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Diffstat (limited to 'splash/SplashXPath.cc')
| -rw-r--r-- | splash/SplashXPath.cc | 645 |
1 files changed, 645 insertions, 0 deletions
diff --git a/splash/SplashXPath.cc b/splash/SplashXPath.cc new file mode 100644 index 0000000..4c77765 --- /dev/null +++ b/splash/SplashXPath.cc @@ -0,0 +1,645 @@ +//======================================================================== +// +// SplashXPath.cc +// +// Copyright 2003-2013 Glyph & Cog, LLC +// +//======================================================================== + +#include <aconf.h> + +#ifdef USE_GCC_PRAGMAS +#pragma implementation +#endif + +#include <stdlib.h> +#include <string.h> +#if HAVE_STD_SORT +#include <algorithm> +#endif +#include "gmem.h" +#include "gmempp.h" +#include "SplashMath.h" +#include "SplashPath.h" +#include "SplashXPath.h" + +//------------------------------------------------------------------------ + +#define minCosSquaredJoinAngle 0.75 +#define maxPointToLineDistanceSquared 0.04 + +//------------------------------------------------------------------------ + +struct SplashXPathPoint { + SplashCoord x, y; +}; + +struct SplashXPathAdjust { + int firstPt, lastPt; // range of points + GBool vert; // vertical or horizontal hint + SplashCoord x0a, x0b, // hint boundaries + xma, xmb, + x1a, x1b; + SplashCoord x0, x1, xm; // adjusted coordinates +}; + +//------------------------------------------------------------------------ + +// Transform a point from user space to device space. +inline void SplashXPath::transform(SplashCoord *matrix, + SplashCoord xi, SplashCoord yi, + SplashCoord *xo, SplashCoord *yo) { + // [ m[0] m[1] 0 ] + // [xo yo 1] = [xi yi 1] * [ m[2] m[3] 0 ] + // [ m[4] m[5] 1 ] + *xo = xi * matrix[0] + yi * matrix[2] + matrix[4]; + *yo = xi * matrix[1] + yi * matrix[3] + matrix[5]; +} + +//------------------------------------------------------------------------ +// SplashXPath +//------------------------------------------------------------------------ + +// SplashXPath segment coords are clipped to +/-maxCoord to avoid +// problems. The xMin/yMin/xMax/yMax fields are 32-bit integers, so +// coords need to be < 2^31 / aa{Horiz,Vert}. +#define maxCoord 100000000.0 + +void SplashXPath::clampCoords(SplashCoord *x, SplashCoord *y) { +#if !USE_FIXEDPOINT + if (*x > maxCoord) { + *x = maxCoord; + } else if (*x < -maxCoord) { + *x = -maxCoord; + } + if (*y > maxCoord) { + *y = maxCoord; + } else if (*y < -maxCoord) { + *y = -maxCoord; + } +#endif +} + +SplashXPath::SplashXPath(SplashPath *path, SplashCoord *matrix, + SplashCoord flatness, GBool closeSubpaths, + GBool simplify, + SplashStrokeAdjustMode strokeAdjMode) { + SplashXPathPoint *pts; + SplashCoord x0, y0, x1, y1, x2, y2, x3, y3, xsp, ysp, t; + int curSubpath, firstSegInSubpath, i; + GBool adjusted; + + //--- transform the points + pts = (SplashXPathPoint *)gmallocn(path->length, sizeof(SplashXPathPoint)); + for (i = 0; i < path->length; ++i) { + transform(matrix, path->pts[i].x, path->pts[i].y, &pts[i].x, &pts[i].y); + clampCoords(&pts[i].x, &pts[i].y); + } + + //--- do stroke adjustment + if (path->hints) { + adjusted = strokeAdjust(pts, path->hints, path->hintsLength, + strokeAdjMode); + } else { + adjusted = gFalse; + } + + //--- construct the segments + + segs = NULL; + length = size = 0; + + x0 = y0 = xsp = ysp = 0; // make gcc happy + curSubpath = 0; + firstSegInSubpath = 0; + i = 0; + while (i < path->length) { + + // first point in subpath - skip it + if (path->flags[i] & splashPathFirst) { + x0 = pts[i].x; + y0 = pts[i].y; + xsp = x0; + ysp = y0; + curSubpath = i; + ++i; + + } else { + + // curve segment + if (path->flags[i] & splashPathCurve) { + x1 = pts[i].x; + y1 = pts[i].y; + x2 = pts[i+1].x; + y2 = pts[i+1].y; + x3 = pts[i+2].x; + y3 = pts[i+2].y; + addCurve(x0, y0, x1, y1, x2, y2, x3, y3, + flatness, + (path->flags[i-1] & splashPathFirst), + (path->flags[i+2] & splashPathLast), + !closeSubpaths && + (path->flags[i-1] & splashPathFirst) && + !(path->flags[i-1] & splashPathClosed), + !closeSubpaths && + (path->flags[i+2] & splashPathLast) && + !(path->flags[i+2] & splashPathClosed)); + x0 = x3; + y0 = y3; + i += 3; + + // line segment + } else { + x1 = pts[i].x; + y1 = pts[i].y; + addSegment(x0, y0, x1, y1); + x0 = x1; + y0 = y1; + ++i; + } + + // end a subpath + if (path->flags[i-1] & splashPathLast) { + if (closeSubpaths && + (pts[i-1].x != pts[curSubpath].x || + pts[i-1].y != pts[curSubpath].y)) { + addSegment(x0, y0, xsp, ysp); + } + if (simplify && !adjusted) { + mergeSegments(firstSegInSubpath); + } + firstSegInSubpath = length; + } + } + } + + gfree(pts); + + finishSegments(); + + //--- check for a rectangle + isRect = gFalse; + rectX0 = rectY0 = rectX1 = rectY1 = 0; + if (length == 4) { +#if HAVE_STD_SORT + std::sort(segs, segs + length, SplashXPathSeg::cmpY); +#else + qsort(segs, length, sizeof(SplashXPathSeg), &SplashXPathSeg::cmpY); +#endif + if (segs[0].y0 == segs[0].y1 && + segs[1].x0 == segs[1].x1 && + segs[2].x0 == segs[2].x1 && + segs[3].y0 == segs[3].y1) { + isRect = gTrue; + rectX0 = segs[1].x0; + rectX1 = segs[2].x0; + rectY0 = segs[0].y0; + rectY1 = segs[3].y0; + } else if (segs[0].x0 == segs[0].x1 && + segs[1].y0 == segs[1].y1 && + segs[2].x0 == segs[2].x1 && + segs[3].y0 == segs[3].y1) { + isRect = gTrue; + rectX0 = segs[0].x0; + rectX1 = segs[2].x0; + rectY0 = segs[1].y0; + rectY1 = segs[3].y0; + } else if (segs[0].x0 == segs[0].x1 && + segs[1].x0 == segs[1].x1 && + segs[2].y0 == segs[2].y1 && + segs[3].y0 == segs[3].y1) { + isRect = gTrue; + rectX0 = segs[0].x0; + rectX1 = segs[1].x0; + rectY0 = segs[2].y0; + rectY1 = segs[3].y0; + } + if (isRect) { + if (rectX0 > rectX1) { + t = rectX0; rectX0 = rectX1; rectX1 = t; + } + if (rectY0 > rectY1) { + t = rectY0; rectY0 = rectY1; rectY1 = t; + } + } + } +} + +GBool SplashXPath::strokeAdjust(SplashXPathPoint *pts, + SplashPathHint *hints, int nHints, + SplashStrokeAdjustMode strokeAdjMode) { + SplashXPathAdjust *adjusts, *adjust; + SplashPathHint *hint; + SplashCoord x0, y0, x1, y1, x2, y2, x3, y3; + SplashCoord adj0, adj1, w, d; + int xi0, xi1; + int i, j; + GBool adjusted; + + adjusted = gFalse; + + // set up the stroke adjustment hints + adjusts = (SplashXPathAdjust *)gmallocn(nHints, sizeof(SplashXPathAdjust)); + for (i = 0; i < nHints; ++i) { + hint = &hints[i]; + x0 = pts[hint->ctrl0 ].x; y0 = pts[hint->ctrl0 ].y; + x1 = pts[hint->ctrl0 + 1].x; y1 = pts[hint->ctrl0 + 1].y; + x2 = pts[hint->ctrl1 ].x; y2 = pts[hint->ctrl1 ].y; + x3 = pts[hint->ctrl1 + 1].x; y3 = pts[hint->ctrl1 + 1].y; + w = -1; + if (splashAbs(x0 - x1) < 0.01 && splashAbs(x2 - x3) < 