feat(clipboard): use wl-copy if present

README.md

@@ -77,7 +77,7 @@ swappy -g "$(swaymsg -t get_tree | jq -r '.. | select(.pid? and .visible?) | .re
 
 ## Limitations
 
-- **Copy**: Copy to clipboard won't work if you close swappy (the content of the clipboard is lost). This because GTK 3.24 [has not implemented persistent storage](https://gitlab.gnome.org/GNOME/gtk/blob/3.24.13/gdk/wayland/gdkdisplay-wayland.c#L857). We need to do it on the [Wayland level](https://github.com/swaywm/wlr-protocols/blob/master/unstable/wlr-data-control-unstable-v1.xml), or wait for GTK 4. For now, Paste your Swappshot where you want to before you close the app.
+- **Copy**: If you don't have [wl-clipboard] installed, copy to clipboard won't work if you close swappy (the content of the clipboard is lost). This because GTK 3.24 [has not implemented persistent storage on wayland backend yet](https://gitlab.gnome.org/GNOME/gtk/blob/3.24.13/gdk/wayland/gdkdisplay-wayland.c#L857). We need to do it on the [Wayland level](https://github.com/swaywm/wlr-protocols/blob/master/unstable/wlr-data-control-unstable-v1.xml), or wait for GTK 4. For now, we use `wl-copy` if installed and revert to `gtk` clipboard if not found.
 
 ## Installation
 
@@ -118,4 +118,5 @@ MIT
 [slurp]: https://github.com/emersion/slurp
 [grim]: https://github.com/emersion/grim
 [sway]: https://github.com/swaywm/sway
+[wl-clipboard]: https://github.com/bugaevc/wl-clipboard
 [wlr-screencopy-unstable-v1]: https://github.com/swaywm/wlr-protocols/blob/master/unstable/wlr-screencopy-unstable-v1.xml

src/clipboard.c

@@ -1,16 +1,80 @@
 #include "clipboard.h"
 
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
 #include "notification.h"
+#include "util.h"
+
+#define gtk_clipboard_t GtkClipboard
+#define gdk_pixbuf_t GdkPixbuf
+
+static gboolean send_pixbuf_to_wl_copy(gdk_pixbuf_t *pixbuf) {
+  pid_t clipboard_process = 0;
+  int pipefd[2];
+  int status;
+  gsize size;
+  gchar *buffer = NULL;
+  GError *error = NULL;
+
+  if (pipe(pipefd) < 0) {
+    g_warning("unable to pipe for copy process to work");
+    return false;
+  }
+  clipboard_process = fork();
+  if (clipboard_process == -1) {
+    g_warning("unable to fork process for copy");
+    return false;
+  }
+  if (clipboard_process == 0) {
+    close(pipefd[1]);
+    dup2(pipefd[0], STDIN_FILENO);
+    close(pipefd[0]);
+    execlp("wl-copy", "wl-copy", NULL);
+    g_warning(
+        "Unable to copy contents to clipboard. Please make sure you have "
+        "`wl-clipboard`, `xclip`, or `xsel` installed.");
+    exit(1);
+  }
+  close(pipefd[0]);
+
+  gdk_pixbuf_save_to_buffer(pixbuf, &buffer, &size, "png", &error, NULL);
+
+  if (error != NULL) {
+    g_critical("unable to save pixbuf to buffer for copy: %s", error->message);
+    g_error_free(error);
+    return false;
+  }
+
+  write(pipefd[1], buffer, size);
+  close(pipefd[1]);
+  g_free(buffer);
+  waitpid(clipboard_process, &status, 0);
+
+  if (WIFEXITED(status)) {
+    return WEXITSTATUS(status) == 0;  // Make sure the child exited properly
+  }
+
+  return false;
+}
+
+static void send_pixbuf_to_gdk_clipboard(gdk_pixbuf_t *pixbuf) {
+  gtk_clipboard_t *clipboard = gtk_clipboard_get(GDK_SELECTION_CLIPBOARD);
+  gtk_clipboard_set_image(clipboard, pixbuf);
+  gtk_clipboard_store(clipboard);  // Does not work for Wayland gdk backend
+}
 
 bool clipboard_copy_drawing_area_to_selection(struct swappy_state *state) {
-  GtkClipboard *clipboard = gtk_clipboard_get(GDK_SELECTION_CLIPBOARD);
   int width = gtk_widget_get_allocated_width(state->ui->area);
   int height = gtk_widget_get_allocated_height(state->ui->area);
-  GdkPixbuf *pixbuf =
+  gdk_pixbuf_t *pixbuf =
       gdk_pixbuf_get_from_surface(state->cairo_surface, 0, 0, width, height);
 
-  gtk_clipboard_set_image(clipboard, pixbuf);
-  gtk_clipboard_store(clipboard);
+  // Try `wl-copy` first and fall back to gtk function. See README.md.
+  if (!send_pixbuf_to_wl_copy(pixbuf)) {
+    send_pixbuf_to_gdk_clipboard(pixbuf);
+  }
 
   char message[MAX_PATH];
   snprintf(message, MAX_PATH, "Swappshot copied to clipboard\n");