/
saveGIF.go
61 lines (48 loc) · 1.27 KB
/
saveGIF.go
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package main
import (
"github.com/nfnt/resize"
"image"
"image/color"
"image/gif"
"io"
)
type GIFManipulator struct {
gif *gif.GIF
}
func NewGIFManipulator(reader io.ReadSeeker, format string, image image.Image) (Manipulator, error) {
if _, err := reader.Seek(0, 0); err != nil {
return nil, err
}
g, err := gif.DecodeAll(reader)
if err != nil {
return nil, err
}
return &GIFManipulator{gif: g}, nil
}
func (m *GIFManipulator) Format() string {
return "gif"
}
func (m *GIFManipulator) Bounds() image.Rectangle {
if len(m.gif.Image) == 0 {
return image.Rectangle{}
}
return m.gif.Image[0].Bounds()
}
func (m *GIFManipulator) Resize(width, height uint) {
for i, v := range m.gif.Image {
resizedImg := resize.Resize(width, height, v, resize.NearestNeighbor)
m.gif.Image[i] = imageToPalleted(resizedImg, m.gif.Image[i].Palette)
}
}
func (m *GIFManipulator) Save(writer io.Writer) error {
return gif.EncodeAll(writer, m.gif)
}
func imageToPalleted(img image.Image, palette color.Palette) *image.Paletted {
palleted := image.NewPaletted(img.Bounds(), palette)
for x := palleted.Bounds().Min.X; x < palleted.Bounds().Max.X; x++ {
for y := palleted.Bounds().Min.Y; y < palleted.Bounds().Max.Y; y++ {
palleted.Set(x, y, img.At(x, y))
}
}
return palleted
}