add a patch for Guido Vollbeding's FixPix dithering.

This is a big win for 15/16 bit displays.
Obtained from: Guido Vollbeding <guivol@esc.de>

1 files changed, 472 insertions, 0 deletions

diff --git a/graphics/xv/files/patch-ae b/graphics/xv/files/patch-ae
new file mode 100644
index 00000000000..21d5cf583fe
--- /dev/null
+++ b/graphics/xv/files/patch-ae
@@ -0,0 +1,472 @@
+--- xvimage.c~	Fri Jan 13 18:11:36 1995
++++ xvimage.c	Tue Oct 15 16:41:47 1996
+@@ -46,6 +46,274 @@
+ static int  ReadImageFile1    PARM((char *, PICINFO *));
+ 
+ 
++/* The following array represents the pixel values for each shade of
++ * the primary color components.
++ * If 'p' is a pointer to a source image rgb-byte-triplet, we can
++ * construct the output pixel value simply by 'oring' together
++ * the corresponding components:
++ *
++ *	unsigned char *p;
++ *	unsigned long pixval;
++ *
++ *	pixval  = screen_rgb[0][*p++];
++ *	pixval |= screen_rgb[1][*p++];
++ *	pixval |= screen_rgb[2][*p++];
++ *
++ * This is both efficient and generic, since the only assumption
++ * is that the primary color components have separate bits.
++ * The order and distribution of bits does not matter, and we
++ * don't need additional vaiables and shifting/masking code.
++ * The array size is 3 KBytes total and thus very reasonable.
++ */
++
++static unsigned long screen_rgb[3][256];
++
++/* The following array holds the exact color representations
++ * reported by the system.
++ * This is useful for less than 24 bit deep displays as a base
++ * for additional dithering to get smoother output.
++ */
++
++static byte screen_set[3][256];
++
++/* The following routine initializes the screen_rgb and screen_set
++ * arrays.
++ * Since it is executed only once per program run, it does not need
++ * to be super-efficient.
++ *
++ * The method is to draw points in a pixmap with the specified shades
++ * of primary colors and then get the corresponding XImage pixel
++ * representation.
++ * Thus we can get away with any Bit-order/Byte-Order dependencies.
++ *
++ * The routine uses some global X variables: theDisp, theScreen,
++ * and dispDEEP. Adapt these to your application as necessary.
++ * I've not passed them in as parameters, since for other platforms
++ * than X these may be different (see vfixpix.c), and so the
++ * screen_init() interface is unique.
++ *
++ * BUG: I've read in the "Xlib Programming Manual" from O'Reilly &
++ * Associates, that the DefaultColormap in TrueColor might not
++ * provide the full shade representation in XAllocColor.
++ * In this case one had to provide a 'best' colormap instead.
++ * However, my tests with Xaccel on a Linux-Box with a Mach64
++ * card were fully successful, so I leave that potential problem
++ * to you at the moment and would appreciate any suggestions...
++ */
++
++static void screen_init()
++{
++  static int init_flag; /* assume auto-init as 0 */
++  Pixmap check_map;
++  GC check_gc;
++  XColor check_col;
++  XImage *check_image;
++  int ci, i;
++
++  if (init_flag) return;
++  init_flag = 1;
++
++  check_map = XCreatePixmap(theDisp, RootWindow(theDisp,theScreen),
++			    1, 1, dispDEEP);
++  check_gc = XCreateGC(theDisp, RootWindow(theDisp,theScreen), 0, NULL);
++  for (ci = 0; ci < 3; ci++) {
++    for (i = 0; i < 256; i++) {
++      check_col.flags = DoRed | DoGreen | DoBlue;
++      check_col.red = 0;
++      check_col.green = 0;
++      check_col.blue = 0;
++      /* Do proper upscaling from unsigned 8 bit (image data values)
++	 to unsigned 16 bit (X color representation). */
++      ((unsigned short *)&check_col.red)[ci] = (unsigned short)((i << 8) | i);
++      if (!XAllocColor(theDisp, DefaultColormap(theDisp,theScreen), &check_col))
++	FatalError("XAllocColor in screen_init() failed"); /* shouldn't happen */
++      screen_set[ci][i] =
++	(((unsigned short *)&check_col.red)[ci] >> 8) & 0xff;
++      XSetForeground(theDisp, check_gc, check_col.pixel);
++      XDrawPoint(theDisp, check_map, check_gc, 0, 0);
++      check_image = XGetImage(theDisp, check_map, 0, 0, 1, 1,
++			      AllPlanes, ZPixmap);
++      if (!check_image) FatalError("XGetImage in screen_init() failed");
++      switch (check_image->bits_per_pixel) {
++      case 8:
++	screen_rgb[ci][i] = *(CARD8 *)check_image->data;
++	break;
++      case 16:
++	screen_rgb[ci][i] = *(CARD16 *)check_image->data;
++	break;
++      case 24:
++	screen_rgb[ci][i] =
++	  ((unsigned long)*(CARD8 *)check_image->data << 16) |
++	  ((unsigned long)*(CARD8 *)(check_image->data + 1) << 8) |
++	  (unsigned long)*(CARD8 *)(check_image->data + 2);
++	break;
++      case 32:
++	screen_rgb[ci][i] = *(CARD32 *)check_image->data;
++	break;
++      }
++      XDestroyImage(check_image);
++    }
++  }
++  XFreeGC(theDisp, check_gc);
++  XFreePixmap(theDisp, check_map);
++}
++
++
++/* The following switch should better be provided at runtime for
++ * comparison purposes.
