我正在使用Freeimage.sf.net加载一个png24bit,并希望将其保存为黑/白png。 使用freeimage convert png 24bit to 1bit black/white = gray/white?
FIBITMAP bib = Freeimage.Load("<24bit_png>");
FIBITMAP conv = FreeImage.ConvertColorDepth(bib, FREE_IMAGE_COLOR_DEPTH. FICD_01_BPP_THRESHOLD, (byte) 128);
FreeImage.Unload(bin); bib.SetNull();
FreeImage.Save(FREE_IMAGE_FORMAT.FIF_PNG, conv, "<out_png>", FREE_IMAGE_SAVE_FLAGS.PNG_Z_BEST_COMPRESSION);
FreeImage.Unload(conv); conv.SetNull();
但不黑/白色,因为它是#0b120c /白? 为什么阈值不会创建一个bw-palette?