void AffineUnit::calculate_matrix(
double in_x1,
double in_y1,
double in_x2,
double in_y2,
double out_x1,
double out_y1,
double out_x2,
double out_y2,
double out_x3,
double out_y3,
double out_x4,
double out_y4,
AffineMatrix *result)
{
AffineMatrix matrix;
double scalex;
double scaley;
scalex = scaley = 1.0;
if((in_x2 - in_x1) > 0)
scalex = 1.0 / (double)(in_x2 - in_x1);
if((in_y2 - in_y1) > 0)
scaley = 1.0 / (double)(in_y2 - in_y1);
// Determine the perspective transform that maps from
// the unit cube to the transformed coordinates
double dx1, dx2, dx3, dy1, dy2, dy3;
double det1, det2;
dx1 = out_x2 - out_x4;
dx2 = out_x3 - out_x4;
dx3 = out_x1 - out_x2 + out_x4 - out_x3;
dy1 = out_y2 - out_y4;
dy2 = out_y3 - out_y4;
dy3 = out_y1 - out_y2 + out_y4 - out_y3;
// Is the mapping affine?
if((dx3 == 0.0) && (dy3 == 0.0))
{
matrix.values[0][0] = out_x2 - out_x1;
matrix.values[0][1] = out_x4 - out_x2;
matrix.values[0][2] = out_x1;
matrix.values[1][0] = out_y2 - out_y1;
matrix.values[1][1] = out_y4 - out_y2;
matrix.values[1][2] = out_y1;
matrix.values[2][0] = 0.0;
matrix.values[2][1] = 0.0;
}
else
{
det1 = dx3 * dy2 - dy3 * dx2;
det2 = dx1 * dy2 - dy1 * dx2;
matrix.values[2][0] = det1 / det2;
det1 = dx1 * dy3 - dy1 * dx3;
det2 = dx1 * dy2 - dy1 * dx2;
matrix.values[2][1] = det1 / det2;
matrix.values[0][0] = out_x2 - out_x1 + matrix.values[2][0] * out_x2;
matrix.values[0][1] = out_x3 - out_x1 + matrix.values[2][1] * out_x3;
matrix.values[0][2] = out_x1;
matrix.values[1][0] = out_y2 - out_y1 + matrix.values[2][0] * out_y2;
matrix.values[1][1] = out_y3 - out_y1 + matrix.values[2][1] * out_y3;
matrix.values[1][2] = out_y1;
}
matrix.values[2][2] = 1.0;
result->identity();
result->translate(-in_x1, -in_y1);
result->scale(scalex, scaley);
matrix.multiply(result);
}
void AffineUnit::calculate_matrix(
double in_x1,
double in_y1,
double in_x2,
double in_y2,
double out_x1,
double out_y1,
double out_x2,
double out_y2,
double out_x3,
double out_y3,
double out_x4,
double out_y4,
AffineMatrix *result)
{
AffineMatrix matrix;
double scalex;
double scaley;
scalex = scaley = 1.0;
if((in_x2 - in_x1) > 0)
scalex = 1.0 / (double)(in_x2 - in_x1);
if((in_y2 - in_y1) > 0)
scaley = 1.0 / (double)(in_y2 - in_y1);
/* Determine the perspective transform that maps from
* the unit cube to the transformed coordinates
*/
double dx1, dx2, dx3, dy1, dy2, dy3;
double det1, det2;
dx1 = out_x2 - out_x4;
dx2 = out_x3 - out_x4;
dx3 = out_x1 - out_x2 + out_x4 - out_x3;
dy1 = out_y2 - out_y4;
dy2 = out_y3 - out_y4;
dy3 = out_y1 - out_y2 + out_y4 - out_y3;
// printf("AffineUnit::calculate_matrix %f %f %f %f %f %f\n",
// dx1,
// dx2,
// dx3,
// dy1,
// dy2,
// dy3
// );
/* Is the mapping affine? */
if((dx3 == 0.0) && (dy3 == 0.0))
{
matrix.values[0][0] = out_x2 - out_x1;
matrix.values[0][1] = out_x4 - out_x2;
matrix.values[0][2] = out_x1;
matrix.values[1][0] = out_y2 - out_y1;
matrix.values[1][1] = out_y4 - out_y2;
matrix.values[1][2] = out_y1;
matrix.values[2][0] = 0.0;
matrix.values[2][1] = 0.0;
}
else
{
det1 = dx3 * dy2 - dy3 * dx2;
det2 = dx1 * dy2 - dy1 * dx2;
matrix.values[2][0] = det1 / det2;
det1 = dx1 * dy3 - dy1 * dx3;
det2 = dx1 * dy2 - dy1 * dx2;
matrix.values[2][1] = det1 / det2;
matrix.values[0][0] = out_x2 - out_x1 + matrix.values[2][0] * out_x2;
matrix.values[0][1] = out_x3 - out_x1 + matrix.values[2][1] * out_x3;
matrix.values[0][2] = out_x1;
matrix.values[1][0] = out_y2 - out_y1 + matrix.values[2][0] * out_y2;
matrix.values[1][1] = out_y3 - out_y1 + matrix.values[2][1] * out_y3;
matrix.values[1][2] = out_y1;
}
matrix.values[2][2] = 1.0;
// printf("AffineUnit::calculate_matrix 1 %f %f\n", dx3, dy3);
// matrix.dump();
result->identity();
result->translate(-in_x1, -in_y1);
result->scale(scalex, scaley);
matrix.multiply(result);
// double test[3][3] = { { 0.0896, 0.0, 0.0 },
// { 0.0, 0.0896, 0.0 },
// { -0.00126, 0.0, 1.0 } };
// memcpy(&result->values[0][0], test, sizeof(test));
// printf("AffineUnit::calculate_matrix 4 %p\n", result);
// result->dump();
}