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8310f6eb79
if both height and width are specified, we assume you want an image at exactly those dimensions, so use imaging.Thumbnail, which will resize and crop the image. if either height or width are left unspecified, then it's just a simple resize request.
65 lines
1.4 KiB
Go
65 lines
1.4 KiB
Go
// Package transform handles image transformation such as resizing.
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package transform
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import (
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"bytes"
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"image"
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"image/gif"
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"image/jpeg"
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"image/png"
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"reflect"
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"github.com/disintegration/imaging"
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"github.com/willnorris/go-imageproxy/data"
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)
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var emptyOptions = new(data.Options)
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// Transform the provided image.
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func Transform(img data.Image, opt *data.Options) (*data.Image, error) {
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if opt == nil || reflect.DeepEqual(opt, emptyOptions) {
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// bail if no transformation was requested
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return &img, nil
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}
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if opt.Width == 0 && opt.Height == 0 {
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// TODO(willnorris): Currently, only resize related options are
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// supported, so bail if no sizes are specified. Remove this
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// check if we ever support non-resizing transformations.
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return &img, nil
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}
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// decode image
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m, format, err := image.Decode(bytes.NewReader(img.Bytes))
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if err != nil {
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return nil, err
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}
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// resize
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if opt.Fit {
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m = imaging.Fit(m, opt.Width, opt.Height, imaging.Lanczos)
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} else {
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if opt.Width == 0 || opt.Height == 0 {
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m = imaging.Resize(m, opt.Width, opt.Height, imaging.Lanczos)
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} else {
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m = imaging.Thumbnail(m, opt.Width, opt.Height, imaging.Lanczos)
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}
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}
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// encode image
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buf := new(bytes.Buffer)
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switch format {
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case "gif":
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gif.Encode(buf, m, nil)
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break
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case "jpeg":
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jpeg.Encode(buf, m, nil)
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break
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case "png":
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png.Encode(buf, m)
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break
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}
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img.Bytes = buf.Bytes()
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return &img, nil
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}
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