/
main.go
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/
main.go
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// Copyright (C) 2020 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// img2ico is a utility program that converts images to Windows ICO icons.
package main
import (
"bytes"
"context"
"encoding/binary"
"flag"
"image"
"image/color"
"os"
"github.com/google/gapid/core/app"
"github.com/google/gapid/core/log"
// Import to register image formats.
_ "image/gif"
_ "image/jpeg"
"image/png"
)
var (
out = flag.String("out", "-", "Output file, '-' for stdout")
)
func main() {
app.ShortHelp = "img2ico creates Windows ICO files"
app.Name = "img2ico"
app.Run(run)
}
type header struct {
reserved uint16
imgType uint16
imgCount uint16
}
type entry struct {
width uint8
height uint8
paletteSize uint8
reserved uint8
numPlanes uint16
bpp uint16
imgSize uint32
offset uint32
}
type bmp struct {
headerSize uint32
width uint32
height uint32
planes uint16
bpp uint16
compression uint32
imageSize uint32
wResolution uint32
hResolution uint32
paletteSize uint32
important uint32
}
type pixel struct {
b, g, r, a uint8
}
func run(ctx context.Context) (err error) {
if flag.NArg() < 1 {
app.Usage(ctx, "At least one input image is required")
return nil
}
images := make([]image.Image, 0, flag.NArg())
pngs := [][]byte{}
for _, file := range flag.Args() {
in, err := os.Open(file)
if err != nil {
return log.Errf(ctx, err, "Failed to open %s", file)
}
img, _, err := image.Decode(in)
in.Close()
if err != nil {
return log.Errf(ctx, err, "Failed to decode image %s", file)
}
size := img.Bounds().Size()
if size.X > 256 || size.Y > 256 {
return log.Errf(ctx, nil, "Image %s too big. Cannot be larger than 256x256", file)
}
images = append(images, img)
// Use PNG format for large icons.
if size.X == 256 || size.Y == 256 {
var pngOut bytes.Buffer
png.Encode(&pngOut, img)
pngs = append(pngs, pngOut.Bytes())
}
}
o := os.Stdout
if *out != "-" {
o, err = os.Create(*out)
if err != nil {
return log.Errf(ctx, err, "Failed to create %s", *out)
}
defer o.Close()
}
binary.Write(o, binary.LittleEndian, &header{
imgType: 1, // ICO
imgCount: uint16(len(images)),
})
offset := uint32(6 + 16*len(images))
pngIdx := 0
for _, img := range images {
w, h := img.Bounds().Dx(), img.Bounds().Dy()
size := uint32(40 + w*h*4 + h*((w+31) & ^31)/8)
if w == 256 {
w = 0
}
if h == 256 {
h = 0
}
if w == 0 || h == 0 {
size = uint32(len(pngs[pngIdx]))
pngIdx++
}
binary.Write(o, binary.LittleEndian, &entry{
width: uint8(w),
height: uint8(h),
numPlanes: 1,
bpp: 32,
imgSize: size,
offset: offset,
})
offset += size
}
model := color.NRGBAModel
pngIdx = 0
for _, img := range images {
w, h := img.Bounds().Dx(), img.Bounds().Dy()
if w == 256 || h == 256 {
o.Write(pngs[pngIdx])
pngIdx++
continue
}
binary.Write(o, binary.LittleEndian, &bmp{
headerSize: 40,
width: uint32(w),
height: uint32(2 * h),
planes: 1,
bpp: 32,
imageSize: uint32(w * h * 4),
})
matte := make([]byte, h*((w+31) & ^31)/8)
mattePos := uint(0)
for y := h - 1; y >= 0; y-- {
for x := 0; x < w; x++ {
p := model.Convert(img.At(x, y)).(color.NRGBA)
binary.Write(o, binary.LittleEndian, &pixel{
r: p.R,
g: p.G,
b: p.B,
a: p.A,
})
if p.A == 0 {
matte[mattePos/8] |= byte(0x80 >> (mattePos % 8))
}
mattePos++
}
// Align to 4 bytes.
mattePos = (mattePos + 31) & ^uint(31)
}
o.Write(matte)
}
return nil
}