photoprism/internal/viewer/thumb.go

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package viewer
import (
"fmt"
"math"
"github.com/photoprism/photoprism/internal/thumb"
)
// DownloadUrl returns a download url based on hash, api uri, and download token.
func DownloadUrl(h, apiUri, downloadToken string) string {
return fmt.Sprintf("%s/dl/%s?t=%s", apiUri, h, downloadToken)
}
// ThumbUrl returns a thumbnail url based on hash, thumb name, cdn uri, and preview token.
func ThumbUrl(h, name, contentUri, previewToken string) string {
return fmt.Sprintf("%s/t/%s/%s/%s", contentUri, h, previewToken, name)
}
// Thumb represents a photo viewer thumbnail.
type Thumb struct {
W int `json:"w"`
H int `json:"h"`
Src string `json:"src"`
}
// NewThumb creates a new photo viewer thumb.
func NewThumb(w, h int, hash string, s thumb.Size, contentUri, previewToken string) Thumb {
if s.Width >= w && s.Height >= h {
// Smaller
return Thumb{W: w, H: h, Src: ThumbUrl(hash, s.Name.String(), contentUri, previewToken)}
}
srcAspectRatio := float64(w) / float64(h)
maxAspectRatio := float64(s.Width) / float64(s.Height)
var newW, newH int
if srcAspectRatio > maxAspectRatio {
newW = s.Width
newH = int(math.Round(float64(newW) / srcAspectRatio))
} else {
newH = s.Height
newW = int(math.Round(float64(newH) * srcAspectRatio))
}
return Thumb{W: newW, H: newH, Src: ThumbUrl(hash, s.Name.String(), contentUri, previewToken)}
}