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Diffstat (limited to 'quantize.c')
| -rw-r--r-- | quantize.c | 330 |
1 files changed, 0 insertions, 330 deletions
diff --git a/quantize.c b/quantize.c deleted file mode 100644 index 1cbb41f..0000000 --- a/quantize.c +++ /dev/null @@ -1,330 +0,0 @@ -/***************************************************************************** - * "Gif-Lib" - Yet another gif library. - * - * Written by: Gershon Elber IBM PC Ver 0.1, Jun. 1989 - ****************************************************************************** - * Module to quatize high resolution image into lower one. You may want to - * peek into the following article this code is based on: - * "Color Image Quantization for frame buffer Display", by Paul Heckbert - * SIGGRAPH 1982 page 297-307. - ****************************************************************************** - * History: - * 5 Jan 90 - Version 1.0 by Gershon Elber. - *****************************************************************************/ - -#ifdef HAVE_CONFIG_H -#include <config.h> -#endif - -#ifdef __MSDOS__ -#include <dos.h> -#include <alloc.h> -#include <graphics.h> -#endif /* __MSDOS__ */ - -#include <stdlib.h> -#include <stdio.h> -#include "gif_lib.h" -#include "gif_lib_private.h" - -#define ABS(x) ((x) > 0 ? (x) : (-(x))) - -/* The colors are stripped to 5 bits per primary color if non MSDOS system - * or to 4 (not enough memory...) if MSDOS as first step. - */ -#ifdef __MSDOS__ -#define COLOR_ARRAY_SIZE 4096 -#define BITS_PER_PRIM_COLOR 4 -#define MAX_PRIM_COLOR 0x0f -#else -#define COLOR_ARRAY_SIZE 32768 -#define BITS_PER_PRIM_COLOR 5 -#define MAX_PRIM_COLOR 0x1f -#endif /* __MSDOS__ */ - -static int SortRGBAxis; - -typedef struct QuantizedColorType { - GifByteType RGB[3]; - GifByteType NewColorIndex; - long Count; - struct QuantizedColorType *Pnext; -} QuantizedColorType; - -typedef struct NewColorMapType { - GifByteType RGBMin[3], RGBWidth[3]; - unsigned int NumEntries; /* # of QuantizedColorType in linked list below */ - unsigned long Count; /* Total number of pixels in all the entries */ - QuantizedColorType *QuantizedColors; -} NewColorMapType; - -static int SubdivColorMap(NewColorMapType * NewColorSubdiv, - unsigned int ColorMapSize, - unsigned int *NewColorMapSize); -static int SortCmpRtn(const VoidPtr Entry1, const VoidPtr Entry2); - -/****************************************************************************** - * Quantize high resolution image into lower one. Input image consists of a - * 2D array for each of the RGB colors with size Width by Height. There is no - * Color map for the input. Output is a quantized image with 2D array of - * indexes into the output color map. - * Note input image can be 24 bits at the most (8 for red/green/blue) and - * the output has 256 colors at the most (256 entries in the color map.). - * ColorMapSize specifies size of color map up to 256 and will be updated to - * real size before returning. - * Also non of the parameter are allocated by this routine. - * This function returns GIF_OK if succesfull, GIF_ERROR otherwise. - ******************************************************************************/ -int -QuantizeBuffer(unsigned int Width, - unsigned int Height, - int *ColorMapSize, - GifByteType * RedInput, - GifByteType * GreenInput, - GifByteType * BlueInput, - GifByteType * OutputBuffer, - GifColorType * OutputColorMap) { - - unsigned int Index, NumOfEntries; - int i, j, MaxRGBError[3]; - unsigned int NewColorMapSize; - long Red, Green, Blue; - NewColorMapType NewColorSubdiv[256]; - QuantizedColorType *ColorArrayEntries, *QuantizedColor; - - ColorArrayEntries = (QuantizedColorType *)malloc( - sizeof(QuantizedColorType) * COLOR_ARRAY_SIZE); - if (ColorArrayEntries == NULL) { - _GifError = E_GIF_ERR_NOT_ENOUGH_MEM; - return GIF_ERROR; - } - - for (i = 0; i < COLOR_ARRAY_SIZE; i++) { - ColorArrayEntries[i].RGB[0] = i >> (2 * BITS_PER_PRIM_COLOR); - ColorArrayEntries[i].RGB[1] = (i >> BITS_PER_PRIM_COLOR) & - MAX_PRIM_COLOR; - ColorArrayEntries[i].RGB[2] = i & MAX_PRIM_COLOR; - ColorArrayEntries[i].Count = 0; - } - - /* Sample the colors and their distribution: */ - for (i = 0; i < (int)(Width * Height); i++) { - Index = ((RedInput[i] >> (8 - BITS_PER_PRIM_COLOR)) << - (2 * BITS_PER_PRIM_COLOR)) + - ((GreenInput[i] >> (8 - BITS_PER_PRIM_COLOR)) << - BITS_PER_PRIM_COLOR) + - (BlueInput[i] >> (8 - BITS_PER_PRIM_COLOR)); - ColorArrayEntries[Index].Count++; - } - - /* Put all the colors in the first entry of the color map, and call the - * recursive subdivision process. */ - for (i = 0; i < 256; i++) { - NewColorSubdiv[i].QuantizedColors = NULL; - NewColorSubdiv[i].Count = NewColorSubdiv[i].NumEntries = 0; - for (j = 0; j < 3; j++) { - NewColorSubdiv[i].RGBMin[j] = 0; - NewColorSubdiv[i].RGBWidth[j] = 255; - } - } - - /* Find the non empty entries in the color table and chain them: */ - for (i = 0; i < COLOR_ARRAY_SIZE; i++) - if (ColorArrayEntries[i].Count > 0) - break; - QuantizedColor = NewColorSubdiv[0].QuantizedColors = &ColorArrayEntries[i]; - NumOfEntries = 1; - while (++i < COLOR_ARRAY_SIZE) - if (ColorArrayEntries[i].Count > 0) { - QuantizedColor->Pnext = &ColorArrayEntries[i]; - QuantizedColor = &ColorArrayEntries[i]; - NumOfEntries++; - } - QuantizedColor->Pnext = NULL; - - NewColorSubdiv[0].NumEntries = NumOfEntries; /* Different sampled colors */ - NewColorSubdiv[0].Count = ((long)Width) * Height; /* Pixels */ - NewColorMapSize = 1; - if (SubdivColorMap(NewColorSubdiv, *ColorMapSize, &NewColorMapSize) != - GIF_OK) { - free((char *)ColorArrayEntries); - return GIF_ERROR; - } - if (NewColorMapSize < *ColorMapSize) { - /* And clear rest of color map: */ - for (i = NewColorMapSize; i < *ColorMapSize; i++) - OutputColorMap[i].Red = OutputColorMap[i].Green = - OutputColorMap[i].Blue = 0; - } - - /* Average the colors in each entry to be the color to be used in the - * output color map, and plug it into the output color map itself. */ - for (i = 0; i < NewColorMapSize; i++) { - if ((j = NewColorSubdiv[i].NumEntries) > 0) { - QuantizedColor = NewColorSubdiv[i].QuantizedColors; - Red = Green = Blue = 0; - while (QuantizedColor) { - QuantizedColor->NewColorIndex = i; - Red += QuantizedColor->RGB[0]; - Green += QuantizedColor->RGB[1]; - Blue += QuantizedColor->RGB[2]; - QuantizedColor = QuantizedColor->Pnext; - } - OutputColorMap[i].Red = (Red << (8 - BITS_PER_PRIM_COLOR)) / j; - OutputColorMap[i].Green = (Green << (8 - BITS_PER_PRIM_COLOR)) / j; - OutputColorMap[i].Blue = (Blue << (8 - BITS_PER_PRIM_COLOR)) / j; - } else - fprintf(stderr, - "\n%s: Null entry in quantized color map - that's weird.\n", - PROGRAM_NAME); - } - - /* Finally scan the input buffer again and put the mapped index in the - * output buffer. */ - MaxRGBError[0] = MaxRGBError[1] = MaxRGBError[2] = 0; - for (i = 0; i < (int)(Width * Height); i++) { - Index = ((RedInput[i] >> (8 - BITS_PER_PRIM_COLOR)) << - (2 * BITS_PER_PRIM_COLOR)) + - ((GreenInput[i] >> (8 - BITS_PER_PRIM_COLOR)) << - BITS_PER_PRIM_COLOR) + - (BlueInput[i] >> (8 - BITS_PER_PRIM_COLOR)); - Index = ColorArrayEntries[Index].NewColorIndex; - OutputBuffer[i] = Index; - if (MaxRGBError[0] < ABS(OutputColorMap[Index].Red - RedInput[i])) - MaxRGBError[0] = ABS(OutputColorMap[Index].Red - RedInput[i]); - if (MaxRGBError[1] < ABS(OutputColorMap[Index].Green - GreenInput[i])) - MaxRGBError[1] = ABS(OutputColorMap[Index].Green - GreenInput[i]); - if (MaxRGBError[2] < ABS(OutputColorMap[Index].Blue - BlueInput[i])) - MaxRGBError[2] = ABS(OutputColorMap[Index].Blue - BlueInput[i]); - } - -#ifdef DEBUG - fprintf(stderr, - "Quantization L(0) errors: Red = %d, Green = %d, Blue = %d.