GIF palette optimization added.

This commit is contained in:
Harald Oehlmann 2020-04-08 21:36:22 +02:00
parent 22570f6c73
commit d99bda9385

View File

@ -42,15 +42,13 @@
#include <malloc.h>
#endif
#define SSET "0123456789ABCDEF"
#define SSET "0123456789ABCDEF"
/* Index of transparent color, -1 for no transparent color
* This might be set into a variable if transparency is activated as an option
*/
#define TRANSPARENT_INDEX (15)
#define TRANSPARENT_INDEX (-1)
/* Used bit depth: 10 value pallet is 4 bit */
#define DESTINATION_IMAGE_BITS 4
#include <stdlib.h>
typedef struct s_statestruct {
@ -67,28 +65,24 @@ typedef struct s_statestruct {
unsigned short NodeAxon[4096];
unsigned short NodeNext[4096];
unsigned char NodePix[4096];
unsigned char colourCode[10];
unsigned char colourPaletteIndex[10];
} statestruct;
/* Transform a Pixel to a lzw colourmap index.
* See the 16 entries colour map definition in the code at the end for the mapping
/* Transform a Pixel to a lzw colourmap index and move to next pixel.
* All colour values are listed in colourCode with corresponding palette index
*/
static unsigned char PixelToCode(unsigned char PixelValue)
static unsigned char NextPaletteIndex(statestruct *pState)
{
switch (PixelValue)
{
case '0': return 0; /* standard background */
case '1': return 1; /* standard foreground */
case 'W': return 2; /* white */
case 'C': return 3; /* cyan */
case 'B': return 4; /* blue */
case 'M': return 5; /* magenta */
case 'R': return 6; /* red */
case 'Y': return 7; /* yellow */
case 'G': return 8; /* green */
case 'K': return 9; /* black */
case 'T': return 15; /* transparent */
default: return 15; /* error case - return */
unsigned char pixelColour;
int colourIndex;
pixelColour = *(pState->pIn);
(pState->pIn)++;
(pState->InLen)--;
for (colourIndex = 0;; colourIndex++) {
if (pixelColour == pState->colourCode[colourIndex])
return pState->colourPaletteIndex[colourIndex];
}
}
@ -109,6 +103,7 @@ static char BufferNextByte(statestruct *pState) {
}
if (pState->OutPosCur >= pState->OutLength)
return 1;
(pState->pOut)[pState->OutPosCur] = 0x00;
return 0;
}
@ -135,7 +130,7 @@ static char AddCodeToBuffer(statestruct *pState, unsigned short CodeIn, unsigned
/* The remaining bits of CodeIn fit in the current byte. */
if (CodeBits > 0) {
(pState->pOut)[pState->OutPosCur] |= (unsigned char)
(CodeIn << (8 - pState->OutBitsFree));
(CodeIn << (8 - pState->OutBitsFree));
pState->OutBitsFree -= CodeBits;
}
return 0;
@ -168,18 +163,14 @@ static char NextCode(statestruct *pState, unsigned char * pPixelValueCur, unsign
if ((pState->InLen) == 0)
return AddCodeToBuffer(pState, UpNode, CodeBits);
*pPixelValueCur = PixelToCode(*(pState->pIn));
(pState->pIn)++;
(pState->InLen)--;
*pPixelValueCur = NextPaletteIndex(pState);
/* Follow the string table and the data stream to the end of the longest string that has a code */
while (0 != (DownNode = FindPixelOutlet(pState, UpNode, *pPixelValueCur))) {
UpNode = DownNode;
if ((pState->InLen) == 0)
return AddCodeToBuffer(pState, UpNode, CodeBits);
*pPixelValueCur = PixelToCode(*(pState->pIn));
(pState->pIn)++;
(pState->InLen)--;
*pPixelValueCur = NextPaletteIndex(pState);
}
/* Submit 'UpNode' which is the code of the longest string */
if (AddCodeToBuffer(pState, UpNode, CodeBits))
