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// basisu_resampler.h
// Copyright (C) 2019 Binomial LLC. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#pragma once
#include "transcoder/basisu.h"
#define BASISU_RESAMPLER_DEBUG_OPS (0)
#define BASISU_RESAMPLER_DEFAULT_FILTER "lanczos4"
#define BASISU_RESAMPLER_MAX_DIMENSION (16384)
namespace basisu
{
// float or double
typedef float Resample_Real;
class Resampler
{
public:
typedef Resample_Real Sample;
struct Contrib
{
Resample_Real weight;
uint16_t pixel;
};
struct Contrib_List
{
uint16_t n;
Contrib *p;
};
enum Boundary_Op
{
BOUNDARY_WRAP = 0,
BOUNDARY_REFLECT = 1,
BOUNDARY_CLAMP = 2
};
enum Status
{
STATUS_OKAY = 0,
STATUS_OUT_OF_MEMORY = 1,
STATUS_BAD_FILTER_NAME = 2,
STATUS_SCAN_BUFFER_FULL = 3
};
// src_x/src_y - Input dimensions
// dst_x/dst_y - Output dimensions
// boundary_op - How to sample pixels near the image boundaries
// sample_low/sample_high - Clamp output samples to specified range, or disable clamping if sample_low >= sample_high
// Pclist_x/Pclist_y - Optional pointers to contributor lists from another instance of a Resampler
// src_x_ofs/src_y_ofs - Offset input image by specified amount (fractional values okay)
Resampler(
int src_x, int src_y,
int dst_x, int dst_y,
Boundary_Op boundary_op = BOUNDARY_CLAMP,
Resample_Real sample_low = 0.0f, Resample_Real sample_high = 0.0f,
const char *Pfilter_name = BASISU_RESAMPLER_DEFAULT_FILTER,
Contrib_List *Pclist_x = NULL,
Contrib_List *Pclist_y = NULL,
Resample_Real filter_x_scale = 1.0f,
Resample_Real filter_y_scale = 1.0f,
Resample_Real src_x_ofs = 0.0f,
Resample_Real src_y_ofs = 0.0f);
~Resampler();
// Reinits resampler so it can handle another frame.
void restart();
// false on out of memory.
bool put_line(const Sample *Psrc);
// NULL if no scanlines are currently available (give the resampler more scanlines!)
const Sample *get_line();
Status status() const
{
return m_status;
}
// Returned contributor lists can be shared with another Resampler.
void get_clists(Contrib_List **ptr_clist_x, Contrib_List **ptr_clist_y);
Contrib_List *get_clist_x() const
{
return m_Pclist_x;
}
Contrib_List *get_clist_y() const
{
return m_Pclist_y;
}
// Filter accessors.
static int get_filter_num();
static const char *get_filter_name(int filter_num);
static Contrib_List *make_clist(
int src_x, int dst_x, Boundary_Op boundary_op,
Resample_Real(*Pfilter)(Resample_Real),
Resample_Real filter_support,
Resample_Real filter_scale,
Resample_Real src_ofs);
private:
Resampler();
Resampler(const Resampler &o);
Resampler &operator=(const Resampler &o);
#ifdef BASISU_RESAMPLER_DEBUG_OPS
int total_ops;
#endif
int m_intermediate_x;
int m_resample_src_x;
int m_resample_src_y;
int m_resample_dst_x;
int m_resample_dst_y;
Boundary_Op m_boundary_op;
Sample *m_Pdst_buf;
Sample *m_Ptmp_buf;
Contrib_List *m_Pclist_x;
Contrib_List *m_Pclist_y;
bool m_clist_x_forced;
bool m_clist_y_forced;
bool m_delay_x_resample;
int *m_Psrc_y_count;
uint8_t *m_Psrc_y_flag;
// The maximum number of scanlines that can be buffered at one time.
enum
{
MAX_SCAN_BUF_SIZE = BASISU_RESAMPLER_MAX_DIMENSION
};
struct Scan_Buf
{
int scan_buf_y[MAX_SCAN_BUF_SIZE];
Sample *scan_buf_l[MAX_SCAN_BUF_SIZE];
};
Scan_Buf *m_Pscan_buf;
int m_cur_src_y;
int m_cur_dst_y;
Status m_status;
void resample_x(Sample *Pdst, const Sample *Psrc);
void scale_y_mov(Sample *Ptmp, const Sample *Psrc, Resample_Real weight, int dst_x);
void scale_y_add(Sample *Ptmp, const Sample *Psrc, Resample_Real weight, int dst_x);
void clamp(Sample *Pdst, int n);
void resample_y(Sample *Pdst);
static int reflect(const int j, const int src_x, const Boundary_Op boundary_op);
inline int count_ops(Contrib_List *Pclist, int k)
{
int i, t = 0;
for (i = 0; i < k; i++)
t += Pclist[i].n;
return (t);
}
Resample_Real m_lo;
Resample_Real m_hi;
inline Resample_Real clamp_sample(Resample_Real f) const
{
if (f < m_lo)
f = m_lo;
else if (f > m_hi)
f = m_hi;
return f;
}
};
} // namespace basisu
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