src/gpu/batches/GrRectBatchFactory.cpp

/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "GrRectBatchFactory.h"

#include "GrAAStrokeRectBatch.h"

#include "SkStrokeRec.h"

namespace GrRectBatchFactory {

GrDrawBatch* CreateAAStroke(GrColor color,
                            const SkMatrix& viewMatrix,
                            const SkRect& rect,
                            const SkRect& devRect,
                            const SkStrokeRec& stroke) {
    SkVector devStrokeSize;
    SkScalar width = stroke.getWidth();
    if (width > 0) {
        devStrokeSize.set(width, width);
        viewMatrix.mapVectors(&devStrokeSize, 1);
        devStrokeSize.setAbs(devStrokeSize);
    } else {
        devStrokeSize.set(SK_Scalar1, SK_Scalar1);
    }

    const SkScalar dx = devStrokeSize.fX;
    const SkScalar dy = devStrokeSize.fY;
    const SkScalar rx = SkScalarMul(dx, SK_ScalarHalf);
    const SkScalar ry = SkScalarMul(dy, SK_ScalarHalf);

    SkRect devOutside(devRect);
    devOutside.outset(rx, ry);

    bool miterStroke = true;
    // For hairlines, make bevel and round joins appear the same as mitered ones.
    // small miter limit means right angles show bevel...
    if ((width > 0) && (stroke.getJoin() != SkPaint::kMiter_Join ||
                        stroke.getMiter() < SK_ScalarSqrt2)) {
        miterStroke = false;
    }

    SkRect devInside(devRect);
    devInside.inset(rx, ry);

    // If we have a degenerate stroking rect(ie the stroke is larger than inner rect) then we
    // make a degenerate inside rect to avoid double hitting.  We will also jam all of the points
    // together when we render these rects.
    SkScalar spare;
    {
        SkScalar w = devRect.width() - dx;
        SkScalar h = devRect.height() - dy;
        spare = SkTMin(w, h);
    }

    bool degenerate = spare <= 0;
    if (degenerate) {
        devInside.fLeft = devInside.fRight = devRect.centerX();
        devInside.fTop = devInside.fBottom = devRect.centerY();
    }

    SkRect devOutsideAssist(devRect);

    // For bevel-stroke, use 2 SkRect instances(devOutside and devOutsideAssist)
    // to draw the outer of the rect. Because there are 8 vertices on the outer
    // edge, while vertex number of inner edge is 4, the same as miter-stroke.
    if (!miterStroke) {
        devOutside.inset(0, ry);
        devOutsideAssist.outset(0, ry);
    }

    return GrAAStrokeRectBatch::Create(color, viewMatrix, devOutside, devOutsideAssist, devInside,
                                       miterStroke, degenerate);
}

GrDrawBatch* CreateAAFillNestedRects(GrColor color,
                                     const SkMatrix& viewMatrix,
                                     const SkRect rects[2]) {
    SkASSERT(viewMatrix.rectStaysRect());
    SkASSERT(!rects[0].isEmpty() && !rects[1].isEmpty());

    SkRect devOutside, devInside;
    viewMatrix.mapRect(&devOutside, rects[0]);
    viewMatrix.mapRect(&devInside, rects[1]);

    return GrAAStrokeRectBatch::Create(color, viewMatrix, devOutside, devOutside, devInside, true,
                                       devInside.isEmpty());
}

};