@ -201,95 +192,115 @@ static char NextCode(statestruct *pState, unsigned char * pPixelValueCur, unsign
return 1;
}
static int gif_lzw(unsigned char *pOut, int OutLength, unsigned char *pIn, int InLen) {
static int gif_lzw(statestruct *pState, int paletteBitSize) {
unsigned char PixelValueCur;
unsigned char CodeBits;
unsigned short Pos;
statestruct State;
State.pIn = pIn;
State.InLen = InLen;
State.pOut = pOut;
State.OutLength = OutLength;
// > Get first data byte
if (State.InLen == 0)
if (pState->InLen == 0)
return 0;
PixelValueCur = NextPaletteIndex(pState);
/* Number of bits per data item (=pixel)
* We need at least a value of 2, otherwise the cc and eoi code consumes
* the whole string table
*/
if (paletteBitSize == 1)
paletteBitSize = 2;
/* initial size of compression codes */
CodeBits = paletteBitSize+1;
pState->ClearCode = (1 << paletteBitSize);
pState->FreeCode = pState->ClearCode+2;
pState->OutBitsFree = 8;
pState->OutPosCur = -1;
pState->fByteCountByteSet = 0;
if (BufferNextByte(pState))
return 0;
PixelValueCur = PixelToCode(*(State.pIn));
(State.pIn)++;
(State.InLen)--;
CodeBits = DESTINATION_IMAGE_BITS+1;
State.ClearCode = (1 << DESTINATION_IMAGE_BITS);
State.FreeCode = State.ClearCode+2;
State.OutBitsFree = 8;
State.OutPosCur = -1;
State.fByteCountByteSet = 0;
for (Pos = 0; Pos < pState->ClearCode; Pos++)
(pState->NodePix)[Pos] = (unsigned char) Pos;
if (BufferNextByte(&State))
return 0;
for (Pos = 0; Pos < State.ClearCode; Pos++)
State.NodePix[Pos] = (unsigned char) Pos;
FlushStringTable(&State);
FlushStringTable(pState);
/* Write what the GIF specification calls the "code size". */
(State.pOut)[State.OutPosCur] = DESTINATION_IMAGE_BITS;
(pState->pOut)[pState->OutPosCur] = paletteBitSize;
/* Reserve first bytecount byte */
if (BufferNextByte(&State))
if (BufferNextByte(pState))
return 0;
State.OutByteCountPos = State.OutPosCur;
if (BufferNextByte(&State))
pState->OutByteCountPos = pState->OutPosCur;
if (BufferNextByte(pState))
return 0;
State.fByteCountByteSet = 1;
pState->fByteCountByteSet = 1;
/* Submit one 'ClearCode' as the first code */
if (AddCodeToBuffer(&State, State.ClearCode, CodeBits))
if (AddCodeToBuffer(pState, pState->ClearCode, CodeBits))
return 0;
for (;;) {
char Res;
/* generate and save the next code, which may consist of multiple input pixels. */
Res = NextCode(&State, &PixelValueCur, CodeBits);
Res = NextCode(pState, &PixelValueCur, CodeBits);
if (Res < 0)
return 0;
//* Check for end of data stream */
if (!Res) {
/* submit 'eoi' as the last item of the code stream */
if (AddCodeToBuffer(&State, (unsigned short) (State.ClearCode + 1), CodeBits))
if (AddCodeToBuffer(pState, (unsigned short) (pState->ClearCode + 1), CodeBits))
return 0;
State.fByteCountByteSet = 0;
if (State.OutBitsFree < 8) {
if (BufferNextByte(&State))
pState->fByteCountByteSet = 0;
if (pState->OutBitsFree < 8) {
if (BufferNextByte(pState))
return 0;
}
// > Update last bytecount byte;
if (State.OutByteCountPos < State.OutPosCur) {
(State.pOut)[State.OutByteCountPos] = (unsigned char) (State.OutPosCur - State.OutByteCountPos - 1);
if (pState->OutByteCountPos < pState->OutPosCur) {
(pState->pOut)[pState->OutByteCountPos] = (unsigned char) (pState->OutPosCur - pState->OutByteCountPos - 1);
}
