swaybg: implement scaling mode "fit"

1 files changed, 23 insertions, 0 deletions

diff --git a/swaybg/main.c b/swaybg/main.c
index 7cfe1320..e4c699c1 100644
--- a/swaybg/main.c
+++ b/swaybg/main.c
@@ -15,6 +15,7 @@ struct registry *registry;
 enum scaling_mode_t {
         SCALING_MODE_STRETCH,
         SCALING_MODE_FILL,
+        SCALING_MODE_FIT,
         SCALING_MODE_CENTER,
         SCALING_MODE_TILE,
 };
@@ -66,6 +67,8 @@ int main(int argc, const char **argv) {
                 scaling_mode = SCALING_MODE_STRETCH;
         } else if (strcmp(scaling_mode_str, "fill") == 0) {
                 scaling_mode = SCALING_MODE_FILL;
+        } else if (strcmp(scaling_mode_str, "fit") == 0) {
+                scaling_mode = SCALING_MODE_FIT;
         } else if (strcmp(scaling_mode_str, "center") == 0) {
                 scaling_mode = SCALING_MODE_CENTER;
         } else if (strcmp(scaling_mode_str, "tile") == 0) {
@@ -105,6 +108,26 @@ int main(int argc, const char **argv) {
                                                 }
                                         }
                                         break;
+                                case SCALING_MODE_FIT:
+                                        {
+                                                double window_ratio = (double) window->width / window->height;
+                                                double bg_ratio = width / height;
+
+                                                if (window_ratio > bg_ratio) {
+                                                        double scale = (double) window->height / height;
+                                                        cairo_scale(window->cairo, scale, scale);
+                                                        cairo_set_source_surface(window->cairo, image,
+                                                                        (double) window->width/2 / scale - width/2,
+                                                                        0);
+                                                } else {
+                                                        double scale = (double) window->width / width;
+                                                        cairo_scale(window->cairo, scale, scale);
+                                                        cairo_set_source_surface(window->cairo, image,
+                                                                        0,
+                                                                        (double) window->height/2 / scale - height/2);
+                                                }
+                                        }
+                                        break;
                                 case SCALING_MODE_CENTER:
                                         cairo_set_source_surface(window->cairo, image,
                                                         (double) window->width/2 - width/2,