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70 lines
1.6 KiB
70 lines
1.6 KiB
// Copyright © 2023 OpenIM. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package utils
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import (
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"errors"
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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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"io"
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"os"
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"github.com/nfnt/resize"
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"golang.org/x/image/bmp"
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)
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func GenSmallImage(src, dst string) error {
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fIn, _ := os.Open(src)
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defer fIn.Close()
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fOut, _ := os.Create(dst)
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defer fOut.Close()
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if err := scale(fIn, fOut, 0, 0, 0); err != nil {
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return err
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}
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return nil
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}
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func scale(in io.Reader, out io.Writer, width, height, quality int) error {
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origin, fm, err := image.Decode(in)
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if err != nil {
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return err
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}
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if width == 0 || height == 0 {
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width = origin.Bounds().Max.X / 2
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height = origin.Bounds().Max.Y / 2
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}
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if quality == 0 {
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quality = 25
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}
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canvas := resize.Thumbnail(uint(width), uint(height), origin, resize.Lanczos3)
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switch fm {
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case "jpeg":
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return jpeg.Encode(out, canvas, &jpeg.Options{quality})
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case "png":
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return png.Encode(out, canvas)
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case "gif":
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return gif.Encode(out, canvas, &gif.Options{})
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case "bmp":
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return bmp.Encode(out, canvas)
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default:
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return errors.New("ERROR FORMAT")
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}
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}
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