splash.cc

这是一个做pdf阅读器的源代码文件,是大家学习阅读器资料的很好参考

      }

      // blend fill color with background
      if (pixAcc != 0) {
	pipe.shape = (pixAcc == n * m)
	                 ? (SplashCoord)1
	                 : (SplashCoord)pixAcc / (SplashCoord)(n * m);
	if (vectorAntialias && clipRes2 != splashClipAllInside) {
	  drawAAPixel(&pipe, tx + x2, ty + y2);
	} else {
	  drawPixel(&pipe, tx + x2, ty + y2, clipRes2 == splashClipAllInside);
	}
      }

      // x scale Bresenham
      xSrc += xStep;

      // x shear
      x1 += xSign;

      // y shear
      y1 += yShear1;
    }
  }

  // free memory
  gfree(pixBuf);

  return splashOk;
}

SplashError Splash::drawImage(SplashImageSource src, void *srcData,
			      SplashColorMode srcMode, GBool srcAlpha,
			      int w, int h, SplashCoord *mat) {
  SplashPipe pipe;
  GBool ok, rot;
  SplashCoord xScale, yScale, xShear, yShear, yShear1;
  int tx, tx2, ty, ty2, scaledWidth, scaledHeight, xSign, ySign;
  int ulx, uly, llx, lly, urx, ury, lrx, lry;
  int ulx1, uly1, llx1, lly1, urx1, ury1, lrx1, lry1;
  int xMin, xMax, yMin, yMax;
  SplashClipResult clipRes, clipRes2;
  int yp, yq, yt, yStep, lastYStep;
  int xp, xq, xt, xStep, xSrc;
  int k1, spanXMin, spanXMax, spanY;
  SplashColorPtr colorBuf, p;
  SplashColor pix;
  Guchar *alphaBuf, *q;
#if SPLASH_CMYK
  int pixAcc0, pixAcc1, pixAcc2, pixAcc3;
#else
  int pixAcc0, pixAcc1, pixAcc2;
#endif
  int alphaAcc;
  SplashCoord pixMul, alphaMul, alpha;
  int x, y, x1, x2, y2;
  SplashCoord y1;
  int nComps, n, m, i, j;

  if (debugMode) {
    printf("drawImage: srcMode=%d srcAlpha=%d w=%d h=%d mat=[%.2f %.2f %.2f %.2f %.2f %.2f]\n",
	   srcMode, srcAlpha, w, h, (double)mat[0], (double)mat[1], (double)mat[2],
	   (double)mat[3], (double)mat[4], (double)mat[5]);
  }

  // check color modes
  ok = gFalse; // make gcc happy
  nComps = 0; // make gcc happy
  switch (bitmap->mode) {
  case splashModeMono1:
  case splashModeMono8:
    ok = srcMode == splashModeMono8;
    nComps = 1;
    break;
  case splashModeRGB8:
    ok = srcMode == splashModeRGB8;
    nComps = 3;
    break;
  case splashModeBGR8:
    ok = srcMode == splashModeBGR8;
    nComps = 3;
    break;
#if SPLASH_CMYK
  case splashModeCMYK8:
    ok = srcMode == splashModeCMYK8;
    nComps = 4;
    break;
#endif
  }
  if (!ok) {
    return splashErrModeMismatch;
  }

  // check for singular matrix
  if (splashAbs(mat[0] * mat[3] - mat[1] * mat[2]) < 0.000001) {
    return splashErrSingularMatrix;
  }

