[client] x11: change to a more visible "dot" cursor

This change alters the small square dot cursor to a more visible 16x16
cursor for X11. A new option `spice:largeDotCursor` can be set to use an
alternative 32x32 cursor for the vision impaired.

client/displayservers/X11/CMakeLists.txt

@@ -17,6 +17,7 @@ add_library(displayserver_X11 STATIC
   x11.c
   atoms.c
   clipboard.c
+  cursor.c
 
   wm/default.c
   wm/i3.c
@@ -27,6 +28,7 @@ add_definitions(-D GLX_GLXEXT_PROTOTYPES)
 target_link_libraries(displayserver_X11
   PkgConfig::DISPLAYSERVER_X11
   lg_common
+  lg_resources
 )
 
 target_include_directories(displayserver_X11

client/displayservers/X11/cursor.c

@@ -0,0 +1,105 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2023 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * 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 2 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, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "cursor.h"
+#include "common/util.h"
+
+#include <string.h>
+#include <errno.h>
+
+struct MemFile
+{
+  const char * data;
+  int          size;
+  int          pos;
+};
+
+static int x11cursor_read(XcursorFile *file, unsigned char * buf, int len)
+{
+  struct MemFile * f = (struct MemFile *)file->closure;
+
+  if (f->pos == f->size)
+    return 0;
+
+  len = min(f->size - f->pos, len);
+  memcpy(buf, f->data + f->pos, len);
+  f->pos += len;
+
+  return len;
+}
+
+static int x11cursor_write(XcursorFile *file, unsigned char * buf, int len)
+{
+  errno = -EINVAL;
+  return -1;
+}
+
+static int x11cursor_seek(XcursorFile *file, long offset, int whence)
+{
+  struct MemFile * f = (struct MemFile *)file->closure;
+  long target;
+
+  switch(whence)
+  {
+    case SEEK_SET:
+      target = offset;
+      break;
+
+    case SEEK_CUR:
+      target = f->pos + offset;
+      break;
+
+    case SEEK_END:
+      target = f->size + offset;
+      break;
+
+    default:
+      errno = -EINVAL;
+      return -1;
+  }
+
+  if (target < 0 || target > f->size)
+  {
+    errno = -EINVAL;
+    return -1;
+  }
+  f->pos = target;
+  return target;
+}
+
+XcursorImages * x11cursor_load(const char * cursor, int size)
+{
+  struct MemFile closure =
+  {
+    .data = cursor,
+    .size = size,
+    .pos  = 0
+  };
+
+  XcursorFile f =
+  {
+    .closure = &closure,
+    .read    = x11cursor_read,
+    .write   = x11cursor_write,
+    .seek    = x11cursor_seek
+  };
+
+  return XcursorXcFileLoadAllImages(&f);
+}

client/displayservers/X11/cursor.h

@@ -0,0 +1,29 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2023 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * 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 2 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, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _H_X11DS_CURSOR_
+#define _H_X11DS_CURSOR_
+
+#include <X11/Xlib.h>
+#include <X11/Xcursor/Xcursor.h>
+
+XcursorImages * x11cursor_load(const char * cursor, int size);
+
+#endif

client/displayservers/X11/x11.c

@@ -23,7 +23,11 @@
 #include "x11.h"
 #include "atoms.h"
 #include "clipboard.h"
+#include "cursor.h"
+
 #include "resources/icondata.h"
+#include "resources/no-input-cursor/16.xcur.h"
+#include "resources/no-input-cursor/32.xcur.h"
 
 #include <string.h>
 #include <unistd.h>
@@ -626,29 +630,17 @@ static bool x11Init(const LG_DSInitParams params)
     XFreePixmap(x11.display, temp);
   }
 