State.OutPosCur++;
return State.OutPosCur;
pState->OutPosCur++;
return pState->OutPosCur;
}
/* Check for currently last code */
if (State.FreeCode == (1U << CodeBits))
if (pState->FreeCode == (1U << CodeBits))
CodeBits++;
State.FreeCode++;
pState->FreeCode++;
/* Check for full stringtable */
if (State.FreeCode == 0xfff) {
FlushStringTable(&State);
if (AddCodeToBuffer(&State, State.ClearCode, CodeBits))
if (pState->FreeCode == 0xfff) {
FlushStringTable(pState);
if (AddCodeToBuffer(pState, pState->ClearCode, CodeBits))
return 0;
CodeBits = (unsigned char) (1 + DESTINATION_IMAGE_BITS);
State.FreeCode = (unsigned short) (State.ClearCode + 2);
CodeBits = (unsigned char) (1 + paletteBitSize);
pState->FreeCode = (unsigned short) (pState->ClearCode + 2);
}
}
}
/*
* Called function to save in gif format
*/
INTERNAL int gif_pixel_plot(struct zint_symbol *symbol, char *pixelbuf) {
unsigned char outbuf[10];
FILE *gif_file;
unsigned short usTemp;
int byte_out;
int colourCount;
unsigned char paletteRGB[10][3];
int paletteCount, paletteCountCur, paletteIndex;
int pixelIndex;
int paletteBitSize;
int paletteSize;
statestruct State;
unsigned char backgroundColourIndex;
unsigned char RGBCur[3];
int colourIndex;
int fFound;
unsigned char pixelColour;
#ifdef _MSC_VER
char * lzwoutbuf;
#endif
@ -315,18 +326,145 @@ INTERNAL int gif_pixel_plot(struct zint_symbol *symbol, char *pixelbuf) {
return ZINT_ERROR_FILE_ACCESS;
}
}
/*ImageWidth = 2;
ImageHeight = 2;
rotated_bitmap[0] = 1;
rotated_bitmap[1] = 1;
rotated_bitmap[2] = 0;
rotated_bitmap[3] = 0;
/*
* Build a table of the used palette items.
* Currently, there are the following 10 colour codes:
* '0': standard background
* '1': standard foreground
* 'W': white
* 'C': cyan
* 'B': blue
* 'M': magenta
* 'R': red
* 'Y': yellow
* 'G': green
* 'K': black
* '0' and '1' may be identical to one of the other values
*
* A data structure is set up as follows:
* state.colourCode: list of colour codes
* paletteIndex: palette index of the corresponding colour code
* There are colourCount entries in the upper lists.
* paletteRGB: RGB value at the palette position
* There are paletteCount entries.
* This value is smaller to colourCount, if multiple colour codes have the
* same RGB value and point to the same palette value.
* Example:
* 0 1 W K are present. 0 is equal to white, while 1 is blue
* The resulting tables are:
* paletteItem: ['0']=0 (white), ['1']=1 (blue), ['W']=0 (white),
* ['K']=2 (black)
* Thus, there are 4 colour codes and 3 palette entries.
*/
colourCount = 0;
paletteCount = 0;
/* loop over all pixels */
for ( pixelIndex = 0; pixelIndex < (symbol->bitmap_height * symbol->bitmap_width); pixelIndex++)
{
fFound = 0;
/* get pixel colour code */
pixelColour = pixelbuf[pixelIndex];
/* look, if colour code is already in colour list */
for (colourIndex = 0; colourIndex < colourCount; colourIndex++) {
if ((State.colourCode)[colourIndex] == pixelColour) {
fFound = 1;
break;
}
}
/* If colour is already present, go to next colour code */
if (fFound)
continue;
/* Colour code not present - add colour code */
/* Get RGB value */
switch (pixelColour) {
case '0': /* standard background */
RGBCur[0] = (unsigned char) (16 * ctoi(symbol->bgcolour[0])) + ctoi(symbol->bgcolour[1]);
