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package main
// This more complicated example shows how to dither a GIF animation.
import (
"fmt"
"image"
"image/color"
"image/gif"
_ "image/png" // For frame decoding
"os"
"github.com/makeworld-the-better-one/dither/v2"
)
const numFrames = 20
func main() {
// Create the kind of Dither we want
palette := []color.Color{
color.Black,
color.White,
color.RGBA{255, 0, 0, 255}, // Red
color.RGBA{0, 255, 0, 255}, // Green
color.RGBA{0, 0, 255, 255}, // Blue
}
d := dither.NewDitherer(palette)
d.Matrix = dither.FloydSteinberg // Why not?
// Decode first frame and get image.Config for use in gif.GIF.
// gif.GIF requires *image.Paletted is used, so DitherPaletted
// is called instead of Dither.
f, err := os.Open("../input/ball_001.png")
if err != nil {
panic(err)
}
img, _, err := image.Decode(f)
if err != nil {
panic(err)
}
f.Close()
firstFrame, config := d.DitherPalettedConfig(img)
frames := make([]*image.Paletted, numFrames)
frames[0] = firstFrame
// Decode other frames
for i := 1; i < numFrames; i++ {
f, err := os.Open(fmt.Sprintf("../input/ball_0%02d.png", i))
if err != nil {
panic(err)
}
img, _, err := image.Decode(f)
if err != nil {
panic(err)
}
f.Close()
frames[i] = d.DitherPaletted(img)
}
// Frame delay - same for each frame
delays := make([]int, numFrames)
for i := range delays {
delays[i] = 7
}
// Setup GIF and encode
g := gif.GIF{
Image: frames,
Delay: delays,
// By specifying a Config, we can set a global color table for the GIF.
// This is more efficient then each frame having its own color table, which
// is the default when there's no config.
Config: config,
}
f2, err := os.Create("../output/gif_animation.gif")
if err != nil {
panic(err)
}
err = gif.EncodeAll(f2, &g)
if err != nil {
panic(err)
}
}
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