pixops.c

linux下电话本所依赖的一些图形库

                         ((y >> (SCALE_SHIFT - SUBSAMPLE_BITS)) & SUBSAMPLE_MASK) *
                         filter->x.n * filter->y.n * SUBSAMPLE;
      guchar *new_outbuf;
      guint32 tcolor1, tcolor2;
      
      guchar *outbuf = dest_buf + dest_rowstride * i;
      guchar *outbuf_end = outbuf + dest_channels * (render_x1 - render_x0);

      if (((i + check_y) >> check_shift) & 1)
	{
	  tcolor1 = color2;
	  tcolor2 = color1;
	}
      else
	{
	  tcolor1 = color1;
	  tcolor2 = color2;
	}

      for (j=0; j<filter->y.n; j++)
	{
	  if (y_start <  0)
	    line_bufs[j] = (guchar *)src_buf;
	  else if (y_start < src_height)
	    line_bufs[j] = (guchar *)src_buf + src_rowstride * y_start;
	  else
	    line_bufs[j] = (guchar *)src_buf + src_rowstride * (src_height - 1);

	  y_start++;
	}

      dest_x = check_x;
      x = render_x0 * x_step + scaled_x_offset;
      x_start = x >> SCALE_SHIFT;

      while (x_start < 0 && outbuf < outbuf_end)
	{
	  process_pixel (run_weights + ((x >> (SCALE_SHIFT - SUBSAMPLE_BITS)) & SUBSAMPLE_MASK) * (filter->x.n * filter->y.n), filter->x.n, filter->y.n,
			 outbuf, dest_x, dest_channels, dest_has_alpha,
			 line_bufs, src_channels, src_has_alpha,
			 x >> SCALE_SHIFT, src_width,
			 check_size, tcolor1, tcolor2, pixel_func);
	  
	  x += x_step;
	  x_start = x >> SCALE_SHIFT;
	  dest_x++;
	  outbuf += dest_channels;
	}

      new_outbuf = (*line_func) (run_weights, filter->x.n, filter->y.n,
				 outbuf, dest_x,
				 dest_buf + dest_rowstride * i + run_end_index * dest_channels,
				 dest_channels, dest_has_alpha,
				 line_bufs, src_channels, src_has_alpha,
				 x, x_step, src_width, check_size, tcolor1, tcolor2);

      dest_x += (new_outbuf - outbuf) / dest_channels;

      x = (dest_x - check_x + render_x0) * x_step + scaled_x_offset;
      outbuf = new_outbuf;

      while (outbuf < outbuf_end)
	{
	  process_pixel (run_weights + ((x >> (SCALE_SHIFT - SUBSAMPLE_BITS)) & SUBSAMPLE_MASK) * (filter->x.n * filter->y.n), filter->x.n, filter->y.n,
			 outbuf, dest_x, dest_channels, dest_has_alpha,
			 line_bufs, src_channels, src_has_alpha,
			 x >> SCALE_SHIFT, src_width,
			 check_size, tcolor1, tcolor2, pixel_func);
	  
	  x += x_step;
	  dest_x++;
	  outbuf += dest_channels;
	}

      y += y_step;
    }

  g_free (line_bufs);
  g_free (filter_weights);
}

/* Compute weights for reconstruction by replication followed by
 * sampling with a box filter
 */
static void
tile_make_weights (PixopsFilterDimension *dim,
		   double                 scale)
{
  int n = ceil (1 / scale + 1);
  double *pixel_weights = g_new (double, SUBSAMPLE * n);
  int offset;
  int i;

  dim->n = n;
  dim->offset = 0;
  dim->weights = pixel_weights;

  for (offset = 0; offset < SUBSAMPLE; offset++)
    {
      double x = (double)offset / SUBSAMPLE;
      double a = x + 1 / scale;

      for (i = 0; i < n; i++)
        {
          if (i < x)
            {
              if (i + 1 > x)
                *(pixel_weights++)  = (MIN (i + 1, a) - x) * scale;
              else
                *(pixel_weights++) = 0;
            }
          else
            {
              if (a > i)
                *(pixel_weights++)  = (MIN (i + 1, a) - i) * scale;
              else
                *(pixel_weights++) = 0;
            }
       }
    }
}

