--- rxvt-unicode/src/rxvtimg.C	2012/06/04 15:30:41	1.13
+++ rxvt-unicode/src/rxvtimg.C	2012/06/14 19:44:31	1.89
@@ -4,19 +4,208 @@
 
 #if HAVE_IMG
 
-#define float_to_component(d) ((d) * 65535.99)
+#if 0
+struct pict
+{
+  Display *dpy;
+  Picture pic;
+
+  operator Picture () const
+  {
+    return pic;
+  }
+
+  pict ()
+  : pic (0)
+  {
+  }
+
+  pict (rxvt_img *img, XRenderPictFormat *format = 0)
+  : dpy (img->s->display->dpy)
+  {
+    XRenderPictureAttributes pa;
+    pa.repeat = img->repeat;
+    pic = XRenderCreatePicture (dpy, img->pm, format ? format : img->format, CPRepeat, &pa);
+  }
+
+  ~pict ()
+  {
+    if (pic)
+      XRenderFreePicture (dpy, pic);
+  }
+};
+#endif
 
-rxvt_img::rxvt_img (rxvt_screen *screen, XRenderPictFormat *format, int width, int height)
-: s(screen), w(width), h(height), format(format), shared(false)
+static XRenderPictFormat *
+find_alpha_format_for (Display *dpy, XRenderPictFormat *format)
 {
-  pm = XCreatePixmap (s->display->dpy, s->display->root, w, h, format->depth);
+  if (format->direct.alphaMask)
+    return format; // already has alpha
+
+  // try to find a suitable alpha format, one bit alpha is enough for our purposes
+  if (format->type == PictTypeDirect)
+    for (int n = 0; XRenderPictFormat *f = XRenderFindFormat (dpy, 0, 0, n); ++n)
+      if (f->direct.alphaMask
+          && f->type == PictTypeDirect
+          && ecb_popcount32 (f->direct.redMask  ) >= ecb_popcount32 (format->direct.redMask  )
+          && ecb_popcount32 (f->direct.greenMask) >= ecb_popcount32 (format->direct.greenMask)
+          && ecb_popcount32 (f->direct.blueMask ) >= ecb_popcount32 (format->direct.blueMask ))
+        return f;
+
+  // should be a very good fallback
+  return XRenderFindStandardFormat (dpy, PictStandardARGB32);
 }
 
-rxvt_img::rxvt_img (rxvt_screen *screen, XRenderPictFormat *format, int width, int height, Pixmap pixmap)
-: s(screen), pm(pixmap), w(width), h(height), format(format), shared(false)
+rxvt_img::rxvt_img (rxvt_screen *screen, XRenderPictFormat *format, int x, int y, int width, int height, int repeat)
+: s(screen), x(x), y(y), w(width), h(height), format(format), repeat(repeat),
+  pm(0), ref(0)
 {
 }
 
