support background setter for specific screen

The following adds the ability, when using `feh` as a background setter,
to use a specific Xinerama screen to render a provided image. Along with
the provided '--bg-*' option, the '--xinerama-index' argument will be
used to identify the index of the detected Xinerama screen to use.

Signed-off-by: James Knight <james.d.knight@live.com>

4 files changed, 96 insertions, 21 deletions

diff --git a/man/feh.pre b/man/feh.pre
index 10ea58f..b994478 100644
--- a/man/feh.pre
+++ b/man/feh.pre
@@ -470,6 +470,13 @@ managers.
 Disable Xinerama support.  Only makes sense when you have Xinerama support
 compiled in.
 .
+.It Cm --xinerama-index
+.
+Force Xinerama screen index to use.  Only makes sense when you have 
+Xinerama support compiled in and using
+.Nm
+as a background setter.
+.
 .It Cm -j , --output-dir Ar directory
 .
 Save files to
@@ -820,7 +827,12 @@ on screen 0, the second on screen 1, and so on.
 .
 Use
 .Cm --no-xinerama
-to treat the whole X display as one screen when setting wallpapers.
+to treat the whole X display as one screen when setting wallpapers. You
+may also use
+.Cm --xinerama-index
+to use
+.Nm
+as a background setter for a specific screen.
 .
 .Bl -tag -width indent
 .
diff --git a/src/options.c b/src/options.c
index cbeb729..bff46c3 100644
--- a/src/options.c
+++ b/src/options.c
@@ -71,6 +71,7 @@ void init_parse_options(int argc, char **argv)
 	/* if we're using xinerama, then enable it by default */
 	opt.xinerama = 1;
 #endif				/* HAVE_LIBXINERAMA */
+	opt.xinerama_index = -1;
 
 	feh_getopt_theme(argc, argv);
 
@@ -404,6 +405,7 @@ static void feh_parse_option_array(int argc, char **argv, int finalrun)
 		{"no-fehbg"      , 0, 0, 236},
 		{"keep-zoom-vp"  , 0, 0, 237},
 		{"scroll-step"   , 1, 0, 238},
+		{"xinerama-index", 1, 0, 239},
 
 		{0, 0, 0, 0}
 	};
@@ -744,6 +746,9 @@ static void feh_parse_option_array(int argc, char **argv, int finalrun)
 		case 238:
 			opt.scroll_step = atoi(optarg);
 			break;
+		case 239:
+			opt.xinerama_index = atoi(optarg);
+			break;
 		default:
 			break;
 		}
diff --git a/src/options.h b/src/options.h
index a22cc05..923aa41 100644
--- a/src/options.h
+++ b/src/options.h
@@ -109,6 +109,7 @@ struct __fehoptions {
 	int default_zoom;
 	int zoom_mode;
 	unsigned char adjust_reload;
+	int xinerama_index;
 
 	/* signed in case someone wants to invert scrolling real quick */
 	int scroll_step;
diff --git a/src/wallpaper.c b/src/wallpaper.c
index 9327d74..b992ec1 100644
--- a/src/wallpaper.c
+++ b/src/wallpaper.c
@@ -298,11 +298,23 @@ void feh_wm_set_bg(char *fil, Imlib_Image im, int centered, int scaled,
 
 		/* string for sticking in ~/.fehbg */
 		char *fehbg = NULL;
+		char fehbg_args[512];
+		fehbg_args[0] = '\0';
 		char *home;
 		char filbuf[4096];
-		char fehbg_xinerama[] = "--no-xinerama";
 		char *bgfill = NULL;
 		bgfill = opt.image_bg == IMAGE_BG_WHITE ?  "--image-bg white" : "--image-bg black" ;
+		
+		if (opt.xinerama)
+		{
+			if (opt.xinerama_index >= 0)
+			{
+				snprintf(fehbg_args, sizeof(fehbg_args),
+					"--xinerama-index %d", opt.xinerama_index);
+			}
+		}
+		else
+			snprintf(fehbg_args, sizeof(fehbg_args), "--no-xinerama");
 
 		/* local display to set closedownmode on */
 		Display *disp2;
@@ -310,9 +322,6 @@ void feh_wm_set_bg(char *fil, Imlib_Image im, int centered, int scaled,
 		int depth2;
 		int in, out, w, h;
 
-		if (opt.xinerama)
-			fehbg_xinerama[0] = '\0';
-
 		D(("Falling back to XSetRootWindowPixmap\n"));
 
 		/* Put the filename in filbuf between ' and escape ' in the filename */
@@ -357,16 +366,33 @@ void feh_wm_set_bg(char *fil, Imlib_Image im, int centered, int scaled,
 			pmap_d1 = XCreatePixmap(disp, root, scr->width, scr->height, depth);
 
 #ifdef HAVE_LIBXINERAMA
+			if (opt.xinerama_index >= 0)
+			{
+				if (opt.image_bg == IMAGE_BG_WHITE)
+					gcval.foreground = WhitePixel(disp, DefaultScreen(disp));
+				else
+					gcval.foreground = BlackPixel(disp, DefaultScreen(disp));
+				gc = XCreateGC(disp, root, GCForeground, &gcval);
+				XFillRectangle(disp, pmap_d1, gc, 0, 0, scr->width, scr->height);
+			}
+			
 			if (opt.xinerama && xinerama_screens)
+			{
 				for (i = 0; i < num_xinerama_screens; i++)
-					feh_wm_set_bg_scaled(pmap_d1, im, use_filelist,
-						xinerama_screens[i].x_org, xinerama_screens[i].y_org,
-						xinerama_screens[i].width, xinerama_screens[i].height);
+				{
+					if (opt.xinerama_index < 0 || opt.xinerama_index == i)
+					{
+						feh_wm_set_bg_scaled(pmap_d1, im, use_filelist,
+							xinerama_screens[i].x_org, xinerama_screens[i].y_org,
+							xinerama_screens[i].width, xinerama_screens[i].height);
+					}
+				}
+			}
 			else
 #endif			/* HAVE_LIBXINERAMA */
 				feh_wm_set_bg_scaled(pmap_d1, im, use_filelist,
 					0, 0, scr->width, scr->height);
-			fehbg = estrjoin(" ", "feh", fehbg_xinerama, "--bg-scale", filbuf, NULL);
+			fehbg = estrjoin(" ", "feh", fehbg_args, "--bg-scale", filbuf, NULL);
 		} else if (centered) {
 
