remove unused reduce order code

src/pathops/SkReduceOrder.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkReduceOrder.h"
 
 int SkReduceOrder::reduce(const SkDLine& line) {
     fLine[0] = line[0];
     int different = line[0] != line[1];
     fLine[1] = line[different];
     return 1 + different;
 }
 
-static double interp_quad_coords(double a, double b, double c, double t) {
-    double ab = SkDInterp(a, b, t);
-    double bc = SkDInterp(b, c, t);
-    return SkDInterp(ab, bc, t);
-}
-
 static int coincident_line(const SkDQuad& quad, SkDQuad& reduction) {
     reduction[0] = reduction[1] = quad[0];
     return 1;
 }
 
 static int reductionLineCount(const SkDQuad& reduction) {
     return 1 + !reduction[0].approximatelyEqual(reduction[1]);
 }
 
-static int vertical_line(const SkDQuad& quad, SkReduceOrder::Style reduceStyle,
-        SkDQuad& reduction) {
-    double tValue;
+static int vertical_line(const SkDQuad& quad, SkDQuad& reduction) {
     reduction[0] = quad[0];
     reduction[1] = quad[2];
-    if (reduceStyle == SkReduceOrder::kFill_Style) {
-        return reductionLineCount(reduction);
-    }
-    int smaller = reduction[1].fY > reduction[0].fY;
-    int larger = smaller ^ 1;
-    if (SkDQuad::FindExtrema(quad[0].fY, quad[1].fY, quad[2].fY, &tValue)) {
-        double yExtrema = interp_quad_coords(quad[0].fY, quad[1].fY, quad[2].fY, tValue);
-        if (reduction[smaller].fY > yExtrema) {
-            reduction[smaller].fY = yExtrema;
-        } else if (reduction[larger].fY < yExtrema) {
-            reduction[larger].fY = yExtrema;
-        }
-    }
     return reductionLineCount(reduction);
 }
 
-static int horizontal_line(const SkDQuad& quad, SkReduceOrder::Style reduceStyle,
-        SkDQuad& reduction) {
-    double tValue;
+static int horizontal_line(const SkDQuad& quad, SkDQuad& reduction) {
     reduction[0] = quad[0];
     reduction[1] = quad[2];
-    if (reduceStyle == SkReduceOrder::kFill_Style) {
-        return reductionLineCount(reduction);
-    }
-    int smaller = reduction[1].fX > reduction[0].fX;
-    int larger = smaller ^ 1;
-    if (SkDQuad::FindExtrema(quad[0].fX, quad[1].fX, quad[2].fX, &tValue)) {
-        double xExtrema = interp_quad_coords(quad[0].fX, quad[1].fX, quad[2].fX, tValue);
-        if (reduction[smaller].fX > xExtrema) {
-            reduction[smaller].fX = xExtrema;
-        }  else if (reduction[larger].fX < xExtrema) {
-            reduction[larger].fX = xExtrema;
-        }
-    }
     return reductionLineCount(reduction);
 }
 
-static int check_linear(const SkDQuad& quad, SkReduceOrder::Style reduceStyle,
+static int check_linear(const SkDQuad& quad,
         int minX, int maxX, int minY, int maxY, SkDQuad& reduction) {
     int startIndex = 0;
     int endIndex = 2;
     while (quad[startIndex].approximatelyEqual(quad[endIndex])) {
         --endIndex;
         if (endIndex == 0) {
             SkDebugf("%s shouldn't get here if all four points are about equal", __FUNCTION__);
             SkASSERT(0);
         }
     }
     if (!quad.isLinear(startIndex, endIndex)) {
         return 0;
     }
     // four are colinear: return line formed by outside
     reduction[0] = quad[0];
     reduction[1] = quad[2];
-    if (reduceStyle == SkReduceOrder::kFill_Style) {
-        return reductionLineCount(reduction);
-    }
-    int sameSide;
-    bool useX = quad[maxX].fX - quad[minX].fX >= quad[maxY].fY - quad[minY].fY;
-    if (useX) {
-        sameSide = SkDSign(quad[0].fX - quad[1].fX) + SkDSign(quad[2].fX - quad[1].fX);
-    } else {
-        sameSide = SkDSign(quad[0].fY - quad[1].fY) + SkDSign(quad[2].fY - quad[1].fY);
-    }
-    if ((sameSide & 3) != 2) {
-        return reductionLineCount(reduction);
-    }
-    double tValue;
-    int root;
-    if (useX) {
-        root = SkDQuad::FindExtrema(quad[0].fX, quad[1].fX, quad[2].fX, &tValue);
-    } else {
-        root = SkDQuad::FindExtrema(quad[0].fY, quad[1].fY, quad[2].fY, &tValue);
-    }
-    if (root) {
-        SkDPoint extrema;
-        extrema.fX = interp_quad_coords(quad[0].fX, quad[1].fX, quad[2].fX, tValue);
-        extrema.fY = interp_quad_coords(quad[0].fY, quad[1].fY, quad[2].fY, tValue);
-        // sameSide > 0 means mid is smaller than either [0] or [2], so replace smaller
-        int replace;
-        if (useX) {
-            if ((extrema.fX < quad[0].fX) ^ (extrema.fX < quad[2].fX)) {
-                return reductionLineCount(reduction);
-            }
-            replace = ((extrema.fX < quad[0].fX) | (extrema.fX < quad[2].fX))
-                    ^ (quad[0].fX < quad[2].fX);
-        } else {
-            if ((extrema.fY < quad[0].fY) ^ (extrema.fY < quad[2].fY)) {
-                return reductionLineCount(reduction);
-            }
-            replace = ((extrema.fY < quad[0].fY) | (extrema.fY < quad[2].fY))
-                    ^ (quad[0].fY < quad[2].fY);
-        }
-        reduction[replace] = extrema;
-    }
     return reductionLineCount(reduction);
 }
 
