06:26 +02:00
|
|
|
"image/png"
|
2018-01-11 17:14:52 +02:00
|
|
|
"math"
|
2018-01-13 15:11:54 +02:00
|
|
|
"os"
|
2018-01-14 14:49:48 +02:00
|
|
|
// "image/color"
|
2018-01-15 15:19:13 +02:00
|
|
|
"github.com/pkg/errors"
|
2018-01-11 17:14:52 +02:00
|
|
|
)
|
|
|
|
|
|
2018-01-15 09:59:53 +02:00
|
|
|
// SeamCarver is an interface that Carver uses to implement the Resize function.
|
|
|
|
|
// It takes an image and the output as parameters and returns the resized image
|
|
|
|
|
// and the error, if exists.
|
|
|
|
|
type SeamCarver interface {
|
2018-01-15 10:06:26 +02:00
|
|
|
Resize(*image.NRGBA, *image.NRGBA, string) (*os.File, error)
|
2018-01-11 17:14:52 +02:00
|
|
|
}
|
|
|
|
|
|
2018-01-15 09:59:53 +02:00
|
|
|
// Seam struct containing the pixel coordinate values.
|
2018-01-13 15:11:54 +02:00
|
|
|
type Seam struct {
|
2018-01-11 17:14:52 +02:00
|
|
|
X int
|
|
|
|
|
Y int
|
|
|
|
|
}
|
|
|
|
|
|
2018-01-15 09:59:53 +02:00
|
|
|
// NewCarver returns an initialized Carver structure.
|
|
|
|
|
func NewCarver(width, height, threshold, blur int, rw, rh, perc int) *Carver {
|
|
|
|
|
return &Carver{
|
|
|
|
|
width,
|
|
|
|
|
height,
|
|
|
|
|
make([]float64, width*height),
|
|
|
|
|
threshold,
|
|
|
|
|
blur,
|
|
|
|
|
rw, rh,
|
|
|
|
|
perc,
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Get energy pixel value.
|
|
|
|
|
func (c *Carver) get(x, y int) float64 {
|
2018-01-15 10:06:26 +02:00
|
|
|
px := x + y*c.Width
|
2018-01-15 09:59:53 +02:00
|
|
|
return c.Points[px]
|
2018-01-11 17:14:52 +02:00
|
|
|
}
|
|
|
|
|
|
2018-01-15 09:59:53 +02:00
|
|
|
// Set energy pixel value.
|
|
|
|
|
func (c *Carver) set(x, y int, px float64) {
|
2018-01-15 10:06:26 +02:00
|
|
|
idx := x + y*c.Width
|
2018-01-15 09:59:53 +02:00
|
|
|
c.Points[idx] = px
|
2018-01-11 17:14:52 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Compute the minimum energy level based on the following logic:
|
|
|
|
|
// - traverse the image from the second row to the last row
|
|
|
|
|
// and compute the cumulative minimum energy M for all possible
|
|
|
|
|
// connected seams for each entry (i, j).
|
|
|
|
|
//
|
|
|
|
|
// - the minimum energy level is calculated by summing up the current pixel value
|
|
|
|
|
// with the minimum pixel value of the neighboring pixels from the previous row.
|
2018-01-15 09:59:53 +02:00
|
|
|
func (c *Carver) computeSeams(img *image.NRGBA) []float64 {
|
2018-01-13 15:11:54 +02:00
|
|
|
var src *image.NRGBA
|
|
|
|
|
bounds := img.Bounds()
|
|
|
|
|
iw, ih := bounds.Dx(), bounds.Dy()
|
2018-01-15 09:59:53 +02:00
|
|
|
sobel := SobelFilter(Grayscale(img), float64(c.SobelThreshold))
|
2018-01-14 14:49:48 +02:00
|
|
|
|
2018-01-15 09:59:53 +02:00
|
|
|
if c.BlurRadius > 0 {
|
|
|
|
|
src = Stackblur(sobel, uint32(iw), uint32(ih), uint32(c.BlurRadius))
|
2018-01-13 15:11:54 +02:00
|
|
|
} else {
|
|
|
|
|
src = sobel
|
|
|
|
|
}
|
2018-01-15 09:59:53 +02:00
|
|
|
for x := 0; x < c.Width; x++ {
|
|
|
|
|
for y := 0; y < c.Height; y++ {
|
2018-01-14 14:49:48 +02:00
|
|
|
r, _, _, a := src.At(x, y).RGBA()
|
2018-01-15 10:06:26 +02:00
|
|
|
c.set(x, y, float64(r)/float64(a))
|
2018-01-11 17:14:52 +02:00
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
2018-01-15 09:59:53 +02:00
|
|
|
// Compute the minimum energy level and set the resulting value into carver table.
