support wrapped bilinear scaling

to get rid of seams in repeating patterns.

https://github.com/mapbox/mapbox-gl-styles/issues/50#issuecomment-86159351
This commit is contained in:
Ansis Brammanis
2015-03-25 17:59:18 -07:00
committed by Konstantin Käfer
parent 9080f25d31
commit 14e8b4bb09
4 changed files with 27 additions and 26 deletions

View File

@@ -165,7 +165,7 @@ void SpriteAtlas::copy(const Rect<dimension>& dst, const SpritePosition& src, co
static_cast<uint32_t>(dst.originalW * pixelRatio),
static_cast<uint32_t>(dst.originalH * pixelRatio) };
util::bilinearScale(srcData, srcSize, srcPos, dstData, dstSize, dstPos);
util::bilinearScale(srcData, srcSize, srcPos, dstData, dstSize, dstPos, wrap);
// Add borders around the copied image if required.
if (wrap) {

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@@ -49,38 +49,39 @@ namespace util {
void bilinearScale(const uint32_t* srcData, const vec2<uint32_t>& srcSize,
const Rect<uint32_t>& srcPos, uint32_t* dstData, const vec2<uint32_t>& dstSize,
const Rect<uint32_t>& dstPos) {
const Rect<uint32_t>& dstPos, bool wrap) {
const auto factor = getFactor(srcPos, dstPos);
const auto bounds = getBounds(srcSize, srcPos, dstSize, dstPos, factor);
double fractSrcY = srcPos.y;
double fractSrcX;
uint32_t x, y;
size_t i = dstSize.x * dstPos.y + dstPos.x;
for (y = 0; y < bounds.y; y++) {
fractSrcX = srcPos.x;
const uint32_t srcY0 = fractSrcY;
const uint32_t srcY1 = std::min(srcY0 + 1, srcSize.y - 1);
const double fractY = y * factor.y;
const uint32_t Y0 = fractY;
const uint32_t Y1 = wrap ? (Y0 + 1) % srcPos.h : (Y0 + 1);
const uint32_t srcY0 = srcPos.y + Y0;
const uint32_t srcY1 = std::min(srcPos.y + Y1, srcSize.y - 1);
for (x = 0; x < bounds.x; x++) {
const uint32_t srcX0 = fractSrcX;
const uint32_t srcX1 = std::min(srcX0 + 1, srcSize.x - 1);
const double fractX = x * factor.x;
const uint32_t X0 = fractX;
const uint32_t X1 = wrap ? (X0 + 1) % srcPos.w : (X0 + 1);
const uint32_t srcX0 = srcPos.x + X0;
const uint32_t srcX1 = std::min(srcPos.x + X1, srcSize.x - 1);
const uint32_t tl = srcData[srcSize.x * srcY0 + srcX0];
const uint32_t tr = srcData[srcSize.x * srcY0 + srcX1];
const uint32_t bl = srcData[srcSize.x * srcY1 + srcX0];
const uint32_t br = srcData[srcSize.x * srcY1 + srcX1];
const double dx = fractSrcX - srcX0;
const double dy = fractSrcY - srcY0;
const double dx = fractX - X0;
const double dy = fractY - Y0;
uint32_t& dst = dstData[i + x];
b<0>(dst) = bilinearInterpolate(b<0>(tl), b<0>(tr), b<0>(bl), b<0>(br), dx, dy);
b<1>(dst) = bilinearInterpolate(b<1>(tl), b<1>(tr), b<1>(bl), b<1>(br), dx, dy);
b<2>(dst) = bilinearInterpolate(b<2>(tl), b<2>(tr), b<2>(bl), b<2>(br), dx, dy);
b<3>(dst) = bilinearInterpolate(b<3>(tl), b<3>(tr), b<3>(bl), b<3>(br), dx, dy);
fractSrcX += factor.x;
}
i += dstSize.x;
fractSrcY += factor.y;
}
}
@@ -108,4 +109,4 @@ void nearestNeighborScale(const uint32_t* srcData, const vec2<uint32_t>& srcSize
}
}
}
}

