#include <SkQuadClipper.h>

Public Member Functions
	SkQuadClipper ()

void	setClip (const SkIRect &clip)

bool	clipQuad (const SkPoint src[3], SkPoint dst[3])

Detailed Description

This class is initialized with a clip rectangle, and then can be fed quads, which must already be monotonic in Y.

In the future, it might return a series of segments, allowing it to clip also in X, to ensure that all segments fit in a finite coordinate system.

Definition at line 24 of file SkQuadClipper.h.

Constructor & Destructor Documentation

◆ SkQuadClipper()

SkQuadClipper::SkQuadClipper ( )

Definition at line 14 of file SkQuadClipper.cpp.

                             {
    fClip.setEmpty();
}

Member Function Documentation

◆ clipQuad()

bool SkQuadClipper::clipQuad	(	const SkPoint	src[3],
		SkPoint	dst[3]
	)

Definition at line 54 of file SkQuadClipper.cpp.

                                                                    {
    bool reverse;
 
    // we need the data to be monotonically increasing in Y
    if (srcPts[0].fY > srcPts[2].fY) {
        dst[0] = srcPts[2];
        dst[1] = srcPts[1];
        dst[2] = srcPts[0];
        reverse = true;
    } else {
        memcpy(dst, srcPts, 3 * sizeof(SkPoint));
        reverse = false;
    }
 
    // are we completely above or below
    const SkScalar ctop = fClip.fTop;
    const SkScalar cbot = fClip.fBottom;
    if (dst[2].fY <= ctop || dst[0].fY >= cbot) {
        return false;
    }
 
    SkScalar t;
    SkPoint tmp[5]; // for SkChopQuadAt
 
    // are we partially above
    if (dst[0].fY < ctop) {
        if (chopMonoQuadAtY(dst, ctop, &t)) {
            // take the 2nd chopped quad
            SkChopQuadAt(dst, tmp, t);
            dst[0] = tmp[2];
            dst[1] = tmp[3];
        } else {
            // if chopMonoQuadAtY failed, then we may have hit inexact numerics
            // so we just clamp against the top
            for (int i = 0; i < 3; i++) {
                if (dst[i].fY < ctop) {
                    dst[i].fY = ctop;
                }
            }
        }
    }
 
    // are we partially below
    if (dst[2].fY > cbot) {
        if (chopMonoQuadAtY(dst, cbot, &t)) {
            SkChopQuadAt(dst, tmp, t);
            dst[1] = tmp[1];
            dst[2] = tmp[2];
        } else {
            // if chopMonoQuadAtY failed, then we may have hit inexact numerics
            // so we just clamp against the bottom
            for (int i = 0; i < 3; i++) {
                if (dst[i].fY > cbot) {
                    dst[i].fY = cbot;
                }
            }
        }
    }
 
    if (reverse) {
        using std::swap;
        swap(dst[0], dst[2]);
    }
    return true;
}

◆ setClip()

void SkQuadClipper::setClip ( const SkIRect & clip )

Definition at line 18 of file SkQuadClipper.cpp.

                                               {
    // conver to scalars, since that's where we'll see the points
    fClip.set(clip);
}

The documentation for this class was generated from the following files: