PassOwnPtr<RasterShapeIntervals> RasterShapeIntervals::computeShapeMarginIntervals(int shapeMargin) const
{
int marginIntervalsSize = (offset() > shapeMargin) ? size() : size() - offset() * 2 + shapeMargin * 2;
OwnPtr<RasterShapeIntervals> result = adoptPtr(new RasterShapeIntervals(marginIntervalsSize, std::max(shapeMargin, offset())));
MarginIntervalGenerator marginIntervalGenerator(shapeMargin);
for (int y = bounds().y(); y < bounds().maxY(); ++y) {
const IntShapeInterval& intervalAtY = intervalAt(y);
if (intervalAtY.isEmpty())
continue;
marginIntervalGenerator.set(y, intervalAtY);
int marginY0 = std::max(minY(), y - shapeMargin);
int marginY1 = std::min(maxY(), y + shapeMargin + 1);
for (int marginY = y - 1; marginY >= marginY0; --marginY) {
if (marginY > bounds().y() && intervalAt(marginY).contains(intervalAtY))
break;
result->intervalAt(marginY).unite(marginIntervalGenerator.intervalAt(marginY));
}
result->intervalAt(y).unite(marginIntervalGenerator.intervalAt(y));
for (int marginY = y + 1; marginY < marginY1; ++marginY) {
if (marginY < bounds().maxY() && intervalAt(marginY).contains(intervalAtY))
break;
result->intervalAt(marginY).unite(marginIntervalGenerator.intervalAt(marginY));
}
}
result->initializeBounds();
return result.release();
}
void RasterShapeIntervals::buildBoundsPath(Path& path) const
{
int maxY = bounds().maxY();
for (int y = bounds().y(); y < maxY; y++) {
if (intervalAt(y).isEmpty())
continue;
IntShapeInterval extent = intervalAt(y);
int endY = y + 1;
for (; endY < maxY; endY++) {
if (intervalAt(endY).isEmpty() || intervalAt(endY) != extent)
break;
}
path.addRect(FloatRect(extent.x1(), y, extent.width(), endY - y));
y = endY - 1;
}
}
void RasterShapeIntervals::initializeBounds()
{
m_bounds = IntRect();
for (int y = minY(); y < maxY(); ++y) {
const IntShapeInterval& intervalAtY = intervalAt(y);
if (intervalAtY.isEmpty())
continue;
m_bounds.unite(IntRect(intervalAtY.x1(), y, intervalAtY.width(), 1));
}
}
std::unique_ptr<Shape> Shape::createRasterShape(Image* image, float threshold, const LayoutRect& imageR, const LayoutRect& marginR, WritingMode writingMode, float margin)
{
IntRect imageRect = pixelSnappedIntRect(imageR);
IntRect marginRect = pixelSnappedIntRect(marginR);
auto intervals = std::make_unique<RasterShapeIntervals>(marginRect.height(), -marginRect.y());
std::unique_ptr<ImageBuffer> imageBuffer = ImageBuffer::create(imageRect.size());
if (imageBuffer) {
GraphicsContext* graphicsContext = imageBuffer->context();
graphicsContext->drawImage(image, ColorSpaceDeviceRGB, IntRect(IntPoint(), imageRect.size()));
RefPtr<Uint8ClampedArray> pixelArray = imageBuffer->getUnmultipliedImageData(IntRect(IntPoint(), imageRect.size()));
unsigned pixelArrayLength = pixelArray->length();
unsigned pixelArrayOffset = 3; // Each pixel is four bytes: RGBA.
uint8_t alphaPixelThreshold = threshold * 255;
int minBufferY = std::max(0, marginRect.y() - imageRect.y());
int maxBufferY = std::min(imageRect.height(), marginRect.maxY() - imageRect.y());
if (static_cast<unsigned>(imageRect.width() * imageRect.height() * 4) == pixelArrayLength) {
for (int y = minBufferY; y < maxBufferY; ++y) {
int startX = -1;
for (int x = 0; x < imageRect.width(); ++x, pixelArrayOffset += 4) {
uint8_t alpha = pixelArray->item(pixelArrayOffset);
bool alphaAboveThreshold = alpha > alphaPixelThreshold;
if (startX == -1 && alphaAboveThreshold) {
startX = x;
} else if (startX != -1 && (!alphaAboveThreshold || x == imageRect.width() - 1)) {
// We're creating "end-point exclusive" intervals here. The value of an interval's x1 is
// the first index of an above-threshold pixel for y, and the value of x2 is 1+ the index
// of the last above-threshold pixel.
int endX = alphaAboveThreshold ? x + 1 : x;
intervals->intervalAt(y + imageRect.y()).unite(IntShapeInterval(startX + imageRect.x(), endX + imageRect.x()));
startX = -1;
}
}
}
}
}
auto rasterShape = std::make_unique<RasterShape>(WTF::move(intervals), marginRect.size());
rasterShape->m_writingMode = writingMode;
rasterShape->m_margin = margin;
return WTF::move(rasterShape);
}
