[gimp] Bug 791360 - Add Screenshot implementation for KDE/Wayland.

[Jehan Pagès <jehanp src gnome org>]

commit b9034e26a92e80351982b2f46af061a9b1b349e9
Author: Jehan <jehan girinstud io>
Date:   Fri Dec 8 19:17:58 2017 +0100

    Bug 791360 - Add Screenshot implementation for KDE/Wayland.
    
    Only thing I could not properly figure out yet is how to select an area.
    The "screenshotArea" method is there in KDE API, but it needs
    coordinates and I can't find the API to grab coordinates in Wayland (as
    in GNOME shell API).

 plug-ins/screenshot/Makefile.am       |    2 +
 plug-ins/screenshot/screenshot-kwin.c |  192 +++++++++++++++++++++++++++++++++
 plug-ins/screenshot/screenshot-kwin.h |   32 ++++++
 plug-ins/screenshot/screenshot.c      |    8 ++
 plug-ins/screenshot/screenshot.h      |    1 +
 5 files changed, 235 insertions(+), 0 deletions(-)
---
diff --git a/plug-ins/screenshot/Makefile.am b/plug-ins/screenshot/Makefile.am
index 0ab4490..daf3364 100644
--- a/plug-ins/screenshot/Makefile.am
+++ b/plug-ins/screenshot/Makefile.am
@@ -49,6 +49,8 @@ screenshot_SOURCES = \
        screenshot-gnome-shell.c        \
        screenshot-gnome-shell.h        \
        screenshot-icon.h               \
+       screenshot-kwin.c               \
+       screenshot-kwin.h               \
        screenshot-osx.c                \
        screenshot-osx.h                \
        screenshot-x11.c                \
diff --git a/plug-ins/screenshot/screenshot-kwin.c b/plug-ins/screenshot/screenshot-kwin.c
new file mode 100644
index 0000000..54e9f28
--- /dev/null
+++ b/plug-ins/screenshot/screenshot-kwin.c
@@ -0,0 +1,192 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * Screenshot plug-in
+ * Copyright 1998-2007 Sven Neumann <sven gimp org>
+ * Copyright 2003      Henrik Brix Andersen <brix gimp org>
+ * Copyright 2016      Michael Natterer <mitch gimp org>
+ * Copyright 2017      Jehan <jehan gimp org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <glib.h>
+#include <glib/gstdio.h> /* g_unlink() */
+
+#include <libgimp/gimp.h>
+#include <libgimp/gimpui.h>
+
+#include "screenshot.h"
+#include "screenshot-kwin.h"
+
+
+static GDBusProxy *proxy = NULL;
+
+
+gboolean
+screenshot_kwin_available (void)
+{
+  proxy = g_dbus_proxy_new_for_bus_sync (G_BUS_TYPE_SESSION,
+                                         G_DBUS_PROXY_FLAGS_DO_NOT_AUTO_START,
+                                         NULL,
+                                         "org.kde.KWin",
+                                         "/Screenshot",
+                                         "org.kde.kwin.Screenshot",
+                                         NULL, NULL);
+
+  if (proxy)
+    {
+      GError *error = NULL;
+
+      g_dbus_proxy_call_sync (proxy, "org.freedesktop.DBus.Peer.Ping",
+                              NULL,
+                              G_DBUS_CALL_FLAGS_NONE,
+                              -1, NULL, &error);
+      if (! error)
+        return TRUE;
+
+      g_clear_error (&error);
+
+      g_object_unref (proxy);
+      proxy = NULL;
+    }
+
+  return FALSE;
+}
+
+ScreenshotCapabilities
+screenshot_kwin_get_capabilities (void)
+{
+  return (SCREENSHOT_CAN_SHOOT_DECORATIONS |
+          SCREENSHOT_CAN_SHOOT_POINTER);
+  /* TODO: SCREENSHOT_CAN_SHOOT_REGION.
+   * The KDE API has "screenshotArea" method but no method to get
+   * coordinates could be found. See below.
+   */
+}
+
+GimpPDBStatusType
+screenshot_kwin_shoot (ScreenshotValues  *shootvals,
+                              GdkScreen         *screen,
+                              gint32            *image_ID,
+                              GError           **error)
+{
+  gchar       *filename;
+  const gchar *method = NULL;
+  GVariant    *args   = NULL;
+  GVariant    *retval;
+  gint         monitor = shootvals->monitor;
+  gint32       mask;
+
+  if (shootvals->select_delay > 0)
+    screenshot_delay (shootvals->select_delay);
+
+  switch (shootvals->shoot_type)
+    {
+    case SHOOT_ROOT:
+      method = "screenshotFullscreen";
+      args   = g_variant_new ("(b)", shootvals->show_cursor);
+
+      /* FIXME: figure profile */
+      break;
+
+    case SHOOT_REGION:
+      break;
+      /* FIXME: GNOME-shell has a "SelectArea" returning coordinates
+       * which can be fed to "ScreenshotArea". KDE has the equivalent
+       * "screenshotArea", but no "SelectArea" equivalent that I could
+       * find.
+       * Also at first, I expected "interactive" method to take care of
+       * the whole selecting-are-then-screenshotting workflow, but this
+       * is apparently only made to select interactively a specific
+       * window, not an area.
+       */
