C++ SkScalarAbs函数代码示例

bool SkBitmapController::State::processHighRequest(const SkBitmapProvider& provider) {
    if (fQuality != kHigh_SkFilterQuality) {
        return false;
    }

    fQuality = kMedium_SkFilterQuality;

    SkScalar invScaleX = fInvMatrix.getScaleX();
    SkScalar invScaleY = fInvMatrix.getScaleY();
    if (fInvMatrix.getType() & SkMatrix::kAffine_Mask) {
        SkSize scale;
        if (!fInvMatrix.decomposeScale(&scale)) {
            return false;
        }
        invScaleX = scale.width();
        invScaleY = scale.height();
    }
    invScaleX = SkScalarAbs(invScaleX);
    invScaleY = SkScalarAbs(invScaleY);

    if (invScaleX >= 1 - SK_ScalarNearlyZero || invScaleY >= 1 - SK_ScalarNearlyZero) {
        // we're down-scaling so abort HQ
        return false;
    }

    // Confirmed that we can use HQ (w/ rasterpipeline)
    fQuality = kHigh_SkFilterQuality;
    (void)provider.asBitmap(&fResultBitmap);
    return true;
}

SkIRect SkDisplacementMapEffect::onFilterNodeBounds(const SkIRect& src, const SkMatrix& ctm,
                                                    MapDirection) const {
    SkVector scale = SkVector::Make(fScale, fScale);
    ctm.mapVectors(&scale, 1);
    return src.makeOutset(SkScalarCeilToInt(SkScalarAbs(scale.fX) * SK_ScalarHalf),
                          SkScalarCeilToInt(SkScalarAbs(scale.fY) * SK_ScalarHalf));
}

static SkVector map_sigma(const SkSize& localSigma, const SkMatrix& ctm) {
    SkVector sigma = SkVector::Make(localSigma.width(), localSigma.height());
    ctm.mapVectors(&sigma, 1);
    sigma.fX = SkMinScalar(SkScalarAbs(sigma.fX), MAX_SIGMA);
    sigma.fY = SkMinScalar(SkScalarAbs(sigma.fY), MAX_SIGMA);
    return sigma;
}

	bool draw(SkCanvas* canvas, const SkString& newText, SkScalar x, SkScalar y, SkPaint& paint)
	{
		SkScalar scale;

		if (fInterp.timeToValues(SkTime::GetMSecs(), &scale) == SkInterpolator::kFreezeEnd_Result)
		{
			canvas->drawText(newText.c_str(), newText.size(), x, y, paint);
			return false;
		}
		else
		{
			U8 alpha = paint.getAlpha();
			SkScalar above, below;
			(void)paint.measureText(nil, 0, &above, &below);
			SkScalar height = below - above;
			SkScalar dy = SkScalarMul(height, scale);
			if (scale < 0)
				height = -height;

			// draw the old
			paint.setAlpha((U8)SkScalarMul(alpha, SK_Scalar1 - SkScalarAbs(scale)));
			canvas->drawText(fOldText.c_str(), fOldText.size(), x, y - dy, paint);
			// draw the new
			paint.setAlpha((U8)SkScalarMul(alpha, SkScalarAbs(scale)));
			canvas->drawText(newText.c_str(), newText.size(), x, y + height - dy, paint);
			// restore the paint
			paint.setAlpha(alpha);
			return true;
		}
	}

/*  Returns 0 for 1 quad, and 1 for two quads, either way the answer is
    stored in dst[]. Guarantees that the 1/2 quads will be monotonic.
 */
int SkChopQuadAtXExtrema(const SkPoint src[3], SkPoint dst[5])
{
    SkASSERT(src);
    SkASSERT(dst);
    