|
|
|
|
|
for x := 0; x < c.Width; x++ {
|
|
|
|
|
for y := 1; y < c.Height; y++ {
|
2018-01-13 15:11:54 +02:00
|
|
|
var left, middle, right float64
|
|
|
|
|
left, right = math.MaxFloat64, math.MaxFloat64
|
2018-01-11 17:14:52 +02:00
|
|
|
|
2018-01-13 15:11:54 +02:00
|
|
|
// Do not compute edge cases: pixels are far left.
|
|
|
|
|
if x > 0 {
|
2018-01-15 09:59:53 +02:00
|
|
|
left = c.get(x-1, y-1)
|
2018-01-13 15:11:54 +02:00
|
|
|
}
|
2018-01-15 09:59:53 +02:00
|
|
|
middle = c.get(x, y-1)
|
2018-01-13 15:11:54 +02:00
|
|
|
// Do not compute edge cases: pixels are far right.
|
2018-01-15 09:59:53 +02:00
|
|
|
if x < c.Width-1 {
|
|
|
|
|
right = c.get(x+1, y-1)
|
2018-01-13 15:11:54 +02:00
|
|
|
}
|
|
|
|
|
// Obtain the minimum pixel value
|
|
|
|
|
min := math.Min(math.Min(left, middle), right)
|
2018-01-15 10:06:26 +02:00
|
|
|
c.set(x, y, c.get(x, y)+min)
|
2018-01-11 17:14:52 +02:00
|
|
|
}
|
|
|
|
|
}
|
2018-01-15 09:59:53 +02:00
|
|
|
return c.Points
|
2018-01-11 17:14:52 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Find the lowest vertical energy seam.
|
2018-01-15 09:59:53 +02:00
|
|
|
func (c *Carver) findLowestEnergySeams() []Seam {
|
2018-01-11 17:14:52 +02:00
|
|
|
// Find the lowest cost seam from the energy matrix starting from the last row.
|
|
|
|
|
var min float64 = math.MaxFloat64
|
|
|
|
|
var px int
|
2018-01-13 15:11:54 +02:00
|
|
|
seams := make([]Seam, 0)
|
2018-01-11 17:14:52 +02:00
|
|
|
|
2018-01-14 14:49:48 +02:00
|
|
|
// Find the pixel on the last row with the minimum cumulative energy and use this as the starting pixel
|
2018-01-15 09:59:53 +02:00
|
|
|
for x := 0; x < c.Width; x++ {
|
|
|
|
|
seam := c.get(x, c.Height-1)
|
2018-01-14 14:49:48 +02:00
|
|
|
if seam < min && seam > 0 {
|
2018-01-11 17:14:52 +02:00
|
|
|
min = seam
|
|
|
|
|
px = x
|
|
|
|
|
}
|
|
|
|
|
}
|
2018-01-15 10:06:26 +02:00
|
|
|
seams = append(seams, Seam{X: px, Y: c.Height - 1})
|
2018-01-13 15:11:54 +02:00
|
|
|
var left, middle, right float64
|
2018-01-11 17:14:52 +02:00
|
|
|
|
|
|
|
|
// Walk up in the matrix table,
|
|
|
|
|
// check the immediate three top pixel seam level and
|
|
|
|
|
// add add the one which has the lowest cumulative energy.
