Add method=Image.LIBIMAGEQUANT for quantize()

PIL/Image.py

@@ -185,6 +185,7 @@ ADAPTIVE = 1
 MEDIANCUT = 0
 MAXCOVERAGE = 1
 FASTOCTREE = 2
+LIBIMAGEQUANT = 3
 
 # categories
 NORMAL = 0
@@ -967,6 +968,7 @@ class Image(object):
         :param method: 0 = median cut
                        1 = maximum coverage
                        2 = fast octree
+                       3 = libimagequant
         :param kmeans: Integer
         :param palette: Quantize to the :py:class:`PIL.ImagingPalette` palette.
         :returns: A new image
@@ -981,10 +983,11 @@ class Image(object):
             if self.mode == 'RGBA':
                 method = 2
 
-        if self.mode == 'RGBA' and method != 2:
+        if self.mode == 'RGBA' and method not in (2, 3):
             # Caller specified an invalid mode.
-            raise ValueError('Fast Octree (method == 2) is the ' +
-                             ' only valid method for quantizing RGBA images')
+            raise ValueError(
+                'Fast Octree (method == 2) and libimagequant (method == 3) ' +
+                'are the only valid methods for quantizing RGBA images')
 
         if palette:
             # use palette from reference image

Tests/test_image_quantize.py

@@ -15,6 +15,14 @@ class TestImageQuantize(PillowTestCase):
         im = im.quantize(palette=hopper("P"))
         self.assert_image(im, "P", im.size)
 
+    def test_libimagequant_quantize(self):
+        im = hopper()
+
+        im = im.quantize(100, Image.LIBIMAGEQUANT)
+        self.assert_image(im, "P", im.size)
+
+        assert len(im.getcolors()) == 100
+
     def test_octree_quantize(self):
         im = hopper()
 

libImaging/Quant.c

@@ -1484,7 +1484,7 @@ ImagingQuantize(Imaging im, int colors, int mode, int kmeans)
         return ImagingError_ModeError();
 
     /* only octree supports RGBA */
-    if (!strcmp(im->mode, "RGBA") && mode != 2)
+    if (!strcmp(im->mode, "RGBA") && mode != 2 && mode != 3)
        return ImagingError_ModeError();
 
     p = malloc(sizeof(Pixel) * im->xsize * im->ysize);
@@ -1503,8 +1503,10 @@ ImagingQuantize(Imaging im, int colors, int mode, int kmeans)
            should be done by a simple copy... */
 
         for (i = y = 0; y < im->ysize; y++)
-            for (x = 0; x < im->xsize; x++, i++)
+            for (x = 0; x < im->xsize; x++, i++) {
                 p[i].c.r = p[i].c.g = p[i].c.b = im->image8[y][x];
+                p[i].c.a = 255;
+            }
 
     } else if (!strcmp(im->mode, "P")) {
         /* palette */
@@ -1517,6 +1519,7 @@ ImagingQuantize(Imaging im, int colors, int mode, int kmeans)
                 p[i].c.r = pp[v*4+0];
                 p[i].c.g = pp[v*4+1];
                 p[i].c.b = pp[v*4+2];
+                p[i].c.a = pp[v*4+3];
             }
 
     } else if (!strcmp(im->mode, "RGB") || !strcmp(im->mode, "RGBA")) {
@@ -1572,6 +1575,21 @@ ImagingQuantize(Imaging im, int colors, int mode, int kmeans)
             withAlpha
             );
         break;
+    case 3:
+        if (!strcmp(im->mode, "RGBA")) {
+            withAlpha = 1;
+        }
+        result = quantize_pngquant(
+            p,
+            im->xsize,
+            im->ysize,
+            colors,
+            &palette,
+            &paletteLength,
+            &newData,
+            withAlpha
+            );
+        break;
     default:
         result = 0;
         break;