    SkScalar a = src[0].fX;
    SkScalar b = src[1].fX;
    SkScalar c = src[2].fX;
    
    if (is_not_monotonic(a, b, c)) {
        SkScalar tValue;
        if (valid_unit_divide(a - b, a - b - b + c, &tValue)) {
            SkChopQuadAt(src, dst, tValue);
            flatten_double_quad_extrema(&dst[0].fX);
            return 1;
        }
        // if we get here, we need to force dst to be monotonic, even though
        // we couldn't compute a unit_divide value (probably underflow).
        b = SkScalarAbs(a - b) < SkScalarAbs(b - c) ? a : c;
    }
    dst[0].set(a, src[0].fY);
    dst[1].set(b, src[1].fY);
    dst[2].set(c, src[2].fY);
    return 0;
}

void SkDisplacementMapEffect::computeFastBounds(const SkRect& src, SkRect* dst) const {
    if (this->getColorInput()) {
        this->getColorInput()->computeFastBounds(src, dst);
    } else {
        *dst = src;
    }
    dst->outset(SkScalarAbs(fScale) * SK_ScalarHalf, SkScalarAbs(fScale) * SK_ScalarHalf);
}

bool SkPathMeasure::conic_too_curvy(const SkPoint& firstPt, const SkPoint& midTPt,
                            const SkPoint& lastPt) {
    SkPoint midEnds = firstPt + lastPt;
    midEnds *= 0.5f;
    SkVector dxy = midTPt - midEnds;
    SkScalar dist = SkMaxScalar(SkScalarAbs(dxy.fX), SkScalarAbs(dxy.fY));
    return dist > fTolerance;
}

// very tiny points cause numerical instability : don't allow them
static void force_small_to_zero(SkPoint* pt) {
    if (SkScalarAbs(pt->fX) < FLT_EPSILON_ORDERABLE_ERR) {
        pt->fX = 0;
    }
    if (SkScalarAbs(pt->fY) < FLT_EPSILON_ORDERABLE_ERR) {
        pt->fY = 0;
    }
}

static void unit_axis_align(SkVector* unit) {
    const SkScalar TOLERANCE = SkDoubleToScalar(0.15);
    if (SkScalarAbs(unit->fX) < TOLERANCE) {
        unit->fX = 0;
        unit->fY = SkScalarSign(unit->fY);
    } else if (SkScalarAbs(unit->fY) < TOLERANCE) {
        unit->fX = SkScalarSign(unit->fX);
        unit->fY = 0;
    }
}

static bool has_aligned_samples(const SkRect& srcRect, const SkRect& transformedRect) {
    // detect pixel disalignment
    if (SkScalarAbs(SkScalarRoundToScalar(transformedRect.left()) - transformedRect.left()) < kColorBleedTolerance &&
        SkScalarAbs(SkScalarRoundToScalar(transformedRect.top())  - transformedRect.top())  < kColorBleedTolerance &&
        SkScalarAbs(transformedRect.width()  - srcRect.width())  < kColorBleedTolerance &&
        SkScalarAbs(transformedRect.height() - srcRect.height()) < kColorBleedTolerance) {
        return true;
    }
    return false;
}

static bool quad_too_curvy(const SkPoint pts[3]) {
    // diff = (a/4 + b/2 + c/4) - (a/2 + c/2)
    // diff = -a/4 + b/2 - c/4
    SkScalar dx = SkScalarHalf(pts[1].fX) -
                        SkScalarHalf(SkScalarHalf(pts[0].fX + pts[2].fX));
    SkScalar dy = SkScalarHalf(pts[1].fY) -
                        SkScalarHalf(SkScalarHalf(pts[0].fY + pts[2].fY));

    SkScalar dist = SkMaxScalar(SkScalarAbs(dx), SkScalarAbs(dy));
    return dist > CHEAP_DIST_LIMIT;
}

bool SkPathMeasure::quad_too_curvy(const SkPoint pts[3]) {
    // diff = (a/4 + b/2 + c/4) - (a/2 + c/2)
    // diff = -a/4 + b/2 - c/4
    SkScalar dx = SkScalarHalf(pts[1].fX) -
                        SkScalarHalf(SkScalarHalf(pts[0].fX + pts[2].fX));
    SkScalar dy = SkScalarHalf(pts[1].fY) -
                        SkScalarHalf(SkScalarHalf(pts[0].fY + pts[2].fY));

