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// Copyright 2012 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "include/non_linearity_filter_interpreter.h"
#include <cstring>
#include <linux/in.h>
namespace {
const size_t kIntPackedSize = 4;
const size_t kDoublePackedSize = 8;
}
namespace gestures {
NonLinearityFilterInterpreter::NonLinearityFilterInterpreter(
PropRegistry* prop_reg,
Interpreter* next,
Tracer* tracer)
: FilterInterpreter(nullptr, next, tracer, false),
x_range_len_(0), y_range_len_(0), p_range_len_(0),
enabled_(prop_reg, "Enable non-linearity correction", false),
data_location_(prop_reg, "Non-linearity correction data file", "") {
InitName();
LoadData();
}
unsigned int NonLinearityFilterInterpreter::ErrorIndex(size_t x_index,
size_t y_index,
size_t p_index) const {
unsigned int index = x_index * y_range_len_ * p_range_len_ +
y_index * p_range_len_ + p_index;
if (index >= x_range_len_ * y_range_len_ * p_range_len_)
index = 0;
return index;
}
int NonLinearityFilterInterpreter::ReadObject(void* buf, size_t object_size,
FILE* fd) {
int objs_read = fread(buf, object_size, 1, fd);
/* If this machine is big endian, reverse the bytes in the object */
if (object_size == kDoublePackedSize)
__le64_to_cpu(*static_cast<double*>(buf));
if (object_size == kIntPackedSize)
__le32_to_cpu(*static_cast<int32_t*>(buf));
return objs_read;
}
bool NonLinearityFilterInterpreter::LoadRange(std::unique_ptr<double[]>& arr,
size_t& len, FILE* fd) {
int tmp;
if (!ReadObject(&tmp, kIntPackedSize, fd))
return false;
len = tmp;
arr.reset(new double[len]);
for (size_t i = 0; i < len; i++) {
double tmp;
if (!ReadObject(&tmp, kDoublePackedSize, fd))
return false;
else
arr[i] = tmp;
}
return true;
}
void NonLinearityFilterInterpreter::LoadData() {
if (strlen(data_location_.val_) == 0) {
return;
}
FILE* data_fd = fopen(data_location_.val_, "rb");
if (!data_fd) {
// TODO(b/329268257): make this an Err, not a Log.
Log("Unable to open non-linearity filter data '%s'", data_location_.val_);
return;
}
// Load the ranges
if (!LoadRange(x_range_, x_range_len_, data_fd))
goto abort_load;
if (!LoadRange(y_range_, y_range_len_, data_fd))
goto abort_load;
if (!LoadRange(p_range_, p_range_len_, data_fd))
goto abort_load;
// Load the error readings themselves
err_.reset(new Error[x_range_len_ * y_range_len_ * p_range_len_]);
Error tmp;
for(unsigned int x = 0; x < x_range_len_; x++) {
for(unsigned int y = 0; y < y_range_len_; y++) {
for(unsigned int p = 0; p < p_range_len_; p++) {
if (!ReadObject(&tmp.x_error, kDoublePackedSize, data_fd) ||
!ReadObject(&tmp.y_error, kDoublePackedSize, data_fd)) {
goto abort_load;
}
err_[ErrorIndex(x, y, p)] = tmp;
}
}
}
fclose(data_fd);
return;
abort_load:
x_range_.reset();
x_range_len_ = 0;
y_range_.reset();
y_range_len_ = 0;
p_range_.reset();
p_range_len_ = 0;
err_.reset();
fclose(data_fd);
}
void NonLinearityFilterInterpreter::SyncInterpretImpl(HardwareState& hwstate,
stime_t* timeout) {
