Initial alpha transparency editing support

Detail:
  * Allow creation of new format sprites:
    - Alpha mask sprites
    - Alpha channel sprites
  * Enhanced Brush tool ideas:
    - Alpha channel sprite support + sprite brushes effectively provide
      airbrush support
  New brushes are provided in the brush tool with Gaussian blur.

  By relying on the underlying OS_SpriteOp calls, only RGB blending of alpha
  sprites is supported; when you paint over a transparent or translucent
  region of a sprite, it always turns fully opaque, except when using the
  Transparent colour.

  On an alpha masked sprite, painting in the transparent colour always turns
  the affected pixels fully transparent.
Admin:
  Submmission for Paint bounty.

Version 2.46. Tagged as 'Paint-2_46'

VersionASM

@@ -9,12 +9,12 @@
                         GBLS    Module_ApplicationDate
                         GBLS    Module_HelpVersion
                         GBLS    Module_ComponentName
-Module_MajorVersion     SETS    "2.45"
-Module_Version          SETA    245
+Module_MajorVersion     SETS    "2.46"
+Module_Version          SETA    246
 Module_MinorVersion     SETS    ""
-Module_Date             SETS    "16 Oct 2021"
-Module_ApplicationDate  SETS    "16-Oct-21"
+Module_Date             SETS    "12 Feb 2022"
+Module_ApplicationDate  SETS    "12-Feb-22"
 Module_ComponentName    SETS    "Paint"
-Module_FullVersion      SETS    "2.45"
-Module_HelpVersion      SETS    "2.45 (16 Oct 2021)"
+Module_FullVersion      SETS    "2.46"
+Module_HelpVersion      SETS    "2.46 (12 Feb 2022)"
                         END

VersionNum

-/* (2.45)
+/* (2.46)
  *
  * This file is automatically maintained by srccommit, do not edit manually.
  *
  */
-#define Module_MajorVersion_CMHG        2.45
+#define Module_MajorVersion_CMHG        2.46
 #define Module_MinorVersion_CMHG
-#define Module_Date_CMHG                16 Oct 2021
+#define Module_Date_CMHG                12 Feb 2022
 
-#define Module_MajorVersion             "2.45"
-#define Module_Version                  245
+#define Module_MajorVersion             "2.46"
+#define Module_Version                  246
 #define Module_MinorVersion             ""
-#define Module_Date                     "16 Oct 2021"
+#define Module_Date                     "12 Feb 2022"
 
-#define Module_ApplicationDate          "16-Oct-21"
+#define Module_ApplicationDate          "12-Feb-22"
 
 #define Module_ComponentName            "Paint"
 
-#define Module_FullVersion              "2.45"
-#define Module_HelpVersion              "2.45 (16 Oct 2021)"
-#define Module_LibraryVersionInfo       "2:45"
+#define Module_FullVersion              "2.46"
+#define Module_HelpVersion              "2.46 (12 Feb 2022)"
+#define Module_LibraryVersionInfo       "2:46"

c/Menus

@@ -2457,10 +2457,20 @@ void menus_sprite_handler (void *handle, char *hit)
 
           ftracef1 ("%s mask\n", create? "Create" : "Delete");
           if (create)
-            if (!menus_ensure_size (sarea, psprite_address (sprite)->next))
+          { int bytesneeded;
+            psprite_info sinfo;
+            psprite_read_full_info (sprite, &sinfo);
+            /* If a wide mask will be created, simply doubling the sprite size may not be enough */
+            if (sinfo.mode & 0x80000000)
+              bytesneeded = psprite_size (sinfo.width, sinfo.height, sinfo.mode, 1, 0) -
+                            psprite_size (sinfo.width, sinfo.height, sinfo.mode, 0, 0);
+            else
+              bytesneeded = psprite_address (sprite)->next;
+            if (!menus_ensure_size (sarea, bytesneeded))
             { msg = msgs_lookup ("PntEG");
               goto masked;
             }
+          }
 
           if ((error = (create? sprite_create_mask: sprite_remove_mask)
               (*sarea, &sid)) != NULL)
@@ -2468,6 +2478,11 @@ void menus_sprite_handler (void *handle, char *hit)
             goto masked;
           }
 