+rxvt_img::rxvt_img (const rxvt_img &img)
+: s(img.s), x(img.x), y(img.y), w(img.w), h(img.h), format(img.format), repeat(img.repeat), pm(img.pm), ref(img.ref)
+{
+  ++ref->cnt;
+}
+
+rxvt_img *
+rxvt_img::new_from_root (rxvt_screen *s)
+{
+  Display *dpy = s->display->dpy;
+  unsigned int root_pm_w, root_pm_h;
+  Pixmap root_pixmap = s->display->get_pixmap_property (s->display->xa[XA_XROOTPMAP_ID]);
+  if (root_pixmap == None)
+    root_pixmap = s->display->get_pixmap_property (s->display->xa[XA_ESETROOT_PMAP_ID]);
+
+  if (root_pixmap == None)
+    return 0;
+
+  Window wdummy;
+  int idummy;
+  unsigned int udummy;
+
+  if (!XGetGeometry (dpy, root_pixmap, &wdummy, &idummy, &idummy, &root_pm_w, &root_pm_h, &udummy, &udummy))
+    return 0;
+
+  rxvt_img *img = new rxvt_img (
+     s,
+     XRenderFindVisualFormat (dpy, DefaultVisual (dpy, s->display->screen)),
+     0,
+     0,
+     root_pm_w,
+     root_pm_h
+  );
+
+  img->pm = root_pixmap;
+  img->ref = new pixref (root_pm_w, root_pm_h);
+  img->ref->ours = false;
+
+  return img;
+}
+
+# if HAVE_PIXBUF
+
+rxvt_img *
+rxvt_img::new_from_pixbuf (rxvt_screen *s, GdkPixbuf *pb)
+{
+  Display *dpy = s->display->dpy;
+
+  int width  = gdk_pixbuf_get_width  (pb);
+  int height = gdk_pixbuf_get_height (pb);
+
+  if (width > 32767 || height > 32767) // well, we *could* upload in chunks
+    rxvt_fatal ("rxvt_img::new_from_pixbuf: image too big (maximum size 32768x32768).\n");
+
+  // since we require rgb24/argb32 formats from xrender we assume
+  // that both 24 and 32 bpp MUST be supported by any screen that supports xrender
+
+  int byte_order = ecb_big_endian () ? MSBFirst : LSBFirst;
+
+  XImage xi;
+
+  xi.width            = width;
+  xi.height           = height;
+  xi.xoffset          = 0;
+  xi.format           = ZPixmap;
+  xi.byte_order       = ImageByteOrder (dpy);
+  xi.bitmap_unit      = 0;         //XY only, unused
+  xi.bitmap_bit_order = 0;         //XY only, unused
+  xi.bitmap_pad       = BitmapPad (dpy);
+  xi.depth            = 32;
+  xi.bytes_per_line   = 0;
+  xi.bits_per_pixel   = 32;         //Z only
+  xi.red_mask         = 0x00000000; //Z only, unused
+  xi.green_mask       = 0x00000000; //Z only, unused
+  xi.blue_mask        = 0x00000000; //Z only, unused
+  xi.obdata           = 0;          // probably unused
+
+  bool byte_order_mismatch = byte_order != xi.byte_order;
+
+  if (!XInitImage (&xi))
+    rxvt_fatal ("unable to initialise ximage, please report.\n");
+
+  if (height > INT_MAX / xi.bytes_per_line)
+    rxvt_fatal ("rxvt_img::new_from_pixbuf: image too big for Xlib.\n");
+
+  xi.data = (char *)rxvt_malloc (height * xi.bytes_per_line);
+
+  int rowstride = gdk_pixbuf_get_rowstride (pb);
+  bool pb_has_alpha = gdk_pixbuf_get_has_alpha (pb);
+  unsigned char *row = gdk_pixbuf_get_pixels (pb);
+
+  char *line = xi.data;
+
+  for (int y = 0; y < height; y++)
+    {
+      unsigned char *src = row;
+      uint32_t      *dst = (uint32_t *)line;
+
+      if (!pb_has_alpha)
+        for (int x = 0; x < width; x++)
+          {
+            uint8_t r = *src++;
+            uint8_t g = *src++;
+            uint8_t b = *src++;
+
+            uint32_t v = (255 << 24) | (r << 16) | (g << 8) | b;
+            
+            if (ecb_big_endian () ? !byte_order_mismatch : byte_order_mismatch)
+              v = ecb_bswap32 (v);
+
+            *dst++ = v;
+          }
+      else
+        for (int x = 0; x < width; x++)
+          {
+            uint32_t v = *(uint32_t *)src; src += 4;
+
+            if (ecb_big_endian ())
+              v = ecb_bswap32 (v);
+
+            v = ecb_rotl32 (v, 8); // abgr to bgra
+
+            if (!byte_order_mismatch)
+              v = ecb_bswap32 (v);
+
+            *dst++ = v;
+          }
+
+      row += rowstride;
+      line += xi.bytes_per_line;
+    }
+
+  rxvt_img *img = new rxvt_img (s, XRenderFindStandardFormat (dpy, PictStandardARGB32), 0, 0, width, height);
+  img->alloc ();
+
+  GC gc = XCreateGC (dpy, img->pm, 0, 0);
+  XPutImage (dpy, img->pm, gc, &xi, 0, 0, 0, 0, width, height);
+  XFreeGC (dpy, gc);
+
+  free (xi.data);
+
+  return img;
+}
+
 rxvt_img *
 rxvt_img::new_from_file (rxvt_screen *s, const char *filename)
 {
@@ -26,58 +215,114 @@
   if (!pb)
     rxvt_fatal ("rxvt_img::new_from_file: %s\n", err->message);
 
