basn3p08-trns.png...

#SNG: from basn3p08-trns.png
IHDR {
    width: 32; height: 32; bitdepth: 8;
    using color palette;
}
gAMA {1.0000}
PLTE {
    (255,  3,  7)     # rgb = (0xff,0x03,0x07)
    (255,  4,  7)     # rgb = (0xff,0x04,0x07)
    (255,  9,  7)     # rgb = (0xff,0x09,0x07)
    (217, 14,  7)     # rgb = (0xd9,0x0e,0x07)
    (255, 14,  7)     # rgb = (0xff,0x0e,0x07)
    (  2, 22, 19)     # rgb = (0x02,0x16,0x13)
    (255, 26,  7)     # rgb = (0xff,0x1a,0x07)

			b = append(b, trns...)
		}
		b = append(b, idat...)
		b = append(b, iend...)

		var want color.Color
		m, err := Decode(bytes.NewReader(b))
		switch i {
		case 0:
			if err != nil {
				t.Errorf("%d tRNS chunks: %v", i, err)
				continue
			}
			want = color.RGBA{0xff, 0x00, 0x00, 0xff}
		case 1:
			if err != nil {
				t.Errorf("%d tRNS chunks: %v", i, err)
				continue

#SNG: from ftbbn0g01.png
IHDR {
    width: 32; height: 32; bitdepth: 8;
    using grayscale;
}
bKGD {gray: 0;}
tRNS {
    gray: 0;
}
IMAGE {
    pixels hex
0000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000

#SNG: from ftbbn0g02.png
IHDR {
    width: 32; height: 32; bitdepth: 8;
    using grayscale;
}
gAMA {0.45455}
bKGD {gray: 0;}
tRNS {
    gray: 0;
}
IMAGE {
    pixels hex
0000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000

#SNG: from ftbbn0g04.png
IHDR {
    width: 32; height: 32; bitdepth: 8;
    using grayscale;
}
gAMA {1.0000}
bKGD {gray: 0;}
tRNS {
    gray: 255;
}
IMAGE {
    pixels hex
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
ffffffffffffffffffffffffffffddcceeffffffffffffffffffffffffffffff
ffffffffffffffffffffffeebb776655446699ddffffffffffffffffffffffff

sizes makes them useful for testing bit-depths smaller than a byte.

basn3a08.png was generated from basn6a08.png using the pngnq tool, which
converted it to the 8-bit paletted image with alpha values in tRNS chunk.

The *.sng files in this directory were generated from the *.png files by the
sng command-line tool and some hand editing. The files basn0g0{1,2,4}.sng and

	case cbTC8, cbTC16:
		if length != 6 {
			return FormatError("bad tRNS length")
		}
		n, err := io.ReadFull(d.r, d.tmp[:length])
		if err != nil {
			return err
		}
		d.crc.Write(d.tmp[:n])

		copy(d.transparent[:], d.tmp[:length])
		d.useTransparent = true

	case cbP1, cbP2, cbP4, cbP8:
		if length > 256 {
			return FormatError("bad tRNS length")
		}
		n, err := io.ReadFull(d.r, d.tmp[:length])

#SNG: from ftbrn2c08.png
IHDR {
    width: 32; height: 32; bitdepth: 8;
    using color;
}
gAMA {1.0000}
bKGD {red: 255;  green: 0;  blue: 0;}
tRNS {
    red: 255; green: 255; blue: 255;
}
IMAGE {
    pixels hex
ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff ffffff 

#SNG: from ftbgn2c16.png
IHDR {
    width: 32; height: 32; bitdepth: 16;
    using color;
}
gAMA {1.0000}
bKGD {red: 0;  green: 65535;  blue: 0;}
tRNS {
    red: 65535; green: 65535; blue: 65535;
}
IMAGE {
    pixels hex