+          if (!create && (psprite_address (sprite)->mode & 0x80000000))
+          { /* Unset wide mask flag as it can cause maskless sprites not to render correctly */
+            psprite_address (sprite)->mode &= ~0x80000000;
+          }
+
           if (sprite->colourdialogue == 0) colours_set_extent (sprite);
           menus_ensure_size (sarea, 0);
           sprwindow_invalidate (sprite);

c/PSprite

@@ -64,6 +64,7 @@
 #include <stdint.h>
 #include <swis.h>
 #include "Global/VduExt.h"
+#include "Global/Sprite.h"
 
 #include "bbc.h"
 #include "colourtran.h"
@@ -123,10 +124,12 @@ static wimp_w Source; /* handle of the source window */
 static unsigned Mode; /*just a cache to avoid flicker*/
 static menu colours_menu = 0;
 static menu palette_menu = 0;
+static menu transparency_menu = 0;
 static menu last_menu = 0;
 static main__menu_str dummy;
 static int selected_colours = 0;
 static palette_type selected_palette = palette_type_none;
+static transparency_type selected_transparency = transparency_type_onoffmask;
 
 /*mode numbers to use for x x y modes (indexed by lb_bpp)*/
 static int
@@ -177,6 +180,57 @@ BOOL psprite_hasmask (main_sprite *sprite)
   return addr->image != addr->mask;
 }
 
+/************************************
+ * Has the sprite got an alpha mask *
+ ***********************************/
+
+BOOL psprite_hasalphamask (main_sprite *sprite)
+
+{ return psprite_transparency_type (sprite) == transparency_type_alphamask;
+}
+
+/***************************************
+ * Has the sprite got an alpha channel *
+ **************************************/
+
+BOOL psprite_hasalphachannel (main_sprite *sprite)
+
+{ return psprite_transparency_type (sprite) == transparency_type_alphachannel;
+}
+
+/***************************************
+ * Is alpha supported on this sprite   *
+ **************************************/
+
+BOOL psprite_canalphablend (main_sprite *sprite)
+
+{ transparency_type tt = psprite_transparency_type (sprite);
+  return tt == transparency_type_alphachannel || tt == transparency_type_alphamask;
+}
+
+/***************************************
+ * Does the OS support alpha masks     *
+ **************************************/
+
+BOOL psprite_havealphamasks (void)
+
+{ /*If the OS supports an alpha mask in a 2 colour mode, we'll assume
+    they're supported in all the available colour depths*/
+  /*A return value of 5 indicates the kernel has used the fallback of 32bpp
+    indicating the alpha mask isn't supported.*/
+  return bbc_modevar (0x881680b5u, bbc_Log2BPP) != 5;
+}
+
+/***************************************
+ * Does the OS support alpha channels  *
+ **************************************/
+
+BOOL psprite_havealphachannels (void)
+
+{ /* Check if 32k-colour alpha channels are supported, as 4k colour may be unavailable */
+  return bbc_modevar (0x78508051u, bbc_Log2BPP) != 5;
+}
+
 /********************************
  * Calculate sizeof a sprite    *
  ********************************/
@@ -1392,7 +1446,7 @@ os_error *psprite_plot_scaled_m (int x, int y, main_sprite *sprite,
     flags = mode;
     table = NULL;
   }
-  /* Opacity, TODO use alpha instead if supported: */
+  /* Opacity */
   flags |= translucency << 8;
 
   ftracef0 ("putting sprite scaled ...\n");
@@ -2691,6 +2745,7 @@ static void Decode (int *lb_bpp_out, unsigned int *mode_out)
       wierdly set multiple icons in the same E S G*/
   int x_eig = 0, y_eig = 0, lb_bpp = 0;
   unsigned int mode;
+  BOOL force_mode_word = FALSE;
 
   ftracef0 ("Decode\n");
 