-  /* create the square cursor */
-  {
-    static char data[] = { 0x07, 0x05, 0x07 };
-    static char mask[] = { 0xff, 0xff, 0xff };
+  XcursorImages * images;
+  if (params.largeCursorDot)
+    images = x11cursor_load(b_no_input_cursor_32_xcur,
+        b_no_input_cursor_32_xcur_size);
+  else
+    images = x11cursor_load(b_no_input_cursor_16_xcur,
+        b_no_input_cursor_16_xcur_size);
 
-    Colormap cmap = DefaultColormap(x11.display, DefaultScreen(x11.display));
-    XColor colors[2] =
-    {
-      { .pixel = BlackPixelOfScreen(DefaultScreenOfDisplay(x11.display)) },
-      { .pixel = WhitePixelOfScreen(DefaultScreenOfDisplay(x11.display)) }
-    };
-
-    XQueryColors(x11.display, cmap, colors, 2);
-
-    Pixmap img = XCreateBitmapFromData(x11.display, x11.window, data, 3, 3);
-    Pixmap msk = XCreateBitmapFromData(x11.display, x11.window, mask, 3, 3);
-
-    x11.cursors[LG_POINTER_SQUARE] = XCreatePixmapCursor(x11.display, img, msk,
-        &colors[0], &colors[1], 1, 1);
-
-    XFreePixmap(x11.display, img);
-    XFreePixmap(x11.display, msk);
-  }
+  x11.cursors[LG_POINTER_SQUARE] =
+    XcursorImagesLoadCursor(x11.display, images);
+  XcursorImagesDestroy(images);
 
   /* initialize the rest of the cursors */
   const char * cursorLookup[LG_POINTER_COUNT] = {

client/include/interface/displayserver.h

@@ -90,6 +90,7 @@ typedef struct LG_DSInitParams
   bool resizable;
   bool borderless;
   bool maximize;
+  bool largeCursorDot;
 
   // if true the renderer requires an OpenGL context
   bool opengl;

client/src/config.c

@@ -499,6 +499,13 @@ static struct Option options[] =
     .type          = OPTION_TYPE_BOOL,
     .value.x_bool  = true
   },
+  {
+    .module        = "spice",
+    .name          = "largeCursorDot",
+    .description   = "Use a larger version of the \"dot\" cursor",
+    .type          = OPTION_TYPE_BOOL,
+    .value.x_bool  = false
+  },
 
   // audio options
   {
@@ -728,6 +735,7 @@ bool config_load(int argc, char * argv[])
     g_params.captureOnStart   = option_get_bool("spice", "captureOnStart");
     g_params.alwaysShowCursor = option_get_bool("spice", "alwaysShowCursor");
     g_params.showCursorDot    = option_get_bool("spice", "showCursorDot");
+    g_params.largeCursorDot   = option_get_bool("spice", "largeCursorDot");
   }
 
   g_params.audioPeriodSize = option_get_int("audio", "periodSize");

client/src/main.c

@@ -1337,6 +1337,7 @@ static int lg_run(void)
     .resizable           = g_params.allowResize,
     .borderless          = g_params.borderless,
     .maximize            = g_params.maximize,
+    .largeCursorDot      = g_params.largeCursorDot,
     .opengl              = needsOpenGL,
     .jitRender           = g_params.jitRender
   };

client/src/main.h

@@ -218,6 +218,7 @@ struct AppParams
   bool                 autoCapture;
   bool                 captureInputOnly;
   bool                 showCursorDot;
+  bool                 largeCursorDot;
 
   int                  audioPeriodSize;
   int                  audioBufferLatency;

resources/CMakeLists.txt

@@ -18,6 +18,8 @@ build_resources(
 	lg-logo.svg
 	status/spice.svg
 	status/recording.svg
+	no-input-cursor/16.xcur
+	no-input-cursor/32.xcur
 )
 
 add_library(lg_resources STATIC ${LG_RESOURCES_OBJS})

resources/no-input-cursor/16.cursor

@@ -0,0 +1 @@
+16 8 8 16.png

resources/no-input-cursor/32.cursor

@@ -0,0 +1 @@
+32 16 16 32.png