-  rxvt_img *img = new rxvt_img (
-     s,
-     XRenderFindStandardFormat (s->display->dpy, gdk_pixbuf_get_has_alpha (pb) ? PictStandardARGB32 : PictStandardRGB24),
-     gdk_pixbuf_get_width (pb),
-     gdk_pixbuf_get_height (pb)
-  );
+  rxvt_img *img = new_from_pixbuf (s, pb);
 
-  img->render (pb, 0, 0, img->w, img->h, 0, 0);
+  g_object_unref (pb);
 
   return img;
 }
 
-rxvt_img::~rxvt_img ()
+# endif
+
+void
+rxvt_img::destroy ()
 {
-  if (!shared)
+  if (--ref->cnt)
+    return;
+
+  if (pm && ref->ours)
     XFreePixmap (s->display->dpy, pm);
+
+  delete ref;
+}
+
+rxvt_img::~rxvt_img ()
+{
+  destroy ();
+}
+
+void
+rxvt_img::alloc ()
+{
+  pm = XCreatePixmap (s->display->dpy, s->display->root, w, h, format->depth);
+  ref = new pixref (w, h);
+}
+
+Picture
+rxvt_img::picture ()
+{
+  Display *dpy = s->display->dpy;
+
+  XRenderPictureAttributes pa;
+  pa.repeat = repeat;
+  Picture pic = XRenderCreatePicture (dpy, pm, format, CPRepeat, &pa);
+
+  return pic;
 }
 
 void
 rxvt_img::unshare ()
 {
-  if (!shared)
+  if (ref->cnt == 1 && ref->ours)
     return;
 
-  rxvt_img *img = clone ();
+  Pixmap pm2 = XCreatePixmap (s->display->dpy, s->display->root, ref->w, ref->h, format->depth);
+  GC gc = XCreateGC (s->display->dpy, pm, 0, 0);
+  XCopyArea (s->display->dpy, pm, pm2, gc, 0, 0, ref->w, ref->h, 0, 0);
+  XFreeGC (s->display->dpy, gc);
 
-  ::swap (pm    , img->pm);
-  ::swap (shared, img->shared);
+  destroy ();
 
-  delete img;
+  pm = pm2;
+  ref = new pixref (ref->w, ref->h);
 }
 
 void
-rxvt_img::fill (const rxvt_color &c)
+rxvt_img::fill (const rgba &c)
 {
-  XGCValues gcv;
-  gcv.foreground = c;
-  GC gc = XCreateGC (s->display->dpy, pm, GCForeground, &gcv);
-  XFillRectangle (s->display->dpy, pm, gc, 0, 0, w, h);
-  XFreeGC (s->display->dpy, gc);
+  XRenderColor rc = { c.r, c.g, c.b, c.a };
+
+  Display *dpy = s->display->dpy;
+  Picture src = picture ();
+  XRenderFillRectangle (dpy, PictOpSrc, src, &rc, 0, 0, w, h);
+  XRenderFreePicture (dpy, src);
+}
+
+void
+rxvt_img::add_alpha ()
+{
+  if (format->direct.alphaMask)
+    return;
+
+  Display *dpy = s->display->dpy;
+
+  rxvt_img *img = new rxvt_img (s, find_alpha_format_for (dpy, format), x, y, w, h, repeat);
+  img->alloc ();
+
+  Picture src = picture ();
+  Picture dst = XRenderCreatePicture (dpy, img->pm, img->format, 0, 0);
+  
+  XRenderComposite (dpy, PictOpSrc, src, None, dst, 0, 0, 0, 0, 0, 0, w, h);
+
+  XRenderFreePicture (dpy, src);
+  XRenderFreePicture (dpy, dst);
+
+  ::swap (img->ref, ref);
+  ::swap (img->pm , pm );
+
+  delete img;
 }
 
 static void
-get_gaussian_kernel (int radius, int width, double *kernel, XFixed *params)
+get_gaussian_kernel (int radius, int width, rxvt_img::nv *kernel, XFixed *params)
 {
-  double sigma = radius / 2.0;
-  double scale = sqrt (2.0 * M_PI) * sigma;
-  double sum = 0.0;
+  rxvt_img::nv sigma = radius / 2.0;
+  rxvt_img::nv scale = sqrt (2.0 * M_PI) * sigma;
+  rxvt_img::nv sum = 0.0;
 
   for (int i = 0; i < width; i++)
     {
-      double x = i - width / 2;
+      rxvt_img::nv x = i - width / 2;
       kernel[i] = exp (-(x * x) / (2.0 * sigma * sigma)) / scale;
       sum += kernel[i];
     }
@@ -89,24 +334,27 @@
     params[i+2] = XDoubleToFixed (kernel[i] / sum);
 }
 
