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Commit 019adb02 authored by Stan Iliev's avatar Stan Iliev
Browse files

Improve comparison of fractions 

Fraction comparison does not work for 143.999985 and 2.000001.
This CL resolves this corner case.

Bug: 140778647
Test: pass CTS
Change-Id: I7e39ba822167a3c36c628255a4c79b1ade976929
parent a219bddf

libs/hwui/pipeline/skia/LayerDrawable.cpp

+6 −19
Original line number Diff line number Diff line
@@ -43,41 +43,28 @@ static bool shouldFilterRect(const SkMatrix& matrix, const SkRect& srcRect, cons 
    if (!matrix.rectStaysRect()) return true;

    SkRect dstDevRect = matrix.mapRect(dstRect);

    float dstW, dstH;

    bool requiresIntegerTranslate = false;

    if (MathUtils::isZero(matrix.getScaleX()) && MathUtils::isZero(matrix.getScaleY())) {

        // Has a 90 or 270 degree rotation, although total matrix may also have scale factors

        // in m10 and m01. Those scalings are automatically handled by mapRect so comparing

        // dimensions is sufficient, but swap width and height comparison.

        dstW = dstDevRect.height();

        dstH = dstDevRect.width();

        requiresIntegerTranslate = true;

    } else {

        // Handle H/V flips or 180 rotation matrices. Axes may have been mirrored, but

        // dimensions are still safe to compare directly.

        dstW = dstDevRect.width();

        dstH = dstDevRect.height();

        requiresIntegerTranslate =

                matrix.getScaleX() < -NON_ZERO_EPSILON || matrix.getScaleY() < -NON_ZERO_EPSILON;

    }

    if (!(MathUtils::areEqual(dstW, srcRect.width()) &&

          MathUtils::areEqual(dstH, srcRect.height()))) {

        return true;

    }

    if (requiresIntegerTranslate) {

    // Device rect and source rect should be integer aligned to ensure there's no difference

    // in how nearest-neighbor sampling is resolved.

    return !(isIntegerAligned(srcRect.x()) &&

             isIntegerAligned(srcRect.y()) &&

             isIntegerAligned(dstDevRect.x()) &&

             isIntegerAligned(dstDevRect.y()));

    } else {

        // As long as src and device rects are translated by the same fractional amount,

        // filtering won't be needed

        return !(MathUtils::areEqual(SkScalarFraction(srcRect.x()),

                                     SkScalarFraction(dstDevRect.x())) &&

                 MathUtils::areEqual(SkScalarFraction(srcRect.y()),

                                     SkScalarFraction(dstDevRect.y())));

    }

}



bool LayerDrawable::DrawLayer(GrContext* context, SkCanvas* canvas, Layer* layer,