(lookup_image): Build mask before applying an algorithm.

Recognize algorithm `disabled'.
(cross_disabled_images): New variable.
(COLOR_INTENSITY): New macro.
(x_detect_edges): Use COLOR_INTENSITY.
(x_disable_image): New function.
(syms_of_xfns): DEFVAR_BOOL cross_disabled_images.

1 files changed, 108 insertions, 25 deletions

diff --git a/src/xfns.c b/src/xfns.c
index c91e49549a4..e57d223ea62 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -744,6 +744,7 @@ struct x_frame_parm_table
   void (*setter) P_ ((struct frame *, Lisp_Object, Lisp_Object));
 };
 
+static void x_disable_image P_ ((struct frame *, struct image *));
 static void x_create_im P_ ((struct frame *));
 void x_set_foreground_color P_ ((struct frame *, Lisp_Object, Lisp_Object));
 static void x_set_line_spacing P_ ((struct frame *, Lisp_Object, Lisp_Object));
@@ -5760,7 +5761,7 @@ lookup_image (f, spec)
         {
           /* Handle image type independent image attributes
              `:ascent ASCENT', `:margin MARGIN', `:relief RELIEF'.  */
-          Lisp_Object ascent, margin, relief, algorithm;
+          Lisp_Object ascent, margin, relief;
           Lisp_Object file;
 
           ascent = image_spec_value (spec, QCascent, NULL);
@@ -5780,26 +5781,6 @@ lookup_image (f, spec)
               img->margin += abs (img->relief);
             }
 
-          /* Should we apply an image transformation algorithm?  */
-          algorithm = image_spec_value (spec, QCalgorithm, NULL);
-          if (img->pixmap)
-            {
-              if (EQ (algorithm, Qlaplace))
-                x_laplace (f, img);
-              else if (EQ (algorithm, Qemboss))
-                x_emboss (f, img);
-              else if (CONSP (algorithm)
-                       && EQ (XCAR (algorithm), Qedge_detection))
-                {
-                  Lisp_Object tem;
-                  tem = XCDR (algorithm);
-                  if (CONSP (tem))
-                    x_edge_detection (f, img,
-                                      Fplist_get (tem, QCmatrix),
-                                      Fplist_get (tem, QCcolor_adjustment));
-                }
-            }
-
           /* Manipulation of the image's mask.  */
           if (img->pixmap)
             {
@@ -5843,6 +5824,31 @@ lookup_image (f, spec)
                     }
                 }
             }
+          
+          /* Should we apply an image transformation algorithm?  */
+          if (img->pixmap)
+            {
+              Lisp_Object algorithm;
+
+              algorithm = image_spec_value (spec, QCalgorithm, NULL);
+              if (EQ (algorithm, Qdisabled))
+                x_disable_image (f, img);
+              else if (EQ (algorithm, Qlaplace))
+                x_laplace (f, img);
+              else if (EQ (algorithm, Qemboss))
+                x_emboss (f, img);
+              else if (CONSP (algorithm)
+                       && EQ (XCAR (algorithm), Qedge_detection))
+                {
+                  Lisp_Object tem;
+                  tem = XCDR (algorithm);
+                  if (CONSP (tem))
+                    x_edge_detection (f, img,
+                                      Fplist_get (tem, QCmatrix),
+                                      Fplist_get (tem, QCcolor_adjustment));
+                }
+            }
+
         }
     }
 
@@ -7347,6 +7353,11 @@ static XColor *x_to_xcolors P_ ((struct frame *, struct image *, int));
 static void x_from_xcolors P_ ((struct frame *, struct image *, XColor *));
 static void x_detect_edges P_ ((struct frame *, struct image *, int[9], int));
 
+/* Non-zero means draw a cross on images having `:algorithm
+   disabled'.  */
+
+int cross_disabled_images;
+
 /* Edge detection matrices for different edge-detection
    strategies.  */
 
@@ -7364,6 +7375,11 @@ static int laplace_matrix[9] = {
         0,      0,       -1             /* y + 1 */
 };
 
+/* Value is the intensity of the color whose red/green/blue values
+   are R, G, and B.  */
+
+#define COLOR_INTENSITY(R, G, B) ((2 * (R) + 3 * (G) + (B)) / 6)
+
 
