| /* |
| * Copyright (C) 2006, 2007, 2008, 2010 Apple Inc. All rights reserved. |
| * Copyright (C) 2007 Alp Toker <alp@atoker.com> |
| * Copyright (C) 2013 Google Inc. 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 COMPUTER, 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/Gradient.h" |
| |
| #include "core/platform/graphics/GraphicsContext.h" |
| #include "core/platform/graphics/skia/SkiaUtils.h" |
| #include "platform/geometry/FloatRect.h" |
| #include "platform/graphics/Color.h" |
| #include "third_party/skia/include/core/SkColorShader.h" |
| #include "third_party/skia/include/core/SkShader.h" |
| #include "third_party/skia/include/effects/SkGradientShader.h" |
| |
| namespace WebCore { |
| |
| Gradient::Gradient(const FloatPoint& p0, const FloatPoint& p1) |
| : m_radial(false) |
| , m_p0(p0) |
| , m_p1(p1) |
| , m_r0(0) |
| , m_r1(0) |
| , m_aspectRatio(1) |
| , m_stopsSorted(false) |
| , m_spreadMethod(SpreadMethodPad) |
| , m_drawInPMColorSpace(false) |
| { |
| } |
| |
| Gradient::Gradient(const FloatPoint& p0, float r0, const FloatPoint& p1, float r1, float aspectRatio) |
| : m_radial(true) |
| , m_p0(p0) |
| , m_p1(p1) |
| , m_r0(r0) |
| , m_r1(r1) |
| , m_aspectRatio(aspectRatio) |
| , m_stopsSorted(false) |
| , m_spreadMethod(SpreadMethodPad) |
| , m_drawInPMColorSpace(false) |
| { |
| } |
| |
| Gradient::~Gradient() |
| { |
| } |
| |
| void Gradient::addColorStop(float value, const Color& color) |
| { |
| float r; |
| float g; |
| float b; |
| float a; |
| color.getRGBA(r, g, b, a); |
| m_stops.append(ColorStop(value, r, g, b, a)); |
| |
| m_stopsSorted = false; |
| m_gradient.clear(); |
| } |
| |
| void Gradient::addColorStop(const Gradient::ColorStop& stop) |
| { |
| m_stops.append(stop); |
| |
| m_stopsSorted = false; |
| m_gradient.clear(); |
| } |
| |
| static inline bool compareStops(const Gradient::ColorStop& a, const Gradient::ColorStop& b) |
| { |
| return a.stop < b.stop; |
| } |
| |
| void Gradient::sortStopsIfNecessary() |
| { |
| if (m_stopsSorted) |
| return; |
| |
| m_stopsSorted = true; |
| |
| if (!m_stops.size()) |
| return; |
| |
| std::stable_sort(m_stops.begin(), m_stops.end(), compareStops); |
| } |
| |
| bool Gradient::hasAlpha() const |
| { |
| for (size_t i = 0; i < m_stops.size(); i++) { |
| if (m_stops[i].alpha < 1) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| void Gradient::setSpreadMethod(GradientSpreadMethod spreadMethod) |
| { |
| // FIXME: Should it become necessary, allow calls to this method after m_gradient has been set. |
| ASSERT(!m_gradient); |
| |
| if (m_spreadMethod == spreadMethod) |
| return; |
| |
| m_spreadMethod = spreadMethod; |
| } |
| |
| void Gradient::setDrawsInPMColorSpace(bool drawInPMColorSpace) |
| { |
| if (drawInPMColorSpace == m_drawInPMColorSpace) |
| return; |
| |
| m_drawInPMColorSpace = drawInPMColorSpace; |
| m_gradient.clear(); |
| } |
| |
| void Gradient::setGradientSpaceTransform(const AffineTransform& gradientSpaceTransformation) |
| { |
| if (m_gradientSpaceTransformation == gradientSpaceTransformation) |
| return; |
| |
| m_gradientSpaceTransformation = gradientSpaceTransformation; |
| if (m_gradient) |
| m_gradient->setLocalMatrix(affineTransformToSkMatrix(m_gradientSpaceTransformation)); |
| } |
| |
| static inline U8CPU F2B(float x) |
| { |
| return static_cast<int>(x * 255); |
| } |
| |
| static SkColor makeSkColor(float a, float r, float g, float b) |
| { |
| return SkColorSetARGB(F2B(a), F2B(r), F2B(g), F2B(b)); |
| } |
| |
| // Determine the total number of stops needed, including pseudo-stops at the |
| // ends as necessary. |
| static size_t totalStopsNeeded(const Gradient::ColorStop* stopData, size_t count) |
| { |
| // N.B.: The tests in this function should kept in sync with the ones in |
| // fillStops(), or badness happens. |
| const Gradient::ColorStop* stop = stopData; |
| size_t countUsed = count; |
| if (count < 1 || stop->stop > 0.0) |
| countUsed++; |
| stop += count - 1; |
| if (count < 1 || stop->stop < 1.0) |
| countUsed++; |
| return countUsed; |
| } |
| |
| // Collect sorted stop position and color information into the pos and colors |