/* Compute weights for a filter that, for minification
 * is the same as 'tiles', and for magnification, is bilinear
 * reconstruction followed by a sampling with a delta function.
 */
static void
bilinear_magnify_make_weights (PixopsFilterDimension *dim,
			       double                 scale)
{
  double *pixel_weights;
  int n;
  int offset;
  int i;

  if (scale > 1.0)            /* Linear */
    {
      n = 2;
      dim->offset = 0.5 * (1 / scale - 1);
    }
  else                          /* Tile */
    {
      n = ceil (1.0 + 1.0 / scale);
      dim->offset = 0.0;
    }

  dim->n = n;
  dim->weights = g_new (double, SUBSAMPLE * n);

  pixel_weights = dim->weights;

  for (offset=0; offset < SUBSAMPLE; offset++)
    {
      double x = (double)offset / SUBSAMPLE;

      if (scale > 1.0)      /* Linear */
        {
          for (i = 0; i < n; i++)
            *(pixel_weights++) = (((i == 0) ? (1 - x) : x) / scale) * scale;
        }
      else                  /* Tile */
        {
          double a = x + 1 / scale;

          /*           x
           * ---------|--.-|----|--.-|-------  SRC
           * ------------|---------|---------  DEST
           */
          for (i = 0; i < n; i++)
            {
              if (i < x)
                {
                  if (i + 1 > x)
                    *(pixel_weights++) = (MIN (i + 1, a) - x) * scale;
                  else
                    *(pixel_weights++) = 0;
                }
              else
                {
                  if (a > i)
                    *(pixel_weights++) = (MIN (i + 1, a) - i) * scale;
                  else
                    *(pixel_weights++) = 0;
                }
            }
        }
    }
}

/* Computes the integral from b0 to b1 of
 *
 * f(x) = x; 0 <= x < 1
 * f(x) = 0; otherwise
 *
 * We combine two of these to compute the convolution of
 * a box filter with a triangular spike.
 */
static double
linear_box_half (double b0, double b1)
{
  double a0, a1;
  double x0, x1;

  a0 = 0.;
  a1 = 1.;

  if (a0 < b0)
    {
      if (a1 > b0)
        {
          x0 = b0;
          x1 = MIN (a1, b1);
        }
      else
        return 0;
    }
  else
    {
      if (b1 > a0)
        {
          x0 = a0;
          x1 = MIN (a1, b1);
        }
      else
        return 0;
    }

  return 0.5 * (x1*x1 - x0*x0);
}

/* Compute weights for reconstructing with bilinear
 * interpolation, then sampling with a box filter
 */
static void
bilinear_box_make_weights (PixopsFilterDimension *dim,
			   double                 scale)
{
  int n = ceil (1/scale + 3.0);
  double *pixel_weights = g_new (double, SUBSAMPLE * n);
  double w;
  int offset, i;

  dim->offset = -1.0;
  dim->n = n;
  dim->weights = pixel_weights;

  for (offset = 0; offset < SUBSAMPLE; offset++)
    {
      double x = (double)offset / SUBSAMPLE;
      double a = x + 1 / scale;

      for (i = 0; i < n; i++)
        {
          w  = linear_box_half (0.5 + i - a, 0.5 + i - x);
          w += linear_box_half (1.5 + x - i, 1.5 + a - i);
      
          *(pixel_weights++) = w * scale;
        }
    }
}

static void
make_weights (PixopsFilter     *filter,
	      PixopsInterpType  interp_type,	      
	      double            scale_x,
	      double            scale_y)
{
  switch (interp_type)
    {
    case PIXOPS_INTERP_NEAREST:
      g_assert_not_reached ();
      break;

    case PIXOPS_INTERP_TILES:
      tile_make_weights (&filter->x, scale_x);
      tile_make_weights (&filter->y, scale_y);
      break;
      
    case PIXOPS_INTERP_BILINEAR:
      bilinear_magnify_make_weights (&filter->x, scale_x);
      bilinear_magnify_make_weights (&filter->y, scale_y);
      break;
      
    case PIXOPS_INTERP_HYPER:
      bilinear_box_make_weights (&filter->x, scale_x);
      bilinear_box_make_weights (&filter->y, scale_y);
      break;
    }
}

void
_pixops_composite_color (guchar         *dest_buf,
			 int             render_x0,
			 int             render_y0,
			 int             render_x1,
			 int             render_y1,
			 int             dest_rowstride,
			 int             dest_channels,
			 gboolean        dest_has_alpha,
			 const guchar   *src_buf,
			 int             src_width,
			 int             src_height,
			 int             src_rowstride,
			 int             src_channels,
			 gboolean        src_has_alpha,
			 double          scale_x,
			 double          scale_y,
			 PixopsInterpType   interp_type,
			 int             overall_alpha,
			 int             check_x,
			 int             check_y,
			 int             check_size,
			 guint32         color1,
			 guint32         color2)
{
  PixopsFilter filter;
  PixopsLineFunc line_func;
  
