oxpoe
59145910b5
- Dialog ikon: nama aplikasi -> Iconify; domain (mikrotik.com) -> ikon resmi situs (manifest 512, apple-touch-icon, favicon) + layanan favicon; URL gambar -> langsung - Contoh kasus: 'winbox' cuma punya 1 ikon tidak nyambung di Iconify, tapi 'mikrotik.com' memberi ikon resminya (5 pilihan, semuanya PNG) - Decoder ICO: entri BMP 24/32-bit (favicon.ico lama) ikut didukung, bukan cuma PNG - FromURL/Fetch selalu mengembalikan PNG; hasil raster/konversi seragam 512px - Tes: deteksi URL gambar/domain, daftar ikon situs, decode ICO BMP, konversi format
110 lines
3.0 KiB
Go
110 lines
3.0 KiB
Go
package icon
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import (
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"bytes"
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"encoding/binary"
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"errors"
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"image"
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"image/color"
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"image/png"
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)
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// decodeICO mengambil gambar terbesar di dalam file .ico.
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//
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// ICO bisa berisi PNG (modern) atau DIB/BMP (format lama, masih sering dipakai
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// favicon). Keduanya didukung: BMP 32-bit pakai alpha, 24-bit pakai AND mask.
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// Entri dengan palet (<= 8-bit) tidak didukung.
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func decodeICO(data []byte) (image.Image, error) {
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if pngData := largestPNGFromICO(data); pngData != nil {
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return png.Decode(bytes.NewReader(pngData))
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}
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if len(data) < 22 || data[0] != 0 || data[1] != 0 || data[2] != 1 || data[3] != 0 {
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return nil, errors.New("bukan file ICO")
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}
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count := int(data[4]) | int(data[5])<<8
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var best image.Image
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bestSize := 0
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for i := 0; i < count; i++ {
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off := 6 + i*16
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if off+16 > len(data) {
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break
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}
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width := int(data[off])
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if width == 0 {
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width = 256
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}
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size := int(data[off+8]) | int(data[off+9])<<8 | int(data[off+10])<<16 | int(data[off+11])<<24
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start := int(data[off+12]) | int(data[off+13])<<8 | int(data[off+14])<<16 | int(data[off+15])<<24
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if size <= 0 || start <= 0 || start+size > len(data) {
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continue
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}
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if width*width <= bestSize {
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continue
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}
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img, err := decodeDIB(data[start : start+size])
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if err != nil {
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continue
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}
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best, bestSize = img, width*width
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}
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if best == nil {
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return nil, errors.New("tidak ada gambar yang bisa dibaca di dalam .ico")
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}
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return best, nil
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}
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// decodeDIB membaca gambar DIB/BMP di dalam entri ICO.
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func decodeDIB(dib []byte) (image.Image, error) {
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if len(dib) < 40 {
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return nil, errors.New("entri ICO terlalu pendek")
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}
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headerSize := int(binary.LittleEndian.Uint32(dib[0:4]))
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width := int(int32(binary.LittleEndian.Uint32(dib[4:8])))
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height := int(int32(binary.LittleEndian.Uint32(dib[8:12]))) / 2 // tinggi DIB = XOR + AND mask
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bitCount := int(binary.LittleEndian.Uint16(dib[14:16]))
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compression := int(binary.LittleEndian.Uint32(dib[16:20]))
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if compression != 0 {
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return nil, errors.New("entri ICO terkompresi tidak didukung")
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}
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if width <= 0 || height <= 0 || width > 512 || height > 512 {
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return nil, errors.New("ukuran entri ICO tidak wajar")
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}
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if bitCount != 24 && bitCount != 32 {
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return nil, errors.New("hanya ICO 24/32-bit yang didukung")
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}
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stride := (width*bitCount/8 + 3) & ^3
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start := headerSize
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if start+stride*height > len(dib) {
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return nil, errors.New("data piksel ICO terpotong")
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}
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img := image.NewNRGBA(image.Rect(0, 0, width, height))
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allTransparent := bitCount == 32
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for y := 0; y < height; y++ {
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row := dib[start+(height-1-y)*stride:] // DIB disimpan dari bawah ke atas
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for x := 0; x < width; x++ {
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px := row[x*bitCount/8:]
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var alpha uint8 = 0xFF
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if bitCount == 32 {
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alpha = px[3]
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if alpha != 0 {
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allTransparent = false
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}
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}
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img.SetNRGBA(x, y, color.NRGBA{R: px[2], G: px[1], B: px[0], A: alpha})
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}
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}
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// sebagian ICO 32-bit tidak mengisi kanal alpha sama sekali
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if allTransparent {
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for i := 3; i < len(img.Pix); i += 4 {
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img.Pix[i] = 0xFF
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}
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}
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return img, nil
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}
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