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@@ -12,7 +12,7 @@ namespace util {
void bilinearScale(const uint32_t* srcData, const vec2<uint32_t>& srcSize,
const Rect<uint32_t>& srcPos, uint32_t* dstData, const vec2<uint32_t>& dstSize,
const Rect<uint32_t>& dstPos);
const Rect<uint32_t>& dstPos, bool wrap);
void nearestNeighborScale(const uint32_t* srcData, const vec2<uint32_t>& srcSize,
const Rect<uint32_t>& srcPos, uint32_t* dstData,

View File

@@ -28,19 +28,19 @@ TEST(Bilinear, Scaling) {
uint32_t *dstData = dst.get();
std::fill(dstData, dstData + dstSize.x * dstSize.y, 0xFFFF00FF);
util::bilinearScale(srcData, srcSize, { 0, 0, 24, 24 }, dstData, dstSize, { 8, 8, 24, 24 });
util::bilinearScale(srcData, srcSize, { 26, 0, 24, 24 }, dstData, dstSize, { 0, 40, 48, 48 });
util::bilinearScale(srcData, srcSize, { 26, 26, 24, 24 }, dstData, dstSize, { 52, 40, 36, 36 });
util::bilinearScale(srcData, srcSize, { 26, 26, 24, 24 }, dstData, dstSize, { 52, 40, 36, 36 });
util::bilinearScale(srcData, srcSize, { 104, 0, 24, 24 }, dstData, dstSize, { 96, 0, 48, 48 });
util::bilinearScale(srcData, srcSize, { 52, 260, 24, 24 }, dstData, dstSize, { 108, 108, 38, 38 });
util::bilinearScale(srcData, srcSize, { 380, 0, 24, 24 }, dstData, dstSize, { 36, 0, 24, 24 });
util::bilinearScale(srcData, srcSize, { 396, 396, 24, 24 }, dstData, dstSize, { 0, 0, 50, 50 });
util::bilinearScale(srcData, srcSize, { 380, 182, 12, 12 }, dstData, dstSize, { 52, 80, 24, 24 });
util::bilinearScale(srcData, srcSize, { 0, 0, 24, 24 }, dstData, dstSize, { 8, 8, 24, 24 }, false);
util::bilinearScale(srcData, srcSize, { 26, 0, 24, 24 }, dstData, dstSize, { 0, 40, 48, 48 }, false);
util::bilinearScale(srcData, srcSize, { 26, 26, 24, 24 }, dstData, dstSize, { 52, 40, 36, 36 }, false);
util::bilinearScale(srcData, srcSize, { 26, 26, 24, 24 }, dstData, dstSize, { 52, 40, 36, 36 }, false);
util::bilinearScale(srcData, srcSize, { 104, 0, 24, 24 }, dstData, dstSize, { 96, 0, 48, 48 }, false);
util::bilinearScale(srcData, srcSize, { 52, 260, 24, 24 }, dstData, dstSize, { 108, 108, 38, 38 }, false);
util::bilinearScale(srcData, srcSize, { 380, 0, 24, 24 }, dstData, dstSize, { 36, 0, 24, 24 }, false);
util::bilinearScale(srcData, srcSize, { 396, 396, 24, 24 }, dstData, dstSize, { 0, 0, 50, 50 }, false);
util::bilinearScale(srcData, srcSize, { 380, 182, 12, 12 }, dstData, dstSize, { 52, 80, 24, 24 }, false);
// From the bottom
util::bilinearScale(srcData, srcSize, { 252, 380, 12, 12 }, dstData, dstSize, { 0, 90, 12, 12 });
util::bilinearScale(srcData, srcSize, { 252, 380, 12, 12 }, dstData, dstSize, { 18, 90, 24, 24 });
util::bilinearScale(srcData, srcSize, { 252, 380, 12, 12 }, dstData, dstSize, { 0, 90, 12, 12 }, false);
util::bilinearScale(srcData, srcSize, { 252, 380, 12, 12 }, dstData, dstSize, { 18, 90, 24, 24 }, false);
const std::string data { reinterpret_cast<char *>(dstData), dstSize.x * dstSize.y * sizeof(uint32_t) };
util::write_file("test/fixtures/sprites/atlas_actual.png", util::compress_png(dstSize.x, dstSize.y, dstData));