  // compute scale, shear, rotation, translation parameters
  rot = splashAbs(mat[1]) > splashAbs(mat[0]);
  if (rot) {
    xScale = -mat[1];
    yScale = mat[2] - (mat[0] * mat[3]) / mat[1];
    xShear = -mat[3] / yScale;
    yShear = -mat[0] / mat[1];
  } else {
    xScale = mat[0];
    yScale = mat[3] - (mat[1] * mat[2]) / mat[0];
    xShear = mat[2] / yScale;
    yShear = mat[1] / mat[0];
  }
  // Note 1: The PDF spec says that all pixels whose *centers* lie
  // within the region get painted -- but that doesn't seem to match
  // up with what Acrobat actually does: it ends up leaving gaps
  // between image stripes.  So we use the same rule here as for
  // fills: any pixel that overlaps the region gets painted.
  // Note 2: The +/-0.01 in these computations is to avoid floating
  // point precision problems which can lead to gaps between image
  // stripes (it can cause image stripes to overlap, but that's a much
  // less visible problem).
  if (xScale >= 0) {
    tx = splashFloor(mat[4] - 0.01);
    tx2 = splashFloor(mat[4] + xScale + 0.01);
  } else {
    tx = splashFloor(mat[4] + 0.01);
    tx2 = splashFloor(mat[4] + xScale - 0.01);
  }
  scaledWidth = abs(tx2 - tx) + 1;
  if (yScale >= 0) {
    ty = splashFloor(mat[5] - 0.01);
    ty2 = splashFloor(mat[5] + yScale + 0.01);
  } else {
    ty = splashFloor(mat[5] + 0.01);
    ty2 = splashFloor(mat[5] + yScale - 0.01);
  }
  scaledHeight = abs(ty2 - ty) + 1;
  xSign = (xScale < 0) ? -1 : 1;
  ySign = (yScale < 0) ? -1 : 1;
  yShear1 = (SplashCoord)xSign * yShear;

  // clipping
  ulx1 = 0;
  uly1 = 0;
  urx1 = xSign * (scaledWidth - 1);
  ury1 = (int)(yShear * urx1);
  llx1 = splashRound(xShear * ySign * (scaledHeight - 1));
  lly1 = ySign * (scaledHeight - 1) + (int)(yShear * llx1);
  lrx1 = xSign * (scaledWidth - 1) +
           splashRound(xShear * ySign * (scaledHeight - 1));
  lry1 = ySign * (scaledHeight - 1) + (int)(yShear * lrx1);
  if (rot) {
    ulx = tx + uly1;    uly = ty - ulx1;
    urx = tx + ury1;    ury = ty - urx1;
    llx = tx + lly1;    lly = ty - llx1;
    lrx = tx + lry1;    lry = ty - lrx1;
  } else {
    ulx = tx + ulx1;    uly = ty + uly1;
    urx = tx + urx1;    ury = ty + ury1;
    llx = tx + llx1;    lly = ty + lly1;
    lrx = tx + lrx1;    lry = ty + lry1;
  }
  xMin = (ulx < urx) ? (ulx < llx) ? (ulx < lrx) ? ulx : lrx
                                   : (llx < lrx) ? llx : lrx
		     : (urx < llx) ? (urx < lrx) ? urx : lrx
                                   : (llx < lrx) ? llx : lrx;
  xMax = (ulx > urx) ? (ulx > llx) ? (ulx > lrx) ? ulx : lrx
                                   : (llx > lrx) ? llx : lrx
		     : (urx > llx) ? (urx > lrx) ? urx : lrx
                                   : (llx > lrx) ? llx : lrx;
  yMin = (uly < ury) ? (uly < lly) ? (uly < lry) ? uly : lry
                                   : (lly < lry) ? lly : lry
		     : (ury < lly) ? (ury < lry) ? ury : lry
                                   : (lly < lry) ? lly : lry;
  yMax = (uly > ury) ? (uly > lly) ? (uly > lry) ? uly : lry
                                   : (lly > lry) ? lly : lry
		     : (ury > lly) ? (ury > lry) ? ury : lry
                                   : (lly > lry) ? lly : lry;
  clipRes = state->clip->testRect(xMin, yMin, xMax, yMax);
  opClipRes = clipRes;
  if (clipRes == splashClipAllOutside) {
    return splashOk;
  }

  // compute Bresenham parameters for x and y scaling
  yp = h / scaledHeight;
  yq = h % scaledHeight;
  xp = w / scaledWidth;
  xq = w % scaledWidth;

  // allocate pixel buffers
  colorBuf = (SplashColorPtr)gmalloc((yp + 1) * w * nComps);
  if (srcAlpha) {
    alphaBuf = (Guchar *)gmalloc((yp + 1) * w);
  } else {
    alphaBuf = NULL;
  }

  pixAcc0 = pixAcc1 = pixAcc2 = 0; // make gcc happy
#if SPLASH_CMYK
  pixAcc3 = 0; // make gcc happy
#endif

