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ImDrawList: added PathEllipticalArcTo(), AddEllipse(), AddEllipseFilled(). (#2743)

Rebased with mods by ocornut: defaults to num_segments==0, supports for auto-tesselation, tweak demo.
This commit is contained in:
Leonardo Serrano 2019-08-22 21:50:02 -07:00 committed by ocornut
parent fa2e5710ac
commit e3d9b875c9
4 changed files with 59 additions and 3 deletions

View file

@ -1217,6 +1217,27 @@ void ImDrawList::PathArcTo(const ImVec2& center, float radius, float a_min, floa
}
}
void ImDrawList::PathEllipticalArcTo(const ImVec2& center, float radius_x, float radius_y, float rot, float a_min, float a_max, int num_segments)
{
if (num_segments <= 0)
num_segments = _CalcCircleAutoSegmentCount(ImMax(radius_x, radius_y)); // A bit pessimistic, maybe there's a better computation to do here.
_Path.reserve(_Path.Size + (num_segments + 1));
const float cos_rot = ImCos(rot);
const float sin_rot = ImSin(rot);
for (int i = 0; i <= num_segments; i++)
{
const float a = a_min + ((float)i / (float)num_segments) * (a_max - a_min);
ImVec2 point(ImCos(a) * radius_x, ImSin(a) * radius_y);
const float rel_x = (point.x * cos_rot) - (point.y * sin_rot);
const float rel_y = (point.x * sin_rot) + (point.y * cos_rot);
point.x = rel_x + center.x;
point.y = rel_y + center.y;
_Path.push_back(point);
}
}
ImVec2 ImBezierCubicCalc(const ImVec2& p1, const ImVec2& p2, const ImVec2& p3, const ImVec2& p4, float t)
{
float u = 1.0f - t;
@ -1547,6 +1568,35 @@ void ImDrawList::AddNgonFilled(const ImVec2& center, float radius, ImU32 col, in
PathFillConvex(col);
}
// Ellipse
void ImDrawList::AddEllipse(const ImVec2& center, float radius_x, float radius_y, ImU32 col, float rot, int num_segments, float thickness)
{
if ((col & IM_COL32_A_MASK) == 0)
return;
if (num_segments <= 0)
num_segments = _CalcCircleAutoSegmentCount(ImMax(radius_x, radius_y)); // A bit pessimistic, maybe there's a better computation to do here.
// Because we are filling a closed shape we remove 1 from the count of segments/points
const float a_max = IM_PI * 2.0f * ((float)num_segments - 1.0f) / (float)num_segments;
PathEllipticalArcTo(center, radius_x, radius_y, rot, 0.0f, a_max, num_segments - 1);
PathStroke(col, true, thickness);
}
void ImDrawList::AddEllipseFilled(const ImVec2& center, float radius_x, float radius_y, ImU32 col, float rot, int num_segments)
{
if ((col & IM_COL32_A_MASK) == 0)
return;
if (num_segments <= 0)
num_segments = _CalcCircleAutoSegmentCount(ImMax(radius_x, radius_y)); // A bit pessimistic, maybe there's a better computation to do here.
// Because we are filling a closed shape we remove 1 from the count of segments/points
const float a_max = IM_PI * 2.0f * ((float)num_segments - 1.0f) / (float)num_segments;
PathEllipticalArcTo(center, radius_x, radius_y, rot, 0.0f, a_max, num_segments - 1);
PathFillConvex(col);
}
// Cubic Bezier takes 4 controls points
void ImDrawList::AddBezierCubic(const ImVec2& p1, const ImVec2& p2, const ImVec2& p3, const ImVec2& p4, ImU32 col, float thickness, int num_segments)
{