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Small optimization in resample

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This commit is contained in:
Dušan Poizl
2024-01-15 08:58:14 +01:00
parent a8a1509db7
commit 428f9c360a
1 changed files with 19 additions and 22 deletions
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rawimage.cpp
+19 -22
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@@ -575,43 +575,40 @@ void boxResample(uint32_t w, uint32_t h, uint32_t ch, uint32_t oldw, uint32_t ol
if constexpr(std::is_same<T, uint16_t>::value)
max = UINT16_MAX;
float sx = (float)oldw / w;
float sy = (float)oldh / h;
float sx_ = (float)w / oldw;
float sy_ = (float)h / oldh;
float s = 1.0 / (sx * sy);
for(uint32_t y = 0; y < h; y++)
float sx = (float)w / oldw;
float sy = (float)h / oldh;
for(uint32_t y = 0; y < h; y++)//iterate over destination Y
{
for(uint32_t x = 0; x < w; x++)
for(uint32_t x = 0; x < w; x++)//iterate over destination X
{
float p[4] = {0.0f};
uint32_t xx = x * oldw / w;
uint32_t xx = x * oldw / w;//calculate source rect
uint32_t yy = y * oldh / h;
uint32_t xe = std::min((x + 1) * oldw / w, oldw - 1);
uint32_t ye = std::min((y + 1) * oldh / h, oldh - 1);
for(uint32_t o = yy; o <= ye; o++)
for(uint32_t o = yy; o <= ye; o++)//iterate over source Y
{
float cy = o * sy_ - y;
if(cy < 0.0f)cy = 1.0f + cy * sy;
else if(sy_ + cy > 1.0f)cy = (1.0f - cy) * sy;
else cy = 1.0f;
if(yy==ye)cy = sy;
for(uint32_t i = xx; i <= xe; i++)
float cy = o * sy - y;
if(cy < 0.0f)cy = sy + cy;
else if(sy + cy > 1.0f)cy = 1.0f - cy;
else cy = sy;
if(yy==ye)cy = 1.0f;
for(uint32_t i = xx; i <= xe; i++)//iterate over source X
{
float cx = i * sx_ - x;
if(cx < 0.0f)cx = 1.0f + cx * sx;
else if(sx_ + cx > 1.0f)cx = (1.0f - cx) * sx;
else cx = 1.0f;
if(xx==xe)cx = sx;
float cx = i * sx - x;
if(cx < 0.0f)cx = sx + cx;
else if(sx + cx > 1.0f)cx = 1.0f - cx;
else cx = sx;
if(xx==xe)cx = 1.0f;
for(uint32_t z = 0; z < ch; z++)
p[z] += in[(o * oldw + i) * ch + z] * cy * cx;
}
}
for(uint32_t z = 0; z < ch; z++)
if constexpr(std::is_floating_point<T>::value)
out[(y * w + x) * ch + z] = p[z] * s;
out[(y * w + x) * ch + z] = p[z];
else
out[(y * w + x) * ch + z] = std::clamp(std::round(p[z] * s), 0.0f, max);
out[(y * w + x) * ch + z] = std::clamp(std::round(p[z]), 0.0f, max);
}
}
}