static uint8_t* create_half_plane_profile(int profileWidth) {
SkASSERT(!(profileWidth & 0x1));
// The full kernel is 6 sigmas wide.
float sigma = profileWidth / 6.f;
int halfKernelSize = profileWidth / 2;
SkAutoTArray<float> halfKernel(halfKernelSize);
uint8_t* profile = new uint8_t[profileWidth];
// The half kernel should sum to 0.5.
const float tot = 2.f * make_unnormalized_half_kernel(halfKernel.get(), halfKernelSize, sigma);
float sum = 0.f;
// Populate the profile from the right edge to the middle.
for (int i = 0; i < halfKernelSize; ++i) {
halfKernel[halfKernelSize - i - 1] /= tot;
sum += halfKernel[halfKernelSize - i - 1];
profile[profileWidth - i - 1] = SkUnitScalarClampToByte(sum);
}
// Populate the profile from the middle to the left edge (by flipping the half kernel and
// continuing the summation).
for (int i = 0; i < halfKernelSize; ++i) {
sum += halfKernel[i];
profile[halfKernelSize - i - 1] = SkUnitScalarClampToByte(sum);
}
// Ensure tail goes to 0.
profile[profileWidth - 1] = 0;
return profile;
}
static uint8_t* create_profile(float halfWH, float sigma) {
int kernelWH = SkScalarCeilToInt(6.0f*sigma);
kernelWH = (kernelWH + 1) & ~1; // make it the next even number up
SkAutoTArray<float> halfKernel(kernelWH*kernelWH/2);
make_half_kernel(halfKernel.get(), kernelWH, sigma);
float offset;
int numSteps;
compute_profile_offset_and_size(halfWH, sigma, &offset, &numSteps);
uint8_t* weights = new uint8_t[numSteps];
for (int i = 0; i < numSteps; ++i) {
weights[i] = eval_at(offset+i, halfWH, halfKernel.get(), kernelWH);
}
return weights;
}
