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#include "vectorimage.h"
std::unique_ptr<VectorImage> ShrinkHorizontally(const ImageInterface& source,
size_t shrinkFactor) {
if (source.Width() == 0) {
return std::unique_ptr<VectorImage>(new VectorImage());
} else {
const size_t newWidth = (source.Width() + shrinkFactor - 1) / shrinkFactor;
const size_t height = source.Height();
std::vector<float> newImage;
newImage.reserve(newWidth * height);
for (size_t x = 0; x != newWidth; ++x) {
size_t binSize = shrinkFactor;
if (binSize + x * shrinkFactor > source.Width())
binSize = source.Width() - x * shrinkFactor;
const float* sourceData = source.Data();
for (size_t y = 0; y != height; ++y) {
float sum = 0.0;
const float* sourceRow = &sourceData[y * source.Stride()];
for (size_t binX = 0; binX < binSize; ++binX) {
const size_t curX = x * shrinkFactor + binX;
sum += sourceRow[curX];
}
newImage.emplace_back(sum / float(binSize));
}
}
return std::unique_ptr<VectorImage>(
new VectorImage(std::move(newImage), newWidth));
}
}
std::unique_ptr<VectorImage> ShrinkVertically(const ImageInterface& source,
size_t shrinkFactor) {
const size_t sourceHeight = source.Height();
const size_t newHeight = (sourceHeight + shrinkFactor - 1) / shrinkFactor;
std::vector<float> newImage;
newImage.reserve(source.Width() * newHeight);
const float* sourceData = source.Data();
for (size_t y = 0; y != newHeight; ++y) {
size_t binSize = shrinkFactor;
if (binSize + y * shrinkFactor > sourceHeight)
binSize = sourceHeight - y * shrinkFactor;
for (size_t x = 0; x != source.Width(); ++x) {
float sum = 0.0;
for (size_t binY = 0; binY < binSize; ++binY) {
const size_t curY = y * shrinkFactor + binY;
const float* sourceRow = &sourceData[curY * source.Stride()];
sum += sourceRow[x];
}
newImage.emplace_back(sum / float(binSize));
}
}
return std::unique_ptr<VectorImage>(
new VectorImage(std::move(newImage), source.Width()));
}
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