Remove unused ShadowBlur

Source/core/platform/graphics/ShadowBlur.cpp

-/*
- * Copyright (C) 2011 Apple Inc. All rights reserved.
- * Copyright (C) 2010 Sencha, Inc. All rights reserved.
- * Copyright (C) 2010 Igalia S.L. All rights reserved.
- * Copyright (C) Research In Motion Limited 2011. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
- * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
- * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include "config.h"
-#include "core/platform/graphics/ShadowBlur.h"
-
-#include "wtf/MathExtras.h"
-#include <algorithm>
-
-using namespace std;
-
-namespace WebCore {
-
-enum {
-    leftLobe = 0,
-    rightLobe = 1
-};
-
-ShadowBlur::ShadowBlur(const FloatSize& radius, const FloatSize& offset, const Color& color)
-    : m_color(color)
-    , m_blurRadius(radius)
-    , m_offset(offset)
-    , m_shadowsIgnoreTransforms(false)
-{
-    updateShadowBlurValues();
-}
-
-void ShadowBlur::updateShadowBlurValues()
-{
-    // Limit blur radius to 128 to avoid lots of very expensive blurring.
-    m_blurRadius = m_blurRadius.shrunkTo(FloatSize(128, 128));
-
-    // The type of shadow is decided by the blur radius, shadow offset, and shadow color.
-    if (!m_color.isValid() || !m_color.alpha()) {
-        // Can't paint the shadow with invalid or invisible color.
-        m_type = NoShadow;
-    } else if (m_blurRadius.width() > 0 || m_blurRadius.height() > 0) {
-        // Shadow is always blurred, even the offset is zero.
-        m_type = BlurShadow;
-    } else if (!m_offset.width() && !m_offset.height()) {
-        // Without blur and zero offset means the shadow is fully hidden.
-        m_type = NoShadow;
-    } else
-        m_type = SolidShadow;
-}
-
-// Instead of integer division, we use 17.15 for fixed-point division.
-static const int blurSumShift = 15;
-
-// Takes a two dimensional array with three rows and two columns for the lobes.
-static void calculateLobes(int lobes[][2], float blurRadius, bool shadowsIgnoreTransforms)
-{
-    int diameter;
-    if (shadowsIgnoreTransforms)
-        diameter = max(2, static_cast<int>(floorf((2 / 3.f) * blurRadius))); // Canvas shadow. FIXME: we should adjust the blur radius higher up.
-    else {
-        // http://dev.w3.org/csswg/css3-background/#box-shadow
-        // Approximate a Gaussian blur with a standard deviation equal to half the blur radius,
-        // which http://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement tell us how to do.
-        // However, shadows rendered according to that spec will extend a little further than m_blurRadius,
-        // so we apply a fudge factor to bring the radius down slightly.
-        float stdDev = blurRadius / 2;
-        const float gaussianKernelFactor = 3 / 4.f * sqrtf(2 * piFloat);
-        const float fudgeFactor = 0.88f;
-        diameter = max(2, static_cast<int>(floorf(stdDev * gaussianKernelFactor * fudgeFactor + 0.5f)));
-    }
-
-    if (diameter & 1) {
-        // if d is odd, use three box-blurs of size 'd', centered on the output pixel.
-        int lobeSize = (diameter - 1) / 2;
-        lobes[0][leftLobe] = lobeSize;
-        lobes[0][rightLobe] = lobeSize;
-        lobes[1][leftLobe] = lobeSize;
-        lobes[1][rightLobe] = lobeSize;
-        lobes[2][leftLobe] = lobeSize;
-        lobes[2][rightLobe] = lobeSize;
-    } else {
-        // if d is even, two box-blurs of size 'd' (the first one centered on the pixel boundary
-        // between the output pixel and the one to the left, the second one centered on the pixel
-        // boundary between the output pixel and the one to the right) and one box blur of size 'd+1' centered on the output pixel
-        int lobeSize = diameter / 2;
-        lobes[0][leftLobe] = lobeSize;
-        lobes[0][rightLobe] = lobeSize - 1;
-        lobes[1][leftLobe] = lobeSize - 1;
-        lobes[1][rightLobe] = lobeSize;
-        lobes[2][leftLobe] = lobeSize;
-        lobes[2][rightLobe] = lobeSize;
-    }
-}
-
-void ShadowBlur::blurLayerImage(unsigned char* imageData, const IntSize& size, int rowStride)
-{
-    const int channels[4] = { 3, 0, 1, 3 };
-
-    int lobes[3][2]; // indexed by pass, and left/right lobe
-    calculateLobes(lobes, m_blurRadius.width(), m_shadowsIgnoreTransforms);
-
-    // First pass is horizontal.
-    int stride = 4;
-    int delta = rowStride;
-    int final = size.height();
-    int dim = size.width();
-
-    // Two stages: horizontal and vertical
-    for (int pass = 0; pass < 2; ++pass) {
-        unsigned char* pixels = imageData;
-
-        if (!pass && !m_blurRadius.width())
-            final = 0; // Do no work if horizonal blur is zero.
-
-        for (int j = 0; j < final; ++j, pixels += delta) {
-            // For each step, we blur the alpha in a channel and store the result
-            // in another channel for the subsequent step.
-            // We use sliding window algorithm to accumulate the alpha values.
-            // This is much more efficient than computing the sum of each pixels
-            // covered by the box kernel size for each x.
-            for (int step = 0; step < 3; ++step) {
-                int side1 = lobes[step][leftLobe];
-                int side2 = lobes[step][rightLobe];
-                int pixelCount = side1 + 1 + side2;
-                int invCount = ((1 << blurSumShift) + pixelCount - 1) / pixelCount;
-                int ofs = 1 + side2;
-                int alpha1 = pixels[channels[step]];
-                int alpha2 = pixels[(dim - 1) * stride + channels[step]];
-
-                unsigned char* ptr = pixels + channels[step + 1];
-                unsigned char* prev = pixels + stride + channels[step];
-                unsigned char* next = pixels + ofs * stride + channels[step];
-
-                int i;
-                int sum = side1 * alpha1 + alpha1;
-                int limit = (dim < side2 + 1) ? dim : side2 + 1;
-
-                for (i = 1; i < limit; ++i, prev += stride)
-                    sum += *prev;
-
-                if (limit <= side2)
-                    sum += (side2 - limit + 1) * alpha2;
-
-                limit = (side1 < dim) ? side1 : dim;
-                for (i = 0; i < limit; ptr += stride, next += stride, ++i, ++ofs) {
-                    *ptr = (sum * invCount) >> blurSumShift;
-                    sum += ((ofs < dim) ? *next : alpha2) - alpha1;
-                }
-
-                prev = pixels + channels[step];
-                for (; ofs < dim; ptr += stride, prev += stride, next += stride, ++i, ++ofs) {
-                    *ptr = (sum * invCount) >> blurSumShift;
-                    sum += (*next) - (*prev);
-                }
-
-                for (; i < dim; ptr += stride, prev += stride, ++i) {
-                    *ptr = (sum * invCount) >> blurSumShift;
-                    sum += alpha2 - (*prev);
-                }
-            }
-        }
-
-        // Last pass is vertical.
-        stride = rowStride;
-        delta = 4;
-        final = size.width();
-        dim = size.height();
-
-        if (!m_blurRadius.height())
-            break;
-
-        if (m_blurRadius.width() != m_blurRadius.height())
-            calculateLobes(lobes, m_blurRadius.height(), m_shadowsIgnoreTransforms);
-    }
-}
-
-} // namespace WebCore