Documentation
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Overview ¶
Package thumbnail provides functionality for generating image thumbnails and computing image hashes (MD5, pHash). It uses lightweight pooling for buffers and hashers to minimize allocations and improve performance.
Index ¶
- func GenerateThumbnailAndHashes(r io.ReadSeeker) (*bytes.Buffer, *sql.NullString, *sql.NullInt64, error)
- func GetBytesBuffer() *bytes.Buffer
- func GetMD5() hash.Hash
- func GetNullInt64() *sql.NullInt64
- func GetNullString() *sql.NullString
- func PutBytesBuffer(buf *bytes.Buffer)
- func PutMD5(h hash.Hash)
- func PutNullInt64(ni *sql.NullInt64)
- func PutNullString(ns *sql.NullString)
- type Generator
- type MockGenerator
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func GenerateThumbnailAndHashes ¶
func GenerateThumbnailAndHashes(r io.ReadSeeker) (*bytes.Buffer, *sql.NullString, *sql.NullInt64, error)
GenerateThumbnailAndHashes creates a thumbnail for the image read from r. If the image (JPEG, TIFF, or WebP) contains an embedded EXIF thumbnail, that thumbnail is decoded instead of the full image, dramatically reducing memory use and CPU time. The source (embedded thumbnail or full image) is fitted inside a 200x150 pixel box with draw.ApproxBiLinear into a pooled RGBA canvas and encoded as JPEG. It also calculates MD5 (over the full file bytes) and pHash: the gallery thumbnail is squashed to 64x64 with draw.ApproxBiLinear into a second pooled RGBA canvas, and imagehash.NewPHash64 is computed over that 64x64 canvas. Both pooled destinations are returned to their pools before the function returns. It returns the JPEG data as a bytes.Buffer, sql.NullString for MD5, and sql.NullInt64 for pHash, or an error if generation fails.
func GetBytesBuffer ¶
GetBytesBuffer retrieves a bytes.Buffer from the pool.
func GetNullInt64 ¶
GetNullInt64 retrieves an sql.NullInt64 from the pool.
func GetNullString ¶
func GetNullString() *sql.NullString
GetNullString retrieves an sql.NullString from the pool.
func PutBytesBuffer ¶
PutBytesBuffer returns a bytes.Buffer to the pool, resetting it first.
func PutNullInt64 ¶
PutNullInt64 returns an sql.NullInt64 to the pool, resetting it first.
func PutNullString ¶
func PutNullString(ns *sql.NullString)
PutNullString returns an sql.NullString to the pool, resetting it first.
Types ¶
type Generator ¶
type Generator interface {
// GenerateThumbnailAndHashes creates a thumbnail and computes MD5/pHash.
// The reader should be an image file.
// Returns thumbnail bytes, MD5 hash, perceptual hash, and any error.
GenerateThumbnailAndHashes(r io.ReadSeeker) (*bytes.Buffer, *sql.NullString, *sql.NullInt64, error)
}
Generator abstracts thumbnail generation and hash computation.
type MockGenerator ¶
type MockGenerator struct {
Thumbnail *bytes.Buffer
MD5 *sql.NullString
PHash *sql.NullInt64
Err error
}
MockGenerator is a mock implementation of Generator for testing.
func (*MockGenerator) GenerateThumbnailAndHashes ¶
func (m *MockGenerator) GenerateThumbnailAndHashes(r io.ReadSeeker) (*bytes.Buffer, *sql.NullString, *sql.NullInt64, error)
GenerateThumbnailAndHashes returns the mock values.
Source Files