RGBCur[1] = (unsigned char) (16 * ctoi(symbol->bgcolour[2])) + ctoi(symbol->bgcolour[3]);
RGBCur[2] = (unsigned char) (16 * ctoi(symbol->bgcolour[4])) + ctoi(symbol->bgcolour[5]);
break;
case '1': /* standard foreground */
RGBCur[0] = (unsigned char) (16 * ctoi(symbol->fgcolour[0])) + ctoi(symbol->fgcolour[1]);
RGBCur[1] = (unsigned char) (16 * ctoi(symbol->fgcolour[2])) + ctoi(symbol->fgcolour[3]);
RGBCur[2] = (unsigned char) (16 * ctoi(symbol->fgcolour[4])) + ctoi(symbol->fgcolour[5]);
break;
case 'W': /* white */
RGBCur[0] = 255; RGBCur[1] = 255; RGBCur[2] = 255;
break;
case 'C': /* cyan */
RGBCur[0] = 0; RGBCur[1] = 255; RGBCur[2] = 255;
break;
case 'B': /* blue */
RGBCur[0] = 0; RGBCur[1] = 0; RGBCur[2] = 255;
break;
case 'M': /* magenta */
RGBCur[0] = 255; RGBCur[1] = 0; RGBCur[2] = 255;
break;
case 'R': /* red */
RGBCur[0] = 255; RGBCur[1] = 0; RGBCur[2] = 0;
break;
case 'Y': /* yellow */
RGBCur[0] = 255; RGBCur[1] = 255; RGBCur[2] = 0;
break;
case 'G': /* green */
RGBCur[0] = 0; RGBCur[1] = 255; RGBCur[2] = 0;
break;
case 'K': /* black */
RGBCur[0] = 0; RGBCur[1] = 0; RGBCur[2] = 0;
break;
default: /* error case - return */
strcpy(symbol->errtxt, "611: unknown pixel colour");
return ZINT_ERROR_INVALID_DATA;
}
/* Search, if RGB value is already present */
fFound = 0;
for (paletteIndex = 0; paletteIndex < paletteCount; paletteIndex++) {
if (RGBCur[0] == paletteRGB[paletteIndex][0]
&& RGBCur[1] == paletteRGB[paletteIndex][1]
&& RGBCur[2] == paletteRGB[paletteIndex][2])
{
fFound = 1;
break;
}
}
/* RGB not present, add it */
if (!fFound) {
paletteIndex = paletteCount;
paletteRGB[paletteIndex][0] = RGBCur[0];
paletteRGB[paletteIndex][1] = RGBCur[1];
paletteRGB[paletteIndex][2] = RGBCur[2];
paletteCount++;
}
/* Add palette index to current colour code */
(State.colourCode)[colourCount] = pixelColour;
(State.colourPaletteIndex)[colourCount] = paletteIndex;
colourCount++;
}
/* find palette bit size from palette size*/
/* 1,2 -> 1, 3,4 ->2, 5,6,7,8->3 */
paletteBitSize = 0;
paletteCountCur = paletteCount-1;
while (paletteCountCur != 0) {
paletteBitSize++;
paletteCountCur >>= 1;
}
/* Minimum is 1 */
if (paletteBitSize == 0)
paletteBitSize = 1;
/* palette size 2 ^ bit size */
paletteSize = 1<<paletteBitSize;
/* GIF signature (6) */
memcpy(outbuf, "GIF87a", 6);
if (TRANSPARENT_INDEX != -1)
outbuf[4] = '9';
fwrite(outbuf, 6, 1, gif_file);
/* Screen Descriptor (7) */
/* Screen Width */
@ -343,57 +481,33 @@ INTERNAL int gif_pixel_plot(struct zint_symbol *symbol, char *pixelbuf) {
* 1 : Global colour map
* 111 : 8 bit colour depth of the palette
* 0 : Not ordered in decreasing importance
* 011 : 4 bit palette
* xxx : palette bit zize - 1
*/
outbuf[4] = (unsigned char) (0xf0 | (0x7 & (DESTINATION_IMAGE_BITS - 1)));
/* Background color = colortable index 0 */
outbuf[5] = 0x00;
outbuf[4] = (unsigned char) (0xf0 | (0x7 & (paletteBitSize - 1)));
/*
* Background colour index
* Default to 0. If colour code 0 or K is present, it is used as index
*/
backgroundColourIndex = 0;
for (colourIndex = 0; colourIndex < colourCount; colourIndex++) {
if ((State.colourCode)[colourIndex] == '0' || (State.colourCode)[colourIndex] == 'W') {
backgroundColourIndex = (State.colourPaletteIndex)[colourIndex];
break;
}
}
outbuf[5] = backgroundColourIndex;
