diff options
Diffstat (limited to 'internal/media/thumbnail.go')
| -rw-r--r-- | internal/media/thumbnail.go | 54 |
1 files changed, 47 insertions, 7 deletions
diff --git a/internal/media/thumbnail.go b/internal/media/thumbnail.go index 36ef24a01..a562dc2ad 100644 --- a/internal/media/thumbnail.go +++ b/internal/media/thumbnail.go @@ -34,6 +34,40 @@ import ( "golang.org/x/image/webp" ) +const ( + maxThumbWidth = 512 + maxThumbHeight = 512 +) + +// thumbSize returns the dimensions to use for an input +// image of given width / height, for its outgoing thumbnail. +// This attempts to maintains the original image aspect ratio. +func thumbSize(width, height int, aspect float32) (int, int) { + + switch { + // Simplest case, within bounds! + case width < maxThumbWidth && + height < maxThumbHeight: + return width, height + + // Width is larger side. + case width > height: + // i.e. height = newWidth * (height / width) + height = int(float32(maxThumbWidth) / aspect) + return maxThumbWidth, height + + // Height is larger side. + case height > width: + // i.e. width = newHeight * (width / height) + width = int(float32(maxThumbHeight) * aspect) + return width, maxThumbHeight + + // Square. + default: + return maxThumbWidth, maxThumbHeight + } +} + // generateThumb generates a thumbnail for the // input file at path, resizing it to the given // dimensions and generating a blurhash if needed. @@ -229,11 +263,17 @@ func generateNativeThumb( img = imaging.Transverse(img) } - // Resize image to dimens. - img = imaging.Resize(img, - width, height, - imaging.Linear, - ) + // Resize image to dimens only if necessary. + if img.Bounds().Dx() > maxThumbWidth || + img.Bounds().Dy() > maxThumbHeight { + // Note: We could call "imaging.Fit" here + // but there's no point, as we've already + // calculated target dimensions beforehand. + img = imaging.Resize(img, + width, height, + imaging.Linear, + ) + } // Open output file at given path. outfile, err := os.Create(outpath) @@ -255,7 +295,7 @@ func generateNativeThumb( if needBlurhash { // for generating blurhashes, it's more cost effective to // lose detail since it's blurry, so make a tiny version. - tiny := imaging.Resize(img, 64, 64, imaging.NearestNeighbor) + tiny := imaging.Resize(img, 32, 0, imaging.NearestNeighbor) // Drop the larger image // ref as soon as possible @@ -294,7 +334,7 @@ func generateWebpBlurhash(filepath string) (string, error) { // for generating blurhashes, it's more cost effective to // lose detail since it's blurry, so make a tiny version. - tiny := imaging.Resize(img, 64, 64, imaging.NearestNeighbor) + tiny := imaging.Resize(img, 32, 0, imaging.NearestNeighbor) // Drop the larger image // ref as soon as possible |