  // initialize the pixel pipe
  pipeInit(&pipe, 0, 0, NULL, pix, state->fillAlpha,
	   srcAlpha || (vectorAntialias && clipRes != splashClipAllInside),
	   gFalse);
  if (vectorAntialias) {
    drawAAPixelInit();
  }

  if (srcAlpha) {

    // init y scale Bresenham
    yt = 0;
    lastYStep = 1;

    for (y = 0; y < scaledHeight; ++y) {

      // y scale Bresenham
      yStep = yp;
      yt += yq;
      if (yt >= scaledHeight) {
	yt -= scaledHeight;
	++yStep;
      }

      // read row(s) from image
      n = (yp > 0) ? yStep : lastYStep;
      if (n > 0) {
	p = colorBuf;
	q = alphaBuf;
	for (i = 0; i < n; ++i) {
	  (*src)(srcData, p, q);
	  p += w * nComps;
	  q += w;
	}
      }
      lastYStep = yStep;

      // loop-invariant constants
      k1 = splashRound(xShear * ySign * y);

      // clipping test
      if (clipRes != splashClipAllInside &&
	  !rot &&
	  (int)(yShear * k1) ==
	    (int)(yShear * (xSign * (scaledWidth - 1) + k1))) {
	if (xSign > 0) {
	  spanXMin = tx + k1;
	  spanXMax = spanXMin + (scaledWidth - 1);
	} else {
	  spanXMax = tx + k1;
	  spanXMin = spanXMax - (scaledWidth - 1);
	}
	spanY = ty + ySign * y + (int)(yShear * k1);
	clipRes2 = state->clip->testSpan(spanXMin, spanXMax, spanY);
	if (clipRes2 == splashClipAllOutside) {
	  continue;
	}
      } else {
	clipRes2 = clipRes;
      }

      // init x scale Bresenham
      xt = 0;
      xSrc = 0;

      // x shear
      x1 = k1;

      // y shear
      y1 = (SplashCoord)ySign * y + yShear * x1;
      // this is a kludge: if yShear1 is negative, then (int)y1 would
      // change immediately after the first pixel, which is not what
      // we want
      if (yShear1 < 0) {
	y1 += 0.999;
      }

      // loop-invariant constants
      n = yStep > 0 ? yStep : 1;

      switch (srcMode) {

      case splashModeMono1:
      case splashModeMono8:
	for (x = 0; x < scaledWidth; ++x) {

	  // x scale Bresenham
	  xStep = xp;
	  xt += xq;
	  if (xt >= scaledWidth) {
	    xt -= scaledWidth;
	    ++xStep;
	  }

	  // rotation
	  if (rot) {
	    x2 = (int)y1;
	    y2 = -x1;
	  } else {
	    x2 = x1;
	    y2 = (int)y1;
	  }

	  // compute the filtered pixel at (x,y) after the x and y scaling
	  // operations
	  m = xStep > 0 ? xStep : 1;
	  alphaAcc = 0;
	  p = colorBuf + xSrc;
	  q = alphaBuf + xSrc;
	  pixAcc0 = 0;
	  for (i = 0; i < n; ++i) {
	    for (j = 0; j < m; ++j) {
	      pixAcc0 += *p++;
	      alphaAcc += *q++;
	    }
	    p += w - m;
	    q += w - m;
	  }
	  pixMul = (SplashCoord)1 / (SplashCoord)(n * m);
	  alphaMul = pixMul * (1.0 / 255.0);
	  alpha = (SplashCoord)alphaAcc * alphaMul;

	  if (alpha > 0) {
	    pix[0] = (int)((SplashCoord)pixAcc0 * pixMul);

	    // set pixel
	    pipe.shape = alpha;
	    if (vectorAntialias && clipRes != splashClipAllInside) {
	      drawAAPixel(&pipe, tx + x2, ty + y2);
	    } else {
	      drawPixel(&pipe, tx + x2, ty + y2,
			clipRes2 == splashClipAllInside);
	    }
	  }

	  // x scale Bresenham
	  xSrc += xStep;

	  // x shear
	  x1 += xSign;

	  // y shear
	  y1 += yShear1;
	}
	break;

      case splashModeRGB8:
      case splashModeBGR8:
	for (x = 0; x < scaledWidth; ++x) {

	  // x scale Bresenham
	  xStep = xp;
	  xt += xq;
	  if (xt >= scaledWidth) {
	    xt -= scaledWidth;
	    ++xStep;
	  }

	  // rotation
	  if (rot) {
	    x2 = (int)y1;
	    y2 = -x1;
	  } else {
	    x2 = x1;
	    y2 = (int)y1;
	  }