@@ -2729,9 +2784,12 @@ static void Decode (int *lb_bpp_out, unsigned int *mode_out)
   }
   ftracef1 ("y_eig %d\n", y_eig);
 
+  force_mode_word = selected_transparency == transparency_type_alphamask ||
+                    selected_transparency == transparency_type_alphachannel;
+
   /*So, is this a mode?*/
   mode = ~0u;
-  if (lb_bpp <= 3)
+  if (!force_mode_word && lb_bpp <= 3)
   { if (x_eig == 1 && y_eig == 1)
       mode = modes_1x1 [lb_bpp];
     else if (x_eig == 1 && y_eig == 2)
@@ -2748,6 +2806,12 @@ static void Decode (int *lb_bpp_out, unsigned int *mode_out)
       mode = (10 << 27) | 180u >> y_eig << 14 | 180u >> x_eig << 1 | 1u;
     else
       mode = lb_bpp + 1 << 27 | 180u >> y_eig << 14 | 180u >> x_eig << 1 | 1u;
+
+    /* Do we want an alpha mask? */
+    if (selected_transparency == transparency_type_alphamask)
+    { ftracef0 ("Alpha mask specified.\n");
+      mode |= 0x80000000;
+    }
     ftracef1 ("mode 0x%X\n", mode);
   }
   else
@@ -2812,6 +2876,11 @@ static menu alter_popup_menu(void *handle)
         last_menu = palette_menu;
         help_register_handler(help_simplehandler, "NEWPALH");
         return calculate_menu_position (palette_menu, &m);
+
+      case d_Create_Transparency_Button:
+        last_menu = transparency_menu;
+        help_register_handler(help_simplehandler, "NEWTRAH");
+        return calculate_menu_position (transparency_menu, &m);
     }
   }
 
@@ -2834,9 +2903,11 @@ static void create_menu_handler( void *handle, char *items)
 { int lb_bpp;
   unsigned mode;
   handle = handle;
-  BOOL extd_16bpp = Have4k64k();
+  BOOL extd_16bpp = Have4k64k ();
   /*Check for Medusa hardware and up (supports colours > 256).*/
   BOOL gt256cols = (bbc_modevar (6 << 27 | 1, bbc_Log2BPP) != -1);
+  BOOL havealphachannels = psprite_havealphachannels ();
+  BOOL havealphamasks = psprite_havealphamasks ();
 
   /* First make absolutely sure nothing invalid is selected */
   if (!extd_16bpp && (selected_colours == 4096 || selected_colours == 65536))
@@ -2851,6 +2922,18 @@ static void create_menu_handler( void *handle, char *items)
     selected_colours = 256;
   }
 
+  if (!havealphamasks && selected_transparency == transparency_type_alphamask)
+  { ftracef1 ("Unsupported transparency selection %d, alpha mask not permitted.\n",
+        selected_transparency);
+    selected_transparency = transparency_type_onoffmask;
+  }
+
+  if (!havealphachannels && selected_transparency == transparency_type_alphachannel)
+  { ftracef1 ("Unsupported transparency selection %d, alpha channel not permitted.\n",
+        selected_transparency);
+    selected_transparency = transparency_type_onoffmask;
+  }
+
   ftracef0 ("Create_Menu_Handler\n");
 
   if (Create == NULL)
@@ -2858,7 +2941,7 @@ static void create_menu_handler( void *handle, char *items)
     return;
   }
 
-  if (last_menu == colours_menu || last_menu == palette_menu)
+  if (last_menu == colours_menu || last_menu == palette_menu || last_menu == transparency_menu)
   { Decode (&lb_bpp, &mode);
     int item = items[0] - 1;
     if (item > 99)
@@ -2892,8 +2975,7 @@ static void create_menu_handler( void *handle, char *items)
       }
 