-void
+rxvt_img *
 rxvt_img::blur (int rh, int rv)
 {
   if (!(s->display->flags & DISPLAY_HAS_RENDER_CONV))
-    return;
+    return clone ();
 
   Display *dpy = s->display->dpy;
   int size = max (rh, rv) * 2 + 1;
-  double *kernel = (double *)malloc (size * sizeof (double));
+  nv *kernel = (nv *)malloc (size * sizeof (nv));
   XFixed *params = (XFixed *)malloc ((size + 2) * sizeof (XFixed));
+  rxvt_img *img = new rxvt_img (s, format, x, y, w, h, repeat);
+  img->alloc ();
 
   XRenderPictureAttributes pa;
-
   pa.repeat = RepeatPad;
   Picture src = XRenderCreatePicture (dpy, pm, format, CPRepeat, &pa);
-  Pixmap tmp = XCreatePixmap (dpy, pm, w, h, format->depth);
-  Picture dst = XRenderCreatePicture (dpy, tmp, format, CPRepeat, &pa);
-  XFreePixmap (dpy, tmp);
+  Picture dst = XRenderCreatePicture (dpy, img->pm, format, 0, 0);
+
+  Pixmap tmp_pm = XCreatePixmap (dpy, pm, w, h, format->depth);
+  Picture tmp = XRenderCreatePicture (dpy, tmp_pm , format, CPRepeat, &pa);
+  XFreePixmap (dpy, tmp_pm);
 
   if (kernel && params)
     {
@@ -118,22 +366,20 @@
                         PictOpSrc,
                         src,
                         None,
-                        dst,
+                        tmp,
                         0, 0,
                         0, 0,
                         0, 0,
                         w, h);
 
-      ::swap (src, dst);
-
       size = rv * 2 + 1;
       get_gaussian_kernel (rv, size, kernel, params);
       ::swap (params[0], params[1]);
 
-      XRenderSetPictureFilter (dpy, src, FilterConvolution, params, size+2);
+      XRenderSetPictureFilter (dpy, tmp, FilterConvolution, params, size+2);
       XRenderComposite (dpy,
                         PictOpSrc,
-                        src,
+                        tmp,
                         None,
                         dst,
                         0, 0,
@@ -144,97 +390,285 @@
 
   free (kernel);
   free (params);
+
   XRenderFreePicture (dpy, src);
   XRenderFreePicture (dpy, dst);
+  XRenderFreePicture (dpy, tmp);
+
+  return img;
 }
 
 static Picture
-create_xrender_mask (Display *dpy, Drawable drawable, Bool argb)
+create_xrender_mask (Display *dpy, Drawable drawable, Bool argb, Bool component_alpha)
 {
   Pixmap pixmap = XCreatePixmap (dpy, drawable, 1, 1, argb ? 32 : 8);
 
   XRenderPictFormat *format = XRenderFindStandardFormat (dpy, argb ? PictStandardARGB32 : PictStandardA8);
   XRenderPictureAttributes pa;
-  pa.repeat = True;
-  Picture mask = XRenderCreatePicture (dpy, pixmap, format, CPRepeat, &pa);
+  pa.repeat = RepeatNormal;
+  pa.component_alpha = component_alpha;
+  Picture mask = XRenderCreatePicture (dpy, pixmap, format, CPRepeat | CPComponentAlpha, &pa);
 
   XFreePixmap (dpy, pixmap);
 
   return mask;
 }
 
+static void
+extract (int32_t cl0, int32_t cl1, int32_t &c, unsigned short &xc)
+{
+  int32_t x = clamp (c, cl0, cl1);
+  c -= x;
+  xc = x;
+}
+
+static bool
+extract (int32_t cl0, int32_t cl1, int32_t &r, int32_t &g, int32_t &b, int32_t &a, unsigned short &xr, unsigned short &xg, unsigned short &xb, unsigned short &xa)
+{
+  extract (cl0, cl1, r, xr);
+  extract (cl0, cl1, g, xg);
+  extract (cl0, cl1, b, xb);
+  extract (cl0, cl1, a, xa);
+
+  return xr | xg | xb | xa;
+}
+
 void
-rxvt_img::brightness (double r, double g, double b, double a)
+rxvt_img::brightness (int32_t r, int32_t g, int32_t b, int32_t a)
 {
+  unshare ();
+
   Display *dpy = s->display->dpy;
-  Picture src = create_xrender_mask (dpy, pm, True);
   Picture dst = XRenderCreatePicture (dpy, pm, format, 0, 0);
 