	  // compute the filtered pixel at (x,y) after the x and y scaling
	  // operations
	  m = xStep > 0 ? xStep : 1;
	  alphaAcc = 0;
	  p = colorBuf + xSrc * 3;
	  q = alphaBuf + xSrc;
	  pixAcc0 = pixAcc1 = pixAcc2 = 0;
	  for (i = 0; i < n; ++i) {
	    for (j = 0; j < m; ++j) {
	      pixAcc0 += *p++;
	      pixAcc1 += *p++;
	      pixAcc2 += *p++;
	      alphaAcc += *q++;
	    }
	    p += 3 * (w - m);
	    q += w - m;
	  }
	  pixMul = (SplashCoord)1 / (SplashCoord)(n * m);
	  alphaMul = pixMul * (1.0 / 255.0);
	  alpha = (SplashCoord)alphaAcc * alphaMul;

	  if (alpha > 0) {
	    pix[0] = (int)((SplashCoord)pixAcc0 * pixMul);
	    pix[1] = (int)((SplashCoord)pixAcc1 * pixMul);
	    pix[2] = (int)((SplashCoord)pixAcc2 * pixMul);

	    // set pixel
	    pipe.shape = alpha;
	    if (vectorAntialias && clipRes != splashClipAllInside) {
	      drawAAPixel(&pipe, tx + x2, ty + y2);
	    } else {
	      drawPixel(&pipe, tx + x2, ty + y2,
			clipRes2 == splashClipAllInside);
	    }
	  }

	  // x scale Bresenham
	  xSrc += xStep;

	  // x shear
	  x1 += xSign;

	  // y shear
	  y1 += yShear1;
	}
	break;

#if SPLASH_CMYK
      case splashModeCMYK8:
	for (x = 0; x < scaledWidth; ++x) {

	  // x scale Bresenham
	  xStep = xp;
	  xt += xq;
	  if (xt >= scaledWidth) {
	    xt -= scaledWidth;
	    ++xStep;
	  }

	  // rotation
	  if (rot) {
	    x2 = (int)y1;
	    y2 = -x1;
	  } else {
	    x2 = x1;
	    y2 = (int)y1;
	  }

	  // compute the filtered pixel at (x,y) after the x and y scaling
	  // operations
	  m = xStep > 0 ? xStep : 1;
	  alphaAcc = 0;
	  p = colorBuf + xSrc * 4;
	  q = alphaBuf + xSrc;
	  pixAcc0 = pixAcc1 = pixAcc2 = pixAcc3 = 0;
	  for (i = 0; i < n; ++i) {
	    for (j = 0; j < m; ++j) {
	      pixAcc0 += *p++;
	      pixAcc1 += *p++;
	      pixAcc2 += *p++;
	      pixAcc3 += *p++;
	      alphaAcc += *q++;
	    }
	    p += 4 * (w - m);
	    q += w - m;
	  }
	  pixMul = (SplashCoord)1 / (SplashCoord)(n * m);
	  alphaMul = pixMul * (1.0 / 255.0);
	  alpha = (SplashCoord)alphaAcc * alphaMul;

	  if (alpha > 0) {
	    pix[0] = (int)((SplashCoord)pixAcc0 * pixMul);
	    pix[1] = (int)((SplashCoord)pixAcc1 * pixMul);
	    pix[2] = (int)((SplashCoord)pixAcc2 * pixMul);
	    pix[3] = (int)((SplashCoord)pixAcc3 * pixMul);

	    // set pixel
	    pipe.shape = alpha;
	    if (vectorAntialias && clipRes != splashClipAllInside) {
	      drawAAPixel(&pipe, tx + x2, ty + y2);
	    } else {
	      drawPixel(&pipe, tx + x2, ty + y2,
			clipRes2 == splashClipAllInside);
	    }
	  }

	  // x scale Bresenham
	  xSrc += xStep;

	  // x shear
	  x1 += xSign;

	  // y shear
	  y1 += yShear1;
	}
	break;
#endif // SPLASH_CMYK
      }
    }

  } else {

    // init y scale Bresenham
    yt = 0;
    lastYStep = 1;

    for (y = 0; y < scaledHeight; ++y) {

      // y scale Bresenham
      yStep = yp;
      yt += yq;
      if (yt >= scaledHeight) {
	yt -= s