++ * At the moment it's only compile time, unfortunately.
++ * Who can make adaptions for use as a runtime switch by a menu option?
++ */
++
++#define DO_FIXPIX_SMOOTH
++
++#ifdef DO_FIXPIX_SMOOTH
++
++/* The following code is based in part on:
++ *
++ * jquant1.c
++ *
++ * Copyright (C) 1991-1996, Thomas G. Lane.
++ * This file is part of the Independent JPEG Group's software.
++ * For conditions of distribution and use, see the accompanying README file.
++ *
++ * This file contains 1-pass color quantization (color mapping) routines.
++ * These routines provide mapping to a fixed color map using equally spaced
++ * color values.  Optional Floyd-Steinberg or ordered dithering is available.
++ */
++
++/* Declarations for Floyd-Steinberg dithering.
++ *
++ * Errors are accumulated into the array fserrors[], at a resolution of
++ * 1/16th of a pixel count.  The error at a given pixel is propagated
++ * to its not-yet-processed neighbors using the standard F-S fractions,
++ *		...	(here)	7/16
++ *		3/16	5/16	1/16
++ * We work left-to-right on even rows, right-to-left on odd rows.
++ *
++ * We can get away with a single array (holding one row's worth of errors)
++ * by using it to store the current row's errors at pixel columns not yet
++ * processed, but the next row's errors at columns already processed.  We
++ * need only a few extra variables to hold the errors immediately around the
++ * current column.  (If we are lucky, those variables are in registers, but
++ * even if not, they're probably cheaper to access than array elements are.)
++ *
++ * The fserrors[] array is indexed [component#][position].
++ * We provide (#columns + 2) entries per component; the extra entry at each
++ * end saves us from special-casing the first and last pixels.
++ */
++
++typedef INT16 FSERROR;		/* 16 bits should be enough */
++typedef int LOCFSERROR;		/* use 'int' for calculation temps */
++
++typedef struct { byte    *colorset;
++		 FSERROR *fserrors;
++	       } FSBUF;
++
++/* Floyd-Steinberg initialization function.
++ *
++ * It is called 'fs2_init' since it's specialized for our purpose and
++ * could be embedded in a more general FS-package.
++ *
++ * Returns a malloced FSBUF pointer which has to be passed as first
++ * parameter to subsequent 'fs2_dither' calls.
++ * The FSBUF structure does not need to be referenced by the calling
++ * application, it can be treated from the app like a void pointer.
++ *
++ * The current implementation does only require to free() this returned
++ * pointer after processing.
++ *
++ * Returns NULL if malloc fails.
++ *
++ * NOTE: The FSBUF structure is designed to allow the 'fs2_dither'
++ * function to work with an *arbitrary* number of color components
++ * at runtime! This is an enhancement over the IJG code base :-).
++ * Only fs2_init() specifies the (maximum) number of components.
++ */
++
++static FSBUF *fs2_init(width)
++int width;
++{
++  FSBUF *fs;
++  FSERROR *p;
++
++  fs = (FSBUF *)
++    malloc(sizeof(FSBUF) * 3 + ((size_t)width + 2) * sizeof(FSERROR) * 3);
++  if (fs == 0) return fs;
++
++  fs[0].colorset = screen_set[0];
++  fs[1].colorset = screen_set[1];
++  fs[2].colorset = screen_set[2];
++
++  p = (FSERROR *)(fs + 3);
++  memset(p, 0, ((size_t)width + 2) * sizeof(FSERROR) * 3);
++
++  fs[0].fserrors = p;
++  fs[1].fserrors = p + 1;
++  fs[2].fserrors = p + 2;
++
++  return fs;
++}
++
++/* Floyd-Steinberg dithering function.
++ *
++ * NOTE:
++ * (1) The image data referenced by 'ptr' is *overwritten* (input *and*
++ *     output) to allow more efficient implementation.
++ * (2) Alternate FS dithering is provided by the sign of 'nc'. Pass in
++ *     a negative value for right-to-left processing. The return value
++ *     provides the right-signed value for subsequent calls!
