void Circle::Draw(QImage &img)
{
int error = -Radius;
int x = Radius;
int y = 0;
// The following while loop may be altered to 'while (x > y)' for a
// performance benefit, as long as a call to 'plot4points' follows
// the body of the loop. This allows for the elimination of the
// '(x != y)' test in 'plot8points', providing a further benefit.
//
// For the sake of clarity, this is not shown here.
while (x >= y)
{
plot8points(Centre.x(), Centre.y(), x, y, lineColor ,img);
error += y;
++y;
error += y;
// The following test may be implemented in assembly language in
// most machines by testing the carry flag after adding 'y' to
// the value of 'error' in the previous step, since 'error'
// nominally has a negative value.
if (error >= 0)
{
error -= x;
--x;
error -= x;
}
}
}
/**
* Midpoint circle algorithm:
* http://en.wikipedia.org/wiki/Midpoint_circle_algorithm
*/
void fgui_draw_circle(uint16_t cx, uint16_t cy, uint16_t radius, uint32_t color)
{
int16_t error = -radius;
int16_t x = radius;
int16_t y = 0;
// The following while loop may altered to 'while (x > y)' for a
// performance benefit, as long as a call to 'plot4points' follows
// the body of the loop. This allows for the elimination of the
// '(x != y)' test in 'plot8points', providing a further benefit.
//
// For the sake of clarity, this is not shown here.
while (x >= y) {
plot8points(cx, cy, x, y, color);
error += y;
y++;
error += y;
// The following test may be implemented in assembly language in
// most machines by testing the carry flag after adding 'y' to
// the value of 'error' in the previous step, since 'error'
// nominally has a negative value.
if (error >= 0) {
error -= x;
x--;
error -= x;
}
}
}
/*
Example: lcd.createCircle(30, 30, 30, 1);
cx and cy mark the distance from the origin point.
*/
void easyT6963::drawCircle(uint8_t cx, uint8_t cy, uint8_t radius, bool color){
int error = -radius;
uint8_t x = radius;
uint8_t y = 0;
while (x >= y){
plot8points(cx, cy, x, y, color);
error += y;
++y;
error += y;
if (error >= 0){
--x;
error -= x;
error -= x;
}
}
}
// Draw circle using Bresenham's midpoint circle algorithm
// From http://en.wikipedia.org/wiki/Midpoint_circle_algorithm
void Draw_Circle(int x0, int y0, int radius, int borderColor) {
int error = -radius;
int x = radius;
int y = 0;
while (x >= y) {
plot8points(x0, y0, x, y, borderColor);
error += y;
++y;
error += y;
if (error >= 0) {
error -= x;
--x;
error -= x;
}
}
}
void T6963::createCircle(int cx, int cy, int radius) //cx and cy mark the distance from the origin point.
{
int error = -radius;
int x = radius;
int y = 0;
while (x >= y){
plot8points(cx, cy, x, y);
error += y;
++y;
error += y;
if (error >= 0){
--x;
error -= x;
error -= x;
}
}
}
void Circle::drawCircle(QImage *img)
{
QPoint startPoint(controlPoints[0]), endPoint(controlPoints[1]);
int cx(startPoint.x()), cy(endPoint.y());
int radius = round(sqrt(pow(endPoint.x() - startPoint.x(), 2) + pow(endPoint.y() - startPoint.y(), 2)));
int error = -radius;
int x = radius;
int y = 0;
while (x >= y) {
plot8points(cx, cy, x, y, img, fill);
error += y;
++y;
error += y;
if (error >= 0) {
--x;
error -= x;
error -= x;
}
}
}
