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rotate-me-fast
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FIll new interpolated pixels. 

- Take input image in argument.
- Allow set_pixel() out of bounds, noop.
master
Fabien Freling 2014-06-26 23:45:02 +02:00
parent 00543d258d
commit 6a94c79ac2
2 changed files with 26 additions and 14 deletions
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2
TODO.md
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@ -3,4 +3,6 @@
[X] Use atan2 at beginning and end of line.
Interpolation in-between values
[X] Test pixel perfect 90
[ ] Fix out-of-bounds pixel set
[ ] Optimization for square images?

38
rotation.cpp
View File

@ -104,9 +104,10 @@ struct Image {
{
if (x >= width || y >= height)
{
cerr << "Point (" << x << ", " << y << ") out of bounds" << endl;
cerr << __LINE__ << " | Point (" << x << ", " << y << ") out of bounds" << endl;
cerr << " Image dimensions: " << width << " x " << height << endl;
assert(false);
// assert(false);
return;
}
int const index = y * width + x;
r_chan[index] = r;
@ -501,13 +502,11 @@ Image rotate(Image const& src, double angle)
int origin_nb_steps = max(abs(bl.x - tl.x), abs(bl.y - tl.y));
double origin_y_inc = (src_bl.y - src_tl.y) / origin_nb_steps;
double origin_x_inc = (src_bl.x - src_tl.x) / origin_nb_steps;
//cout << " origin steps: " << origin_nb_steps << " (" << origin_x_inc << ", " << origin_y_inc << ")" << endl;
// steps for line in source image
int line_nb_steps = max(abs(tr.x - tl.x), abs(tr.y - tl.y));
double line_y_inc = (src_tr.y - src_tl.y) / line_nb_steps;
double line_x_inc = (src_tr.x - src_tl.x) / line_nb_steps;
//cout << " line steps: " << line_nb_steps << " (" << line_x_inc << ", " << line_y_inc << ")" << endl;
// steps for first column in rotated image
double rotated_y_inc = (bl.y - tl.y) / (float) origin_nb_steps;
@ -515,7 +514,6 @@ Image rotate(Image const& src, double angle)
// steps for line in rotated image
DPoint bresenham((tr.x - tl.x) / (float) line_nb_steps, (tr.y - tl.y) / (float) line_nb_steps);
cout << "bresenham: " << bresenham << endl;
for (int y_i = 0; y_i <= (int) origin_nb_steps; ++y_i)
{
@ -523,6 +521,8 @@ Image rotate(Image const& src, double angle)
DPoint const src_origin(src_tl.x + y_i * origin_x_inc, src_tl.y + y_i * origin_y_inc);
APoint const rot_origin(tl.x + y_i * rotated_x_inc, tl.y + y_i * rotated_y_inc);
APoint previous = rot_origin;
for (int x_i = 0; x_i <= (int) line_nb_steps; ++x_i)
{
DPoint const src_rotated_point(src_origin.x + x_i * line_x_inc, src_origin.y + x_i * line_y_inc);
@ -546,6 +546,13 @@ Image rotate(Image const& src, double angle)
// TODO: bypass variables, access src pixels
src.get_pixel(src_p, r, g, b);
rotated.set_pixel(rot_point, r, g, b);
// Fill missing points, created by interpolation
if (previous.x != rot_point.x && previous.y != rot_point.y)
{
rotated.set_pixel(APoint(rot_point.x, previous.y), r, g, b);
}
previous = rot_point;
}
}
@ -677,9 +684,9 @@ void check_lines()
draw_outline(rect1, 90, "rect1");
}
bool check_90()
bool check_90(string const& path)
{
Image const src("img/lena.ppm");
Image const src(path);
Image const rotated = rotate(src, 90);
for (unsigned int y = 0; y < rotated.height; ++y)
@ -708,8 +715,14 @@ bool check_90()
// Main
//
int main()
int main(int argc, char* argv[])
{
if (argc < 2)
{
cout << "Usage: " << argv[0] << " image.ppm" << endl;
return 1;
}
bool perform_check = true;
if (perform_check)
@ -722,19 +735,16 @@ int main()
//check_lines();
if (!check_90())
if (false && !check_90(argv[1]))
{
cerr << __LINE__ << " | 90 degrees check failed" << endl;
return 1;
}
}
//Image img("img/luigi.ppm");
//Image img("img/wallpaper.ppm");
Image img("img/mini_lena.ppm");
Image img(argv[1]);
//for (double rotation : {0, 1, 5, 15, 30, 45, 60, 75, 90, 110, 140, 160, 180, 200, 210, 235, 260, 270, 300, 315, 355, 359})
for (double rotation : {0, 45, 90})
for (double rotation = 0; rotation <= 360; rotation += 5)
{
auto const before = chrono::high_resolution_clock::now();