#ifdef USE_MMX
  gboolean found_mmx = _pixops_have_mmx ();
#endif

  g_return_if_fail (!(dest_channels == 3 && dest_has_alpha));
  g_return_if_fail (!(src_channels == 3 && src_has_alpha));

  if (scale_x == 0 || scale_y == 0)
    return;

  if (!src_has_alpha && overall_alpha == 255)
    {
      _pixops_scale (dest_buf, render_x0, render_y0, render_x1, render_y1,
		     dest_rowstride, dest_channels, dest_has_alpha,
		     src_buf, src_width, src_height, src_rowstride, src_channels,
		     src_has_alpha, scale_x, scale_y, interp_type);
      return;
    }

  if (interp_type == PIXOPS_INTERP_NEAREST)
    {
      pixops_composite_color_nearest (dest_buf, render_x0, render_y0, render_x1, render_y1,
				      dest_rowstride, dest_channels, dest_has_alpha,
				      src_buf, src_width, src_height, src_rowstride, src_channels, src_has_alpha,
				      scale_x, scale_y, overall_alpha,
				      check_x, check_y, check_size, color1, color2);
      return;
    }
  
  filter.overall_alpha = overall_alpha / 255.;
  make_weights (&filter, interp_type, scale_x, scale_y);

#ifdef USE_MMX
  if (filter.x.n == 2 && filter.y.n == 2 &&
      dest_channels == 4 && src_channels == 4 && src_has_alpha && !dest_has_alpha && found_mmx)
    line_func = composite_line_color_22_4a4_mmx_stub;
  else
#endif
    line_func = composite_line_color;
  
  pixops_process (dest_buf, render_x0, render_y0, render_x1, render_y1,
		  dest_rowstride, dest_channels, dest_has_alpha,
		  src_buf, src_width, src_height, src_rowstride, src_channels,
		  src_has_alpha, scale_x, scale_y, check_x, check_y, check_size, color1, color2,
		  &filter, line_func, composite_pixel_color);

  g_free (filter.x.weights);
  g_free (filter.y.weights);
}

/**
 * _pixops_composite:
 * @dest_buf: pointer to location to store result
 * @render_x0: x0 of region of scaled source to store into @dest_buf
 * @render_y0: y0 of region of scaled source to store into @dest_buf
 * @render_x1: x1 of region of scaled source to store into @dest_buf
 * @render_y1: y1 of region of scaled source to store into @dest_buf
 * @dest_rowstride: rowstride of @dest_buf
 * @dest_channels: number of channels in @dest_buf
 * @dest_has_alpha: whether @dest_buf has alpha
 * @src_buf: pointer to source pixels
 * @src_width: width of source (used for clipping)
 * @src_height: height of source (used for clipping)
 * @src_rowstride: rowstride of source
 * @src_channels: number of channels in @src_buf
 * @src_has_alpha: whether @src_buf has alpha
 * @scale_x: amount to scale source by in X direction
 * @scale_y: amount to scale source by in Y direction
 * @interp_type: type of enumeration
 * @overall_alpha: overall alpha factor to multiply source by
 * 
 * Scale source buffer by scale_x / scale_y, then composite a given rectangle
 * of the result into the destination buffer.
 **/
void
_pixops_composite (guchar        *dest_buf,
		   int            render_x0,
		   int            render_y0,
		   int            render_x1,
		   int            render_y1,
		   int            dest_rowstride,
		   int            dest_channels,
		   gboolean       dest_has_alpha,
		   const guchar  *src_buf,
		   int            src_width,
		   int            src_height,
		   int            src_rowstride,
		   int            src_channels,
		   gboolean       src_has_alpha,
		   double         scale_x,
		   double         scale_y,
		   PixopsInterpType  interp_type,
		   int            overall_alpha)
{
  PixopsFilter filter;
  PixopsLineFunc line_func;
  
