1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
|
package themagicpipe
import (
"os/exec"
"encoding/base64"
"errors"
"bytes"
"strings"
)
// Where the magic happens, the base64 data url image is sent through Imagemagick
// and converted to indexed colors 400x200 png
func DataURLConverter(dataURL string) (string, error) {
if !strings.HasPrefix(dataURL, "data:image/png;base64,") {
return "", errors.New("invalid dataURL")
}
imageBase64 := strings.TrimPrefix(dataURL, "data:image/png;base64,")
imageRaw, err := base64.StdEncoding.DecodeString(imageBase64)
if err != nil {
return "", err
}
converter := exec.Command("convert", "-", "-background", "white", "-flatten", "-resize", "400x200!", "-remap", "palette.png", "PNG8:-")
converter.Stdin = bytes.NewBuffer(imageRaw)
var output []byte
output, err = converter.Output()
if err != nil {
return "", err
}
imageBase64Processed := base64.StdEncoding.EncodeToString(output)
return "data:image/png;base64," + imageBase64Processed, nil
}
|