       switch (item)
-      {
-        case 0:
+      { case 0:
           dbox_setfield (Create, d_Create_Colours, text);
           selected_colours = 2;
           break;
@@ -2932,7 +3014,7 @@ static void create_menu_handler( void *handle, char *items)
         menu_setflags(colours_menu, i, item == i - 1, (i > 4 &&
             selected_palette != palette_type_none) || (fixed_palette && i != 4));
     }
-    else /* (last_menu == palette_menu) */
+    else if (last_menu == palette_menu)
     { char tag[9], *text;
       sprintf (tag, "NEWPAL%d", item);
       text = msgs_lookup (tag);
@@ -2942,8 +3024,7 @@ static void create_menu_handler( void *handle, char *items)
       if (text[0] == '|')
         text++;
       switch (item)
-      {
-        case 0:
+      { case 0:
           dbox_setfield (Create, d_Create_Palette, text);
           selected_palette = palette_type_none;
           break;
@@ -2966,7 +3047,47 @@ static void create_menu_handler( void *handle, char *items)
       }
       for (int i = 1; i < 6; ++i)
         menu_setflags(palette_menu, i, item == i - 1, (i > 3 &&
-            selected_colours != 256) || (i > 1 && selected_colours > 256));
+            selected_colours != 256) || (i > 1 && selected_colours > 256) ||
+            (i > 1 && selected_transparency == transparency_type_alphachannel));
+    }
+    else /* (last_menu == transparency_menu) */
+    { char tag[9], *text;
+      sprintf (tag, "NEWTRA%d", item);
+      text = msgs_lookup (tag);
+      if (!text || strcmp (text, tag) == 0)
+        return;
+
+      /* Prevent unsupported selections */
+      if (!havealphamasks && item == 2)
+      { ftracef1 ("Unsupported transparency item %d, alpha masks not permitted.\n", item);
+        item = 1;
+      }
+      else if (!havealphachannels && item == 3)
+      { ftracef1 ("Unsupported transparency item %d, alpha channels not permitted.\n", item);
+        item = 1;
+      }
+
+      switch (item)
+      { case 0:
+          dbox_setfield (Create, d_Create_Transparency, text);
+          selected_transparency = transparency_type_none;
+          break;
+        case 1:
+          dbox_setfield (Create, d_Create_Transparency, text);
+          selected_transparency = transparency_type_onoffmask;
+          break;
+        case 2:
+          dbox_setfield (Create, d_Create_Transparency, text);
+          selected_transparency = transparency_type_alphamask;
+          break;
+        case 3:
+          dbox_setfield (Create, d_Create_Transparency, text);
+          selected_transparency = transparency_type_alphachannel;
+          break;
+      }
+      for (int i = 1; i < 5; ++i)
+        menu_setflags(transparency_menu, i, item == i - 1, (i == 4 &&
+            (selected_palette != palette_type_none || selected_colours < 4096 || selected_colours == 65536)));
     }
 
     /* Update palette menu flags */
@@ -2978,11 +3099,15 @@ static void create_menu_handler( void *handle, char *items)
     }
 
     /* Enable the 64 & 16 entry fixed options for 256 colours only */
-    menu_setflags(palette_menu, 4, selected_palette == palette_type_64fixed, selected_colours != 256);
-    menu_setflags(palette_menu, 5, selected_palette == palette_type_16fixed, selected_colours != 256);
-    /* Disable all palette types (except None) for > 256 colours */
-    menu_setflags(palette_menu, 2, selected_palette == palette_type_colour, selected_colours > 256);
-    menu_setflags(palette_menu, 3, selected_palette == palette_type_greyscale, selected_colours > 256);
+    menu_setflags(palette_menu, 4, selected_palette == palette_type_64fixed, (selected_colours != 256) ||
+        (selected_transparency == transparency_type_alphachannel));
+    menu_setflags(palette_menu, 5, selected_palette == palette_type_16fixed, (selected_colours != 256) ||
+        (selected_transparency == transparency_type_alphachannel));
+    /* Disable all palette types (except None) for > 256 colours and for alpha channel */
+    menu_setflags(palette_menu, 2, selected_palette == palette_type_colour, (selected_colours > 256) ||
+        (selected_transparency == transparency_type_alphachannel));
+    menu_setflags(palette_menu, 3, selected_palette == palette_type_greyscale, (selected_colours > 256) ||
+        (selected_transparency == transparency_type_alphachannel));
 