++ * (3) This particular implementation assumes *no* padding between lines!
++ *     Adapt this if necessary.
++ */
++
++static int fs2_dither(fs, ptr, nc, num_rows, num_cols)
++FSBUF *fs;
++byte *ptr;
++int nc, num_rows, num_cols;
++{
++  int abs_nc, ci, row, col;
++  LOCFSERROR delta, cur, belowerr, bpreverr;
++  byte *dataptr, *colsetptr;
++  FSERROR *errorptr;
++
++  if ((abs_nc = nc) < 0) abs_nc = -abs_nc;
++  for (row = 0; row < num_rows; row++) {
++    for (ci = 0; ci < abs_nc; ci++, ptr++) {
++      dataptr = ptr;
++      colsetptr = fs[ci].colorset;
++      errorptr = fs[ci].fserrors;
++      if (nc < 0) {
++	dataptr += (num_cols - 1) * abs_nc;
++	errorptr += (num_cols + 1) * abs_nc;
++      }
++      cur = belowerr = bpreverr = 0;
++      for (col = 0; col < num_cols; col++) {
++	cur += errorptr[nc];
++	cur += 8; cur >>= 4;
++	if ((cur += *dataptr) < 0) cur = 0;
++	else if (cur > 255) cur = 255;
++	*dataptr = cur & 0xff;
++	cur -= colsetptr[cur];
++	delta = cur << 1; cur += delta;
++	bpreverr += cur; cur += delta;
++	belowerr += cur; cur += delta;
++	errorptr[0] = (FSERROR)bpreverr;
++	bpreverr = belowerr;
++	belowerr = delta >> 1;
++	dataptr += nc;
++	errorptr += nc;
++      }
++      errorptr[0] = (FSERROR)bpreverr;
++    }
++    ptr += (num_cols - 1) * abs_nc;
++    nc = -nc;
++  }
++  return nc;
++}
++
++#endif /* DO_FIXPIX_SMOOTH */
++
+ 
+ #define DO_CROP 0
+ #define DO_ZOOM 1
+@@ -1883,33 +2151,17 @@
+     /* Non-ColorMapped Visuals:  TrueColor, DirectColor                     */
+     /************************************************************************/
+ 
+-    unsigned long r, g, b, rmask, gmask, bmask, xcol;
+-    int           rshift, gshift, bshift, bperpix, bperline, border, cshift;
+-    int           maplen;
++    unsigned long xcol;
++    int           bperpix, bperline;
+     byte         *imagedata, *lip, *ip, *pp;
+ 
+ 
+-    /* compute various shifting constants that we'll need... */
+-
+-    rmask = theVisual->red_mask;
+-    gmask = theVisual->green_mask;
+-    bmask = theVisual->blue_mask;
+-
+-    rshift = 7 - highbit(rmask);
+-    gshift = 7 - highbit(gmask);
+-    bshift = 7 - highbit(bmask);
+-
+-    maplen = theVisual->map_entries;
+-    if (maplen>256) maplen=256;
+-    cshift = 7 - highbit((u_long) (maplen-1));
+-
+     xim = XCreateImage(theDisp, theVisual, dispDEEP, ZPixmap, 0, NULL,
+ 		        wide,  high, 32, 0);
+     if (!xim) FatalError("couldn't create X image!");
+ 
+     bperline = xim->bytes_per_line;
+     bperpix  = xim->bits_per_pixel;
+-    border   = xim->byte_order;
+ 
+     imagedata = (byte *) malloc((size_t) (high * bperline));
+     if (!imagedata) FatalError("couldn't malloc imagedata");
+@@ -1923,82 +2175,87 @@
+       FatalError(buf);
+     }
+ 
++    screen_init();
+ 
+-    lip = imagedata;  pp = pic24;
+-    for (i=0; i<high; i++, lip+=bperline) {
+-      for (j=0, ip=lip; j<wide; j++) {
+-	r = *pp++;  g = *pp++;  b = *pp++;
+-
+-	/* shift r,g,b so that high bit of 8-bit color specification is 
+-	 * aligned with high bit of r,g,b-mask in visual, 
+-	 * AND each component with its mask,
+-	 * and OR the three components together
+-	 */
+-
+-	if (theVisual->class == DirectColor) {
+-	  r = (u_long) directConv[(r>>cshift) & 0xff] << cshift;
+-	  g = (u_long) directConv[(g>>cshift) & 0xff] << cshift;
+-	  b = (u_long) directConv[(b>>cshift) & 0xff] << cshift;
+-	}
+-
+-
