14e8b4bb09
to get rid of seams in repeating patterns. https://github.com/mapbox/mapbox-gl-styles/issues/50#issuecomment-86159351
113 lines
4.1 KiB
C++
113 lines
4.1 KiB
C++
#include "scaling.hpp"
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namespace {
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using namespace mbgl;
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inline uint8_t bilinearInterpolate(uint8_t tl, uint8_t tr, uint8_t bl, uint8_t br, double dx, double dy) {
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const double t = dx * (tr - tl) + tl;
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const double b = dx * (br - bl) + bl;
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return t + dy * (b - t);
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}
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template <size_t i>
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inline const uint8_t& b(const uint32_t& w) {
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return reinterpret_cast<const uint8_t*>(&w)[i];
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}
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template <size_t i>
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inline uint8_t& b(uint32_t& w) {
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return reinterpret_cast<uint8_t*>(&w)[i];
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}
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vec2<double> getFactor(const Rect<uint32_t>& srcPos, const Rect<uint32_t>& dstPos) {
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return {
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double(srcPos.w) / dstPos.w,
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double(srcPos.h) / dstPos.h
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};
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}
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vec2<uint32_t> getBounds(const vec2<uint32_t>& srcSize, const Rect<uint32_t>& srcPos,
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const vec2<uint32_t>& dstSize, const Rect<uint32_t>& dstPos,
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const vec2<double>& factor) {
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if (srcPos.x > srcSize.x || srcPos.y > srcSize.y ||
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dstPos.x > dstSize.x || dstPos.y > dstSize.y) {
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// Source or destination position is out of range.
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return { 0, 0 };
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}
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// Make sure we don't read/write values out of range.
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return { std::min(uint32_t(double(srcSize.x - srcPos.x) / factor.x),
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std::min(dstSize.x - dstPos.x, dstPos.w)),
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std::min(uint32_t(double(srcSize.y - srcPos.y) / factor.y),
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std::min(dstSize.y - dstPos.y, dstPos.h)) };
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}
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}
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namespace mbgl {
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namespace util {
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void bilinearScale(const uint32_t* srcData, const vec2<uint32_t>& srcSize,
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const Rect<uint32_t>& srcPos, uint32_t* dstData, const vec2<uint32_t>& dstSize,
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const Rect<uint32_t>& dstPos, bool wrap) {
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const auto factor = getFactor(srcPos, dstPos);
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const auto bounds = getBounds(srcSize, srcPos, dstSize, dstPos, factor);
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uint32_t x, y;
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size_t i = dstSize.x * dstPos.y + dstPos.x;
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for (y = 0; y < bounds.y; y++) {
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const double fractY = y * factor.y;
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const uint32_t Y0 = fractY;
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const uint32_t Y1 = wrap ? (Y0 + 1) % srcPos.h : (Y0 + 1);
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const uint32_t srcY0 = srcPos.y + Y0;
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const uint32_t srcY1 = std::min(srcPos.y + Y1, srcSize.y - 1);
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for (x = 0; x < bounds.x; x++) {
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const double fractX = x * factor.x;
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const uint32_t X0 = fractX;
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const uint32_t X1 = wrap ? (X0 + 1) % srcPos.w : (X0 + 1);
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const uint32_t srcX0 = srcPos.x + X0;
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const uint32_t srcX1 = std::min(srcPos.x + X1, srcSize.x - 1);
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const uint32_t tl = srcData[srcSize.x * srcY0 + srcX0];
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const uint32_t tr = srcData[srcSize.x * srcY0 + srcX1];
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const uint32_t bl = srcData[srcSize.x * srcY1 + srcX0];
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const uint32_t br = srcData[srcSize.x * srcY1 + srcX1];
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const double dx = fractX - X0;
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const double dy = fractY - Y0;
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uint32_t& dst = dstData[i + x];
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b<0>(dst) = bilinearInterpolate(b<0>(tl), b<0>(tr), b<0>(bl), b<0>(br), dx, dy);
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b<1>(dst) = bilinearInterpolate(b<1>(tl), b<1>(tr), b<1>(bl), b<1>(br), dx, dy);
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b<2>(dst) = bilinearInterpolate(b<2>(tl), b<2>(tr), b<2>(bl), b<2>(br), dx, dy);
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b<3>(dst) = bilinearInterpolate(b<3>(tl), b<3>(tr), b<3>(bl), b<3>(br), dx, dy);
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}
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i += dstSize.x;
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}
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}
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void nearestNeighborScale(const uint32_t* srcData, const vec2<uint32_t>& srcSize,
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const Rect<uint32_t>& srcPos, uint32_t* dstData,
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const vec2<uint32_t>& dstSize, const Rect<uint32_t>& dstPos) {
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const auto factor = getFactor(srcPos, dstPos);
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const auto bounds = getBounds(srcSize, srcPos, dstSize, dstPos, factor);
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double fractSrcY = srcPos.y;
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double fractSrcX;
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size_t i = dstSize.x * dstPos.y + dstPos.x;
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uint32_t srcY;
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uint32_t x, y;
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for (y = 0; y < bounds.y; y++) {
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fractSrcX = srcPos.x;
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srcY = srcSize.x * uint32_t(fractSrcY);
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for (x = 0; x < bounds.x; x++) {
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dstData[i + x] = srcData[srcY + uint32_t(fractSrcX)];
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fractSrcX += factor.x;
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}
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i += dstSize.x;
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fractSrcY += factor.y;
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}
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}
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}
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}
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