     /* Update colours menu flags */
 
@@ -3036,6 +3161,37 @@ static void create_menu_handler( void *handle, char *items)
       menu_setflags(colours_menu, 7, selected_colours == 65536, 1);
       menu_setflags(colours_menu, 8, selected_colours == 16777216, 1);
     }
+
+    /* Update transparency menu flags */
+
+    if (selected_palette != palette_type_none || selected_colours < 4096 ||
+        selected_colours == 65536)
+    { /* Fade alpha channel if there's a palette or colours are not 4k, 32k or 16M */
+      menu_setflags(transparency_menu, 4, FALSE, 1);
+    }
+    else
+    { /* Otherwise enable alpha channel, if supported */
+      menu_setflags(transparency_menu, 4, selected_transparency ==
+          transparency_type_alphachannel, !havealphachannels);
+    }
+
+    /* Fade alpha masks if they're not supported */
+    menu_setflags(transparency_menu, 3, selected_transparency ==
+        transparency_type_alphamask, !havealphamasks);
+
+    if (selected_transparency == transparency_type_alphachannel)
+    { /* Fade all colours except 4k, 32k and 16M */
+      menu_setflags(colours_menu, 1, selected_colours == 2, 1);
+      menu_setflags(colours_menu, 2, selected_colours == 4, 1);
+      menu_setflags(colours_menu, 3, selected_colours == 16, 1);
+      menu_setflags(colours_menu, 4, selected_colours == 256, 1);
+      menu_setflags(colours_menu, 7, selected_colours == 65536, 1);
+      /* Palette options were already faded higher up */
+    }
+    else
+    { /* Just need to unfade 256 colours here because that wasn't disabled or enabled in any of the other logic */
+      menu_setflags(colours_menu, 4, selected_colours == 256, 0);
+    }
   }
 }
 
@@ -3043,6 +3199,7 @@ static void make_popup_menus (void)
 
 { char init_colours[255];
   char init_palette[255];
+  char init_transparency[255];
   char *msg;
   int i = 0, len;
 
@@ -3054,9 +3211,13 @@ static void make_popup_menus (void)
   if (palette_menu != NULL)
     menu_dispose (&palette_menu, 0);
 
+  if (transparency_menu != NULL)
+    menu_dispose (&transparency_menu, 0);
+
   /* Read menu text from Messages */
   strcpy (init_colours, "");
   strcpy (init_palette, "");
+  strcpy (init_transparency, "");
 
   i = 0;
   len = 0;
@@ -3107,13 +3268,43 @@ static void make_popup_menus (void)
   if (len > 0)
     init_palette[len - 1] = '\0';
 
+  i = 0;
+  len = 0;
+
+  while (i < 100)
+  { char tag[9];
+    sprintf (tag, "NEWTRA%d", i);
+    msg = msgs_lookup (tag);
+    if (!msg || strcmp (msg, tag) == 0)
+      break;
+    /* Allow a | separator. Remove comma, if found */
+    if (msg[0] == '|' && len > 0)
+    { init_transparency[len - 1] = '\0';
+      len--;
+    }
+    len += strlen (msg) + 1;
+    if (len >= 255)
+    { werr (TRUE, "Transparency menu items text too long.");
+      break;
+    }
+    strcat (init_transparency, msg);
+    strcat (init_transparency, ",");
+    i++;
+  }
+  /* Remove the trailing comma */
+  if (len > 0)
+    init_transparency[len - 1] = '\0';
+
   ftracef1 ("Colours menu string: '%s'.\n", init_colours);
   ftracef1 ("Palette menu string: '%s'.\n", init_palette);
+  ftracef1 ("Transparency menu string: '%s'.\n", init_transparency);
 
   colours_menu = menu_new (msgs_lookup ("PntWC"), init_colours);
 
   palette_menu = menu_new (msgs_lookup ("PntG5"), init_palette);
 
