73 lines
1.5 KiB
Go
73 lines
1.5 KiB
Go
|
package ico
|
||
|
|
|
||
|
|
import (
|
||
|
|
"bufio"
|
||
|
|
"bytes"
|
||
|
|
"encoding/binary"
|
||
|
|
"image"
|
||
|
|
"image/draw"
|
||
|
|
"image/png"
|
||
|
|
"io"
|
||
|
|
)
|
||
|
|
|
||
|
|
type icondir struct {
|
||
|
|
reserved uint16 //lint:ignore U1000 in spec but not used
|
||
|
|
imageType uint16
|
||
|
|
numImages uint16
|
||
|
|
}
|
||
|
|
|
||
|
|
type icondirentry struct {
|
||
|
|
imageWidth uint8
|
||
|
|
imageHeight uint8
|
||
|
|
numColors uint8 //lint:ignore U1000 in spec but not used
|
||
|
|
reserved uint8 //lint:ignore U1000 in spec but not used
|
||
|
|
colorPlanes uint16
|
||
|
|
bitsPerPixel uint16
|
||
|
|
sizeInBytes uint32
|
||
|
|
offset uint32
|
||
|
|
}
|
||
|
|
|
||
|
|
func newIcondir() icondir {
|
||
|
|
var id icondir
|
||
|
|
id.imageType = 1
|
||
|
|
id.numImages = 1
|
||
|
|
return id
|
||
|
|
}
|
||
|
|
|
||
|
|
func newIcondirentry() icondirentry {
|
||
|
|
var ide icondirentry
|
||
|
|
ide.colorPlanes = 1 // windows is supposed to not mind 0 or 1, but other icon files seem to have 1 here
|
||
|
|
ide.bitsPerPixel = 32 // can be 24 for bitmap or 24/32 for png. Set to 32 for now
|
||
|
|
ide.offset = 22 //6 icondir + 16 icondirentry, next image will be this image size + 16 icondirentry, etc
|
||
|
|
return ide
|
||
|
|
}
|
||
|
|
|
||
|
|
func Encode(w io.Writer, im image.Image) error {
|
||
|
|
b := im.Bounds()
|
||
|
|
m := image.NewRGBA(b)
|
||
|
|
draw.Draw(m, b, im, b.Min, draw.Src)
|
||
|
|
|
||
|
|
id := newIcondir()
|
||
|
|
ide := newIcondirentry()
|
||
|
|
|
||
|
|
pngbb := new(bytes.Buffer)
|
||
|
|
pngwriter := bufio.NewWriter(pngbb)
|
||
|
|
png.Encode(pngwriter, m)
|
||
|
|
pngwriter.Flush()
|
||
|
|
ide.sizeInBytes = uint32(len(pngbb.Bytes()))
|
||
|
|
|
||
|
|
bounds := m.Bounds()
|
||
|
|
ide.imageWidth = uint8(bounds.Dx())
|
||
|
|
ide.imageHeight = uint8(bounds.Dy())
|
||
|
|
bb := new(bytes.Buffer)
|
||
|
|
|
||
|
|
var e error
|
||
|
|
binary.Write(bb, binary.LittleEndian, id)
|
||
|
|
binary.Write(bb, binary.LittleEndian, ide)
|
||
|
|
|
||
|
|
w.Write(bb.Bytes())
|
||
|
|
w.Write(pngbb.Bytes())
|
||
|
|
|
||
|
|
return e
|
||
|
|
}
|