73 lines
1.3 KiB
Go
73 lines
1.3 KiB
Go
package images
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import (
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"bytes"
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"encoding/base64"
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"fmt"
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"image"
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"image/jpeg"
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"io"
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)
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type EncodeConfig struct {
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Quality int
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}
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func Encode(w io.Writer, img image.Image, config EncodeConfig) error {
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// Currently a wrapper for renderJpeg, but this function is useful if multiple render formats are needed
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return renderJpeg(w, img, config)
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}
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func renderJpeg(w io.Writer, m image.Image, config EncodeConfig) error {
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o := new(jpeg.Options)
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o.Quality = config.Quality
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return jpeg.Encode(w, m, o)
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}
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func EncodeToBestSize(bb *bytes.Buffer, img image.Image, size ResizeDimension) error {
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q := MaxJpegQuality
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for q > MinJpegQuality-1 {
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err := Encode(bb, img, EncodeConfig{Quality: q})
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if err != nil {
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return err
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}
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if DimensionSizeLimit[size].Ideal > bb.Len() {
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return nil
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}
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if q == MinJpegQuality {
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if DimensionSizeLimit[size].Max > bb.Len() {
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return nil
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}
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return fmt.Errorf(
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"image size after processing exceeds max, expect < '%d', received < '%d'",
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DimensionSizeLimit[size].Max,
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bb.Len(),
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)
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}
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bb.Reset()
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q -= 2
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}
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return nil
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}
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func GetPayloadDataURI(payload []byte) (string, error) {
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if len(payload) == 0 {
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return "", nil
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}
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mt, err := GetMimeType(payload)
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if err != nil {
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return "", err
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}
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b64 := base64.StdEncoding.EncodeToString(payload)
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return "data:image/" + mt + ";base64," + b64, nil
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}
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