libImaging/QuantPngQuant.c

@@ -0,0 +1,141 @@
+/* Copyright (c) 2010 Oliver Tonnhofer <olt@bogosoft.com>, Omniscale
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+*/
+
+/*
+// This file implements a quantization using libimagequant, a part of pngquant.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "QuantPngQuant.h"
+
+#ifdef HAVE_LIBIMAGEQUANT
+#include "libimagequant.h"
+
+int
+quantize_pngquant(
+    Pixel *pixelData,
+    uint32_t width,
+    uint32_t height,
+    uint32_t quantPixels,
+    Pixel **palette,
+    uint32_t *paletteLength,
+    uint32_t **quantizedPixels,
+    int withAlpha)
+{
+    int result = 0;
+    liq_image *image = NULL;
+    liq_attr *attr = NULL;
+    liq_result *remap = NULL;
+    char *charMatrix = NULL;
+    char **charMatrixRows = NULL;
+    *palette = NULL;
+    *paletteLength = 0;
+    *quantizedPixels = NULL;
+
+    /* configure pngquant */
+    attr = liq_attr_create();
+    if (!attr) { goto err; }
+    if (quantPixels) {
+        liq_set_max_colors(attr, quantPixels);
+    }
+
+    /* prepare input image */
+    image = liq_image_create_rgba(
+        attr,
+        pixelData,
+        width,
+        height,
+        0.45455 /* gamma */);
+    if (!image) { goto err; }
+
+    /* quantize the image */
+    remap = liq_quantize_image(attr, image);
+    if (!remap) { goto err; }
+    liq_set_output_gamma(remap, 0.45455);
+    liq_set_dithering_level(remap, 1);
+
+    /* write output palette */
+    const liq_palette *l_palette = liq_get_palette(remap);
+    *paletteLength = l_palette->count;
+    *palette = malloc(sizeof(Pixel) * l_palette->count);
+    if (!*palette) { goto err; }
+    for (unsigned int i = 0; i < l_palette->count; i++) {
+        (*palette)[i].c.b = l_palette->entries[i].b;
+        (*palette)[i].c.g = l_palette->entries[i].g;
+        (*palette)[i].c.r = l_palette->entries[i].r;
+        (*palette)[i].c.a = l_palette->entries[i].a;
+    }
+
+    /* write output pixels (pngquant uses char array) */
+    charMatrix = malloc(width * height);
+    if (!charMatrix) { goto err; }
+    charMatrixRows = malloc(height * sizeof(char*));
+    if (!charMatrixRows) { goto err; }
+    for (unsigned int y = 0; y < height; y++) {
+        charMatrixRows[y] = &charMatrix[y * width];
+    }
+    if (LIQ_OK != liq_write_remapped_image_rows(remap, image, charMatrixRows)) {
+        goto err;
+    }
+
+    /* transcribe output pixels (pillow uses uint32_t array) */
+    *quantizedPixels = malloc(sizeof(uint32_t) * width * height);
+    if (!*quantizedPixels) { goto err; }
+    for (int i = 0; i < width * height; i++) {
+        (*quantizedPixels)[i] = charMatrix[i];
+    }
+
+    result = 1;
+
+err:
+    if (attr) liq_attr_destroy(attr);
+    if (image) liq_image_destroy(image);
+    if (remap) liq_result_destroy(remap);
+    free(charMatrix);
+    free(charMatrixRows);
+    if (!result)  {
+        free(*quantizedPixels);
+        free(*palette);
+    }
+    return result;
+}
+
+#else
+
+/* Offer dummy implementation */
+int
+quantize_pngquant(
+    Pixel *pixelData,
+    uint32_t width,
+    uint32_t height,
+    uint32_t quantPixels,
+    Pixel **palette,
+    uint32_t *paletteLength,
+    uint32_t **quantizedPixels,
+    int withAlpha)
+{
+    return 0;
+}
+
+#endif