#ifdef USE_MMX
  gboolean found_mmx = _pixops_have_mmx ();
#endif

  g_return_if_fail (!(dest_channels == 3 && dest_has_alpha));
  g_return_if_fail (!(src_channels == 3 && src_has_alpha));

  if (scale_x == 0 || scale_y == 0)
    return;

  if (!src_has_alpha && overall_alpha == 255)
    {
      _pixops_scale (dest_buf, render_x0, render_y0, render_x1, render_y1,
		     dest_rowstride, dest_channels, dest_has_alpha,
		     src_buf, src_width, src_height, src_rowstride, src_channels,
		     src_has_alpha, scale_x, scale_y, interp_type);
      return;
    }

  if (interp_type == PIXOPS_INTERP_NEAREST)
    {
      pixops_composite_nearest (dest_buf, render_x0, render_y0, render_x1, render_y1,
				dest_rowstride, dest_channels, dest_has_alpha,
				src_buf, src_width, src_height, src_rowstride, src_channels,
				src_has_alpha, scale_x, scale_y, overall_alpha);
      return;
    }
  
  filter.overall_alpha = overall_alpha / 255.;
  make_weights (&filter, interp_type, scale_x, scale_y);

  if (filter.x.n == 2 && filter.y.n == 2 &&
      dest_channels == 4 && src_channels == 4 && src_has_alpha && !dest_has_alpha)
    {
#ifdef USE_MMX
      if (found_mmx)
	line_func = composite_line_22_4a4_mmx_stub;
      else
#endif	
	line_func = composite_line_22_4a4;
    }
  else
    line_func = composite_line;
  
  pixops_process (dest_buf, render_x0, render_y0, render_x1, render_y1,
		  dest_rowstride, dest_channels, dest_has_alpha,
		  src_buf, src_width, src_height, src_rowstride, src_channels,
		  src_has_alpha, scale_x, scale_y, 0, 0, 0, 0, 0, 
		  &filter, line_func, composite_pixel);

  g_free (filter.x.weights);
  g_free (filter.y.weights);
}

void
_pixops_scale (guchar        *dest_buf,
	       int            render_x0,
	       int            render_y0,
	       int            render_x1,
	       int            render_y1,
	       int            dest_rowstride,
	       int            dest_channels,
	       gboolean       dest_has_alpha,
	       const guchar  *src_buf,
	       int            src_width,
	       int            src_height,
	       int            src_rowstride,
	       int            src_channels,
	       gboolean       src_has_alpha,
	       double         scale_x,
	       double         scale_y,
	       PixopsInterpType  interp_type)
{
  PixopsFilter filter;
  PixopsLineFunc line_func;

#ifdef USE_MMX
  gboolean found_mmx = _pixops_have_mmx ();
#endif

  g_return_if_fail (!(dest_channels == 3 && dest_has_alpha));
  g_return_if_fail (!(src_channels == 3 && src_has_alpha));
  g_return_if_fail (!(src_has_alpha && !dest_has_alpha));

  if (scale_x == 0 || scale_y == 0)
    return;

  if (interp_type == PIXOPS_INTERP_NEAREST)
    {
      pixops_scale_nearest (dest_buf, render_x0, render_y0, render_x1, render_y1,
			    dest_rowstride, dest_channels, dest_has_alpha,
			    src_buf, src_width, src_height, src_rowstride, src_channels, src_has_alpha,
			    scale_x, scale_y);
      return;
    }
  
  filter.overall_alpha = 1.0;
  make_weights (&filter, interp_type, scale_x, scale_y);

  if (filter.x.n == 2 && filter.y.n == 2 && dest_channels == 3 && src_channels == 3)
    {
#ifdef USE_MMX
      if (found_mmx)
	line_func = scale_line_22_33_mmx_stub;
      else
#endif
	line_func = scale_line_22_33;
    }
  else
    line_func = scale_line;
  
  pixops_process (dest_buf, render_x0, render_y0, render_x1, render_y1,
		  dest_rowstride, dest_channels, dest_has_alpha,
		  src_buf, src_width, src_height, src_rowstride, src_channels,
		  src_has_alpha, scale_x, scale_y, 0, 0, 0, 0, 0,
		  &filter, line_func, scale_pixel);

  g_free (filter.x.weights);
  g_free (filter.y.weights);
}