|
2018-01-15 10:06:26 +02:00
|
|
|
for y := c.Height - 2; y >= 0; y-- {
|
2018-01-13 15:11:54 +02:00
|
|
|
left, right = math.MaxFloat64, math.MaxFloat64
|
2018-01-15 09:59:53 +02:00
|
|
|
middle = c.get(px, y)
|
2018-01-11 17:14:52 +02:00
|
|
|
// Leftmost seam, no child to the left
|
|
|
|
|
if px == 0 {
|
2018-01-15 09:59:53 +02:00
|
|
|
right = c.get(px+1, y)
|
|
|
|
|
middle = c.get(px, y)
|
2018-01-13 15:11:54 +02:00
|
|
|
if right < middle {
|
2018-01-11 17:14:52 +02:00
|
|
|
px += 1
|
|
|
|
|
}
|
2018-01-15 10:06:26 +02:00
|
|
|
// Rightmost seam, no child to the right
|
2018-01-15 09:59:53 +02:00
|
|
|
} else if px == c.Width-1 {
|
|
|
|
|
left = c.get(px-1, y)
|
|
|
|
|
middle = c.get(px, y)
|
2018-01-13 15:11:54 +02:00
|
|
|
if left < middle {
|
2018-01-11 17:14:52 +02:00
|
|
|
px -= 1
|
|
|
|
|
}
|
|
|
|
|
} else {
|
2018-01-15 09:59:53 +02:00
|
|
|
left = c.get(px-1, y)
|
|
|
|
|
middle = c.get(px, y)
|
|
|
|
|
right = c.get(px+1, y)
|
2018-01-13 15:11:54 +02:00
|
|
|
min := math.Min(math.Min(left, middle), right)
|
2018-01-11 17:14:52 +02:00
|
|
|
|
|
|
|
|
if min == left {
|
|
|
|
|
px -= 1
|
|
|
|
|
} else if min == right {
|
|
|
|
|
px += 1
|
|
|
|
|
}
|
|
|
|
|
}
|
2018-01-13 15:11:54 +02:00
|
|
|
seams = append(seams, Seam{X: px, Y: y})
|
2018-01-11 17:14:52 +02:00
|
|
|
}
|
|
|
|
|
return seams
|
|
|
|
|
}
|
|
|
|
|
|
2018-01-15 09:59:53 +02:00
|
|
|
// Remove image pixels based on energy seams level.
|
|
|
|
|
func (c *Carver) removeSeam(img *image.NRGBA, seams []Seam) *image.NRGBA {
|
2018-01-13 15:11:54 +02:00
|
|
|
bounds := img.Bounds()
|
2018-01-14 14:49:48 +02:00
|
|
|
dst := image.NewNRGBA(image.Rect(0, 0, bounds.Dx()-1, bounds.Dy()))
|
2018-01-13 15:11:54 +02:00
|
|
|
|
|
|
|
|
for _, seam := range seams {
|
|
|
|
|
y := seam.Y
|
|
|
|
|
for x := 0; x < bounds.Max.X; x++ {
|
|
|
|
|
if seam.X == x {
|
|
|
|
|
continue
|
2018-01-14 14:49:48 +02:00
|
|
|
//dst.Set(x-1, y, color.RGBA{255, 0, 0, 255})
|
2018-01-13 15:11:54 +02:00
|
|
|
} else if seam.X < x {
|
|
|
|
|
dst.Set(x-1, y, img.At(x, y))
|
|
|
|
|
} else {
|
|
|
|
|
dst.Set(x, y, img.At(x, y))
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
return dst
|
|
|
|
|
}
|
|
|
|
|
|
2018-01-15 15:19:13 +02:00
|
|
|
// Rotate image by 90 degree clockwise
|
|
|
|
|
func (c *Carver) rotateImage90(src *image.NRGBA) *image.NRGBA {
|
|
|
|
|
b := src.Bounds()
|
|
|
|
|
dst := image.NewNRGBA(image.Rect(0, 0, b.Max.Y, b.Max.X))
|
|
|
|
|
for dstY := 0; dstY < b.Max.X; dstY++ {
|
|
|
|
|
for dstX := 0; dstX < b.Max.Y; dstX++ {
|
|
|
|
|
srcX := b.Max.X - dstY - 1
|
|
|
|
|
srcY := dstX
|
|
|
|
|
|
|
|
|
|
srcOff := srcY*src.Stride + srcX*4
|
|
|
|
|
dstOff := dstY*dst.Stride + dstX*4
|
|
|
|
|
copy(dst.Pix[dstOff:dstOff+4], src.Pix[srcOff:srcOff+4])
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
return dst
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Rotate image by 270 degree clockwise
|
|
|
|
|
func (c *Carver) rotateImage270(src *image.NRGBA) *image.NRGBA {
|
|
|
|
|
b := src.Bounds()
|
|
|
|
|
dst := image.NewNRGBA(image.Rect(0, 0, b.Max.Y, b.Max.X))
|
|
|
|
|
for dstY := 0; dstY < b.Max.X; dstY++ {
|
|
|
|
|
for dstX := 0; dstX < b.Max.Y; dstX++ {
|
|
|
|
|
srcX := dstY
|
|
|
|
|
srcY := b.Max.Y - dstX - 1
|
|
|
|
|
|
|
|
|
|
srcOff := srcY*src.Stride + srcX*4
|
|
|
|
|
dstOff := dstY*dst.Stride + dstX*4
|
|
|
|
|
copy(dst.Pix[dstOff:dstOff+4], src.Pix[srcOff:srcOff+4])
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
return dst
|
|
|
|
|
}
|
|
|
|
|
|
2018-01-15 09:59:53 +02:00
|
|
|
// Resize is the main function taking the source image and encoding the rescaled image into the output file.