    SkScalar dist = SkMaxScalar(SkScalarAbs(dx), SkScalarAbs(dy));
    return dist > fTolerance;
}

    virtual bool onClick(SkView::Click* click) {
        SkPoint prev = click->fPrev;
        SkPoint curr = click->fCurr;
        bool handled = true;
        switch (click->fState) {
            case SkView::Click::kDown_State:
                if (SkScalarAbs(curr.fX - fCommands->width()) <= SKDEBUGGER_RESIZEBARSIZE) {
                    fCommandsResizing = true;
                }
                else if (SkScalarAbs(curr.fY - (this->height() - fState->height())) <= SKDEBUGGER_RESIZEBARSIZE &&
                         curr.fX > fCommands->width()) {
                    fStateResizing = true;
                }
                else if (curr.fX < fCommands->width()) {
                    fAtomsToRead = fCommands->selectHighlight(
                                                  SkScalarFloorToInt(curr.fY));
                }
                else
                    handled = false;
                break;
            case SkView::Click::kMoved_State:
                if (fCommandsResizing)
                    fCommands->setSize(curr.fX, this->height());
                else if (fStateResizing)
                    fState->setSize(this->width(), this->height() - curr.fY);
                else if (curr.fX < fCommands->width()) {
                    if (curr.fY - prev.fY < 0) {
                        fCommands->scrollDown();
                    }
                    if (curr.fY - prev.fY > 0) {
                        fCommands->scrollUp();
                    }
                }
                else
                    handled = false;
                break;
            case SkView::Click::kUp_State:
                fStateResizing = fCommandsResizing = false;
                break;
            default:
                break;
        }

        fStateOffset = fCommands->width();
        fState->setSize(this->width() - fStateOffset, fState->height());
        fState->setLoc(fStateOffset, this->height() - fState->height());
        if (handled)
            this->inval(NULL);
        return handled;
    }

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) > tol ||
            SkScalarAbs(c0[i].fY - c1[i].fY) > tol
        ) {
            PrintCurve("c0", c0);
            PrintCurve("c1", c1);
            return false;
        }
    }
    return true;
}

// k = (y2 - y0, x0 - x2, (x2 - x0)*y0 - (y2 - y0)*x0 )
// l = (2*w * (y1 - y0), 2*w * (x0 - x1), 2*w * (x1*y0 - x0*y1))
// m = (2*w * (y2 - y1), 2*w * (x1 - x2), 2*w * (x2*y1 - x1*y2))
void GrPathUtils::getConicKLM(const SkPoint p[3], const SkScalar weight, SkScalar klm[9]) {
    const SkScalar w2 = 2.f * weight;
    klm[0] = p[2].fY - p[0].fY;
    klm[1] = p[0].fX - p[2].fX;
    klm[2] = (p[2].fX - p[0].fX) * p[0].fY - (p[2].fY - p[0].fY) * p[0].fX;

    klm[3] = w2 * (p[1].fY - p[0].fY);
    klm[4] = w2 * (p[0].fX - p[1].fX);
    klm[5] = w2 * (p[1].fX * p[0].fY - p[0].fX * p[1].fY);

    klm[6] = w2 * (p[2].fY - p[1].fY);
    klm[7] = w2 * (p[1].fX - p[2].fX);
    klm[8] = w2 * (p[2].fX * p[1].fY - p[1].fX * p[2].fY);

    // scale the max absolute value of coeffs to 10
    SkScalar scale = 0.f;
    for (int i = 0; i < 9; ++i) {
       scale = SkMaxScalar(scale, SkScalarAbs(klm[i]));
    }
    SkASSERT(scale > 0.f);
    scale = 10.f / scale;
    for (int i = 0; i < 9; ++i) {
        klm[i] *= scale;
    }
}