-  XRenderColor mask_c;
-  mask_c.red   = float_to_component (r);
-  mask_c.green = float_to_component (g);
-  mask_c.blue  = float_to_component (b);
-  mask_c.alpha = float_to_component (a);
-  XRenderFillRectangle (dpy, PictOpSrc, src, &mask_c, 0, 0, 1, 1);
+  // loop should not be needed for brightness, as only -1..1 makes sense
+  //while (r | g | b | a)
+    {
+      unsigned short xr, xg, xb, xa;
+      XRenderColor mask_c;
 
-  XRenderComposite (dpy, PictOpAdd, src, None, dst, 0, 0, 0, 0, 0, 0, w, h);
+      if (extract (0, 65535, r, g, b, a, mask_c.red, mask_c.green, mask_c.blue, mask_c.alpha))
+        XRenderFillRectangle (dpy, PictOpAdd, dst, &mask_c, 0, 0, w, h);
+
+      if (extract (-65535, 0, r, g, b, a, mask_c.red, mask_c.green, mask_c.blue, mask_c.alpha))
+        {
+          XRenderColor mask_w = { 65535, 65535, 65535, 65535 };
+          XRenderFillRectangle (dpy, PictOpDifference, dst, &mask_w, 0, 0, w, h);
+          mask_c.red   = -mask_c.red; //TODO: verify that doing clamp, assign, and negation does the right thing
+          mask_c.green = -mask_c.green;
+          mask_c.blue  = -mask_c.blue;
+          mask_c.alpha = -mask_c.alpha;
+          XRenderFillRectangle (dpy, PictOpAdd, dst, &mask_c, 0, 0, w, h);
+          XRenderFillRectangle (dpy, PictOpDifference, dst, &mask_w, 0, 0, w, h);
+        }
+    }
+
+  XRenderFreePicture (dpy, dst);
 }
 
 void
-rxvt_img::contrast (double r, double g, double b, double a)
+rxvt_img::contrast (int32_t r, int32_t g, int32_t b, int32_t a)
 {
-  if (!(s->display->flags & DISPLAY_HAS_RENDER_MUL))
-    return;
+  if (r < 0 || g < 0 || b < 0 || a < 0)
+    rxvt_fatal ("rxvt_img::contrast does not support negative values.\n");
+
+  rxvt_img *img = new rxvt_img (s, format, x, y, w, h, repeat);
+  img->alloc ();
+  img->fill (rgba (0, 0, 0, 0));
+
+  // premultiply (yeah, these are not exact, sue me or fix it)
+  r = (r * (a >> 8)) >> 8;
+  g = (g * (a >> 8)) >> 8;
+  b = (b * (a >> 8)) >> 8;
 
   Display *dpy = s->display->dpy;
-  Picture src = create_xrender_mask (dpy, pm, True);
-  Picture dst = XRenderCreatePicture (dpy, pm, format, 0, 0);
 
-  XRenderColor mask_c;
-  mask_c.red   = float_to_component (r);
-  mask_c.green = float_to_component (g);
-  mask_c.blue  = float_to_component (b);
-  mask_c.alpha = float_to_component (a);
-  XRenderFillRectangle (dpy, PictOpSrc, src, &mask_c, 0, 0, 1, 1);
+  Picture src = picture ();
+  Picture dst = XRenderCreatePicture (dpy, img->pm, format, 0, 0);
+  Picture mul = create_xrender_mask (dpy, pm, True, True);
+
+  //TODO: this operator does not yet implement some useful contrast
+  while (r | g | b | a)
+    {
+      unsigned short xr, xg, xb, xa;
+      XRenderColor mask_c;
+
+      if (extract (0, 65535, r, g, b, a, mask_c.red, mask_c.green, mask_c.blue, mask_c.alpha))
+        {
+          XRenderFillRectangle (dpy, PictOpSrc, mul, &mask_c, 0, 0, 1, 1);
+          XRenderComposite (dpy, PictOpAdd, src, mul, dst, 0, 0, 0, 0, 0, 0, w, h);
+        }
+    }
+
+  XRenderFreePicture (dpy, mul);
+  XRenderFreePicture (dpy, dst);
+  XRenderFreePicture (dpy, src);
+
+  ::swap (img->ref, ref);
+  ::swap (img->pm , pm );
 
