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LibPDF: Remove get_bounds lambda in SampledFunction::evaluate()

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Using `min()` to guarantee the left index is never == `size() - 1`,
even for an interpolation value of 1.0, is less code, and arguably
easier to understand as well.

No behavior change.
This commit is contained in:
Nico Weber 2023-12-02 18:19:23 +09:00 • committed by Andreas Kling
parent d9fd72007e
commit 54883b7d41
1 changed files with 6 additions and 22 deletions
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28
Userland/Libraries/LibPDF/Function.cpp
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@ -193,17 +193,6 @@ PDFErrorOr<ReadonlySpan<float>> SampledFunction::evaluate(ReadonlySpan<float> xs
m_inputs[i] = ec;
}
auto get_bounds = [](float x, float& low, float& high) {
low = floorf(x);
high = ceilf(x);
if (low == high) {
if (low == 0.0f)
high = 1.0f;
else
low = high - 1.0f;
}
};
for (size_t r = 0; r < m_range.size(); ++r) {
// For 1-D input data, we need to sample 2 points, one to the left and one to the right, and then interpolate between them.
// For 2-D input data, we need to sample 4 points (top-left, top-right, bottom-left, bottom-right),
@ -219,24 +208,19 @@ PDFErrorOr<ReadonlySpan<float>> SampledFunction::evaluate(ReadonlySpan<float> xs
coordinates.resize(m_domain.size());
for (size_t mask = 0; mask < (1u << m_domain.size()); ++mask) {
for (size_t i = 0; i < m_domain.size(); ++i) {
float ec = m_inputs[i];
float e0, e1;
get_bounds(ec, e0, e1);
if ((mask & (1u << i)) != 0)
ec = e1;
else
ec = e0;
coordinates[i] = static_cast<int>(ec);
unsigned n = m_sizes[i] - 1;
unsigned left_index = min(m_inputs[i], n - 1);
coordinates[i] = left_index + ((mask >> i) & 1u);
}
samples[mask] = sample(coordinates, r);
}
for (int i = static_cast<int>(m_domain.size() - 1); i >= 0; --i) {
unsigned n = m_sizes[i] - 1;
float ec = m_inputs[i];
float e0, e1;
get_bounds(ec, e0, e1);
unsigned e0 = min(static_cast<unsigned>(ec), n - 1);
for (size_t mask = 0; mask < (1u << i); ++mask)
samples[mask] = interpolate(ec, e0, e1, samples[mask], samples[mask | (1 << i)]);
samples[mask] = mix(samples[mask], samples[mask | (1 << i)], ec - e0);
}
float result = interpolate(samples[0], 0.0f, 255.0f, m_decode[r].lower, m_decode[r].upper);