libImaging/QuantPngQuant.h

@@ -0,0 +1,15 @@
+#ifndef __QUANT_PNGQUANT_H__
+#define __QUANT_PNGQUANT_H__
+
+#include "QuantTypes.h"
+
+int quantize_pngquant(Pixel *,
+    uint32_t,
+    uint32_t,
+    uint32_t,
+    Pixel **,
+    uint32_t *,
+    uint32_t **,
+    int);
+
+#endif

setup.py

@@ -35,7 +35,7 @@ _LIB_IMAGING = (
     "RankFilter", "RawDecode", "RawEncode", "Storage", "SunRleDecode",
     "TgaRleDecode", "Unpack", "UnpackYCC", "UnsharpMask", "XbmDecode",
     "XbmEncode", "ZipDecode", "ZipEncode", "TiffDecode", "Incremental",
-    "Jpeg2KDecode", "Jpeg2KEncode", "BoxBlur")
+    "Jpeg2KDecode", "Jpeg2KEncode", "BoxBlur", "QuantPngQuant")
 
 DEBUG = False
 
@@ -114,6 +114,7 @@ TCL_ROOT = None
 JPEG_ROOT = None
 JPEG2K_ROOT = None
 ZLIB_ROOT = None
+IMAGEQUANT_ROOT = None
 TIFF_ROOT = None
 FREETYPE_ROOT = None
 LCMS_ROOT = None
@@ -122,7 +123,7 @@ LCMS_ROOT = None
 class pil_build_ext(build_ext):
     class feature:
         features = ['zlib', 'jpeg', 'tiff', 'freetype', 'tcl', 'tk', 'lcms',
-                    'webp', 'webpmux', 'jpeg2000']
+                    'webp', 'webpmux', 'jpeg2000', 'imagequant']
 
         required = set(['jpeg', 'zlib'])
 
@@ -185,7 +186,7 @@ class pil_build_ext(build_ext):
         # add configured kits
 
         for root in (TCL_ROOT, JPEG_ROOT, JPEG2K_ROOT, TIFF_ROOT, ZLIB_ROOT,
-                     FREETYPE_ROOT, LCMS_ROOT):
+                     FREETYPE_ROOT, LCMS_ROOT, IMAGEQUANT_ROOT):
             if isinstance(root, type(())):
                 lib_root, include_root = root
             else:
@@ -478,6 +479,14 @@ class pil_build_ext(build_ext):
                 feature.openjpeg_version = '.'.join([str(x) for x in
                                                      best_version])
 
+        if feature.want('imagequant'):
+            _dbg('Looking for imagequant')
+            if _find_include_file(self, 'libimagequant.h'):
+                if _find_library_file(self, "imagequant"):
+                    feature.imagequant = "imagequant"
+                elif _find_library_file(self, "libimagequant"):
+                    feature.imagequant = "libimagequant"
+
         if feature.want('tiff'):
             _dbg('Looking for tiff')
             if _find_include_file(self, 'tiff.h'):
@@ -591,6 +600,9 @@ class pil_build_ext(build_ext):
         if feature.zlib:
             libs.append(feature.zlib)
             defs.append(("HAVE_LIBZ", None))
+        if feature.imagequant:
+            libs.append(feature.imagequant)
+            defs.append(("HAVE_LIBIMAGEQUANT", None))
         if feature.tiff:
             libs.append(feature.tiff)
             defs.append(("HAVE_LIBTIFF", None))
@@ -698,6 +710,7 @@ class pil_build_ext(build_ext):
             (feature.jpeg2000, "OPENJPEG (JPEG2000)",
              feature.openjpeg_version),
             (feature.zlib, "ZLIB (PNG/ZIP)"),
+            (feature.imagequant, "LIBIMAGEQUANT"),
             (feature.tiff, "LIBTIFF"),
             (feature.freetype, "FREETYPE2"),
             (feature.lcms, "LITTLECMS2"),