skia2/tests/ClipCubicTest.cpp

#include "Test.h"

#include "../../src/core/SkCubicClipper.h"
#include "SkGeometry.h"


static void PrintCurve(const char *name, const SkPoint crv[4]) {
    printf("%s: %.10g, %.10g, %.10g, %.10g, %.10g, %.10g, %.10g, %.10g\n",
            name,
            crv[0].fX, crv[0].fY,
            crv[1].fX, crv[1].fY,
            crv[2].fX, crv[2].fY,
            crv[3].fX, crv[3].fY);
                     
}


static bool CurvesAreEqual(
  const SkPoint c0[4], const SkPoint c1[4], float tol) {
      for (int i = 0; i < 4; i++) {
          if (SkScalarAbs(c0[i].fX - c1[i].fX) > SkFloatToScalar(tol) ||
              SkScalarAbs(c0[i].fY - c1[i].fY) > SkFloatToScalar(tol)
          ) {
              PrintCurve("c0", c0);
              PrintCurve("c1", c1);
              return false;
          }
      }
      return true;
}


static SkPoint* SetCurve(
    float x0, float y0,
    float x1, float y1,
    float x2, float y2,
    float x3, float y3,
    SkPoint crv[4]
) {
    crv[0].fX = SkFloatToScalar(x0);   crv[0].fY = SkFloatToScalar(y0);
    crv[1].fX = SkFloatToScalar(x1);   crv[1].fY = SkFloatToScalar(y1);
    crv[2].fX = SkFloatToScalar(x2);   crv[2].fY = SkFloatToScalar(y2);
    crv[3].fX = SkFloatToScalar(x3);   crv[3].fY = SkFloatToScalar(y3);
    return crv;
}
    

static void TestCubicClipping(skiatest::Reporter* reporter) {
  static SkPoint crv[4] = {
    { SkFloatToScalar(0), SkFloatToScalar(0)  },
    { SkFloatToScalar(2), SkFloatToScalar(3)  },
    { SkFloatToScalar(1), SkFloatToScalar(10) },
    { SkFloatToScalar(4), SkFloatToScalar(12) }
  };
  
  SkCubicClipper clipper;
  SkPoint clipped[4], shouldbe[4];
  SkIRect clipRect;
  bool success;
  const float tol = 1e-4;

  // Test no clip, with plenty of room.
  clipRect.set(-2, -2, 6, 14);
  clipper.setClip(clipRect);
  success = clipper.clipCubic(crv, clipped);
  REPORTER_ASSERT(reporter, success == true);
  REPORTER_ASSERT(reporter, CurvesAreEqual(clipped, SetCurve(
      0, 0, 2, 3, 1, 10, 4, 12, shouldbe
  ), tol));

  // Test no clip, touching first point.
  clipRect.set(-2, 0, 6, 14);
  clipper.setClip(clipRect);
  success = clipper.clipCubic(crv, clipped);
  REPORTER_ASSERT(reporter, success == true);
  REPORTER_ASSERT(reporter, CurvesAreEqual(clipped, SetCurve(
      0, 0, 2, 3, 1, 10, 4, 12, shouldbe
  ), tol));

  // Test no clip, touching last point.
  clipRect.set(-2, -2, 6, 12);
  clipper.setClip(clipRect);
  success = clipper.clipCubic(crv, clipped);
  REPORTER_ASSERT(reporter, success == true);
  REPORTER_ASSERT(reporter, CurvesAreEqual(clipped, SetCurve(
      0, 0, 2, 3, 1, 10, 4, 12, shouldbe
  ), tol));

  // Test all clip.
  clipRect.set(-2, 14, 6, 20);
  clipper.setClip(clipRect);
  success = clipper.clipCubic(crv, clipped);
  REPORTER_ASSERT(reporter, success == false);

  // Test clip at 1.
  clipRect.set(-2, 1, 6, 14);
  clipper.setClip(clipRect);
  success = clipper.clipCubic(crv, clipped);
  REPORTER_ASSERT(reporter, success == true);
  REPORTER_ASSERT(reporter, CurvesAreEqual(clipped, SetCurve(
      0.5126125216, 1,
      1.841195941,  4.337081432,
      1.297019958,  10.19801331,
      4,            12,
      shouldbe
  ), tol));

  // Test clip at 2.
  clipRect.set(-2, 2, 6, 14);
  clipper.setClip(clipRect);
  success = clipper.clipCubic(crv, clipped);
  REPORTER_ASSERT(reporter, success == true);
  REPORTER_ASSERT(reporter, CurvesAreEqual(clipped, SetCurve(
      00.8412352204, 2,
      1.767683744,   5.400758266,
      1.55052948,    10.36701965,
      4,             12,
      shouldbe
  ), tol));

  // Test clip at 11.
  clipRect.set(-2, -2, 6, 11);
  clipper.setClip(clipRect);
  success = clipper.clipCubic(crv, clipped);
  REPORTER_ASSERT(reporter, success == true);
  REPORTER_ASSERT(reporter, CurvesAreEqual(clipped, SetCurve(
      0,           0,
      1.742904663, 2.614356995,
      1.207521796, 8.266430855,
      3.026495695, 11,
      shouldbe
  ), tol));

  // Test clip at 10.
  clipRect.set(-2, -2, 6, 10);
  clipper.setClip(clipRect);
  success = clipper.clipCubic(crv, clipped);
  REPORTER_ASSERT(reporter, success == true);
  REPORTER_ASSERT(reporter, CurvesAreEqual(clipped, SetCurve(
      0,           0,
      1.551193237, 2.326789856,
      1.297736168, 7.059780121,
      2.505550385, 10,
      shouldbe
  ), tol));
}




#include "TestClassDef.h"
DEFINE_TESTCLASS("CubicClipper", CubicClippingTestClass, TestCubicClipping)