gd.c

下载来的一个看图软件的源代码

		  if (gdImageGetTransparent (src) == mapTo)
		    {
		      tox++;
		      continue;
		    }
		}
	      else
		{
		  c = gdImageGetPixel (src, x, y);
		  /* Added 7/24/95: support transparent copies */
		  if (gdImageGetTransparent (src) == c)
		    {
		      tox += stx[x - srcX];
		      continue;
		    }
		  if (src->trueColor)
		    {
		      /* Remap to the palette available in the
		         destination image. This is slow and
		         works badly. */
		      mapTo = gdImageColorResolveAlpha (dst,
						      gdTrueColorGetRed (c),
						    gdTrueColorGetGreen (c),
						     gdTrueColorGetBlue (c),
						   gdTrueColorGetAlpha (c));
		    }
		  else
		    {
		      /* Have we established a mapping for this color? */
		      if (colorMap[c] == (-1))
			{
			  /* If it's the same image, mapping is trivial */
			  if (dst == src)
			    {
			      nc = c;
			    }
			  else
			    {
			      /* Find or create the best match */
			      mapTo = gdImageColorResolveAlpha (dst,
						      gdTrueColorGetRed (c),
						    gdTrueColorGetGreen (c),
						     gdTrueColorGetBlue (c),
						   gdTrueColorGetAlpha (c));
			    }
			  colorMap[c] = nc;
			}
		      mapTo = colorMap[c];
		    }
		}
	      for (i = 0; (i < stx[x - srcX]); i++)
		{
		  gdImageSetPixel (dst, tox, toy, mapTo);
		  tox++;
		}
	    }
	  toy++;
	}
    }
  gdFree (stx);
  gdFree (sty);
}

/* When gd 1.x was first created, floating point was to be avoided.
   These days it is often faster than table lookups or integer
   arithmetic. The routine below is shamelessly, gloriously
   floating point. TBB */

void
gdImageCopyResampled (gdImagePtr dst,
		      gdImagePtr src,
		      int dstX, int dstY,
		      int srcX, int srcY,
		      int dstW, int dstH,
		      int srcW, int srcH)
{
  int x, y;
  float sx, sy;
  if (!dst->trueColor)
    {
      gdImageCopyResized (
			   dst, src, dstX, dstY, srcX, srcY, dstW, dstH,
			   srcW, srcH);
      return;
    }
  for (y = dstY; (y < dstY + dstH); y++)
    {
      for (x = dstX; (x < dstX + dstW); x++)
	{
	  int pd = gdImageGetPixel (dst, x, y);
	  float sy1, sy2, sx1, sx2;
	  float sx, sy;
	  float spixels = 0;
	  float red = 0.0, green = 0.0, blue = 0.0, alpha = 0.0;
	  sy1 = ((float) y - (float) dstY) * (float) srcH /
	    (float) dstH;
	  sy2 = ((float) (y + 1) - (float) dstY) * (float) srcH /
	    (float) dstH;
	  sy = sy1;
	  do
	    {
	      float yportion;
	      if (floor (sy) == floor (sy1))
		{
		  yportion = 1.0 - (sy - floor (sy));
		  if (yportion > sy2 - sy1)
		    {
		      yportion = sy2 - sy1;
		    }
		  sy = floor (sy);
		}
	      else if (sy == floor (sy2))
		{
		  yportion = sy2 - floor (sy2);
		}
	      else
		{
		  yportion = 1.0;
		}
	      sx1 = ((float) x - (float) dstX) * (float) srcW /
		dstW;
	      sx2 = ((float) (x + 1) - (float) dstX) * (float) srcW /
		dstW;
	      sx = sx1;
	      do
		{
		  float xportion;
		  float pcontribution;
		  int p;
		  if (floor (sx) == floor (sx1))
		    {
		      xportion = 1.0 - (sx - floor (sx));
		      if (xportion > sx2 - sx1)
			{
			  xportion = sx2 - sx1;
			}
		      sx = floor (sx);
		    }
		  else if (sx == floor (sx2))
		    {
		      xportion = sx2 - floor (sx2);
		    }
		  else
		    {
		      xportion = 1.0;
		    }
		  pcontribution = xportion * yportion;
		  p = gdImageGetTrueColorPixel (
						 src,
						 (int) sx,
						 (int) sy);
		  red += gdTrueColorGetRed (p) * pcontribution;
		  green += gdTrueColorGetGreen (p) * pcontribution;
		  blue += gdTrueColorGetBlue (p) * pcontribution;
		  alpha += gdTrueColorGetAlpha (p) * pcontribution;
		  spixels += xportion * yportion;
		  sx += 1.0;
		}
	      while (sx < sx2);
	      sy += 1.0;
	    }
	  while (sy < sy2);
	  if (spixels != 0.0)
	    {
	      red /= spixels;
	      green /= spixels;
	      blue /= spixels;
	      alpha /= spixels;
	    }
	  /* Clamping to allow for rounding errors above */
	  if (red > 255.0)
	    {
	      red = 255.0;
	    }
	  if (green > 255.0)
	    {
	      green = 255.0;
	    }
	  if (blue > 255.0)
	    {
	      blue = 255.0;
	    }
	  if (alpha > gdAlphaMax)
	    {
	      alpha = gdAlphaMax;
	    }
	  gdImageSetPixel (dst,
			   x, y,
			   gdTrueColorAlpha ((int) red,
					     (int) green,
					     (int) blue,
					     (int) alpha));
	}
    }
}

