/* -*- mode: c++; c-basic-offset: 4 -*- */

/* image.h

*

*/

#ifndef MPL_IMAGE_H

#define MPL_IMAGE_H

#include <vector>

// utilities for irregular grids

void _bin_indices_middle(

unsigned int *irows, int nrows, const float *ys1, unsigned long ny, float dy, float y_min);

void _bin_indices_middle_linear(float *arows,

unsigned int *irows,

int nrows,

const float *y,

unsigned long ny,

float dy,

float y_min);

void _bin_indices(int *irows, int nrows, const double *y, unsigned long ny, double sc, double offs);

template <class CoordinateArray, class ColorArray, class OutputArray>

void pcolor(CoordinateArray &x,

CoordinateArray &y,

ColorArray &d,

unsigned int rows,

unsigned int cols,

float bounds[4],

int interpolation,

OutputArray &out)

{

if (rows >= 32768 || cols >= 32768) {

throw std::runtime_error("rows and cols must both be less than 32768");

}

float x_min = bounds[0];

float x_max = bounds[1];

float y_min = bounds[2];

float y_max = bounds[3];

float width = x_max - x_min;

float height = y_max - y_min;

float dx = width / ((float)cols);

float dy = height / ((float)rows);

// Check we have something to output to

if (rows == 0 || cols == 0) {

throw std::runtime_error("Cannot scale to zero size");

}

if (d.dim(2) != 4) {

throw std::runtime_error("data must be in RGBA format");

}

// Check dimensions match

unsigned long nx = x.dim(0);

unsigned long ny = y.dim(0);

if (nx != (unsigned long)d.dim(1) || ny != (unsigned long)d.dim(0)) {

throw std::runtime_error("data and axis dimensions do not match");

}

// Allocate memory for pointer arrays

std::vector<unsigned int> rowstarts(rows);

std::vector<unsigned int> colstarts(cols);

// Calculate the pointer arrays to map input x to output x

unsigned int i, j;

unsigned int *colstart = &colstarts[0];

unsigned int *rowstart = &rowstarts[0];

const float *xs1 = x.data();

const float *ys1 = y.data();

// Copy data to output buffer

const unsigned char *start;

const unsigned char *inposition;

size_t inrowsize = nx * 4;

size_t rowsize = cols * 4;

unsigned char *position = (unsigned char *)out.data();

unsigned char *oldposition = NULL;

start = d.data();

if (interpolation == NEAREST) {

_bin_indices_middle(colstart, cols, xs1, nx, dx, x_min);

_bin_indices_middle(rowstart, rows, ys1, ny, dy, y_min);

for (i = 0; i < rows; i++, rowstart++) {

if (i > 0 && *rowstart == 0) {

memcpy(position, oldposition, rowsize * sizeof(unsigned char));

oldposition = position;

position += rowsize;

} else {

oldposition = position;

start += *rowstart * inrowsize;

inposition = start;

for (j = 0, colstart = &colstarts[0]; j < cols; j++, position += 4, colstart++) {

inposition += *colstart * 4;

memcpy(position, inposition, 4 * sizeof(unsigned char));

}

}

}

} else if (interpolation == BILINEAR) {

std::vector<float> acols(cols);

std::vector<float> arows(rows);

_bin_indices_middle_linear(&acols[0], colstart, cols, xs1, nx, dx, x_min);

_bin_indices_middle_linear(&arows[0], rowstart, rows, ys1, ny, dy, y_min);

double a00, a01, a10, a11, alpha, beta;

// Copy data to output buffer

for (i = 0; i < rows; i++) {

for (j = 0; j < cols; j++) {

alpha = arows[i];

beta = acols[j];

a00 = alpha * beta;

a01 = alpha * (1.0 - beta);

a10 = (1.0 - alpha) * beta;

a11 = 1.0 - a00 - a01 - a10;

for (size_t k = 0; k < 4; ++k) {

position[k] =

d(rowstart[i], colstart[j], k) * a00 +

d(rowstart[i], colstart[j] + 1, k) * a01 +

d(rowstart[i] + 1, colstart[j], k) * a10 +

d(rowstart[i] + 1, colstart[j] + 1, k) * a11;

}

position += 4;

}

}

}

}

template <class CoordinateArray, class ColorArray, class Color, class OutputArray>

void pcolor2(CoordinateArray &x,

CoordinateArray &y,

ColorArray &d,

unsigned int rows,

unsigned int cols,

float bounds[4],

Color &bg,

OutputArray &out)

{

double x_left = bounds[0];

double x_right = bounds[1];

double y_bot = bounds[2];

double y_top = bounds[3];

// Check we have something to output to

if (rows == 0 || cols == 0) {

throw std::runtime_error("rows or cols is zero; there are no pixels");

}

if (d.dim(2) != 4) {

throw std::runtime_error("data must be in RGBA format");

}

// Check dimensions match

unsigned long nx = x.dim(0);

unsigned long ny = y.dim(0);

if (nx != (unsigned long)d.dim(1) + 1 || ny != (unsigned long)d.dim(0) + 1) {

throw std::runtime_error("data and axis bin boundary dimensions are incompatible");

}

if (bg.dim(0) != 4) {

throw std::runtime_error("bg must be in RGBA format");

}

std::vector<int> irows(rows);

std::vector<int> jcols(cols);

// Calculate the pointer arrays to map input x to output x

size_t i, j;

const double *x0 = x.data();

const double *y0 = y.data();

double sx = cols / (x_right - x_left);

double sy = rows / (y_top - y_bot);

_bin_indices(&jcols[0], cols, x0, nx, sx, x_left);

_bin_indices(&irows[0], rows, y0, ny, sy, y_bot);

// Copy data to output buffer

unsigned char *position = (unsigned char *)out.data();

for (i = 0; i < rows; i++) {

for (j = 0; j < cols; j++) {

if (irows[i] == -1 || jcols[j] == -1) {

memcpy(position, (const unsigned char *)bg.data(), 4 * sizeof(unsigned char));

} else {

for (size_t k = 0; k < 4; ++k) {

position[k] = d(irows[i], jcols[j], k);

}

}

position += 4;

}

}

}

#endif