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/*
GoToSocial
Copyright (C) 2021-2023 GoToSocial Authors admin@gotosocial.org
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package media
import (
"bufio"
"image"
"image/color"
"image/draw"
"image/jpeg"
"image/png"
"io"
"sync"
"github.com/buckket/go-blurhash"
"github.com/disintegration/imaging"
"github.com/superseriousbusiness/gotosocial/internal/iotools"
// import to init webp encode/decoding.
_ "golang.org/x/image/webp"
)
var (
// pngEncoder provides our global PNG encoding with
// specified compression level, and memory pooled buffers.
pngEncoder = png.Encoder{
CompressionLevel: png.DefaultCompression,
BufferPool: &pngEncoderBufferPool{},
}
// jpegBufferPool is a memory pool of byte buffers for JPEG encoding.
jpegBufferPool = sync.Pool{
New: func() any {
return bufio.NewWriter(nil)
},
}
)
// gtsImage is a thin wrapper around the standard library image
// interface to provide our own useful helper functions for image
// size and aspect ratio calculations, streamed encoding to various
// types, and creating reduced size thumbnail images.
type gtsImage struct{ image image.Image }
// blankImage generates a blank image of given dimensions.
func blankImage(width int, height int) *gtsImage {
// create a rectangle with the same dimensions as the video
img := image.NewRGBA(image.Rect(0, 0, width, height))
// fill the rectangle with our desired fill color.
draw.Draw(img, img.Bounds(), &image.Uniform{
color.RGBA{42, 43, 47, 0},
}, image.Point{}, draw.Src)
return >sImage{image: img}
}
// decodeImage will decode image from reader stream and return image wrapped in our own gtsImage{} type.
func decodeImage(r io.Reader, opts ...imaging.DecodeOption) (*gtsImage, error) {
img, err := imaging.Decode(r, opts...)
if err != nil {
return nil, err
}
return >sImage{image: img}, nil
}
// Width returns the image width in pixels.
func (m *gtsImage) Width() uint32 {
return uint32(m.image.Bounds().Size().X)
}
// Height returns the image height in pixels.
func (m *gtsImage) Height() uint32 {
return uint32(m.image.Bounds().Size().Y)
}
// Size returns the total number of image pixels.
func (m *gtsImage) Size() uint64 {
return uint64(m.image.Bounds().Size().X) *
uint64(m.image.Bounds().Size().Y)
}
// AspectRatio returns the image ratio of width:height.
func (m *gtsImage) AspectRatio() float32 {
return float32(m.image.Bounds().Size().X) /
float32(m.image.Bounds().Size().Y)
}
// Thumbnail returns a small sized copy of gtsImage{}, limited to 512x512 if not small enough.
func (m *gtsImage) Thumbnail() *gtsImage {
const (
// max thumb
// dimensions.
maxWidth = 512
maxHeight = 512
)
// Check the receiving image is within max thumnail bounds.
if m.Width() <= maxWidth && m.Height() <= maxHeight {
return >sImage{image: imaging.Clone(m.image)}
}
// Image is too large, needs to be resized to thumbnail max.
img := imaging.Fit(m.image, maxWidth, maxHeight, imaging.Linear)
return >sImage{image: img}
}
// Blurhash calculates the blurhash for the receiving image data.
func (m *gtsImage) Blurhash() (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(m.image, 32, 0, imaging.NearestNeighbor)
// Encode blurhash from resized version
return blurhash.Encode(4, 3, tiny)
}
// ToJPEG creates a new streaming JPEG encoder from receiving image, and a size ptr
// which stores the number of bytes written during the image encoding process.
func (m *gtsImage) ToJPEG(opts *jpeg.Options) io.Reader {
return iotools.StreamWriteFunc(func(w io.Writer) error {
// Get encoding buffer
bw := getJPEGBuffer(w)
// Encode JPEG to buffered writer.
err := jpeg.Encode(bw, m.image, opts)
// Replace buffer.
//
// NOTE: jpeg.Encode() already
// performs a bufio.Writer.Flush().
putJPEGBuffer(bw)
return err
})
}
// ToPNG creates a new streaming PNG encoder from receiving image, and a size ptr
// which stores the number of bytes written during the image encoding process.
func (m *gtsImage) ToPNG() io.Reader {
return iotools.StreamWriteFunc(func(w io.Writer) error {
return pngEncoder.Encode(w, m.image)
})
}
// getJPEGBuffer fetches a reset JPEG encoding buffer from global JPEG buffer pool.
func getJPEGBuffer(w io.Writer) *bufio.Writer {
buf, _ := jpegBufferPool.Get().(*bufio.Writer)
buf.Reset(w)
return buf
}
// putJPEGBuffer resets the given bufio writer and places in global JPEG buffer pool.
func putJPEGBuffer(buf *bufio.Writer) {
buf.Reset(nil)
jpegBufferPool.Put(buf)
}
// pngEncoderBufferPool implements png.EncoderBufferPool.
type pngEncoderBufferPool sync.Pool
func (p *pngEncoderBufferPool) Get() *png.EncoderBuffer {
buf, _ := (*sync.Pool)(p).Get().(*png.EncoderBuffer)
return buf
}
func (p *pngEncoderBufferPool) Put(buf *png.EncoderBuffer) {
(*sync.Pool)(p).Put(buf)
}
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