/* Byte 7 must be 0x00 */
outbuf[6] = 0x00;
fwrite(outbuf, 7, 1, gif_file);
/* Global Color Table (16*3) */
/* Colour index 0: RGB 0 color */
outbuf[0] = (unsigned char) (16 * ctoi(symbol->bgcolour[0])) + ctoi(symbol->bgcolour[1]);
outbuf[1] = (unsigned char) (16 * ctoi(symbol->bgcolour[2])) + ctoi(symbol->bgcolour[3]);
outbuf[2] = (unsigned char) (16 * ctoi(symbol->bgcolour[4])) + ctoi(symbol->bgcolour[5]);
/* Colour index 1: RGB 1 color */
outbuf[3] = (unsigned char) (16 * ctoi(symbol->fgcolour[0])) + ctoi(symbol->fgcolour[1]);
outbuf[4] = (unsigned char) (16 * ctoi(symbol->fgcolour[2])) + ctoi(symbol->fgcolour[3]);
outbuf[5] = (unsigned char) (16 * ctoi(symbol->fgcolour[4])) + ctoi(symbol->fgcolour[5]);
/* Colour index 2: "W" for White color */
outbuf[6] = 255; outbuf[7] = 255; outbuf[8] = 255;
fwrite(outbuf, 9, 1, gif_file);
/* Colour index 3: "C" for Cyan colour */
outbuf[0] = 0; outbuf[1] = 255; outbuf[2] = 255;
/* Colour index 4: "B" for Blue colour */
outbuf[3] = 0; outbuf[4] = 0; outbuf[5] = 255;
/* Colour index 5: "M" for Magenta colour */
outbuf[6] = 255; outbuf[7] = 0; outbuf[8] = 255;
fwrite(outbuf, 9, 1, gif_file);
/* Colour index 6: "R" for red colour */
outbuf[0] = 255; outbuf[1] = 0; outbuf[2] = 0;
/* Colour index 7: "Y" for yellow colour */
outbuf[3] = 255; outbuf[4] = 255; outbuf[5] = 0;
/* Colour index 8: "G" for green colour */
outbuf[6] = 0; outbuf[7] = 255; outbuf[8] = 0;
fwrite(outbuf, 9, 1, gif_file);
/* Colour index 9: "K" for black colour */
outbuf[0] = 0; outbuf[1] = 0; outbuf[2] = 0;
/* Colour index 10: unused, set to black colour*/
outbuf[3] = 0; outbuf[4] = 0; outbuf[5] = 0;
/* Colour index 11: unused, set to black colour */
outbuf[6] = 0; outbuf[7] = 0; outbuf[8] = 0;
fwrite(outbuf, 9, 1, gif_file);
/* Colour index 12: unused, set to black colour */
outbuf[0] = 0; outbuf[1] = 0; outbuf[2] = 0;
/* Colour index 13: unused, set to black colour*/
outbuf[3] = 0; outbuf[4] = 0; outbuf[5] = 0;
/* Colour index 14: unused, set to black colour */
outbuf[6] = 0; outbuf[7] = 0; outbuf[8] = 0;
fwrite(outbuf, 9, 1, gif_file);
/* Colour index 15: transparent colour */
outbuf[0] = 0; outbuf[1] = 0; outbuf[2] = 0;
fwrite(outbuf, 3, 1, gif_file);
/* Global Color Table (paletteSize*3) */
fwrite(paletteRGB, 3*paletteCount, 1, gif_file);
/* add unused palette items to fill palette size */
for (paletteIndex = paletteCount; paletteIndex < paletteSize; paletteIndex++) {
unsigned char RGBCur[3] = {0,0,0};
fwrite(RGBCur, 3, 1, gif_file);
}
/* Graphic control extension (8) */
/* A graphic control extension block is used for overlay gifs.
@ -445,12 +559,14 @@ INTERNAL int gif_pixel_plot(struct zint_symbol *symbol, char *pixelbuf) {
outbuf[9] = 0x00;
fwrite(outbuf, 10, 1, gif_file);
/* prepare state array */
State.pIn = (unsigned char *) pixelbuf;
State.InLen = symbol->bitmap_height * symbol->bitmap_width;
State.pOut = (unsigned char *) lzwoutbuf;
State.OutLength = symbol->bitmap_height * symbol->bitmap_width;
/* call lzw encoding */
byte_out = gif_lzw(
(unsigned char *) lzwoutbuf,
symbol->bitmap_height * symbol->bitmap_width,
(unsigned char *) pixelbuf,
symbol->bitmap_height * symbol->bitmap_width);
byte_out = gif_lzw(&State, paletteBitSize);
if (byte_out <= 0) {
fclose(gif_file);
return ZINT_ERROR_MEMORY;