SkQuadClipper.cpp File Reference

#include "src/core/SkGeometry.h"
#include "src/core/SkQuadClipper.h"
#include <cstring>
#include <utility>

Go to the source code of this file.

Functions
static bool	chopMonoQuadAt (SkScalar c0, SkScalar c1, SkScalar c2, SkScalar target, SkScalar *t)
static bool	chopMonoQuadAtY (SkPoint pts[3], SkScalar y, SkScalar *t)

Function Documentation

chopMonoQuadAt()

static bool chopMonoQuadAt ( SkScalar  c0, SkScalar  c1, SkScalar  c2, SkScalar  target, SkScalar *  t  )

static

Definition at line 25 of file SkQuadClipper.cpp.

                                                         {
    /* Solve F(t) = y where F(t) := [0](1-t)^2 + 2[1]t(1-t) + [2]t^2
     *  We solve for t, using quadratic equation, hence we have to rearrange
     * our cooefficents to look like At^2 + Bt + C
     */
    SkScalar A = c0 - c1 - c1 + c2;
    SkScalar B = 2*(c1 - c0);
    SkScalar C = c0 - target;
 
    SkScalar roots[2];  // we only expect one, but make room for 2 for safety
    int count = SkFindUnitQuadRoots(A, B, C, roots);
    if (count) {
        *t = roots[0];
        return true;
    }
    return false;
}

chopMonoQuadAtY()

static bool chopMonoQuadAtY ( SkPoint  pts[3], SkScalar  y, SkScalar *  t  )

static

Definition at line 44 of file SkQuadClipper.cpp.

                                                                     {
    return chopMonoQuadAt(pts[0].fY, pts[1].fY, pts[2].fY, y, t);
}