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// 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 minio
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import (
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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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_ "golang.org/x/image/bmp"
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_ "golang.org/x/image/tiff"
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_ "golang.org/x/image/webp"
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)
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const (
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formatPng = "png"
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formatJpeg = "jpeg"
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formatJpg = "jpg"
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formatGif = "gif"
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)
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func ImageStat(reader io.Reader) (image.Image, string, error) {
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return image.Decode(reader)
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}
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func ImageWidthHeight(img image.Image) (int, int) {
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bounds := img.Bounds().Max
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return bounds.X, bounds.Y
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}
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func resizeImage(img image.Image, maxWidth, maxHeight int) image.Image {
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bounds := img.Bounds()
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imgWidth := bounds.Max.X
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imgHeight := bounds.Max.Y
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// 计算缩放比例
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scaleWidth := float64(maxWidth) / float64(imgWidth)
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scaleHeight := float64(maxHeight) / float64(imgHeight)
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// 如果都为0，则不缩放，返回原始图片
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if maxWidth == 0 && maxHeight == 0 {
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return img
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}
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// 如果宽度和高度都大于0，则选择较小的缩放比例，以保持宽高比
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if maxWidth > 0 && maxHeight > 0 {
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scale := scaleWidth
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if scaleHeight < scaleWidth {
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scale = scaleHeight
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}
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// 计算缩略图尺寸
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thumbnailWidth := int(float64(imgWidth) * scale)
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thumbnailHeight := int(float64(imgHeight) * scale)
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// 使用"image"库的Resample方法生成缩略图
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thumbnail := image.NewRGBA(image.Rect(0, 0, thumbnailWidth, thumbnailHeight))
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for y := 0; y < thumbnailHeight; y++ {
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for x := 0; x < thumbnailWidth; x++ {
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srcX := int(float64(x) / scale)
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srcY := int(float64(y) / scale)
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thumbnail.Set(x, y, img.At(srcX, srcY))
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}
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}
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return thumbnail
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}
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// 如果只指定了宽度或高度，则根据最大不超过的规则生成缩略图
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if maxWidth > 0 {
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thumbnailWidth := maxWidth
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thumbnailHeight := int(float64(imgHeight) * scaleWidth)
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// 使用"image"库的Resample方法生成缩略图
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thumbnail := image.NewRGBA(image.Rect(0, 0, thumbnailWidth, thumbnailHeight))
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for y := 0; y < thumbnailHeight; y++ {
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for x := 0; x < thumbnailWidth; x++ {
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srcX := int(float64(x) / scaleWidth)
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srcY := int(float64(y) / scaleWidth)
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thumbnail.Set(x, y, img.At(srcX, srcY))
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}
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}
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return thumbnail
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}
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if maxHeight > 0 {
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thumbnailWidth := int(float64(imgWidth) * scaleHeight)
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thumbnailHeight := maxHeight
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// 使用"image"库的Resample方法生成缩略图
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thumbnail := image.NewRGBA(image.Rect(0, 0, thumbnailWidth, thumbnailHeight))
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for y := 0; y < thumbnailHeight; y++ {
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for x := 0; x < thumbnailWidth; x++ {
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srcX := int(float64(x) / scaleHeight)
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srcY := int(float64(y) / scaleHeight)
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thumbnail.Set(x, y, img.At(srcX, srcY))
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}
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}
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return thumbnail
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}
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// 默认情况下，返回原始图片
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return img
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}
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