+      method = "screenshotArea";
+      args   = g_variant_new ("(iiii)",
+                              shootvals->x1,
+                              shootvals->y1,
+                              shootvals->x2 - shootvals->x1,
+                              shootvals->y2 - shootvals->y1);
+      args   = NULL;
+
+      break;
+
+    case SHOOT_WINDOW:
+      /* XXX I expected "screenshotWindowUnderCursor" method to be the
+       * right one, but it returns nothing, nor is there a file
+       * descriptor in argument. So I don't understand how to grab the
+       * screenshot. Also "interactive" changes the cursor to a
+       * crosshair, waiting for click, which is more helpful than
+       * immediate screenshot under cursor.
+       */
+      method = "interactive";
+      mask = (shootvals->decorate ? 1 : 0) |
+             (shootvals->show_cursor ? 1 << 1 : 0);
+      args   = g_variant_new ("(i)", mask);
+
+      /* FIXME: figure monitor */
+      break;
+    }
+
+  retval = g_dbus_proxy_call_sync (proxy, method, args,
+                                   G_DBUS_CALL_FLAGS_NONE,
+                                   -1, NULL, error);
+  if (! retval)
+    goto failure;
+
+  g_variant_get (retval, "(s)",
+                 &filename);
+  g_variant_unref (retval);
+
+  if (filename)
+    {
+      GimpColorProfile *profile;
+
+      *image_ID = gimp_file_load (GIMP_RUN_NONINTERACTIVE,
+                                  filename, filename);
+      gimp_image_set_filename (*image_ID, "screenshot.png");
+
+      /* This is very wrong in multi-display setups since we have no
+       * idea which profile is to be used. Let's keep it anyway and
+       * assume always the monitor 0, which will still work in common
+       * cases.
+       */
+      profile = gimp_screen_get_color_profile (screen, monitor);
+
+      if (profile)
+        {
+          gimp_image_set_color_profile (*image_ID, profile);
+          g_object_unref (profile);
+        }
+
+      g_unlink (filename);
+      g_free (filename);
+
+      g_object_unref (proxy);
+      proxy = NULL;
+
+      return GIMP_PDB_SUCCESS;
+    }
+
+ failure:
+
+  g_free (filename);
+
+  g_object_unref (proxy);
+  proxy = NULL;
+
+  return GIMP_PDB_EXECUTION_ERROR;
+}
diff --git a/plug-ins/screenshot/screenshot-kwin.h b/plug-ins/screenshot/screenshot-kwin.h
new file mode 100644
index 0000000..bec5c0f
--- /dev/null
+++ b/plug-ins/screenshot/screenshot-kwin.h
@@ -0,0 +1,32 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __SCREENSHOT_KWIN_H__
+#define __SCREENSHOT_KWIN_H__
+
+
+gboolean               screenshot_kwin_available        (void);
+
+ScreenshotCapabilities screenshot_kwin_get_capabilities (void);
+
+GimpPDBStatusType      screenshot_kwin_shoot            (ScreenshotValues  *shootvals,
+                                                         GdkScreen         *screen,
+                                                         gint32            *image_ID,
+                                                         GError           **error);
+
+
+#endif /* __SCREENSHOT_KWIN_H__ */
diff --git a/plug-ins/screenshot/screenshot.c b/plug-ins/screenshot/screenshot.c
index 47608a7..0b7b379 100644
--- a/plug-ins/screenshot/screenshot.c
+++ b/plug-ins/screenshot/screenshot.c
@@ -29,6 +29,7 @@
 #include "screenshot.h"
 #include "screenshot-gnome-shell.h"
 #include "screenshot-icon.h"
+#include "screenshot-kwin.h"
 #include "screenshot-osx.h"
 #include "screenshot-x11.h"
 #include "screenshot-win32.h"
@@ -202,6 +203,11 @@ run (const gchar      *name,
       backend      = SCREENSHOT_BACKEND_GNOME_SHELL;
       capabilities = screenshot_gnome_shell_get_capabilities ();
     }
+  else if (! backend && screenshot_kwin_available ())
+    {
+      backend      = SCREENSHOT_BACKEND_KWIN;
+      capabilities = screenshot_kwin_get_capabilities ();
+    }
 
 #ifdef GDK_WINDOWING_X11
   if (! backend && screenshot_x11_available ())
@@ -357,6 +363,8 @@ shoot (GdkScreen  *screen,
 
   if (backend == SCREENSHOT_BACKEND_GNOME_SHELL)
     return screenshot_gnome_shell_shoot (&shootvals, screen, image_ID, error);
+  else if (backend == SCREENSHOT_BACKEND_KWIN)
+    return screenshot_kwin_shoot (&shootvals, screen, image_ID, error);
 
 #ifdef GDK_WINDOWING_X11
   if (backend == SCREENSHOT_BACKEND_X11)
diff --git a/plug-ins/screenshot/screenshot.h b/plug-ins/screenshot/screenshot.h
index 592e6bc..0f2de70 100644
--- a/plug-ins/screenshot/screenshot.h
+++ b/plug-ins/screenshot/screenshot.h
@@ -25,6 +25,7 @@ typedef enum
   SCREENSHOT_BACKEND_OSX,
   SCREENSHOT_BACKEND_WIN32,
   SCREENSHOT_BACKEND_GNOME_SHELL,
+  SCREENSHOT_BACKEND_KWIN,
   SCREENSHOT_BACKEND_X11
 } ScreenshotBackend;