0.01) { + adjusts[i].vert = gTrue; + adj0 = x0; + adj1 = x2; + if (hint->projectingCap) { + w = splashAbs(y1 - y0); + } + } else if (splashAbs(y0 - y1) < 0.01 && splashAbs(y2 - y3) < 0.01) { + adjusts[i].vert = gFalse; + adj0 = y0; + adj1 = y2; + if (hint->projectingCap) { + w = splashAbs(x1 - x0); + } + } else { + goto done; + } + if (adj0 > adj1) { + x0 = adj0; + adj0 = adj1; + adj1 = x0; + } + d = adj1 - adj0; + if (d > 0.04) { + d = 0.01; + } else { + d *= 0.25; + } + adjusts[i].x0a = adj0 - d; + adjusts[i].x0b = adj0 + d; + adjusts[i].xma = (SplashCoord)0.5 * (adj0 + adj1) - d; + adjusts[i].xmb = (SplashCoord)0.5 * (adj0 + adj1) + d; + adjusts[i].x1a = adj1 - d; + adjusts[i].x1b = adj1 + d; + splashStrokeAdjust(adj0, adj1, &xi0, &xi1, strokeAdjMode, w); + adjusts[i].x0 = (SplashCoord)xi0; + // the "minus epsilon" thing here is needed when vector + // antialiasing is turned off -- otherwise stroke adjusted lines + // will touch an extra pixel on one edge + adjusts[i].x1 = (SplashCoord)xi1 - 0.001; + adjusts[i].xm = (SplashCoord)0.5 * (adjusts[i].x0 + adjusts[i].x1); + adjusts[i].firstPt = hint->firstPt; + adjusts[i].lastPt = hint->lastPt; + } + + // perform stroke adjustment + for (i = 0, adjust = adjusts; i < nHints; ++i, ++adjust) { + for (j = adjust->firstPt; j <= adjust->lastPt; ++j) { + if (adjust->vert) { + x0 = pts[j].x; + if (x0 > adjust->x0a && x0 < adjust->x0b) { + pts[j].x = adjust->x0; + } else if (x0 > adjust->xma && x0 < adjust->xmb) { + pts[j].x = adjust->xm; + } else if (x0 > adjust->x1a && x0 < adjust->x1b) { + pts[j].x = adjust->x1; + } + } else { + y0 = pts[j].y; + if (y0 > adjust->x0a && y0 < adjust->x0b) { + pts[j].y = adjust->x0; + } else if (y0 > adjust->xma && y0 < adjust->xmb) { + pts[j].y = adjust->xm; + } else if (y0 > adjust->x1a && y0 < adjust->x1b) { + pts[j].y = adjust->x1; + } + } + } + } + adjusted = gTrue; + + done: + gfree(adjusts); + return adjusted; +} + +SplashXPath::SplashXPath(SplashXPath *xPath) { + length = xPath->length; + size = xPath->size; + segs = (SplashXPathSeg *)gmallocn(size, sizeof(SplashXPathSeg)); + memcpy(segs, xPath->segs, length * sizeof(SplashXPathSeg)); + xMin = xPath->xMin; + yMin = xPath->yMin; + xMax = xPath->xMax; + yMax = xPath->yMax; +} + +SplashXPath::~SplashXPath() { + gfree(segs); +} + +// Add space for <nSegs> more segments +void SplashXPath::grow(int nSegs) { + if (length + nSegs > size) { + if (size == 0) { + size = 32; + } + while (size < length + nSegs) { + size *= 2; + } + segs = (SplashXPathSeg *)greallocn(segs, size, sizeof(SplashXPathSeg)); + } +} + +void SplashXPath::addCurve(SplashCoord x0, SplashCoord y0, + SplashCoord x1, SplashCoord y1, + SplashCoord x2, SplashCoord y2, + SplashCoord x3, SplashCoord y3, + SplashCoord flatness, + GBool first, GBool last, GBool end0, GBool end1) { + SplashCoord cx[splashMaxCurveSplits + 1][3]; + SplashCoord cy[splashMaxCurveSplits + 1][3]; + int cNext[splashMaxCurveSplits + 1]; + SplashCoord xl0, xl1, xl2, xr0, xr1, xr2, xr3, xx1, xx2, xh; + SplashCoord yl0, yl1, yl2, yr0, yr1, yr2, yr3, yy1, yy2, yh; + SplashCoord dx, dy, mx, my, d1, d2, flatness2; + int p1, p2, p3; + +#if USE_FIXEDPOINT + flatness2 = flatness; +#else + flatness2 = flatness * flatness; +#endif + + // initial segment + p1 = 0; + p2 = splashMaxCurveSplits; + cx[p1][0] = x0; cy[p1][0] = y0; + cx[p1][1] = x1; cy[p1][1] = y1; + cx[p1][2] = x2; cy[p1][2] = y2; + cx[p2][0] = x3; cy[p2][0] = y3; + cNext[p1] = p2; + + while (p1 < splashMaxCurveSplits) { + + // get the next segment + xl0 = cx[p1][0]; yl0 = cy[p1][0]; + xx1 = cx[p1][1]; yy1 = cy[p1][1]; + xx2 = cx[p1][2]; yy2 = cy[p1][2]; + p2 = cNext[p1]; + xr3 = cx[p2][0]; yr3 = cy[p2][0]; + + // compute the distances from the control points to the + // midpoint of the straight line (this is a bit of a hack, but + // it's much faster than computing the actual distances to the + // line) + mx = (xl0 + xr3) * 0.5; + my = (yl0 + yr3) * 0.5; +#if USE_FIXEDPOINT + d1 = splashDist(xx1, yy1, mx, my); + d2 = splashDist(xx2, yy2, mx, my); +#else + dx = xx1 - mx; + dy = yy1 - my; + d1 = dx*dx + dy*dy; + dx = xx2 - mx; + dy = yy2 - my; + d2 = dx*dx + dy*dy; +#endif + + // if the curve is flat enough, or no more subdivisions are + // allowed, add the straight line segment + if (p2 - p1 == 1 || (d1 <= flatness2 && d2 <= flatness2)) { + addSegment(xl0, yl0, xr3, yr3); + p1 = p2; + + // otherwise, subdivide the curve + } else { + xl1 = (xl0 + xx1) * 0.5; + yl1 = (yl0 + yy1) * 0.5; + xh = (xx1 + xx2) * 0.5; + yh = (yy1 + yy2) * 0.5; + xl2 = (xl1 + xh) * 0.5; + yl2 = (yl1 + yh) * 0.5; + xr2 = (xx2 + xr3) * 0.5; + yr2 = (yy2 + yr3) * 0.5; + xr1 = (xh + xr2) * 0.5; + yr1 = (yh + yr2) * 0.5; + xr0 = (xl2 + xr1) * 0.5; + yr0 = (yl2 + yr1) * 0.5; + // add the new subdivision points + p3 = (p1 + p2) / 2; + cx[p1][1] = xl1; cy[p1][1] = yl1; + cx[p1][2] = xl2; cy[p1][2] = yl2; + cNext[p1] = p3; + cx[p3][0] = xr0; cy[p3][0] = yr0; + cx[p3][1] = xr1; cy[p3][1] = yr1; + cx[p3][2] = xr2; cy[p3][2] = yr2; + cNext[p3] = p2; + } + } +} + +void SplashXPath::addSegment(SplashCoord x0, SplashCoord y0, + SplashCoord x1, SplashCoord y1) { + grow(1); + segs[length].x0 = x0; + segs[length].y0 = y0; + segs[length].x1 = x1; + segs[length].y1 = y1; + ++length; +} + +// Returns true if the angle between (x0,y0)-(x1,y1) and +// (x1,y1)-(x2,y2) is close to 180 degrees. +static GBool joinAngleIsFlat(SplashCoord x0, SplashCoord y0, + SplashCoord x1, SplashCoord y1, + SplashCoord x2, SplashCoord y2) { + SplashCoord dx1, dy1, dx2, dy2, d, len1, len2; + + dx1 = x1 - x0; + dy1 = y1 - y0; + dx2 = x2 - x1; + dy2 = y2 - y1; + d = dx1 * dx2 + dy1 * dy2; + len1 = dx1 * dx1 + dy1 * dy1; + len2 = dx2 * dx2 + dy2 * dy2; + return d > 0 && d * d > len1 * len2 * minCosSquaredJoinAngle; +} + +// Returns true if (x1,y1) is sufficiently close to the segment +// (x0,y0)-(x2,y2), looking at the perpendicular point-to-line +// distance. +static GBool pointCloseToSegment(SplashCoord x0, SplashCoord y0, + SplashCoord x1, SplashCoord y1, + SplashCoord x2, SplashCoord y2) { + SplashCoord t1, t2, dx, dy; + + // compute the perpendicular distance from the point to the segment, + // i.e., the projection of (x0,y0)-(x1,y1) onto a unit normal to the + // segment (this actually computes the square of the distance) + dx = x2 - x0; + dy = y2 - y0; + t1 = dx*dx + dy*dy; + if (t1 < 0.0001) { + // degenerate case: (x0,y0) and (x2,y2) are (nearly) identical -- + // just compute the distance to (x1,y1) + dx = x0 - x1; + dy = y0 - y1; + t2 = dx*dx + dy*dy; + return t2 < maxPointToLineDistanceSquared; + } + t2 = x1 * dy - dx * y1 - x0 * y2 + x2 * y0; + // actual distance = t2 / sqrt(t1) + return t2 * t2 < t1 * maxPointToLineDistanceSquared; +} + +// Attempt to simplify the path by merging sequences of consecutive +// segments in [first] .. [length]-1. +void SplashXPath::mergeSegments(int first) { + GBool horiz, vert; + int in, out, prev, i, j; + + in = out = first; + while (in < length) { + + // skip zero-length segments + if (segs[in].x0 == segs[in].x1 && segs[in].y0 == segs[in].y1) { + ++in; + continue; + } + + horiz = segs[in].y0 == segs[in].y1; + vert = segs[in].x0 == segs[in].x1; + + // check for a sequence of mergeable segments: in .. i + prev = in; + for (i = in + 1; i < length; ++i) { + + // skip zero-length segments + if (segs[i].x0 == segs[i].x1 && segs[i].y0 == segs[i].y1) { + continue; + } + + // check for a horizontal or vertical segment + if ((horiz && segs[in].y0 != segs[in].y1) || + (vert && segs[in].x0 != segs[in].x1)) { + break; + } + + // check the angle between segs i-1 and i + // (actually, we compare seg i to the previous non-zero-length + // segment, which may not be i-1) + if (!joinAngleIsFlat(segs[prev].x0, segs[prev].y0, + segs[i].x0, segs[i].y0, + segs[i].x1, segs[i].y1)) { + break; + } + + // check the distances from the ends of segs in .. i-1 to the + // proposed new segment + for (j = in; j < i; ++j) { + if (!pointCloseToSegment(segs[in].x0, segs[in].y0, + segs[j].x1, segs[j].y1, + segs[i].x1, segs[i].y1)) { + break; + } + } + if (j < i) { + break; + } + + prev = i; + } + + // we can merge segs: in .. i-1 + // (this may be the single segment: in) + segs[out].x0 = segs[in].x0; + segs[out].y0 = segs[in].y0; + segs[out].x1 = segs[i-1].x1; + segs[out].y1 = segs[i-1].y1; + in = i; + ++out; + } + + length = out; +} + +void SplashXPath::finishSegments() { + SplashXPathSeg *seg; + SplashCoord xMinFP, xMaxFP, yMinFP, yMaxFP, t; + int i; + + xMinFP = yMinFP = xMaxFP = yMaxFP = 0; + + for (i = 0; i < length; ++i) { + seg = &segs[i]; + + //--- compute the slopes + if (seg->y0 <= seg->y1) { + seg->count = 1; + } else { + t = seg->x0; seg->x0 = seg->x1; seg->x1 = t; + t = seg->y0; seg->y0 = seg->y1; seg->y1 = t; + seg->count = -1; + } +#if USE_FIXEDPOINT + if (seg->y0 == seg->y1 || seg->x0 == seg->x1 || + !FixedPoint::divCheck(seg->x1 - seg->x0, seg->y1 - seg->y0, + &seg->dxdy) || + !FixedPoint::divCheck(seg->y1 - seg->y0, seg->x1 - seg->x0, + &seg->dydx)) { + seg->dxdy = 0; + seg->dydx = 0; + } +#else + if (splashAbs(seg->y1 - seg->y0) < 1e-200 || + splashAbs(seg->x1 - seg->x0) < 1e-200) { + seg->dxdy = 0; + seg->dydx = 0; + } else { + seg->dxdy = (seg->x1 - seg->x0) / (seg->y1 - seg->y0); + if (seg->dxdy == 0) { + seg->dydx = 0; + } else { + seg->dydx = 1 / seg->dxdy; + } + } +#endif + + //--- update bbox + if (i == 0) { + if (seg->x0 <= seg->x1) { + xMinFP = seg->x0; + xMaxFP = seg->x1; + } else { + xMinFP = seg->x1; + xMaxFP = seg->x0; + } + yMinFP = seg->y0; + yMaxFP = seg->y1; + } else { + if (seg->x0 < xMinFP) { + xMinFP = seg->x0; + } else if (seg->x0 > xMaxFP) { + xMaxFP = seg->x0; + } + if (seg->x1 < xMinFP) { + xMinFP = seg->x1; + } else if (seg->x1 > xMaxFP) { + xMaxFP = seg->x1; + } + if (seg->y0 < yMinFP) { + yMinFP = seg->y0; + } + if (seg->y1 > yMaxFP) { + yMaxFP = seg->y1; + } + } + } + + xMin = splashFloor(xMinFP); + yMin = splashFloor(yMinFP); + xMax = splashFloor(xMaxFP); + yMax = splashFloor(yMaxFP); +} |