 /* On frame F, return an array of XColor structures describing image
    IMG->pixmap.  Each XColor structure has its pixel color set.  RGB_P
@@ -7499,7 +7515,7 @@ x_detect_edges (f, img, matrix, color_adjust)
       
       for (x = 1; x < img->width - 1; ++x, ++p)
         {
-          int r, g, b, intensity, y1, x1;
+          int r, g, b, y1, x1;
 
           r = g = b = i = 0;
           for (y1 = y - 1; y1 < y + 2; ++y1)
@@ -7515,9 +7531,7 @@ x_detect_edges (f, img, matrix, color_adjust)
           r = (r / sum + color_adjust) & 0xffff;
           g = (g / sum + color_adjust) & 0xffff;
           b = (b / sum + color_adjust) & 0xffff;
-
-          intensity = (2 * r + 3 * g + b) / 6;
-          p->red = p->green = p->blue = intensity;
+          p->red = p->green = p->blue = COLOR_INTENSITY (r, g, b);
         }
     }
 
@@ -7593,6 +7607,69 @@ x_edge_detection (f, img, matrix, color_adjust)
 }
 
 
+/* Transform image IMG on frame F so that it looks disabled.  */
+
+static void
+x_disable_image (f, img)
+     struct frame *f;
+     struct image *img;
+{
+  struct x_display_info *dpyinfo = FRAME_X_DISPLAY_INFO (f);
+  
+  if (dpyinfo->n_planes >= 2)
+    {
+      /* Color (or grayscale).  Convert to gray, and equalize.  Just
+         drawing such images with a stipple can look very odd, so
+         we're using this method instead.  */
+      XColor *colors = x_to_xcolors (f, img, 1);
+      XColor *p, *end;
+      const int h = 15000;
+      const int l = 30000;
+
+      for (p = colors, end = colors + img->width * img->height;
+           p < end;
+           ++p)
+        {
+          int i = COLOR_INTENSITY (p->red, p->green, p->blue);
+          int i2 = (0xffff - h - l) * i / 0xffff + l;
+          p->red = p->green = p->blue = i2;
+        }
+
+      x_from_xcolors (f, img, colors);
+    }
+
+  /* Draw a cross over the disabled image, if we must or if we
+     should.  */
+  if (dpyinfo->n_planes < 2 || cross_disabled_images)
+    {
+      Display *dpy = FRAME_X_DISPLAY (f);
+      GC gc;
+
+      BLOCK_INPUT;
+      gc = XCreateGC (dpy, img->pixmap, 0, NULL);
+      XSetForeground (dpy, gc, BLACK_PIX_DEFAULT (f));
+      XDrawLine (dpy, img->pixmap, gc, 0, 0,
+                 img->width - 1, img->height - 1);
+      XDrawLine (dpy, img->pixmap, gc, 0, img->height - 1,
+                 img->width - 1, 0);
+      XFreeGC (dpy, gc);
+
+      if (img->mask)
+        {
+          gc = XCreateGC (dpy, img->mask, 0, NULL);
+          XSetForeground (dpy, gc, WHITE_PIX_DEFAULT (f));
+          XDrawLine (dpy, img->mask, gc, 0, 0,
+                     img->width - 1, img->height - 1);
+          XDrawLine (dpy, img->mask, gc, 0, img->height - 1,
+                     img->width - 1, 0);
+          XFreeGC (dpy, gc);
+        }
+      
+      UNBLOCK_INPUT;
+    }
+}
+
+
 /* Build a mask for image IMG which is used on frame F.  FILE is the
    name of an image file, for error messages.  HOW determines how to
    determine the background color of IMG.  If it is a list '(R G B)',
@@ -10838,6 +10915,12 @@ syms_of_xfns ()
 
   init_x_parm_symbols ();
 
+  DEFVAR_BOOL ("cross-disabled-images", &cross_disabled_images,
+    "Non-nil means always draw a cross over disabled images.\n\
+Disabled images are those having an `:algorithm disabled' property.\n\
+A cross is always drawn on black & white displays.");
+  cross_disabled_images = 0;
+
   DEFVAR_LISP ("x-bitmap-file-path", &Vx_bitmap_file_path,
     "List of directories to search for bitmap files for X.");
   Vx_bitmap_file_path = decode_env_path ((char *) 0, PATH_BITMAPS);