+-	/* shift the bits around */
+-	if (rshift<0) r = r << (-rshift);
+-	         else r = r >> rshift;
+-	
+-	if (gshift<0) g = g << (-gshift);
+-	         else g = g >> gshift;
+-
+-	if (bshift<0) b = b << (-bshift);
+-	         else b = b >> bshift;
+-
+-	r = r & rmask;
+-	g = g & gmask;
+-	b = b & bmask;
+-
+-	xcol = r | g | b;
+-
+-	if (bperpix == 32) {
+-	  if (border == MSBFirst) {
+-	    *ip++ = (xcol>>24) & 0xff;
+-	    *ip++ = (xcol>>16) & 0xff;
+-	    *ip++ = (xcol>>8)  & 0xff;
+-	    *ip++ =  xcol      & 0xff;
+-	  }
+-	  else {  /* LSBFirst */
+-	    *ip++ =  xcol      & 0xff;
+-	    *ip++ = (xcol>>8)  & 0xff;
+-	    *ip++ = (xcol>>16) & 0xff;
+-	    *ip++ = (xcol>>24) & 0xff;
+-	  }
+-	}
+-
+-	else if (bperpix == 24) {
+-	  if (border == MSBFirst) {
+-	    *ip++ = (xcol>>16) & 0xff;
+-	    *ip++ = (xcol>>8)  & 0xff;
+-	    *ip++ =  xcol      & 0xff;
+-	  }
+-	  else {  /* LSBFirst */
+-	    *ip++ =  xcol      & 0xff;
+-	    *ip++ = (xcol>>8)  & 0xff;
+-	    *ip++ = (xcol>>16) & 0xff;
++#ifdef DO_FIXPIX_SMOOTH
++#if 0
++    /* If we wouldn't have to save the original pic24 image data,
++     * the following code would do the dither job by overwriting
++     * the image data, and the normal render code would then work
++     * without any change on that data.
++     * Unfortunately, this approach would hurt the xv assumptions...
++     */
++    if (bperpix < 24) {
++      FSBUF *fs = fs2_init(wide);
++      if (fs) {
++	fs2_dither(fs, pic24, 3, high, wide);
++	free(fs);
++      }
++    }
++#else
++    /* ...so we have to take a different approach with linewise
++     * dithering/rendering in a loop using a temporary line buffer.
++     */
++    if (bperpix < 24) {
++      int alldone = 0;
++      FSBUF *fs = fs2_init(wide);
++      if (fs) {
++	byte *row_buf = malloc((size_t)wide * 3);
++	if (row_buf) {
++	  int nc = 3;
++	  byte *picp = pic24;  lip = imagedata;
++	  for (i=0; i<high; i++, lip+=bperline, picp+=(size_t)wide*3) {
++	    memcpy(row_buf, picp, (size_t)wide * 3);
++	    nc = fs2_dither(fs, row_buf, nc, 1, wide);
++	    for (j=0, ip=lip, pp=row_buf; j<wide; j++) {
++
++	      xcol  = screen_rgb[0][*pp++];
++	      xcol |= screen_rgb[1][*pp++];
++	      xcol |= screen_rgb[2][*pp++];
++
++	      switch (bperpix) {
++	      case 8:
++		*ip++ = xcol & 0xff;
++		break;
++	      case 16:
++		*((CARD16 *)ip)++ = (CARD16)xcol;
++		break;
++	      }
++	    }
+ 	  }
++	  alldone = 1;
++	  free(row_buf);
+ 	}
++	free(fs);
++      }
++      if (alldone) return xim;
++    }
++#endif
++#endif
+ 
+-	else if (bperpix == 16) {
+-	  if (border == MSBFirst) {
+-	    *ip++ = (xcol>>8)  & 0xff;
+-	    *ip++ =  xcol      & 0xff;
+-	  }
+-	  else {  /* LSBFirst */
+-	    *ip++ =  xcol      & 0xff;
+-	    *ip++ = (xcol>>8)  & 0xff;
+-	  }
+-	}
++    lip = imagedata;  pp = pic24;
++    for (i=0; i<high; i++, lip+=bperline) {
++      for (j=0, ip=lip; j<wide; j++) {
+ 
+-	else if (bperpix == 8) {
+-	  *ip++ =  xcol      & 0xff;
++	xcol  = screen_rgb[0][*pp++];
++	xcol |= screen_rgb[1][*pp++];
++	xcol |= screen_rgb[2][*pp++];
++
++	switch (bperpix) {
++	case 8:
++	  *ip++ = xcol & 0xff;
++	  break;
++	case 16:
++	  *((CARD16 *)ip)++ = (CARD16)xcol;
++	  break;
++	case 24:
++	  *ip++ = (xcol >> 16) & 0xff;
++	  *ip++ = (xcol >> 8)  & 0xff;
++	  *ip++ =  xcol        & 0xff;
++	  break;
++	case 32:
++	  *((CARD32 *)ip)++ = (CARD32)xcol;
++	  break;
+ 	}
+       }
+     }