centered_image.patch

diff --git a/unlock_indicator.c b/unlock_indicator.c.new
index a0decb4..8d8cd96 100644
--- a/unlock_indicator.c
+++ b/unlock_indicator.c.new
@@ -94,8 +94,27 @@ xcb_pixmap_t draw_image(uint32_t *resolution) {
 
     if (img) {
         if (!tile) {
-            cairo_set_source_surface(xcb_ctx, img, 0, 0);
-            cairo_paint(xcb_ctx);
+            int iw = cairo_image_surface_get_width(img);
+            int ih = cairo_image_surface_get_height(img);
+            if (xr_screens > 0) {
+                /* Composite the unlock indicator in the middle of each screen. */
+                for (int screen = 0; screen < xr_screens; screen++) {
+                    int w = xr_resolutions[screen].width;
+                    int h = xr_resolutions[screen].height;
+                    cairo_set_source_surface(xcb_ctx, img,
+                            xr_resolutions[screen].x + ((w - iw) >> 1),
+                            xr_resolutions[screen].y + ((h - ih) >> 1));
+                    cairo_paint(xcb_ctx);
+                }
+            } else {
+                /* We have no information about the screen sizes/positions, so we just
+                 * place the unlock indicator in the middle of the X root window and
+                 * hope for the best. */
+                int w = last_resolution[0];
+                int h = last_resolution[1];
+                cairo_set_source_surface(xcb_ctx, img, (w - iw) >> 1, (h - ih) >> 1);
+                cairo_paint(xcb_ctx);
+            }
         } else {
             /* create a pattern and fill a rectangle as big as the screen */
             cairo_pattern_t *pattern;