Initial QSfera import

Server/vendor/github.com/kovidgoyal/imaging/webp/webp.go

@@ -0,0 +1,138 @@
+package webp
+
+import (
+	"image"
+	"image/color"
+	"io"
+)
+
+// AnimatedWEBP is the struct of a AnimatedWEBP container and the image data contained within.
+type AnimatedWEBP struct {
+	Frames []Frame
+	Header ANIMHeader
+	Config image.Config
+}
+
+type Frame struct {
+	Header ANMFHeader
+	Frame  image.Image
+}
+
+type VP8XHeader struct {
+	ICCProfile   bool
+	Alpha        bool
+	ExifMetadata bool
+	XmpMetadata  bool
+	Animation    bool
+	CanvasWidth  uint32
+	CanvasHeight uint32
+}
+
+type ALPHHeader struct {
+	Preprocessing   uint8
+	FilteringMethod uint8
+	Compression     uint8
+}
+
+type ANIMHeader struct {
+	BackgroundColor color.Color
+	LoopCount       uint16
+}
+
+type ANMFHeader struct {
+	FrameX         uint32
+	FrameY         uint32
+	FrameWidth     uint32
+	FrameHeight    uint32
+	FrameDuration  uint32
+	AlphaBlend     bool
+	DisposalBitSet bool
+}
+
+func parseALPHHeader(r io.Reader) ALPHHeader {
+	h := make([]byte, 1)
+	_, _ = io.ReadFull(r, h)
+
+	const (
+		twoBits = byte(3)
+	)
+
+	return ALPHHeader{
+		Preprocessing:   h[0] >> 4 & twoBits,
+		FilteringMethod: h[0] >> 2 & twoBits,
+		Compression:     h[0] & twoBits,
+	}
+}
+
+func parseANIMHeader(r io.Reader) ANIMHeader {
+	h := make([]byte, 6)
+	_, _ = io.ReadFull(r, h)
+
+	loopCount := uint16(h[4]) | uint16(h[5])<<8
+	bg := color.RGBA{
+		R: h[2],
+		G: h[1],
+		B: h[0],
+		A: h[3],
+	}
+
+	return ANIMHeader{
+		BackgroundColor: bg,
+		LoopCount:       loopCount,
+	}
+}
+
+func parseANMFHeader(r io.Reader) ANMFHeader {
+	h := make([]byte, 16)
+	_, _ = io.ReadFull(r, h)
+
+	const (
+		disposeBit = 1
+		blendBit   = 1 << 1
+	)
+
+	return ANMFHeader{
+		FrameX:         u24(h[0:3]),
+		FrameY:         u24(h[3:6]),
+		FrameWidth:     u24(h[6:9]) + 1,
+		FrameHeight:    u24(h[9:12]) + 1,
+		FrameDuration:  u24(h[12:15]),
+		AlphaBlend:     (h[15] & blendBit) == 0,
+		DisposalBitSet: (h[15] & disposeBit) != 0,
+	}
+}
+
+func parseVP8XHeader(r io.Reader) VP8XHeader {
+	const (
+		anim  = 1 << 1
+		xmp   = 1 << 2
+		exif  = 1 << 3
+		alpha = 1 << 4
+		icc   = 1 << 5
+	)
+
+	h := make([]byte, 10)
+	_, _ = io.ReadFull(r, h)
+
+	widthMinusOne := u24(h[4:])
+	heightMinusOne := u24(h[7:])
+
+	header := VP8XHeader{
+		ICCProfile:   h[0]&icc != 0,
+		Alpha:        h[0]&alpha != 0,
+		ExifMetadata: h[0]&exif != 0,
+		XmpMetadata:  h[0]&xmp != 0,
+		Animation:    h[0]&anim != 0,
+		CanvasWidth:  widthMinusOne + 1,
+		CanvasHeight: heightMinusOne + 1,
+	}
+	return header
+}
+
+func u24(b []byte) uint32 {
+	return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16
+}
+
+func u32(b []byte) uint32 {
+	return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
+}