DrawList: added special case rendering for the stroked rects when the raounding radius gets really small compared to the stroke thickness.

# Conflicts:
#	imgui.h
#	imgui_draw.cpp
This commit is contained in:
Mikko Mononen
2026-04-24 10:14:11 +03:00
committed by ocornut
parent 30e53cc6d8
commit 765ef774b0
2 changed files with 111 additions and 25 deletions

View File

@@ -3650,6 +3650,7 @@ struct ImDrawList
IMGUI_API void _AddRectBaked(const ImVec2& p_min, const ImVec2& p_max, ImU32 col, float r, float t, ImVec4 tex_uvs, ImDrawFlags flags);
IMGUI_API void _AddPolylineThin(const ImVec2* points, ImVec2* normals, float* sqr_lengths, const int points_count, ImU32 col, float thickness, ImDrawFlags flags, ImVec4 tex_uvs);
IMGUI_API void _AddPolylineThick(const ImVec2* points, ImVec2* normals, float* sqr_lengths, const int points_count, ImU32 col, float thickness, ImDrawFlags flags);
IMGUI_API void _AddRectTinyRounding(const ImVec2& p_min, const ImVec2& p_max, ImU32 col, float rounding, float thickness, ImDrawFlags flags);
};
// All draw data to render a Dear ImGui frame