 			D(("centering\n"));
@@ -381,10 +407,17 @@ void feh_wm_set_bg(char *fil, Imlib_Image im, int centered, int scaled,
 
 #ifdef HAVE_LIBXINERAMA
 			if (opt.xinerama && xinerama_screens)
+			{
 				for (i = 0; i < num_xinerama_screens; i++)
-					feh_wm_set_bg_centered(pmap_d1, im, use_filelist,
-						xinerama_screens[i].x_org, xinerama_screens[i].y_org,
-						xinerama_screens[i].width, xinerama_screens[i].height);
+				{
+					if (opt.xinerama_index < 0 || opt.xinerama_index == i)
+					{
+						feh_wm_set_bg_centered(pmap_d1, im, use_filelist,
+							xinerama_screens[i].x_org, xinerama_screens[i].y_org,
+							xinerama_screens[i].width, xinerama_screens[i].height);
+					}
+				}
+			}
 			else
 #endif				/* HAVE_LIBXINERAMA */
 				feh_wm_set_bg_centered(pmap_d1, im, use_filelist,
@@ -392,24 +425,41 @@ void feh_wm_set_bg(char *fil, Imlib_Image im, int centered, int scaled,
 
 			XFreeGC(disp, gc);
 
-			fehbg = estrjoin(" ", "feh", fehbg_xinerama, bgfill, "--bg-center", filbuf, NULL);
+			fehbg = estrjoin(" ", "feh", fehbg_args, bgfill, "--bg-center", filbuf, NULL);
 
 		} else if (filled == 1) {
 
 			pmap_d1 = XCreatePixmap(disp, root, scr->width, scr->height, depth);
 
 #ifdef HAVE_LIBXINERAMA
+			if (opt.xinerama_index >= 0)
+			{
+				if (opt.image_bg == IMAGE_BG_WHITE)
+					gcval.foreground = WhitePixel(disp, DefaultScreen(disp));
+				else
+					gcval.foreground = BlackPixel(disp, DefaultScreen(disp));
+				gc = XCreateGC(disp, root, GCForeground, &gcval);
+				XFillRectangle(disp, pmap_d1, gc, 0, 0, scr->width, scr->height);
+			}
+			
 			if (opt.xinerama && xinerama_screens)
+			{
 				for (i = 0; i < num_xinerama_screens; i++)
-					feh_wm_set_bg_filled(pmap_d1, im, use_filelist,
-						xinerama_screens[i].x_org, xinerama_screens[i].y_org,
-						xinerama_screens[i].width, xinerama_screens[i].height);
+				{
+					if (opt.xinerama_index < 0 || opt.xinerama_index == i)
+					{
+						feh_wm_set_bg_filled(pmap_d1, im, use_filelist,
+							xinerama_screens[i].x_org, xinerama_screens[i].y_org,
+							xinerama_screens[i].width, xinerama_screens[i].height);
+					}
+				}
+			}
 			else
 #endif				/* HAVE_LIBXINERAMA */
 				feh_wm_set_bg_filled(pmap_d1, im, use_filelist
 					, 0, 0, scr->width, scr->height);
 
-			fehbg = estrjoin(" ", "feh", fehbg_xinerama, "--bg-fill", filbuf, NULL);
+			fehbg = estrjoin(" ", "feh", fehbg_args, "--bg-fill", filbuf, NULL);
 
 		} else if (filled == 2) {
 
@@ -423,10 +473,17 @@ void feh_wm_set_bg(char *fil, Imlib_Image im, int centered, int scaled,
 
 #ifdef HAVE_LIBXINERAMA
 			if (opt.xinerama && xinerama_screens)
+			{
 				for (i = 0; i < num_xinerama_screens; i++)
-					feh_wm_set_bg_maxed(pmap_d1, im, use_filelist,
-						xinerama_screens[i].x_org, xinerama_screens[i].y_org,
-						xinerama_screens[i].width, xinerama_screens[i].height);
+				{
+					if (opt.xinerama_index < 0 || opt.xinerama_index == i)
+					{
+						feh_wm_set_bg_maxed(pmap_d1, im, use_filelist,
+							xinerama_screens[i].x_org, xinerama_screens[i].y_org,
+							xinerama_screens[i].width, xinerama_screens[i].height);
+					}
+				}
+			}
 			else
 #endif				/* HAVE_LIBXINERAMA */
 				feh_wm_set_bg_maxed(pmap_d1, im, use_filelist,
@@ -434,7 +491,7 @@ void feh_wm_set_bg(char *fil, Imlib_Image im, int centered, int scaled,
 
 			XFreeGC(disp, gc);
 
-			fehbg = estrjoin(" ", "feh", fehbg_xinerama, bgfill, "--bg-max", filbuf, NULL);
+			fehbg = estrjoin(" ", "feh", fehbg_args, bgfill, "--bg-max", filbuf, NULL);
 
 		} else {
 			if (use_filelist)