| // buffers, ensuring stops at both 0.0 and 1.0. The buffers must be large |
| // enough to hold information for all stops, including the new endpoints if |
| // stops at 0.0 and 1.0 aren't already included. |
| static void fillStops(const Gradient::ColorStop* stopData, |
| size_t count, SkScalar* pos, SkColor* colors) |
| { |
| const Gradient::ColorStop* stop = stopData; |
| size_t start = 0; |
| if (count < 1) { |
| // A gradient with no stops must be transparent black. |
| pos[0] = WebCoreFloatToSkScalar(0.0); |
| colors[0] = makeSkColor(0.0, 0.0, 0.0, 0.0); |
| start = 1; |
| } else if (stop->stop > 0.0) { |
| // Copy the first stop to 0.0. The first stop position may have a slight |
| // rounding error, but we don't care in this float comparison, since |
| // 0.0 comes through cleanly and people aren't likely to want a gradient |
| // with a stop at (0 + epsilon). |
| pos[0] = WebCoreFloatToSkScalar(0.0); |
| colors[0] = makeSkColor(stop->alpha, stop->red, stop->green, stop->blue); |
| start = 1; |
| } |
| |
| for (size_t i = start; i < start + count; i++) { |
| pos[i] = WebCoreFloatToSkScalar(stop->stop); |
| colors[i] = makeSkColor(stop->alpha, stop->red, stop->green, stop->blue); |
| ++stop; |
| } |
| |
| // Copy the last stop to 1.0 if needed. See comment above about this float |
| // comparison. |
| if (count < 1 || (--stop)->stop < 1.0) { |
| pos[start + count] = WebCoreFloatToSkScalar(1.0); |
| colors[start + count] = colors[start + count - 1]; |
| } |
| } |
| |
| SkShader* Gradient::shader() |
| { |
| if (m_gradient) |
| return m_gradient.get(); |
| |
| sortStopsIfNecessary(); |
| ASSERT(m_stopsSorted); |
| |
| size_t countUsed = totalStopsNeeded(m_stops.data(), m_stops.size()); |
| ASSERT(countUsed >= 2); |
| ASSERT(countUsed >= m_stops.size()); |
| |
| // FIXME: Why is all this manual pointer math needed?! |
| SkAutoMalloc storage(countUsed * (sizeof(SkColor) + sizeof(SkScalar))); |
| SkColor* colors = (SkColor*)storage.get(); |
| SkScalar* pos = (SkScalar*)(colors + countUsed); |
| |
| fillStops(m_stops.data(), m_stops.size(), pos, colors); |
| |
| SkShader::TileMode tile = SkShader::kClamp_TileMode; |
| switch (m_spreadMethod) { |
| case SpreadMethodReflect: |
| tile = SkShader::kMirror_TileMode; |
| break; |
| case SpreadMethodRepeat: |
| tile = SkShader::kRepeat_TileMode; |
| break; |
| case SpreadMethodPad: |
| tile = SkShader::kClamp_TileMode; |
| break; |
| } |
| |
| uint32_t shouldDrawInPMColorSpace = m_drawInPMColorSpace ? SkGradientShader::kInterpolateColorsInPremul_Flag : 0; |
| if (m_radial) { |
| // Since the two-point radial gradient is slower than the plain radial, |
| // only use it if we have to. |
| if (m_p0 == m_p1 && m_r0 <= 0.0f) { |
| m_gradient = adoptRef(SkGradientShader::CreateRadial(m_p1, m_r1, colors, pos, static_cast<int>(countUsed), tile, 0, shouldDrawInPMColorSpace)); |
| } else { |
| // The radii we give to Skia must be positive. If we're given a |
| // negative radius, ask for zero instead. |
| SkScalar radius0 = m_r0 >= 0.0f ? WebCoreFloatToSkScalar(m_r0) : 0; |
| SkScalar radius1 = m_r1 >= 0.0f ? WebCoreFloatToSkScalar(m_r1) : 0; |
| m_gradient = adoptRef(SkGradientShader::CreateTwoPointConical(m_p0, radius0, m_p1, radius1, colors, pos, static_cast<int>(countUsed), tile, 0, shouldDrawInPMColorSpace)); |
| } |
| |
| if (aspectRatio() != 1) { |
| // CSS3 elliptical gradients: apply the elliptical scaling at the |
| // gradient center point. |
| m_gradientSpaceTransformation.translate(m_p0.x(), m_p0.y()); |
| m_gradientSpaceTransformation.scale(1, 1 / aspectRatio()); |
| m_gradientSpaceTransformation.translate(-m_p0.x(), -m_p0.y()); |
| ASSERT(m_p0 == m_p1); |
| } |
| } else { |
| SkPoint pts[2] = { m_p0, m_p1 }; |
| m_gradient = adoptRef(SkGradientShader::CreateLinear(pts, colors, pos, static_cast<int>(countUsed), tile, 0, shouldDrawInPMColorSpace)); |
| } |
| |
| if (!m_gradient) { |
| // use last color, since our "geometry" was degenerate (e.g. radius==0) |
| m_gradient = adoptRef(new SkColorShader(colors[countUsed - 1])); |
| } else { |
| m_gradient->setLocalMatrix(affineTransformToSkMatrix(m_gradientSpaceTransformation)); |
| } |
| return m_gradient.get(); |
| } |
| |
| } //namespace |