-  XRenderComposite (dpy, PictOpMultiply, src, None, dst, 0, 0, 0, 0, 0, 0, w, h);
+  delete img;
 }
 
 void
-rxvt_img::render (GdkPixbuf *pixbuf, int src_x, int src_y, int width, int height, int dst_x, int dst_y)
+rxvt_img::draw (rxvt_img *img, int op, nv mask)
 {
-  //TODO
+  unshare ();
+
+  Display *dpy = s->display->dpy;
+  Picture src = img->picture ();
+  Picture dst = picture ();
+  Picture mask_p = 0;
+  
+  if (mask != 1.)
+    {
+      mask_p = create_xrender_mask (dpy, img->pm, False, False);
+      XRenderColor mask_c = { 0, 0, 0, float_to_component (mask) };
+      XRenderFillRectangle (dpy, PictOpSrc, mask, &mask_c, 0, 0, 1, 1);
+    }
+
+  XRenderComposite (dpy, op, src, mask_p, dst, x - img->x, y - img->y, 0, 0, 0, 0, w, h);
+
+  XRenderFreePicture (dpy, src);
+  XRenderFreePicture (dpy, dst);
+
+  if (mask_p)
+    XRenderFreePicture (dpy, mask_p);
 }
 
 rxvt_img *
 rxvt_img::clone ()
 {
-  GC gc = XCreateGC (s->display->dpy, pm, 0, 0);
-  Pixmap pm2 = XCreatePixmap (s->display->dpy, pm, w, h, format->depth);
-  XCopyArea (s->display->dpy, pm, pm2, gc, 0, 0, w, h, 0, 0);
-  XFreeGC (s->display->dpy, gc);
-  return new rxvt_img (s, format, w, h, pm2);
+  return new rxvt_img (*this);
 }
 
 rxvt_img *
-rxvt_img::transform (int new_width, int new_height, int repeat, double matrix[9])
+rxvt_img::reify ()
 {
-  rxvt_img *img = new rxvt_img (s, format, new_width, new_height);
+  if (x == 0 && y == 0 && w == ref->w && h == ref->h)
+    return clone ();
 
