8dff1ab906
* Update preview.go Was some complex logic in there. This should be simpler. * Update preview.go Make GenerateThumbnail code more verbose * Update preview.go Finish renaming targetHeight and targetWidth --------- Co-authored-by: Mattermost Build <build@mattermost.com>
66 строки
1.9 KiB
Go
66 строки
1.9 KiB
Go
// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
|
|
// See LICENSE.txt for license information.
|
|
|
|
package imaging
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"image"
|
|
"image/jpeg"
|
|
|
|
"github.com/disintegration/imaging"
|
|
)
|
|
|
|
// GeneratePreview generates the preview for the given image.
|
|
func GeneratePreview(img image.Image, width int) image.Image {
|
|
preview := img
|
|
w := img.Bounds().Dx()
|
|
|
|
if w > width {
|
|
preview = imaging.Resize(img, width, 0, imaging.Lanczos)
|
|
}
|
|
|
|
return preview
|
|
}
|
|
|
|
// GenerateThumbnail generates the thumbnail for the given image.
|
|
func GenerateThumbnail(img image.Image, targetWidth, targetHeight int) image.Image {
|
|
thumb := img
|
|
width := img.Bounds().Dx()
|
|
height := img.Bounds().Dy()
|
|
expectedRatio := float64(targetHeight) / float64(targetWidth)
|
|
|
|
// If both dimensions are over the target size, we scale down until one is not.
|
|
// If one dimension is over the target size, we scale down until both are not.
|
|
// If neither dimension is over the target size, we return the image as is.
|
|
if height > targetHeight || width > targetWidth {
|
|
ratio := float64(height) / float64(width)
|
|
if ratio < expectedRatio {
|
|
if height >= targetHeight {
|
|
thumb = imaging.Resize(img, 0, targetHeight, imaging.Lanczos)
|
|
} else {
|
|
thumb = imaging.Resize(img, targetWidth, 0, imaging.Lanczos)
|
|
}
|
|
} else {
|
|
if width >= targetWidth {
|
|
thumb = imaging.Resize(img, targetWidth, 0, imaging.Lanczos)
|
|
} else {
|
|
thumb = imaging.Resize(img, 0, targetHeight, imaging.Lanczos)
|
|
}
|
|
}
|
|
}
|
|
|
|
return thumb
|
|
}
|
|
|
|
// GenerateMiniPreviewImage generates the mini preview for the given image.
|
|
func GenerateMiniPreviewImage(img image.Image, w, h, q int) ([]byte, error) {
|
|
var buf bytes.Buffer
|
|
preview := imaging.Resize(img, w, h, imaging.Lanczos)
|
|
if err := jpeg.Encode(&buf, preview, &jpeg.Options{Quality: q}); err != nil {
|
|
return nil, fmt.Errorf("failed to encode image to JPEG format: %w", err)
|
|
}
|
|
return buf.Bytes(), nil
|
|
}
|