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/*
* Copyright (C) 2008 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 "Gradient.h"
#include "CSSParser.h"
#include "GraphicsContext.h"
#include "NotImplemented.h"
#include "SkGradientShader.h"
#include "SkiaUtils.h"
namespace WebCore {
void Gradient::platformDestroy()
{
if (m_gradient)
m_gradient->safeUnref();
m_gradient = 0;
}
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 total_stops_needed(const Gradient::ColorStop* stopData, size_t count)
{
const Gradient::ColorStop* stop = stopData;
size_t count_used = count;
if (count < 1 || stop->stop > 0.0)
count_used++;
stop += count - 1;
if (count < 2 || stop->stop < 1.0)
count_used++;
return count_used;
}
// 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 fill_stops(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::platformGradient()
{
if (m_gradient)
return m_gradient;
size_t count_used = total_stops_needed(m_stops.data(), m_stops.size());
ASSERT(count_used >= 2);
ASSERT(count_used >= m_stops.size());
// FIXME: Why is all this manual pointer math needed?!
SkAutoMalloc storage(count_used * (sizeof(SkColor) + sizeof(SkScalar)));
SkColor* colors = (SkColor*)storage.get();
SkScalar* pos = (SkScalar*)(colors + count_used);
fill_stops(m_stops.data(), m_stops.size(), pos, colors);
if (m_radial) {
m_gradient = SkGradientShader::CreateRadial(m_p1,
WebCoreFloatToSkScalar(m_r1), colors, pos,
static_cast<int>(count_used), SkShader::kClamp_TileMode);
} else {
SkPoint pts[2] = { m_p0, m_p1 };
m_gradient = SkGradientShader::CreateLinear(pts, colors, pos,
static_cast<int>(count_used), SkShader::kClamp_TileMode);
}
return m_gradient;
}
void Gradient::fill(GraphicsContext* context, const FloatRect& rect)
{
// Until this is filled, we don't support CSSGradients
notImplemented();
}
} // namespace WebCore
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