 // reduce to a quadratic or smaller
 // look for identical points
 // look for all four points in a line
     // note that three points in a line doesn't simplify a cubic
 // look for approximation with single quadratic
     // save approximation with multiple quadratics for later
-int SkReduceOrder::reduce(const SkDQuad& quad, Style reduceStyle) {
+int SkReduceOrder::reduce(const SkDQuad& quad) {
     int index, minX, maxX, minY, maxY;
     int minXSet, minYSet;
     minX = maxX = minY = maxY = 0;
     minXSet = minYSet = 0;
     for (index = 1; index < 3; ++index) {
         if (quad[minX].fX > quad[index].fX) {
             minX = index;
         }
         if (quad[minY].fY > quad[index].fY) {
             minY = index;
@@ skipping 10 matching lines @@
             minXSet |= 1 << index;
         }
         if (AlmostEqualUlps(quad[index].fY, quad[minY].fY)) {
             minYSet |= 1 << index;
         }
     }
     if (minXSet == 0x7) {  // test for vertical line
         if (minYSet == 0x7) {  // return 1 if all four are coincident
             return coincident_line(quad, fQuad);
         }
-        return vertical_line(quad, reduceStyle, fQuad);
+        return vertical_line(quad, fQuad);
     }
     if (minYSet == 0xF) {  // test for horizontal line
-        return horizontal_line(quad, reduceStyle, fQuad);
+        return horizontal_line(quad, fQuad);
     }
-    int result = check_linear(quad, reduceStyle, minX, maxX, minY, maxY, fQuad);
+    int result = check_linear(quad, minX, maxX, minY, maxY, fQuad);
     if (result) {
         return result;
     }
     fQuad = quad;
     return 3;
 }
 
 ////////////////////////////////////////////////////////////////////////////////////
 
-static double interp_cubic_coords(const double* src, double t) {
-    double ab = SkDInterp(src[0], src[2], t);
-    double bc = SkDInterp(src[2], src[4], t);
-    double cd = SkDInterp(src[4], src[6], t);
-    double abc = SkDInterp(ab, bc, t);
-    double bcd = SkDInterp(bc, cd, t);
-    return SkDInterp(abc, bcd, t);
-}
-
 static int coincident_line(const SkDCubic& cubic, SkDCubic& reduction) {
     reduction[0] = reduction[1] = cubic[0];
     return 1;
 }
 
 static int reductionLineCount(const SkDCubic& reduction) {
     return 1 + !reduction[0].approximatelyEqual(reduction[1]);
 }
 
-static int vertical_line(const SkDCubic& cubic, SkReduceOrder::Style reduceStyle,
-                         SkDCubic& reduction) {
-    double tValues[2];
+static int vertical_line(const SkDCubic& cubic, SkDCubic& reduction) {
     reduction[0] = cubic[0];
     reduction[1] = cubic[3];
-    if (reduceStyle == SkReduceOrder::kFill_Style) {
-        return reductionLineCount(reduction);
-    }
-    int smaller = reduction[1].fY > reduction[0].fY;
-    int larger = smaller ^ 1;
-    int roots = SkDCubic::FindExtrema(cubic[0].fY, cubic[1].fY, cubic[2].fY, cubic[3].fY, tValues);
-    for (int index = 0; index < roots; ++index) {
-        double yExtrema = interp_cubic_coords(&cubic[0].fY, tValues[index]);
-        if (reduction[smaller].fY > yExtrema) {
-            reduction[smaller].fY = yExtrema;
-            continue;
-        }
-        if (reduction[larger].fY < yExtrema) {
-            reduction[larger].fY = yExtrema;
-        }
-    }
     return reductionLineCount(reduction);
 }
 
