6663b6c9
 adorian
projet complet av...
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
#include <kandinsky/context.h>
#include <assert.h>
void KDContext::drawLine(KDPoint p1, KDPoint p2, KDColor c) {
// Find the largest gap
KDPoint left = KDPointZero, right = KDPointZero;
if (p2.x() > p1.x()) {
left = p1;
right = p2;
} else {
left = p2;
right = p1;
}
KDPoint top = KDPointZero, bottom = KDPointZero;
if (p2.y() > p1.y()) {
top = p1;
bottom = p2;
} else {
top = p2;
bottom = p1;
}
assert(right.x() >= left.x());
assert(bottom.y() >= top.y());
KDCoordinate deltaX = 2*(right.x() - left.x());
KDCoordinate deltaY = 2*(bottom.y() - top.y());
KDPoint p = KDPointZero, alwaysTranslate = KDPointZero, conditionalTranslate = KDPointZero;
KDCoordinate scanLength, error, minusError, plusError;
if (deltaX >= deltaY) {
p = left;
scanLength = right.x() - left.x();
error = right.x() - left.x();
minusError = deltaY;
plusError = deltaX;
alwaysTranslate = KDPoint(1,0);
conditionalTranslate = KDPoint(0, (right.y() >= left.y() ? 1 : -1));
} else {
p = top;
scanLength = bottom.y() - top.y();
error = bottom.y() - top.y();
minusError = deltaX;
plusError = deltaY;
alwaysTranslate = KDPoint(0,1);
conditionalTranslate = KDPoint((bottom.x() >= top.x() ? 1 : -1), 0);
}
KDCoordinate scanCounter = 0;
while (scanCounter++ < scanLength) {
setPixel(p, c);
p = p.translatedBy(alwaysTranslate);
error = error - minusError;
if (error <= 0) {
p = p.translatedBy(conditionalTranslate);
error = error + plusError;
}
}
}
|