\n", - MaxRGBError[0], MaxRGBError[1], MaxRGBError[2]); -#endif /* DEBUG */ - - free((char *)ColorArrayEntries); - - *ColorMapSize = NewColorMapSize; - - return GIF_OK; -} - -/****************************************************************************** - * Routine to subdivide the RGB space recursively using median cut in each - * axes alternatingly until ColorMapSize different cubes exists. - * The biggest cube in one dimension is subdivide unless it has only one entry. - * Returns GIF_ERROR if failed, otherwise GIF_OK. - ******************************************************************************/ -static int -SubdivColorMap(NewColorMapType * NewColorSubdiv, - unsigned int ColorMapSize, - unsigned int *NewColorMapSize) { - - int MaxSize; - unsigned int i, j, Index = 0, NumEntries, MinColor, MaxColor; - long Sum, Count; - QuantizedColorType *QuantizedColor, **SortArray; - - while (ColorMapSize > *NewColorMapSize) { - /* Find candidate for subdivision: */ - MaxSize = -1; - for (i = 0; i < *NewColorMapSize; i++) { - for (j = 0; j < 3; j++) { - if ((((int)NewColorSubdiv[i].RGBWidth[j]) > MaxSize) && - (NewColorSubdiv[i].NumEntries > 1)) { - MaxSize = NewColorSubdiv[i].RGBWidth[j]; - Index = i; - SortRGBAxis = j; - } - } - } - - if (MaxSize == -1) - return GIF_OK; - - /* Split the entry Index into two along the axis SortRGBAxis: */ - - /* Sort all elements in that entry along the given axis and split at - * the median. */ - SortArray = (QuantizedColorType **)malloc( - sizeof(QuantizedColorType *) * - NewColorSubdiv[Index].NumEntries); - if (SortArray == NULL) - return GIF_ERROR; - for (j = 0, QuantizedColor = NewColorSubdiv[Index].QuantizedColors; - j < NewColorSubdiv[Index].NumEntries && QuantizedColor != NULL; - j++, QuantizedColor = QuantizedColor->Pnext) - SortArray[j] = QuantizedColor; - - qsort(SortArray, NewColorSubdiv[Index].NumEntries, - sizeof(QuantizedColorType *), SortCmpRtn); - - /* Relink the sorted list into one: */ - for (j = 0; j < NewColorSubdiv[Index].NumEntries - 1; j++) - SortArray[j]->Pnext = SortArray[j + 1]; - SortArray[NewColorSubdiv[Index].NumEntries - 1]->Pnext = NULL; - NewColorSubdiv[Index].QuantizedColors = QuantizedColor = SortArray[0]; - free((char *)SortArray); - - /* Now simply add the Counts until we have half of the Count: */ - Sum = NewColorSubdiv[Index].Count / 2 - QuantizedColor->Count; - NumEntries = 1; - Count = QuantizedColor->Count; - while ((Sum -= QuantizedColor->Pnext->Count) >= 0 && - QuantizedColor->Pnext != NULL && - QuantizedColor->Pnext->Pnext != NULL) { - QuantizedColor = QuantizedColor->Pnext; - NumEntries++; - Count += QuantizedColor->Count; - } - /* Save the values of the last color of the first half, and first - * of the second half so we can update the Bounding Boxes later. - * Also as the colors are quantized and the BBoxes are full 0..255, - * they need to be rescaled. - */ - MaxColor = QuantizedColor->RGB[SortRGBAxis]; /* Max. of first half */ - MinColor = QuantizedColor->Pnext->RGB[SortRGBAxis]; /* of second */ - MaxColor <<= (8 - BITS_PER_PRIM_COLOR); - MinColor <<= (8 - BITS_PER_PRIM_COLOR); - - /* Partition right here: */ - NewColorSubdiv[*NewColorMapSize].QuantizedColors = - QuantizedColor->Pnext; - QuantizedColor->Pnext = NULL; - NewColorSubdiv[*NewColorMapSize].Count = Count; - NewColorSubdiv[Index].Count -= Count; - NewColorSubdiv[*NewColorMapSize].NumEntries = - NewColorSubdiv[Index].NumEntries - NumEntries; - NewColorSubdiv[Index].NumEntries = NumEntries; - for (j = 0; j < 3; j++) { - NewColorSubdiv[*NewColorMapSize].RGBMin[j] = - NewColorSubdiv[Index].RGBMin[j]; - NewColorSubdiv[*NewColorMapSize].RGBWidth[j] = - NewColorSubdiv[Index].RGBWidth[j]; - } - NewColorSubdiv[*NewColorMapSize].RGBWidth[SortRGBAxis] = - NewColorSubdiv[*NewColorMapSize].RGBMin[SortRGBAxis] + - NewColorSubdiv[*NewColorMapSize].RGBWidth[SortRGBAxis] - MinColor; - NewColorSubdiv[*NewColorMapSize].RGBMin[SortRGBAxis] = MinColor; - - NewColorSubdiv[Index].RGBWidth[SortRGBAxis] = - MaxColor - NewColorSubdiv[Index].RGBMin[SortRGBAxis]; - - (*NewColorMapSize)++; - } - - return GIF_OK; -} - -/**************************************************************************** - * Routine called by qsort to compare to entries. - ****************************************************************************/ -static int -SortCmpRtn(const VoidPtr Entry1, - const VoidPtr Entry2) { - - return (*((QuantizedColorType **) Entry1))->RGB[SortRGBAxis] - - (*((QuantizedColorType **) Entry2))->RGB[SortRGBAxis]; -} |