-static int horizontal_line(const SkDCubic& cubic, SkReduceOrder::Style reduceStyle,
-                           SkDCubic& reduction) {
-    double tValues[2];
+static int horizontal_line(const SkDCubic& cubic, SkDCubic& reduction) {
     reduction[0] = cubic[0];
     reduction[1] = cubic[3];
-    if (reduceStyle == SkReduceOrder::kFill_Style) {
-        return reductionLineCount(reduction);
-    }
-    int smaller = reduction[1].fX > reduction[0].fX;
-    int larger = smaller ^ 1;
-    int roots = SkDCubic::FindExtrema(cubic[0].fX, cubic[1].fX, cubic[2].fX, cubic[3].fX, tValues);
-    for (int index = 0; index < roots; ++index) {
-        double xExtrema = interp_cubic_coords(&cubic[0].fX, tValues[index]);
-        if (reduction[smaller].fX > xExtrema) {
-            reduction[smaller].fX = xExtrema;
-            continue;
-        }
-        if (reduction[larger].fX < xExtrema) {
-            reduction[larger].fX = xExtrema;
-        }
-    }
     return reductionLineCount(reduction);
 }
 
 // check to see if it is a quadratic or a line
 static int check_quadratic(const SkDCubic& cubic, SkDCubic& reduction) {
     double dx10 = cubic[1].fX - cubic[0].fX;
     double dx23 = cubic[2].fX - cubic[3].fX;
     double midX = cubic[0].fX + dx10 * 3 / 2;
     double sideAx = midX - cubic[3].fX;
     double sideBx = dx23 * 3 / 2;
@@ skipping 10 matching lines @@
             : !AlmostEqualUlps(sideAy, sideBy)) {
         return 0;
     }
     reduction[0] = cubic[0];
     reduction[1].fX = midX;
     reduction[1].fY = midY;
     reduction[2] = cubic[3];
     return 3;
 }
 
-static int check_linear(const SkDCubic& cubic, SkReduceOrder::Style reduceStyle,
+static int check_linear(const SkDCubic& cubic,
         int minX, int maxX, int minY, int maxY, SkDCubic& reduction) {
     int startIndex = 0;
     int endIndex = 3;
     while (cubic[startIndex].approximatelyEqual(cubic[endIndex])) {
         --endIndex;
         if (endIndex == 0) {
             SkDebugf("%s shouldn't get here if all four points are about equal\n", __FUNCTION__);
             SkASSERT(0);
         }
     }
     if (!cubic.isLinear(startIndex, endIndex)) {
         return 0;
     }
     // four are colinear: return line formed by outside
     reduction[0] = cubic[0];
     reduction[1] = cubic[3];
-    if (reduceStyle == SkReduceOrder::kFill_Style) {
-        return reductionLineCount(reduction);
-    }
-    int sameSide1;
-    int sameSide2;
-    bool useX = cubic[maxX].fX - cubic[minX].fX >= cubic[maxY].fY - cubic[minY].fY;
-    if (useX) {
-        sameSide1 = SkDSign(cubic[0].fX - cubic[1].fX) + SkDSign(cubic[3].fX - cubic[1].fX);
-        sameSide2 = SkDSign(cubic[0].fX - cubic[2].fX) + SkDSign(cubic[3].fX - cubic[2].fX);
-    } else {
-        sameSide1 = SkDSign(cubic[0].fY - cubic[1].fY) + SkDSign(cubic[3].fY - cubic[1].fY);
-        sameSide2 = SkDSign(cubic[0].fY - cubic[2].fY) + SkDSign(cubic[3].fY - cubic[2].fY);
-    }
-    if (sameSide1 == sameSide2 && (sameSide1 & 3) != 2) {
-        return reductionLineCount(reduction);
-    }
-    double tValues[2];
-    int roots;
-    if (useX) {
-        roots = SkDCubic::FindExtrema(cubic[0].fX, cubic[1].fX, cubic[2].fX, cubic[3].fX, tValues);
-    } else {
-        roots = SkDCubic::FindExtrema(cubic[0].fY, cubic[1].fY, cubic[2].fY, cubic[3].fY, tValues);
-    }
-    for (int index = 0; index < roots; ++index) {
-        SkDPoint extrema;
-        extrema.fX = interp_cubic_coords(&cubic[0].fX, tValues[index]);
-        extrema.fY = interp_cubic_coords(&cubic[0].fY, tValues[index]);
-        // sameSide > 0 means mid is smaller than either [0] or [3], so replace smaller
-        int replace;
-        if (useX) {
-            if ((extrema.fX < cubic[0].fX) ^ (extrema.fX < cubic[3].fX)) {
-                continue;
-            }
-            replace = ((extrema.fX < cubic[0].fX) | (extrema.fX < cubic[3].fX))
-                    ^ (cubic[0].fX < cubic[3].fX);
-        } else {
-            if ((extrema.fY < cubic[0].fY) ^ (extrema.fY < cubic[3].fY)) {
-                continue;
-            }
-            replace = ((extrema.fY < cubic[0].fY) | (extrema.fY < cubic[3].fY))
-                    ^ (cubic[0].fY < cubic[3].fY);
-        }
-        reduction[replace] = extrema;
-    }
     return reductionLineCount(reduction);
 }
 
