add fimg_mix_rgb_gray support to fimgfx

tools/fimgfx.c

@@ -21,7 +21,7 @@ typedef struct {
 	} Fx;
 
 enum fxid { Fx_cos01=5, Fx_cos010, Fx_pow2, Fx_sqrt, Fx_gray0, Fx_halfsz0,
-		Fx_rot90, Fx_cmixa,
+		Fx_rot90, Fx_cmixa, Fx_Desat,
 		Fx_xper };
 
 Fx fx_list[] = {
@@ -34,6 +34,7 @@ Fx fx_list[] = {
 	{ "rot90",		Fx_rot90,	0,	0 },
 	{ "cmixa",		Fx_cmixa,	0,	1 },
 	{ "xper",		Fx_xper,	0,	1 },
+	{ "desat",		Fx_Desat,	0,	1 },
 	{ NULL,			0,	0 }
 	};
 
@@ -166,6 +167,11 @@ switch (action) {
 		fprintf(stderr, "halfsize was not implemented\n");
 		return -3;
 
+	case Fx_Desat:
+		fimg_copy_data(&src, &dest);
+		foo = fimg_mix_rgb_gray(&dest, global_fvalue);
+		break;
+
 	default:
 		fprintf(stderr, "%s %s : %d is bad action\n",
 					__FILE__, __func__, action);