   Display *dpy = s->display->dpy;
-  XRenderPictureAttributes pa;
-  pa.repeat = repeat;
-  Picture src = XRenderCreatePicture (dpy,      pm,      format, CPRepeat, &pa);
-  Picture dst = XRenderCreatePicture (dpy, img->pm, img->format,        0,   0);
+
+  // add an alpha channel if...
+  bool alpha = !format->direct.alphaMask // pixmap has none yet
+               && (x || y)               // we need one because of non-zero offset
+               && repeat == RepeatNone;  // and we have no good pixels to fill with
+
+  rxvt_img *img = new rxvt_img (s, alpha ? find_alpha_format_for (dpy, format) : format, 0, 0, w, h, repeat);
+  img->alloc ();
+
+  Picture src = picture ();
+  Picture dst = XRenderCreatePicture (dpy, img->pm, img->format, 0, 0);
+  
+  if (alpha)
+    {
+      XRenderColor rc = { 0, 0, 0, 0 };
+      XRenderFillRectangle (dpy, PictOpSrc, dst, &rc, 0, 0, w, h);//TODO: split into four fillrectangles
+      XRenderComposite (dpy, PictOpSrc, src, None, dst, 0, 0, 0, 0, x, y, ref->w, ref->h);
+    }
+  else
+    XRenderComposite (dpy, PictOpSrc, src, None, dst, -x, -y, 0, 0, 0, 0, w, h);
+
+  XRenderFreePicture (dpy, src);
+  XRenderFreePicture (dpy, dst);
+
+  return img;
+}
+
+rxvt_img *
+rxvt_img::sub_rect (int x, int y, int width, int height)
+{
+  rxvt_img *img = clone ();
+
+  img->x -= x;
+  img->y -= y;
+
+  if (w != width || h != height)
+    {
+      img->w = width;
+      img->h = height;
+
+      rxvt_img *img2 = img->reify ();
+      delete img;
+      img = img2;
+    }
+
+  return img;
+}
+
+static void
+mat_invert (rxvt_img::nv mat[3][3], rxvt_img::nv (&inv)[3][3])
+{
+  rxvt_img::nv s0 = mat [2][2] * mat [1][1] - mat [2][1] * mat [1][2];
+  rxvt_img::nv s1 = mat [2][1] * mat [0][2] - mat [2][2] * mat [0][1];
+  rxvt_img::nv s2 = mat [1][2] * mat [0][1] - mat [1][1] * mat [0][2];
+
+  rxvt_img::nv invdet = 1. / (mat [0][0] * s0 + mat [1][0] * s1 + mat [2][0] * s2);
+
+  inv [0][0] = invdet * s0;
+  inv [0][1] = invdet * s1;
+  inv [0][2] = invdet * s2;
+
+  inv [1][0] = invdet * (mat [2][0] * mat [1][2] - mat [2][2] * mat [1][0]);
+  inv [1][1] = invdet * (mat [2][2] * mat [0][0] - mat [2][0] * mat [0][2]);
+  inv [1][2] = invdet * (mat [1][0] * mat [0][2] - mat [1][2] * mat [0][0]);
+
+  inv [2][0] = invdet * (mat [2][1] * mat [1][0] - mat [2][0] * mat [1][1]);
+  inv [2][1] = invdet * (mat [2][0] * mat [0][1] - mat [2][1] * mat [0][0]);
+  inv [2][2] = invdet * (mat [1][1] * mat [0][0] - mat [1][0] * mat [0][1]);
+}
+
+static rxvt_img::nv
+mat_apply (rxvt_img::nv mat[3][3], int i, rxvt_img::nv x, rxvt_img::nv y)
+{
+  rxvt_img::nv v = mat [i][0] * x + mat [i][1] * y + mat [i][2];
+  rxvt_img::nv w = mat [2][0] * x + mat [2][1] * y + mat [2][2];
+
+  return v * (1. / w);
+}
+
+rxvt_img *
+rxvt_img::transform (nv matrix[3][3])
+{
+  // calculate new pixel bounding box coordinates
+  nv rmin[2], rmax[2];
+
+  for (int i = 0; i < 2; ++i)
+    {
+      nv v;
+      v = mat_apply (matrix, i, 0+x, 0+y);         rmin [i] =            rmax [i] = v;
+      v = mat_apply (matrix, i, w+x, 0+y); min_it (rmin [i], v); max_it (rmax [i],  v);
+      v = mat_apply (matrix, i, 0+x, h+y); min_it (rmin [i], v); max_it (rmax [i],  v);
+      v = mat_apply (matrix, i, w+x, h+y); min_it (rmin [i], v); max_it (rmax [i],  v);
+    }
+
+  // TODO: adjust matrix for subpixel accuracy
+  int dx = floor (rmin [0]);
+  int dy = floor (rmin [1]);
+
+  int new_width  = ceil (rmax [0] - dx);
+  int new_height = ceil (rmax [1] - dy);
+
+  nv inv[3][3];
+  mat_invert (matrix, inv);
+
+  rxvt_img *img = new rxvt_img (s, format, dx, dy, new_width, new_height, repeat);
+  img->alloc ();
+
+  Display *dpy = s->display->dpy;
+  Picture src = picture ();
+  Picture dst = XRenderCreatePicture (dpy, img->pm, img->format, 0, 0);
 
   XTransform xfrm;
 
   for (int i = 0; i < 3; ++i)
     for (int j = 0; j < 3; ++j)
-      xfrm.matrix [i][j] = XDoubleToFixed (matrix [i * 3 + j]);
+      xfrm.matrix [i][j] = XDoubleToFixed (inv [i][j]);
 
+  XRenderSetPictureFilter (dpy, src, "good", 0, 0);
   XRenderSetPictureTransform (dpy, src, &xfrm);
-  XRenderComposite (dpy, PictOpSrc, src, None, dst, 0, 0, 0, 0, 0, 0, new_width, new_height);
+  XRenderComposite (dpy, PictOpSrc, src, None, dst, dx, dy, 0, 0, 0, 0, new_width, new_height);
 
