Use Button1 to open thumbnail

main.c

@@ -268,11 +268,11 @@ void redraw() {
 }
 
 void on_keypress(XKeyEvent *kev) {
-	int sel, x, y;
+	int x, y;
 	unsigned int w, h;
 	char key;
 	KeySym ksym;
-	int changed;
+	int changed, sel;
 
 	if (!kev)
 		return;
@@ -439,7 +439,7 @@ void on_keypress(XKeyEvent *kev) {
 }
 
 void on_buttonpress(XButtonEvent *bev) {
-	int changed;
+	int changed, sel;
 	unsigned int mask;
 
 	if (!bev)
@@ -448,6 +448,7 @@ void on_buttonpress(XButtonEvent *bev) {
 	mask = CLEANMASK(bev->state);
 	changed = 0;
 
+	if (mode == MODE_NORMAL) {
 		switch (bev->button) {
 			case Button1:
 				if (fileidx + 1 < filecnt) {
@@ -489,6 +490,20 @@ void on_buttonpress(XButtonEvent *bev) {
 				changed = img_pan(&img, &win, PAN_RIGHT);
 				break;
 		}
+	} else {
+		/* thumbnail mode */
+		switch (bev->button) {
+			case Button1:
+				if ((sel = tns_translate(&tns, bev->x, bev->y)) >= 0) {
+					fileidx = sel;
+					load_image();
+					mode = MODE_NORMAL;
+					changed = 1;
+					break;
+				}
+				break;
+		}
+	}
 
 	if (changed)
 		redraw();

thumbs.c

@@ -170,3 +170,19 @@ void tns_move_selection(tns_t *tns, win_t *win, movedir_t dir) {
 			break;
 	}
 }
+
+int tns_translate(tns_t *tns, int x, int y) {
+	int n;
+	thumb_t *t;
+
+	if (!tns || x < 5 || y < 5)
+		return -1;
+
+	if ((n = y / thumb_dim * tns-> cols + x / thumb_dim) < tns->cnt) {
+		t = &tns->thumbs[n];
+		if (x > t->x && x < t->x + t->w && y > t->y && y < t->y + t->h)
+			return n;
+	}
+
+	return -1;
+}

thumbs.h

@@ -57,4 +57,6 @@ void tns_highlight(tns_t*, win_t*, int);
 
 void tns_move_selection(tns_t*, win_t*, movedir_t);
 
+int tns_translate(tns_t*, int, int);
+
 #endif /* THUMBS_H */