gdImagePtr
gdImageCreateFromXbm (FILE * fd)
{
  gdImagePtr im;
  int bit;
  int w, h;
  int bytes;
  int ch;
  int i, x, y;
  char *sp;
  char s[161];
  if (!fgets (s, 160, fd))
    {
      return 0;
    }
  sp = &s[0];
  /* Skip #define */
  sp = strchr (sp, ' ');
  if (!sp)
    {
      return 0;
    }
  /* Skip width label */
  sp++;
  sp = strchr (sp, ' ');
  if (!sp)
    {
      return 0;
    }
  /* Get width */
  w = atoi (sp + 1);
  if (!w)
    {
      return 0;
    }
  if (!fgets (s, 160, fd))
    {
      return 0;
    }
  sp = s;
  /* Skip #define */
  sp = strchr (sp, ' ');
  if (!sp)
    {
      return 0;
    }
  /* Skip height label */
  sp++;
  sp = strchr (sp, ' ');
  if (!sp)
    {
      return 0;
    }
  /* Get height */
  h = atoi (sp + 1);
  if (!h)
    {
      return 0;
    }
  /* Skip declaration line */
  if (!fgets (s, 160, fd))
    {
      return 0;
    }
  bytes = (w * h / 8) + 1;
  im = gdImageCreate (w, h);
  gdImageColorAllocate (im, 255, 255, 255);
  gdImageColorAllocate (im, 0, 0, 0);
  x = 0;
  y = 0;
  for (i = 0; (i < bytes); i++)
    {
      char h[3];
      int b;
      /* Skip spaces, commas, CRs, 0x */
      while (1)
	{
	  ch = getc (fd);
	  if (ch == EOF)
	    {
	      goto fail;
	    }
	  if (ch == 'x')
	    {
	      break;
	    }
	}
      /* Get hex value */
      ch = getc (fd);
      if (ch == EOF)
	{
	  goto fail;
	}
      h[0] = ch;
      ch = getc (fd);
      if (ch == EOF)
	{
	  goto fail;
	}
      h[1] = ch;
      h[2] = '\0';
      sscanf (h, "%x", &b);
      for (bit = 1; (bit <= 128); (bit = bit << 1))
	{
	  gdImageSetPixel (im, x++, y, (b & bit) ? 1 : 0);
	  if (x == im->sx)
	    {
	      x = 0;
	      y++;
	      if (y == im->sy)
		{
		  return im;
		}
	      /* Fix 8/8/95 */
	      break;
	    }
	}
    }
  /* Shouldn't happen */
  fprintf (stderr, "Error: bug in gdImageCreateFromXbm!\n");
  return 0;
fail:
  gdImageDestroy (im);
  return 0;
}

void
gdImagePolygon (gdImagePtr im, gdPointPtr p, int n, int c)
{
  int i;
  int lx, ly;
  if (!n)
    {
      return;
    }
  lx = p->x;
  ly = p->y;
  gdImageLine (im, lx, ly, p[n - 1].x, p[n - 1].y, c);
  for (i = 1; (i < n); i++)
    {
      p++;
      gdImageLine (im, lx, ly, p->x, p->y, c);
      lx = p->x;
      ly = p->y;
    }
}

int gdCompareInt (const void *a, const void *b);