+  transparency_menu = menu_new (msgs_lookup ("PntG2"), init_transparency);
+
   /* We don't set menu flags here. They will be handled afterwards. */
 
   event_attachmenumaker (dbox_syshandle (Create), alter_popup_menu, create_menu_handler, NULL);
@@ -3212,7 +3403,7 @@ static void create_create_sprite (dbox d, main_window *window)
   int width, height, sprite_size, white /*GCOL for white pixels*/,
     lb_bpp, *new_pal, e = 0, which_pal;
   unsigned mode;
-  BOOL want_palette, want_mask, mono;
+  BOOL want_palette, want_mask, mono, want_alpha_mask, want_alpha_chan;
   sprite_id sid;
   main_sprite *sprite;
   psprite_info info;
@@ -3242,7 +3433,9 @@ static void create_create_sprite (dbox d, main_window *window)
 
   want_palette = lb_bpp <= 3 && selected_palette != palette_type_none;
   mono = want_palette && selected_palette == palette_type_greyscale;
-  want_mask = !dbox_getnumeric (d, d_Create_Mask);
+  want_mask = selected_transparency != transparency_type_none;
+  want_alpha_mask = selected_transparency == transparency_type_alphamask;
+  want_alpha_chan = selected_transparency == transparency_type_alphachannel;
 
   #if TRACE
     ftracef (__FILE__, __LINE__,
@@ -3270,6 +3463,9 @@ static void create_create_sprite (dbox d, main_window *window)
     goto finish;
   }
 
+  /* Unset wide mask bit as alpha mask will be added separately */
+  mode &= ~0x80000000;
+
   ftracef0 ("creating sprite\n");
   if ((error = sprite_create_rp (*sarea, name, sprite_nopalette, width,
       height, mode, (sprite_ptr *) &addr)) != NULL)
@@ -3277,6 +3473,10 @@ static void create_create_sprite (dbox d, main_window *window)
     goto finish;
   }
 
+  /* Put wide mask bit back */
+  if (want_alpha_mask)
+    addr->mode |= 0x80000000;
+
   /*Just checking ...*/
   ftracef1 ("new sprite mode is %d\n", addr->mode);
 
@@ -3340,13 +3540,41 @@ static void create_create_sprite (dbox d, main_window *window)
     #endif
   }
 
-  sid.s.name = name;
-  sid.tag    = sprite_id_name;
-  if (want_mask)
-    if ((error = sprite_create_mask (*sarea, &sid)) != NULL)
+  /* Add an alpha channel or alpha mask if wanted and available */
+  if (/*want_alpha_mask || Now handled by sprite_create_mask() else SprExtend crashes!*/ want_alpha_chan)
+  { int flags = 0;
+    int space_needed = 0;
+    if (want_alpha_mask)
+    { /* Convert to 8bpp alpha mask */
+      ftracef0 ("About to convert to alpha mask.\n");
+      flags = 0x80000000;
+    }
+    else if (want_alpha_chan)
+    { /*Convert to RISC OS 5-compatible alpha channel*/
+      ftracef0 ("About to convert to alpha channel.\n");
+      flags = 0xC0000000;
+    }
+    error = os_swix4r (OS_SpriteOp, SpriteReason_CreateRemoveAlpha | 0x200, (int)*sarea, (int)addr, flags,
+                                    NULL, NULL, NULL, &space_needed);
+    if (error != NULL)
+    { /* If r3 > 0 it will give amount of extra space needed in area */
+      if (space_needed > 0)
+        ftracef1("More space needed for alpha, %d.", space_needed);
+      msg = error->errmess;
+      goto finish;
+    }
+    ftracef0 ("Alpha conversion succeeded.\n");
+  }
+  else if (want_mask)
+  { sid.s.name = name;
+    sid.tag    = sprite_id_name;
+
+    error = sprite_create_mask (*sarea, &sid);
+    if (error != NULL)
     { msg = error->errmess;
       goto finish;
     }
+  }
 
