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LibGfx: Use integer version of Bresenham's algorithm.

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Oleg Sikorskiy 2021-04-03 17:11:35 +03:00 • committed by Andreas Kling
parent 83b5655977
commit a5db11c1f0
1 changed files with 15 additions and 15 deletions
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30
Userland/Libraries/LibGfx/Painter.cpp
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@ -1387,8 +1387,8 @@ void Painter::draw_line(const IntPoint& p1, const IntPoint& p2, Color color, int
// FIXME: Implement dotted/dashed diagonal lines.
VERIFY(style == LineStyle::Solid);
const double adx = abs(point2.x() - point1.x());
const double ady = abs(point2.y() - point1.y());
const int adx = abs(point2.x() - point1.x());
const int ady = abs(point2.y() - point1.y());
if (adx > ady) {
if (point1.x() > point2.x())
@ -1399,34 +1399,34 @@ void Painter::draw_line(const IntPoint& p1, const IntPoint& p2, Color color, int
}
// FIXME: Implement clipping below.
const double dx = point2.x() - point1.x();
const double dy = point2.y() - point1.y();
double error = 0;
const int dx = point2.x() - point1.x();
const int dy = point2.y() - point1.y();
int error = 0;
if (dx > dy) {
const double y_step = dy == 0 ? 0 : (dy > 0 ? 1 : -1);
const double delta_error = fabs(dy / dx);
const int y_step = dy == 0 ? 0 : (dy > 0 ? 1 : -1);
const int delta_error = 2 * abs(dy);
int y = point1.y();
for (int x = point1.x(); x <= point2.x(); ++x) {
if (clip_rect.contains(x, y))
draw_physical_pixel({ x, y }, color, thickness);
error += delta_error;
if (error >= 0.5) {
y = (double)y + y_step;
error -= 1.0;
if (error >= dx) {
y += y_step;
error -= 2 * dx;
}
}
} else {
const double x_step = dx == 0 ? 0 : (dx > 0 ? 1 : -1);
const double delta_error = fabs(dx / dy);
const int x_step = dx == 0 ? 0 : (dx > 0 ? 1 : -1);
const int delta_error = 2 * abs(dx);
int x = point1.x();
for (int y = point1.y(); y <= point2.y(); ++y) {
if (clip_rect.contains(x, y))
draw_physical_pixel({ x, y }, color, thickness);
error += delta_error;
if (error >= 0.5) {
x = (double)x + x_step;
error -= 1.0;
if (error >= dy) {
x += x_step;
error -= 2 * dy;
}
}
}