/* THANKS to Kirsten Schulz for the polygon fixes! */

/* The intersection finding technique of this code could be improved  */
/* by remembering the previous intertersection, and by using the slope. */
/* That could help to adjust intersections  to produce a nice */
/* interior_extrema. */

void
gdImageFilledPolygon (gdImagePtr im, gdPointPtr p, int n, int c)
{
  int i;
  int y;
  int miny, maxy;
  int x1, y1;
  int x2, y2;
  int ind1, ind2;
  int ints;
  if (!n)
    {
      return;
    }
  if (!im->polyAllocated)
    {
      im->polyInts = (int *) gdMalloc (sizeof (int) * n);
      im->polyAllocated = n;
    }
  if (im->polyAllocated < n)
    {
      while (im->polyAllocated < n)
	{
	  im->polyAllocated *= 2;
	}
      im->polyInts = (int *) gdRealloc (im->polyInts,
					sizeof (int) * im->polyAllocated);
    }
  miny = p[0].y;
  maxy = p[0].y;
  for (i = 1; (i < n); i++)
    {
      if (p[i].y < miny)
	{
	  miny = p[i].y;
	}
      if (p[i].y > maxy)
	{
	  maxy = p[i].y;
	}
    }
  /* Fix in 1.3: count a vertex only once */
  for (y = miny; (y <= maxy); y++)
    {
/*1.4           int interLast = 0; */
/*              int dirLast = 0; */
/*              int interFirst = 1; */
      ints = 0;
      for (i = 0; (i < n); i++)
	{
	  if (!i)
	    {
	      ind1 = n - 1;
	      ind2 = 0;
	    }
	  else
	    {
	      ind1 = i - 1;
	      ind2 = i;
	    }
	  y1 = p[ind1].y;
	  y2 = p[ind2].y;
	  if (y1 < y2)
	    {
	      x1 = p[ind1].x;
	      x2 = p[ind2].x;
	    }
	  else if (y1 > y2)
	    {
	      y2 = p[ind1].y;
	      y1 = p[ind2].y;
	      x2 = p[ind1].x;
	      x1 = p[ind2].x;
	    }
	  else
	    {
	      continue;
	    }
	  if ((y >= y1) && (y < y2))
	    {
	      im->polyInts[ints++] = (y - y1) * (x2 - x1) / (y2 - y1) + x1;
	    }
	  else if ((y == maxy) && (y > y1) && (y <= y2))
	    {
	      im->polyInts[ints++] = (y - y1) * (x2 - x1) / (y2 - y1) + x1;
	    }
	}
      qsort (im->polyInts, ints, sizeof (int), gdCompareInt);

      for (i = 0; (i < (ints)); i += 2)
	{
	  gdImageLine (im, im->polyInts[i], y,
		       im->polyInts[i + 1], y, c);
	}
    }
}

int
gdCompareInt (const void *a, const void *b)
{
  return (*(const int *) a) - (*(const int *) b);
}

void
gdImageSetStyle (gdImagePtr im, int *style, int noOfPixels)
{
  if (im->style)
    {
      gdFree (im->style);
    }
  im->style = (int *)
    gdMalloc (sizeof (int) * noOfPixels);
  memcpy (im->style, style, sizeof (int) * noOfPixels);
  im->styleLength = noOfPixels;
  im->stylePos = 0;
}

void
gdImageSetThickness (gdImagePtr im, int thickness)
{
  im->thick = thickness;
}

void
gdImageSetBrush (gdImagePtr im, gdImagePtr brush)
{
  int i;
  im->brush = brush;
  if ((!im->trueColor) && (!im->brush->trueColor))
    {
      for (i = 0; (i < gdImageColorsTotal (brush)); i++)
	{
	  int index;
	  index = gdImageColorResolveAlpha (im,
					    gdImageRed (brush, i),
					    gdImageGreen (brush, i),
					    gdImageBlue (brush, i),
					    gdImageAlpha (brush, i));
	  im->brushColorMap[i] = index;
	}
    }
}

