6.6.3 - Alpha5 - images.save 方法使用 quality 参数时支持 png 格式的文件体积压缩 (issue #367)

libs/imagequant/external/libimagequant/kmeans.h

@@ -0,0 +1,19 @@
+
+#ifndef KMEANS_H
+#define KMEANS_H
+
+// Spread memory touched by different threads at least 64B apart which I assume is the cache line size. This should avoid memory write contention.
+#define KMEANS_CACHE_LINE_GAP ((64+sizeof(kmeans_state)-1)/sizeof(kmeans_state))
+
+typedef struct {
+    double a, r, g, b, total;
+} kmeans_state;
+
+typedef void (*kmeans_callback)(hist_item *item, float diff);
+
+LIQ_PRIVATE void kmeans_init(const colormap *map, const unsigned int max_threads, kmeans_state state[]);
+LIQ_PRIVATE void kmeans_update_color(const f_pixel acolor, const float value, const colormap *map, unsigned int match, const unsigned int thread, kmeans_state average_color[]);
+LIQ_PRIVATE void kmeans_finalize(colormap *map, const unsigned int max_threads, const kmeans_state state[]);
+LIQ_PRIVATE double kmeans_do_iteration(histogram *hist, colormap *const map, kmeans_callback callback);
+
+#endif