From 1e4f29c34c3631e1d7350b02a199ae6000b33f6d Mon Sep 17 00:00:00 2001
From: Miles Alan <m@milesalan.com>
Date: Wed, 25 Mar 2020 21:40:10 -0500
Subject: [PATCH] Add invert function which changes the current colors' RGB
 values to be inversed

Bind invert function in example config.def.h to Ctrl-Shift-x
---
 config.def.h |  1 +
 x.c          | 37 ++++++++++++++++++++++++++++++++++---
 2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/config.def.h b/config.def.h
index 0e01717..6c7293c 100644
--- a/config.def.h
+++ b/config.def.h
@@ -178,6 +178,7 @@ static Shortcut shortcuts[] = {
 	{ TERMMOD,              XK_Y,           selpaste,       {.i =  0} },
 	{ ShiftMask,            XK_Insert,      selpaste,       {.i =  0} },
 	{ TERMMOD,              XK_Num_Lock,    numlock,        {.i =  0} },
+	{ TERMMOD,              XK_X,           invert,         { }       },
 };
 
 /*
diff --git a/x.c b/x.c
index 0422421..7379969 100644
--- a/x.c
+++ b/x.c
@@ -56,6 +56,7 @@ static void selpaste(const Arg *);
 static void zoom(const Arg *);
 static void zoomabs(const Arg *);
 static void zoomreset(const Arg *);
+static void invert(const Arg *);
 
 /* config.h for applying patches and the configuration. */
 #include "config.h"
@@ -238,8 +239,28 @@ static char *opt_line  = NULL;
 static char *opt_name  = NULL;
 static char *opt_title = NULL;
 
+static int invertcolors = 0;
 static int oldbutton = 3; /* button event on startup: 3 = release */
 
+void
+invert(const Arg *dummy)
+{
+	invertcolors = !invertcolors;
+	redraw();
+}
+
+Color
+invertedcolor(Color *clr) {
+	XRenderColor rc;
+	Color inverted;
+	rc.red = ~clr->color.red;
+	rc.green = ~clr->color.green;
+	rc.blue = ~clr->color.blue;
+	rc.alpha = clr->color.alpha;
+	XftColorAllocValue(xw.dpy, xw.vis, xw.cmap, &rc, &inverted);
+	return inverted;
+}
+
 void
 clipcopy(const Arg *dummy)
 {
@@ -775,9 +796,12 @@ xsetcolorname(int x, const char *name)
 void
 xclear(int x1, int y1, int x2, int y2)
 {
-	XftDrawRect(xw.draw,
-			&dc.col[IS_SET(MODE_REVERSE)? defaultfg : defaultbg],
-			x1, y1, x2-x1, y2-y1);
+	Color c;
+	c = dc.col[IS_SET(MODE_REVERSE)? defaultfg : defaultbg];
+	if (invertcolors) {
+		c = invertedcolor(&c);
+	}
+	XftDrawRect(xw.draw, &c, x1, y1, x2-x1, y2-y1);
 }
 
 void
@@ -1347,6 +1371,13 @@ xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, i
 	if (base.mode & ATTR_INVISIBLE)
 		fg = bg;
 
+	if (invertcolors) {
+		revfg = invertedcolor(fg);
+		revbg = invertedcolor(bg);
+		fg = &revfg;
+		bg = &revbg;
+	}
+
 	/* Intelligent cleaning up of the borders. */
 	if (x == 0) {
 		xclear(0, (y == 0)? 0 : winy, borderpx,
-- 
2.23.1