|
2018-01-15 15:19:13 +02:00
|
|
|
func (c *Carver) Resize(img *image.NRGBA, sobel *image.NRGBA, output string) (*os.File, error) {
|
|
|
|
|
width, height := img.Bounds().Max.X, img.Bounds().Max.Y
|
|
|
|
|
carver := NewCarver(width, height, c.SobelThreshold, c.BlurRadius, c.NewWidth, c.NewHeight, c.Percentage)
|
|
|
|
|
|
2018-01-15 09:59:53 +02:00
|
|
|
resize := func() {
|
2018-01-15 15:19:13 +02:00
|
|
|
carver.computeSeams(img)
|
2018-01-15 09:59:53 +02:00
|
|
|
seams := carver.findLowestEnergySeams()
|
2018-01-15 15:19:13 +02:00
|
|
|
img = carver.removeSeam(img, seams)
|
2018-01-15 09:59:53 +02:00
|
|
|
}
|
2018-01-15 15:19:13 +02:00
|
|
|
|
|
|
|
|
if carver.Percentage > 0 {
|
2018-01-15 09:59:53 +02:00
|
|
|
// Calculate new sizes based on provided percentage.
|
2018-01-15 15:19:13 +02:00
|
|
|
nw := carver.Width - int(float64(carver.Width) - (float64(carver.Percentage)/100 * float64(carver.Width)))
|
|
|
|
|
nh := carver.Height - int(float64(carver.Height) - (float64(carver.Percentage)/100 * float64(carver.Height)))
|
|
|
|
|
|
|
|
|
|
// Resize image horizontally
|
2018-01-15 09:59:53 +02:00
|
|
|
for x := 0; x < nw; x++ {
|
|
|
|
|
resize()
|
|
|
|
|
}
|
2018-01-15 15:19:13 +02:00
|
|
|
// Resize image vertically
|
|
|
|
|
img = c.rotateImage90(img)
|
2018-01-15 09:59:53 +02:00
|
|
|
for y := 0; y < nh; y++ {
|
|
|
|
|
resize()
|
|
|
|
|
}
|
2018-01-15 15:19:13 +02:00
|
|
|
img = c.rotateImage270(img)
|
|
|
|
|
} else if carver.NewWidth > 0 || carver.NewHeight > 0 {
|
|
|
|
|
if carver.NewWidth > 0 {
|
|
|
|
|
if carver.NewWidth > carver.Width {
|
|
|
|
|
err := errors.New("new width should be less than image width.")
|
|
|
|
|
return nil, err
|
|
|
|
|
}
|
2018-01-15 09:59:53 +02:00
|
|
|
for x := 0; x < carver.NewWidth; x++ {
|
|
|
|
|
resize()
|
|
|
|
|
}
|
2018-01-15 15:19:13 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if carver.NewHeight > 0 {
|
|
|
|
|
if carver.NewHeight > carver.Height {
|
|
|
|
|
err := errors.New("new height should be less than image height.")
|
|
|
|
|
return nil, err
|
|
|
|
|
}
|
|
|
|
|
img = c.rotateImage90(img)
|
2018-01-15 09:59:53 +02:00
|
|
|
for y := 0; y < carver.NewHeight; y++ {
|
|
|
|
|
resize()
|
|
|
|
|
}
|
2018-01-15 15:19:13 +02:00
|
|
|
img = c.rotateImage270(img)
|
2018-01-13 15:11:54 +02:00
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
fq, err := os.Create(output)
|
|
|
|
|
if err != nil {
|
|
|
|
|
return nil, err
|
|
|
|
|
}
|
|
|
|
|
defer fq.Close()
|
|
|
|
|
|
2018-01-15 15:19:13 +02:00
|
|
|
if err = png.Encode(fq, img); err != nil {
|
2018-01-13 15:11:54 +02:00
|
|
|
return nil, err
|
|
|
|
|
}
|
|
|
|
|
return fq, nil
|
2018-01-15 10:06:26 +02:00
|
|
|
}
|