void
gdImageSetTile (gdImagePtr im, gdImagePtr tile)
{
  int i;
  im->tile = tile;
  if ((!im->trueColor) && (!im->tile->trueColor))
    {
      for (i = 0; (i < gdImageColorsTotal (tile)); i++)
	{
	  int index;
	  index = gdImageColorResolveAlpha (im,
					    gdImageRed (tile, i),
					    gdImageGreen (tile, i),
					    gdImageBlue (tile, i),
					    gdImageAlpha (tile, i));
	  im->tileColorMap[i] = index;
	}
    }
}

void
gdImageInterlace (gdImagePtr im, int interlaceArg)
{
  im->interlace = interlaceArg;
}

int
gdImageCompare (gdImagePtr im1, gdImagePtr im2)
{
  int x, y;
  int p1, p2;
  int cmpStatus = 0;
  int sx, sy;

  if (im1->interlace != im2->interlace)
    {
      cmpStatus |= GD_CMP_INTERLACE;
    }

  if (im1->transparent != im2->transparent)
    {
      cmpStatus |= GD_CMP_TRANSPARENT;
    }

  if (im1->trueColor != im2->trueColor)
    {
      cmpStatus |= GD_CMP_TRUECOLOR;
    }

  sx = im1->sx;
  if (im1->sx != im2->sx)
    {
      cmpStatus |= GD_CMP_SIZE_X + GD_CMP_IMAGE;
      if (im2->sx < im1->sx)
	{
	  sx = im2->sx;
	}
    }

  sy = im1->sy;
  if (im1->sy != im2->sy)
    {
      cmpStatus |= GD_CMP_SIZE_Y + GD_CMP_IMAGE;
      if (im2->sy < im1->sy)
	{
	  sy = im2->sy;
	}
    }

  if (im1->colorsTotal != im2->colorsTotal)
    {
      cmpStatus |= GD_CMP_NUM_COLORS;
    }

  for (y = 0; (y < sy); y++)
    {
      for (x = 0; (x < sx); x++)
	{
	  p1 = im1->pixels[y][x];
	  p2 = im2->pixels[y][x];
	  if (gdImageRed (im1, p1) != gdImageRed (im2, p2))
	    {
	      cmpStatus |= GD_CMP_COLOR + GD_CMP_IMAGE;
	      break;
	    }
	  if (gdImageGreen (im1, p1) != gdImageGreen (im2, p2))
	    {
	      cmpStatus |= GD_CMP_COLOR + GD_CMP_IMAGE;
	      break;
	    }
	  if (gdImageBlue (im1, p1) != gdImageBlue (im2, p2))
	    {
	      cmpStatus |= GD_CMP_COLOR + GD_CMP_IMAGE;
	      break;
	    }
#if 0
	  /* Soon we'll add alpha channel to palettes */
	  if (gdImageAlpha (im1, p1) != gdImageAlpha (im2, p2))
	    {
	      cmpStatus |= GD_CMP_COLOR + GD_CMP_IMAGE;
	      break;
	    }
#endif
	}
      if (cmpStatus & GD_CMP_COLOR)
	{
	  break;
	};
    }

  return cmpStatus;
}

int
gdAlphaBlend (int dst, int src)
{
  return (((((gdAlphaTransparent - gdTrueColorGetAlpha (src)) *
	     gdTrueColorGetRed (src) / gdAlphaMax) +
	    (gdTrueColorGetAlpha (src) *
	     gdTrueColorGetRed (dst)) / gdAlphaMax) << 16) +
	  ((((gdAlphaTransparent - gdTrueColorGetAlpha (src)) *
	     gdTrueColorGetGreen (src) / gdAlphaMax) +
	    (gdTrueColorGetAlpha (src) *
	     gdTrueColorGetGreen (dst)) / gdAlphaMax) << 8) +
	  (((gdAlphaTransparent - gdTrueColorGetAlpha (src)) *
	    gdTrueColorGetBlue (src) / gdAlphaMax) +
	   (gdTrueColorGetAlpha (src) *
	    gdTrueColorGetBlue (dst)) / gdAlphaMax));
}

void
gdImageAlphaBlending (gdImagePtr im, int alphaBlendingArg)
{
  im->alphaBlendingFlag = alphaBlendingArg;
}

void
gdImageSaveAlpha (gdImagePtr im, int saveAlphaArg)
{
  im->saveAlphaFlag = saveAlphaArg;
}