   XRenderFreePicture (dpy, src);
   XRenderFreePicture (dpy, dst);
@@ -245,25 +679,73 @@
 rxvt_img *
 rxvt_img::scale (int new_width, int new_height)
 {
-  double matrix[9] = {
-    new_width  / (double)w, 0, 0,
-    0, new_height / (double)h, 0,
-    0,                      0, 1
+  if (w == new_width && h == new_height)
+    return clone ();
+
+  nv matrix[3][3] = {
+    { new_width / (nv)w,  0, 0 },
+    { 0, new_height / (nv)h, 0 },
+    { 0,                  0, 1 }
+  };
+
+  int old_repeat_mode = repeat;
+  repeat = RepeatPad; // not right, but xrender can't properly scale it seems
+
+  rxvt_img *img = transform (matrix);
+
+  repeat = old_repeat_mode;
+  img->repeat = repeat;
+
+  return img;
+}
+
+rxvt_img *
+rxvt_img::rotate (int cx, int cy, nv phi)
+{
+  nv s = sin (phi);
+  nv c = cos (phi);
+
+  nv matrix[3][3] = {
+    { c, -s, cx - c * cx + s * cy  + 200 },
+    { s,  c, cy - s * cx - c * cy },
+    { 0,  0,                     1 }
+    //{ c, -s, 0 },
+    //{ s,  c, 0 },
+    //{ 0,  0, 1 }
   };
 
-  return transform (new_width, new_height, RepeatNormal, matrix);
+  //move (-cx, -cy);
+  rxvt_img *img = transform (matrix);
+  //move ( cx,  cy);
+  //img->move (cx, cy);
+
+  return img;
 }
 
 rxvt_img *
-rxvt_img::convert_to (XRenderPictFormat *new_format)
+rxvt_img::convert_format (XRenderPictFormat *new_format, const rgba &bg)
 {
-  rxvt_img *img = new rxvt_img (s, new_format, w, h);
+  if (new_format == format)
+    return clone ();
+
+  rxvt_img *img = new rxvt_img (s, new_format, x, y, w, h, repeat);
+  img->alloc ();
 
   Display *dpy = s->display->dpy;
-  Picture src = XRenderCreatePicture (dpy,      pm,     format, 0, 0);
+  Picture src = picture ();
   Picture dst = XRenderCreatePicture (dpy, img->pm, new_format, 0, 0);
+  int op = PictOpSrc;
 
-  XRenderComposite (dpy, PictOpSrc, src, None, dst, 0, 0, 0, 0, 0, 0, w, h);
+  if (format->direct.alphaMask && !new_format->direct.alphaMask)
+    {
+      // does it have to be that complicated
+      XRenderColor rc = { bg.r, bg.g, bg.b, bg.a };
+      XRenderFillRectangle (dpy, PictOpSrc, dst, &rc, 0, 0, w, h);
+
+      op = PictOpOver;
+    }
+
+  XRenderComposite (dpy, op, src, None, dst, 0, 0, 0, 0, 0, 0, w, h);
 
   XRenderFreePicture (dpy, src);
   XRenderFreePicture (dpy, dst);
@@ -271,5 +753,31 @@
   return img;
 }
 
+rxvt_img *
+rxvt_img::blend (rxvt_img *img, nv factor)
+{
+  rxvt_img *img2 = clone ();
+  Display *dpy = s->display->dpy;
+  Picture src = img->picture ();
+  Picture dst = XRenderCreatePicture (dpy, img2->pm, img2->format, 0, 0);
+  Picture mask = create_xrender_mask (dpy, img->pm, False, False);
+
+  XRenderColor mask_c;
+
+  mask_c.alpha = float_to_component (factor);
+  mask_c.red   =
+  mask_c.green =
+  mask_c.blue  = 0;
+  XRenderFillRectangle (dpy, PictOpSrc, mask, &mask_c, 0, 0, 1, 1);
+
+  XRenderComposite (dpy, PictOpOver, src, mask, dst, 0, 0, 0, 0, 0, 0, w, h);
+
+  XRenderFreePicture (dpy, src);
+  XRenderFreePicture (dpy, dst);
+  XRenderFreePicture (dpy, mask);
+
+  return img2;
+}
+
 #endif