From: Sven Eckelmann <sven@narfation.org>
Date: Sat, 31 Aug 2019 14:13:11 +0200
Subject: Provide gif quantization for giflib >= 5.2
Bug-Debian: https://bugs.debian.org/939031
diff -Naur exact-image-1.0.2.orig/codecs/Makefile exact-image-1.0.2/codecs/Makefile
--- exact-image-1.0.2.orig/codecs/Makefile 2016-06-18 21:49:25.000000000 +0200
+++ exact-image-1.0.2/codecs/Makefile 2020-12-11 15:30:44.374504000 +0100
@@ -21,7 +21,7 @@
ifeq "$(WITHLIBGIF)" "1"
LDFLAGS += -lgif
else
-NOT_SRCS += gif.cc
+NOT_SRCS += gif.cc gif_quantization.c
endif
ifeq "$(WITHJASPER)" "1"
diff -Naur exact-image-1.0.2.orig/codecs/gif.cc exact-image-1.0.2/codecs/gif.cc
--- exact-image-1.0.2.orig/codecs/gif.cc 2017-07-21 16:19:01.000000000 +0200
+++ exact-image-1.0.2/codecs/gif.cc 2020-12-11 15:34:55.340504000 +0100
@@ -160,6 +160,17 @@
return true;
}
+extern "C" int
+eiGifQuantizeBuffer(unsigned int Width,
+ unsigned int Height,
+ int *ColorMapSize,
+ GifByteType * RedInput,
+ GifByteType * GreenInput,
+ GifByteType * BlueInput,
+ GifByteType * OutputBuffer,
+ GifColorType * OutputColorMap);
+
+
bool GIFCodec::writeImage (std::ostream* stream, Image& image, int quality,
const std::string& compress)
{
@@ -203,8 +214,7 @@
*bptr++ = b;
}
-
- if (GifQuantizeBuffer(image.w, image.h, &ColorMapSize,
+ if (eiGifQuantizeBuffer(image.w, image.h, &ColorMapSize,
RedBuffer, GreenBuffer, BlueBuffer,
OutputBuffer, OutputColorMap->Colors) == GIF_ERROR) {
return false;
diff -Naur exact-image-1.0.2.orig/codecs/gif_quantization.c exact-image-1.0.2/codecs/gif_quantization.c
--- exact-image-1.0.2.orig/codecs/gif_quantization.c 1970-01-01 01:00:00.000000000 +0100
+++ exact-image-1.0.2/codecs/gif_quantization.c 2020-12-11 15:30:19.181504000 +0100
@@ -0,0 +1,331 @@
+/*****************************************************************************
+
+ quantize.c - quantize a high resolution image into lower one
+
+ Based on: "Color Image Quantization for frame buffer Display", by
+ Paul Heckbert SIGGRAPH 1982 page 297-307.
+
+ This doesn't really belong in the core library, was undocumented,
+ and was removed in 4.2. Then it turned out some client apps were
+ actually using it, so it was restored in 5.0.
+
+SPDX-License-Identifier: MIT
+
+******************************************************************************/
+
+#include <stdlib.h>
+#include <stdio.h>
+#include "gif_lib.h"
+
+#define ABS(x) ((x) > 0 ? (x) : (-(x)))
+
+#define COLOR_ARRAY_SIZE 32768
+#define BITS_PER_PRIM_COLOR 5
+#define MAX_PRIM_COLOR 0x1f
+
+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 void *Entry1, const void *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 successful, GIF_ERROR otherwise.
+******************************************************************************/
+int
+eiGifQuantizeBuffer(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) {
+ 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;
+ }
+ }
+
+ /* 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) {
+
+ unsigned int i, j, Index = 0;
+ QuantizedColorType *QuantizedColor, **SortArray;
+
+ while (ColorMapSize > *NewColorMapSize) {
+ /* Find candidate for subdivision: */
+ long Sum, Count;
+ int MaxSize = -1;
+ unsigned int NumEntries, MinColor, MaxColor;
+ 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;
+
+ /*
+ * Because qsort isn't stable, this can produce differing
+ * results for the order of tuples depending on platform
+ * details of how qsort() is implemented.
+ *
+ * We mitigate this problem by sorting on all three axes rather
+ * than only the one specied by SortRGBAxis; that way the instability
+ * can only become an issue if there are multiple color indices
+ * referring to identical RGB tuples. Older versions of this
+ * sorted on only the one axis.
+ */
+ 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 (QuantizedColor->Pnext != NULL &&
+ (Sum -= QuantizedColor->Pnext->Count) >= 0 &&
+ 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 */
+ /* coverity[var_deref_op] */
+ 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 two entries.
+*****************************************************************************/
+
+static int
+SortCmpRtn(const void *Entry1,
+ const void *Entry2) {
+ QuantizedColorType *entry1 = (*((QuantizedColorType **) Entry1));
+ QuantizedColorType *entry2 = (*((QuantizedColorType **) Entry2));
+
+ /* sort on all axes of the color space! */
+ int hash1 = entry1->RGB[SortRGBAxis] * 256 * 256
+ + entry1->RGB[(SortRGBAxis+1) % 3] * 256
+ + entry1->RGB[(SortRGBAxis+2) % 3];
+ int hash2 = entry2->RGB[SortRGBAxis] * 256 * 256
+ + entry2->RGB[(SortRGBAxis+1) % 3] * 256
+ + entry2->RGB[(SortRGBAxis+2) % 3];
+
+ return hash1 - hash2;
+}
+
+/* end */
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