const char name[] = "NonLinearityFilterInterpreter::SyncInterpretImpl";
LogHardwareStatePre(name, hwstate);
if (enabled_.val_ && err_.get() && hwstate.finger_cnt == 1) {
FingerState* finger = &(hwstate.fingers[0]);
if (finger) {
Error error = GetError(finger->position_x, finger->position_y,
finger->pressure);
finger->position_x -= error.x_error;
finger->position_y -= error.y_error;
}
}
LogHardwareStatePost(name, hwstate);
next_->SyncInterpret(hwstate, timeout);
}
NonLinearityFilterInterpreter::Error
NonLinearityFilterInterpreter::LinearInterpolate(const Error& p1,
const Error& p2,
float percent_p1) const {
Error ret;
ret.x_error = percent_p1 * p1.x_error + (1.0 - percent_p1) * p2.x_error;
ret.y_error = percent_p1 * p1.y_error + (1.0 - percent_p1) * p2.y_error;
return ret;
}
NonLinearityFilterInterpreter::Error
NonLinearityFilterInterpreter::GetError(float finger_x, float finger_y,
float finger_p) const {
// First, find the 6 values surrounding the point to interpolate over
Bounds x_bounds = FindBounds(finger_x, x_range_, x_range_len_);
Bounds y_bounds = FindBounds(finger_y, y_range_, y_range_len_);
Bounds p_bounds = FindBounds(finger_p, p_range_, p_range_len_);
if (x_bounds.lo == -1 || x_bounds.hi == -1 || y_bounds.lo == -1 ||
y_bounds.hi == -1 || p_bounds.lo == -1 || p_bounds.hi == -1) {
Error error = { 0, 0 };
return error;
}
// Interpolate along the x-axis
float x_hi_perc = (finger_x - x_range_[x_bounds.lo]) /
(x_range_[x_bounds.hi] - x_range_[x_bounds.lo]);
Error e_yhi_phi = LinearInterpolate(
err_[ErrorIndex(x_bounds.hi, y_bounds.hi, p_bounds.hi)],
err_[ErrorIndex(x_bounds.lo, y_bounds.hi, p_bounds.hi)],
x_hi_perc);
Error e_yhi_plo = LinearInterpolate(
err_[ErrorIndex(x_bounds.hi, y_bounds.hi, p_bounds.lo)],
err_[ErrorIndex(x_bounds.lo, y_bounds.hi, p_bounds.lo)],
x_hi_perc);
Error e_ylo_phi = LinearInterpolate(
err_[ErrorIndex(x_bounds.hi, y_bounds.lo, p_bounds.hi)],
err_[ErrorIndex(x_bounds.lo, y_bounds.lo, p_bounds.hi)],
x_hi_perc);
Error e_ylo_plo = LinearInterpolate(
err_[ErrorIndex(x_bounds.hi, y_bounds.lo, p_bounds.lo)],
err_[ErrorIndex(x_bounds.lo, y_bounds.lo, p_bounds.lo)],
x_hi_perc);
// Interpolate along the y-axis
float y_hi_perc = (finger_y - y_range_[y_bounds.lo]) /
(y_range_[y_bounds.hi] - y_range_[y_bounds.lo]);
Error e_plo = LinearInterpolate(e_yhi_plo, e_ylo_plo, y_hi_perc);
Error e_phi = LinearInterpolate(e_yhi_phi, e_ylo_phi, y_hi_perc);
// Finally, interpolate along the p-axis
float p_hi_perc = (finger_p - p_range_[p_bounds.lo]) /
(p_range_[p_bounds.hi] - p_range_[p_bounds.lo]);
Error error = LinearInterpolate(e_phi, e_plo, p_hi_perc);
return error;
}
NonLinearityFilterInterpreter::Bounds
NonLinearityFilterInterpreter::FindBounds(
float value,
const std::unique_ptr<double[]>& range,
size_t len) const {
Bounds bounds;
bounds.lo = bounds.hi = -1;
for (size_t i = 0; i < len; i++) {
if (range[i] <= value) {
bounds.lo = i;
} else {
bounds.hi = i;
break;
}
}
return bounds;
}
} // namespace gestures
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