View File

@@ -2469,23 +2469,108 @@ void ImDrawList::_AddRectBaked(const ImVec2& p_min, const ImVec2& p_max, ImU32 c
PrimUnreserve(idx_allocated - idx_used, vtx_allocated - vtx_used);
}
static void RectCornerArc(ImDrawList* draw_list, float cx, float cy, float radius, const int arc_step, const int arc_point_count, const int corner)
// Draws rounded rectangle where thickness/2 > rounding. If rendered using the regular polyline, the stroke will fold and leave artefact on the corner if rendered with transparency.
// The stroke is positioned inside the rectangle.
void ImDrawList::_AddRectTinyRounding(const ImVec2& p_min, const ImVec2& p_max, ImU32 col, float rounding, float thickness, ImDrawFlags flags)
{
if (radius == 0.f)
thickness += _FringeScale;
// Adjust the rounding to be the outside radius.
rounding += thickness * 0.5f;
const int arc_step = ImClamp(IM_DRAWLIST_ARCFAST_SAMPLE_MAX / this->_CalcCircleAutoSegmentCount(rounding), 1, IM_DRAWLIST_ARCFAST_TABLE_SIZE / 4);
const int arc_point_count = (IM_DRAWLIST_ARCFAST_TABLE_SIZE / 4) / arc_step + 1;
int vtx_count = (4 + arc_point_count) * 4 + 4;
int idx_count = (4 + arc_point_count - 1) * 4 * 3;
PrimReserve(idx_count, vtx_count);
ImDrawVert* start_vtx_ptr = _VtxWritePtr;
ImDrawIdx* start_idx_ptr = _IdxWritePtr;
const float ht = thickness * 0.5f;
const ImVec2 corner_pos[4] = {
ImVec2(p_min.x - ht, p_min.y - ht),
ImVec2(p_max.x + ht, p_min.y - ht),
ImVec2(p_max.x + ht, p_max.y + ht),
ImVec2(p_min.x - ht, p_max.y + ht)
};
static const ImVec2 corner_offset[4] = { {1,1}, {-1,1}, {-1,-1}, {1,-1} };
static const ImDrawFlags corner_flags[4] = { ImDrawFlags_RoundCornersTopLeft, ImDrawFlags_RoundCornersTopRight, ImDrawFlags_RoundCornersBottomRight, ImDrawFlags_RoundCornersBottomLeft };
const float stem_offset = thickness - ImMax(thickness - rounding, _FringeScale);
const ImVec4 tex_uvs = _Data->TexUvLines[IM_DRAWLIST_TEX_LINES_WIDTH_MAX]; // TODO: max uv
const ImVec2 outer_uv0(tex_uvs.x + (0.5f / _FringeScale) * _Data->FontAtlas->TexUvScale.x, tex_uvs.y);
const ImVec2 outer_uv1(tex_uvs.x + ((0.5f + stem_offset) / _FringeScale) * _Data->FontAtlas->TexUvScale.x, tex_uvs.y);
const ImVec2 inner_uv0(tex_uvs.x + (0.5f / _FringeScale) * _Data->FontAtlas->TexUvScale.x, tex_uvs.y);
const ImVec2 inner_uv1(tex_uvs.x + ((0.5f + thickness - stem_offset) / _FringeScale) * _Data->FontAtlas->TexUvScale.x, tex_uvs.y);
int base_idx = (int)_VtxCurrentIdx;
IM_POLYLINE_APPEND_VERTEX(0, 0, outer_uv0, col);
IM_POLYLINE_APPEND_VERTEX(0, 0, outer_uv1, col);
IM_POLYLINE_APPEND_VERTEX(0, 0, inner_uv1, col);
IM_POLYLINE_APPEND_VERTEX(0, 0, inner_uv0, col);
for (int corner = 0; corner < 4; corner++)
{
draw_list->_Path.push_back(ImVec2(cx, cy));
return;
const ImVec2 stem = corner_pos[corner] + corner_offset[corner] * stem_offset;
const ImVec2 inner = corner_pos[corner] + corner_offset[corner] * thickness;
const bool is_rounded = flags & corner_flags[corner];
const int arc_idx = (int)_VtxCurrentIdx;
if (is_rounded)
{
const ImVec2 center = corner_pos[corner] + corner_offset[corner] * rounding;
int a = (IM_DRAWLIST_ARCFAST_TABLE_SIZE / 4) * corner;
for (int i = 0; i < arc_point_count; i++)
{
const ImVec2 dir = _Data->ArcFastVtx[a];
IM_POLYLINE_APPEND_VERTEX(center.x - dir.x * rounding, center.y - dir.y * rounding, outer_uv0, col);
a = (a + arc_step) % IM_DRAWLIST_ARCFAST_TABLE_SIZE;
}
}
else
{
IM_POLYLINE_APPEND_VERTEX(corner_pos[corner].x, corner_pos[corner].y, outer_uv0, col);
}
const int stem0_idx = (int)_VtxCurrentIdx;
IM_POLYLINE_APPEND_VERTEX(stem.x, stem.y, outer_uv1, col);
const int stem1_idx = (int)_VtxCurrentIdx;
IM_POLYLINE_APPEND_VERTEX(stem.x, stem.y, inner_uv1, col);
const int inner_idx = (int)_VtxCurrentIdx;
IM_POLYLINE_APPEND_VERTEX(inner.x, inner.y, inner_uv0, col);
// Arc
if (is_rounded)
{
for (int i = 0; i < arc_point_count-1; i++)
IM_POLYLINE_APPEND_TRI(stem0_idx, arc_idx + i, arc_idx + i + 1);
}
// Connect with previous
IM_POLYLINE_APPEND_TRI(base_idx+0, arc_idx, stem0_idx);