   /* Now shrink the sprite area to be exactly the right size */
   menus_ensure_size (sarea, 0);
@@ -3590,6 +3818,8 @@ static void Create_Handler (wimp_eventstr *e, void *handle)
       { case d_Create_Colours_Button:
         /* Fall through */
         case d_Create_Palette_Button:
+        /* Fall through */
+        case d_Create_Transparency_Button:
         { wimp_eventstr fake;
           fake.e = wimp_EBUT;
           fake.data.but.m.bbits = wimp_BMID;
@@ -3623,6 +3853,10 @@ void psprite_create_show (main_window *window, BOOL auto_open,
     { menu_dispose (&palette_menu, 1);
       palette_menu = NULL;
     }
+    if (transparency_menu)
+    { menu_dispose (&transparency_menu, 1);
+      transparency_menu = NULL;
+    }
   }
 
   if ((Create = dbox_new ("create")) == NULL)
@@ -3654,7 +3888,6 @@ void psprite_create_show (main_window *window, BOOL auto_open,
       x_eig, y_eig, lb_bpp, grey_scale? "TRUE": "FALSE");
 
   dbox_setfield   (Create, d_Create_Name,        sprite_name);
-  dbox_setnumeric (Create, d_Create_Mask,        FALSE);
   dbox_setnumeric (Create, d_Create_Width,       width);
   dbox_setnumeric (Create, d_Create_XEIG_2,      x_eig == 2);
   dbox_setnumeric (Create, d_Create_XEIG_1,      x_eig == 1);
@@ -3763,6 +3996,11 @@ void psprite_create_show (main_window *window, BOOL auto_open,
     menu_setflags(colours_menu, 7, 0, 1); /*64k*/
   }
 
+  /* Simple mask */
+  selected_transparency = transparency_type_onoffmask;
+  dbox_setfield (Create, d_Create_Transparency, msgs_lookup ("NEWTRA1"));
+  menu_setflags(transparency_menu, 2, 1, 0);
+
   Decode (&lb_bpp, &Mode);
 
   if ((unsigned) Mode < 256u)
@@ -3797,6 +4035,12 @@ void psprite_create_show (main_window *window, BOOL auto_open,
     menu_setflags(colours_menu, 8, 0, 1);
   }
 
+  /* Disable any unavailable transparency options here */
+  if (!psprite_havealphamasks ())
+    menu_setflags(transparency_menu, 3, 0, 1);
+  if (!psprite_havealphachannels ())
+    menu_setflags(transparency_menu, 4, 0, 1);
+
   if (auto_open == -1) /* open from menu branch */
   { BOOL open;
 
@@ -3902,3 +4146,18 @@ BOOL HaveBlendTable (void)
   }
   return haveit != 0;
 }
+
+/* Returns true if the version of SpriteExtend present has a bug   *
+ * that requires additional space in the sprite area to make an    *
+ * alpha mask */
+
+BOOL psprite_need_convertalpha_fix (void)
+
+{ static int needfix = -1;
+  if (needfix == -1)
+  { /* TODO Update the version number below when the bug has been fixed in SpriteExtend */
+    os_error *err = os_cli("RMEnsure SpriteExtend 1.86");
+    needfix = (err != NULL);
+  }
+  return needfix != 0;
+}

c/ToolWindow

@@ -103,6 +103,7 @@ static main_sprite *brushpane_icon_sprites [tools_MAX_BRUSH_ICONS];
 static int num_user_brushes = 0;
 static int num_brushpane_icons = 0;
 static int selected_brushpane_icon = -1;
+static int number_of_builtin_brushes = -1;
 
 static char *onlydigits  = "A0-9;Kt";
 static char *allkeys = "Kndt";
@@ -425,14 +426,21 @@ static int get_number_of_builtin_brushes (void)
 { /* Messages tells us how many built-in brush sprites are supplied in
      the Paint:Sprites file, capped at a maximum of
      tools_MAX_BUILTIN_BRUSHES for the brush menu */
-  int num_sys_brushes;
-  char *