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Add Some Unpackers for 2/4 bpp Grayscale Format

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As seen in some tiff image files.
This commit is contained in:
zwhfly 2016-03-28 17:44:06 +08:00
parent fff5536b37
commit 4d147c16d3
1 changed files with 110 additions and 8 deletions
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118
libImaging/Unpack.c
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@ -191,14 +191,64 @@ unpack1IR(UINT8* out, const UINT8* in, int pixels)
static void
unpackL2(UINT8* out, const UINT8* in, int pixels)
{
/* nibbles */
/* nibbles (msb first, white is non-zero) */
while (pixels > 0) {
UINT8 byte = *in++;
switch (pixels) {
default: *out++ = ((byte >> 6) & 3) * 255 / 3; byte <<= 2;
case 3: *out++ = ((byte >> 6) & 3) * 255 / 3; byte <<= 2;
case 2: *out++ = ((byte >> 6) & 3) * 255 / 3; byte <<= 2;
case 1: *out++ = ((byte >> 6) & 3) * 255 / 3;
default: *out++ = ((byte >> 6) & 0x03U) * 0x55U; byte <<= 2;
case 3: *out++ = ((byte >> 6) & 0x03U) * 0x55U; byte <<= 2;
case 2: *out++ = ((byte >> 6) & 0x03U) * 0x55U; byte <<= 2;
case 1: *out++ = ((byte >> 6) & 0x03U) * 0x55U;
}
pixels -= 4;
}
}
static void
unpackL2I(UINT8* out, const UINT8* in, int pixels)
{
/* nibbles (msb first, white is zero) */
while (pixels > 0) {
UINT8 byte = *in++;
switch (pixels) {
default: *out++ = 0xFFU - (UINT8)(((byte >> 6) & 0x03U) * 0x55U); byte <<= 2;
case 3: *out++ = 0xFFU - (UINT8)(((byte >> 6) & 0x03U) * 0x55U); byte <<= 2;
case 2: *out++ = 0xFFU - (UINT8)(((byte >> 6) & 0x03U) * 0x55U); byte <<= 2;
case 1: *out++ = 0xFFU - (UINT8)(((byte >> 6) & 0x03U) * 0x55U);
}
pixels -= 4;
}
}
static void
unpackL2R(UINT8* out, const UINT8* in, int pixels)
{
/* nibbles (bit order reversed, white is non-zero) */
while (pixels > 0) {
UINT8 byte = *in++;
byte = BITFLIP[byte];
switch (pixels) {
default: *out++ = ((byte >> 6) & 0x03U) * 0x55U; byte <<= 2;
case 3: *out++ = ((byte >> 6) & 0x03U) * 0x55U; byte <<= 2;
case 2: *out++ = ((byte >> 6) & 0x03U) * 0x55U; byte <<= 2;
case 1: *out++ = ((byte >> 6) & 0x03U) * 0x55U;
}
pixels -= 4;
}
}
static void
unpackL2IR(UINT8* out, const UINT8* in, int pixels)
{
/* nibbles (bit order reversed, white is zero) */
while (pixels > 0) {
UINT8 byte = *in++;
byte = BITFLIP[byte];
switch (pixels) {
default: *out++ = 0xFFU - (UINT8)(((byte >> 6) & 0x03U) * 0x55U); byte <<= 2;
case 3: *out++ = 0xFFU - (UINT8)(((byte >> 6) & 0x03U) * 0x55U); byte <<= 2;
case 2: *out++ = 0xFFU - (UINT8)(((byte >> 6) & 0x03U) * 0x55U); byte <<= 2;
case 1: *out++ = 0xFFU - (UINT8)(((byte >> 6) & 0x03U) * 0x55U);
}
pixels -= 4;
}
@ -207,12 +257,56 @@ unpackL2(UINT8* out, const UINT8* in, int pixels)
static void
unpackL4(UINT8* out, const UINT8* in, int pixels)
{
/* nibbles */
/* nibbles (msb first, white is non-zero) */
while (pixels > 0) {
UINT8 byte = *in++;
switch (pixels) {
default: *out++ = ((byte >> 4) & 15) * 255 / 15; byte <<= 4;
case 1: *out++ = ((byte >> 4) & 15) * 255 / 15;
default: *out++ = ((byte >> 4) & 0x0FU) * 0x11U; byte <<= 4;
case 1: *out++ = ((byte >> 4) & 0x0FU) * 0x11U;
}
pixels -= 2;
}
}
static void
unpackL4I(UINT8* out, const UINT8* in, int pixels)
{
/* nibbles (msb first, white is zero) */
while (pixels > 0) {
UINT8 byte = *in++;
switch (pixels) {
default: *out++ = 0xFFU - (UINT8)(((byte >> 4) & 0x0FU) * 0x11U); byte <<= 4;
case 1: *out++ = 0xFFU - (UINT8)(((byte >> 4) & 0x0FU) * 0x11U);
}
pixels -= 2;
}
}
static void
unpackL4R(UINT8* out, const UINT8* in, int pixels)
{
/* nibbles (bit order reversed, white is non-zero) */
while (pixels > 0) {
UINT8 byte = *in++;
byte = BITFLIP[byte];
switch (pixels) {
default: *out++ = ((byte >> 4) & 0x0FU) * 0x11U; byte <<= 4;
case 1: *out++ = ((byte >> 4) & 0x0FU) * 0x11U;
}
pixels -= 2;
}
}
static void
unpackL4IR(UINT8* out, const UINT8* in, int pixels)
{
/* nibbles (bit order reversed, white is zero) */
while (pixels > 0) {
UINT8 byte = *in++;
byte = BITFLIP[byte];
switch (pixels) {
default: *out++ = 0xFFU - (UINT8)(((byte >> 4) & 0x0FU) * 0x11U); byte <<= 4;
case 1: *out++ = 0xFFU - (UINT8)(((byte >> 4) & 0x0FU) * 0x11U);
}
pixels -= 2;
}
@ -1053,7 +1147,15 @@ static struct {
/* greyscale */
{"L", "L;2", 2, unpackL2},
{"L", "L;2I", 2, unpackL2I},
{"L", "L;2R", 2, unpackL2R},
{"L", "L;2IR", 2, unpackL2IR},
{"L", "L;4", 4, unpackL4},
{"L", "L;4I", 4, unpackL4I},
{"L", "L;4R", 4, unpackL4R},
{"L", "L;4IR", 4, unpackL4IR},
{"L", "L", 8, copy1},
{"L", "L;I", 8, unpackLI},
{"L", "L;R", 8, unpackLR},