我正在使用Freeimage.sf.net加載一個png24bit,並希望將其保存爲黑/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,因爲它是#0b120c /白? 爲什麼閾值不會創建一個bw-palette?