 /* food for thought:
 http://objectmix.com/graphics/132906-fast-precision-driven-cubic-quadratic-piecewise-degree-reduction-algos-2-a.html
 
 Given points c1, c2, c3 and c4 of a cubic Bezier, the points of the
 corresponding quadratic Bezier are (given in convex combinations of
 points):
 
 q1 = (11/13)c1 + (3/13)c2 -(3/13)c3 + (2/13)c4
 q2 = -c1 + (3/2)c2 + (3/2)c3 - c4
 q3 = (2/13)c1 - (3/13)c2 + (3/13)c3 + (11/13)c4
 
 Of course, this curve does not interpolate the end-points, but it would
 be interesting to see the behaviour of such a curve in an applet.
 
 --
 Kalle Rutanen
 http://kaba.hilvi.org
 
 */
 
 // reduce to a quadratic or smaller
 // look for identical points
 // look for all four points in a line
     // note that three points in a line doesn't simplify a cubic
 // look for approximation with single quadratic
     // save approximation with multiple quadratics for later
-int SkReduceOrder::reduce(const SkDCubic& cubic, Quadratics allowQuadratics,
-        Style reduceStyle) {
+int SkReduceOrder::reduce(const SkDCubic& cubic, Quadratics allowQuadratics) {
     int index, minX, maxX, minY, maxY;
     int minXSet, minYSet;
     minX = maxX = minY = maxY = 0;
     minXSet = minYSet = 0;
     for (index = 1; index < 4; ++index) {
         if (cubic[minX].fX > cubic[index].fX) {
             minX = index;
         }
         if (cubic[minY].fY > cubic[index].fY) {
             minY = index;
@@ skipping 20 matching lines @@
             minXSet |= 1 << index;
         }
         if (approximately_equal_half(cy * inv, cubic[minY].fY * inv)) {
             minYSet |= 1 << index;
         }
     }
     if (minXSet == 0xF) {  // test for vertical line
         if (minYSet == 0xF) {  // return 1 if all four are coincident
             return coincident_line(cubic, fCubic);
         }
-        return vertical_line(cubic, reduceStyle, fCubic);
+        return vertical_line(cubic, fCubic);
     }
     if (minYSet == 0xF) {  // test for horizontal line
-        return horizontal_line(cubic, reduceStyle, fCubic);
+        return horizontal_line(cubic, fCubic);
     }
-    int result = check_linear(cubic, reduceStyle, minX, maxX, minY, maxY, fCubic);
+    int result = check_linear(cubic, minX, maxX, minY, maxY, fCubic);
     if (result) {
         return result;
     }
     if (allowQuadratics == SkReduceOrder::kAllow_Quadratics
             && (result = check_quadratic(cubic, fCubic))) {
         return result;
     }
     fCubic = cubic;
     return 4;
 }
 
 SkPath::Verb SkReduceOrder::Quad(const SkPoint a[3], SkPoint* reducePts) {
     SkDQuad quad;
     quad.set(a);
     SkReduceOrder reducer;
-    int order = reducer.reduce(quad, kFill_Style);
+    int order = reducer.reduce(quad);
     if (order == 2) {  // quad became line
         for (int index = 0; index < order; ++index) {
             *reducePts++ = reducer.fLine[index].asSkPoint();
         }
     }
     return SkPathOpsPointsToVerb(order - 1);
 }
 
 SkPath::Verb SkReduceOrder::Cubic(const SkPoint a[4], SkPoint* reducePts) {
     SkDCubic cubic;
     cubic.set(a);
     SkReduceOrder reducer;
-    int order = reducer.reduce(cubic, kAllow_Quadratics, kFill_Style);
+    int order = reducer.reduce(cubic, kAllow_Quadratics);
     if (order == 2 || order == 3) {  // cubic became line or quad
         for (int index = 0; index < order; ++index) {
             *reducePts++ = reducer.fQuad[index].asSkPoint();
         }
     }
     return SkPathOpsPointsToVerb(order - 1);
 }