IM_POLYLINE_APPEND_TRI(base_idx+0, stem0_idx, base_idx+1);
IM_POLYLINE_APPEND_TRI(base_idx+2, stem1_idx, inner_idx);
IM_POLYLINE_APPEND_TRI(base_idx+2, inner_idx, base_idx+3);
base_idx = stem0_idx - 1;
}
int arc_idx = (IM_DRAWLIST_ARCFAST_TABLE_SIZE / 4) * corner;
for (int i = 0; i < arc_point_count; i++)
{
ImVec2 pt;
pt.x = cx - draw_list->_Data->ArcFastVtx[arc_idx].x * radius;
pt.y = cy - draw_list->_Data->ArcFastVtx[arc_idx].y * radius;
draw_list->_Path.push_back(pt);
arc_idx = (arc_idx + arc_step) % IM_DRAWLIST_ARCFAST_TABLE_SIZE;
}
// Close
start_vtx_ptr[0] = VtxBuffer.Data[base_idx+0];
start_vtx_ptr[1] = VtxBuffer.Data[base_idx+1];
start_vtx_ptr[2] = VtxBuffer.Data[base_idx+2];
start_vtx_ptr[3] = VtxBuffer.Data[base_idx+3];
const int idx_used = (int)(_IdxWritePtr - start_idx_ptr);
const int vtx_used = (int)(_VtxWritePtr - start_vtx_ptr);
IM_ASSERT(idx_used <= idx_count && vtx_used <= vtx_count);
if (idx_used < idx_count || vtx_used < vtx_count)
PrimUnreserve(idx_count - idx_used, vtx_count - vtx_used);
}
// p_min = upper-left, p_max = lower-right
@@ -2570,23 +2655,23 @@ void ImDrawList::AddRect(const ImVec2& p_min, const ImVec2& p_max, ImU32 col, fl
// Constrain rounding to rect dimensions
adjusted_rounding = ImMin(adjusted_rounding, ImFabs(width) * (((flags & ImDrawFlags_RoundCornersTop) == ImDrawFlags_RoundCornersTop) || ((flags & ImDrawFlags_RoundCornersBottom) == ImDrawFlags_RoundCornersBottom) ? 0.5f : 1.0f) - 1.0f);
adjusted_rounding = ImMin(adjusted_rounding, ImFabs(height) * (((flags & ImDrawFlags_RoundCornersLeft) == ImDrawFlags_RoundCornersLeft) || ((flags & ImDrawFlags_RoundCornersRight) == ImDrawFlags_RoundCornersRight) ? 0.5f : 1.0f) - 1.0f);
// We have to have some kind of curve to render the corner with PathStroke().
// The small value limits the rounding to about half the stroke radius.
adjusted_rounding = ImMax(_FringeScale * 0.25f, adjusted_rounding);
if (thickness * 0.5f > adjusted_rounding)
{
// Special case rendering to avoid rendering artifacts at the corners.
// If rendered using the regular polyline, the stroke will fold and leave artifact on the corner if rendered with transparency.
_AddRectTinyRounding(adjusted_min, adjusted_max, col, adjusted_rounding, thickness, flags);
return;
}
const float rounding_tl = (flags & ImDrawFlags_RoundCornersTopLeft) ? adjusted_rounding : 0.0f;
const float rounding_tr = (flags & ImDrawFlags_RoundCornersTopRight) ? adjusted_rounding : 0.0f;
const float rounding_br = (flags & ImDrawFlags_RoundCornersBottomRight) ? adjusted_rounding : 0.0f;
const float rounding_bl = (flags & ImDrawFlags_RoundCornersBottomLeft) ? adjusted_rounding : 0.0f;
// Use custom arcs so that we can specify the point count.
const int arc_step = ImClamp(IM_DRAWLIST_ARCFAST_SAMPLE_MAX / this->_CalcCircleAutoSegmentCount(ImMax(adjusted_rounding, thickness * 0.5f)), 1, IM_DRAWLIST_ARCFAST_TABLE_SIZE / 4);
const int arc_point_count = (IM_DRAWLIST_ARCFAST_TABLE_SIZE / 4) / arc_step + 1;
RectCornerArc(this, adjusted_min.x + rounding_tl, adjusted_min.y + rounding_tl, rounding_tl, arc_step, arc_point_count, 0);
RectCornerArc(this, adjusted_max.x - rounding_tr, adjusted_min.y + rounding_tr, rounding_tr, arc_step, arc_point_count, 1);
RectCornerArc(this, adjusted_max.x - rounding_br, adjusted_max.y - rounding_br, rounding_br, arc_step, arc_point_count, 2);
RectCornerArc(this, adjusted_min.x + rounding_bl, adjusted_max.y - rounding_bl, rounding_bl, arc_step, arc_point_count, 3);
PathArcToFast(ImVec2(adjusted_min.x + rounding_tl, adjusted_min.y + rounding_tl), rounding_tl, 6, 9);
PathArcToFast(ImVec2(adjusted_max.x - rounding_tr, adjusted_min.y + rounding_tr), rounding_tr, 9, 12);
PathArcToFast(ImVec2(adjusted_max.x - rounding_br, adjusted_max.y - rounding_br), rounding_br, 0, 3);
PathArcToFast(ImVec2(adjusted_min.x + rounding_bl, adjusted_max.y - rounding_bl), rounding_bl, 3, 6);
}
PathStroke(col, thickness, ImDrawFlags_Closed | ImDrawFlags_MiterOnly);