From 80ad773c87ae5c1d145635e2e88730fb27bc7ba0 Mon Sep 17 00:00:00 2001 From: ocornut Date: Fri, 28 Aug 2015 13:18:34 +0100 Subject: [PATCH] ImDrawList: added AddBezier(), PathBezierTo() for cubic bezier curves (#311) --- imgui.cpp | 2 ++ imgui.h | 14 +++++++++----- imgui_demo.cpp | 4 ++++ imgui_draw.cpp | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 65 insertions(+), 5 deletions(-) diff --git a/imgui.cpp b/imgui.cpp index c5bdb47a..fb64063d 100644 --- a/imgui.cpp +++ b/imgui.cpp @@ -620,6 +620,7 @@ ImGuiStyle::ImGuiStyle() DisplaySafeAreaPadding = ImVec2(4,4); // If you cannot see the edge of your screen (e.g. on a TV) increase the safe area padding. Covers popups/tooltips as well regular windows. AntiAliasedLines = true; // Enable anti-aliasing on lines/borders. Disable if you are really short on CPU/GPU. AntiAliasedShapes = true; // Enable anti-aliasing on filled shapes (rounded rectangles, circles, etc.) + CurveTessellationTol = 1.25f; // Tessellation tolerance. Decrease for highly tessellated curves (higher quality, more polygons), increase to reduce quality. Colors[ImGuiCol_Text] = ImVec4(0.90f, 0.90f, 0.90f, 1.00f); Colors[ImGuiCol_TextDisabled] = ImVec4(0.60f, 0.60f, 0.60f, 1.00f); @@ -1790,6 +1791,7 @@ void ImGui::NewFrame() IM_ASSERT(g.IO.RenderDrawListsFn != NULL); // Must be implemented IM_ASSERT(g.IO.Fonts->Fonts.Size > 0); // Font Atlas not created. Did you call io.Fonts->GetTexDataAsRGBA32 / GetTexDataAsAlpha8 ? IM_ASSERT(g.IO.Fonts->Fonts[0]->IsLoaded()); // Font Atlas not created. Did you call io.Fonts->GetTexDataAsRGBA32 / GetTexDataAsAlpha8 ? + IM_ASSERT(g.Style.CurveTessellationTol > 0.0f); // Invalid if (!g.Initialized) { diff --git a/imgui.h b/imgui.h index cb040762..d27eeddd 100644 --- a/imgui.h +++ b/imgui.h @@ -647,6 +647,7 @@ struct ImGuiStyle ImVec2 DisplaySafeAreaPadding; // If you cannot see the edge of your screen (e.g. on a TV) increase the safe area padding. Covers popups/tooltips as well regular windows. bool AntiAliasedLines; // Enable anti-aliasing on lines/borders. Disable if you are really tight on CPU/GPU. bool AntiAliasedShapes; // Enable anti-aliasing on filled shapes (rounded rectangles, circles, etc.) + float CurveTessellationTol; // Tessellation tolerance. Decrease for highly tessellated curves (higher quality, more polygons), increase to reduce quality. ImVec4 Colors[ImGuiCol_COUNT]; IMGUI_API ImGuiStyle(); @@ -1100,15 +1101,18 @@ struct ImDrawList IMGUI_API void AddImage(ImTextureID user_texture_id, const ImVec2& a, const ImVec2& b, const ImVec2& uv0, const ImVec2& uv1, ImU32 col = 0xFFFFFFFF); IMGUI_API void AddPolyline(const ImVec2* points, const int num_points, ImU32 col, bool closed, float thickness, bool anti_aliased); IMGUI_API void AddConvexPolyFilled(const ImVec2* points, const int num_points, ImU32 col, bool anti_aliased); + inline void AddBezier(const ImVec2& pos0, const ImVec2& cp0, const ImVec2& cp1, const ImVec2& pos1, ImU32 col, float thickness, int num_segments = 0) { PathBezierTo(pos0, cp0, cp1, pos1, num_segments); PathStroke(col, false, thickness); } // Stateful path API, add points then finish with PathFill() or PathStroke() inline void PathClear() { _Path.resize(0); } - inline void PathLineTo(const ImVec2& p) { _Path.push_back(p); } - IMGUI_API void PathArcTo(const ImVec2& centre, float radius, float a_min, float a_max, int num_segments = 10); - IMGUI_API void PathArcToFast(const ImVec2& centre, float radius, int a_min_of_12, int a_max_of_12); - IMGUI_API void PathRect(const ImVec2& a, const ImVec2& b, float rounding = 0.0f, int rounding_corners = 0x0F); + inline void PathLineTo(const ImVec2& pos) { _Path.push_back(pos); } + inline void PathLineToMergeDuplicate(const ImVec2& pos) { if (_Path.Size == 0 || _Path[_Path.Size-1].x != pos.x || _Path[_Path.Size-1].y != pos.y) _Path.push_back(pos); } inline void PathFill(ImU32 col) { AddConvexPolyFilled(_Path.Data, _Path.Size, col, true); PathClear(); } - inline void PathStroke(ImU32 col, bool closed, float thickness = 1.0f) { AddPolyline(_Path.Data, _Path.Size, col, closed, thickness, true); PathClear(); } + inline void PathStroke(ImU32 col, bool closed, float thickness = 1.0f) { AddPolyline(_Path.Data, _Path.Size, col, closed, thickness, true); PathClear(); } + IMGUI_API void PathArcTo(const ImVec2& centre, float radius, float a_min, float a_max, int num_segments = 10); + IMGUI_API void PathArcToFast(const ImVec2& centre, float radius, int a_min_of_12, int a_max_of_12); // Use precomputed angles for a 12 steps circle + IMGUI_API void PathBezierTo(const ImVec2& p0, const ImVec2& p1, const ImVec2& p2, const ImVec2& p3, int num_segments = 0); + IMGUI_API void PathRect(const ImVec2& rect_min, const ImVec2& rect_max, float rounding = 0.0f, int rounding_corners = 0x0F); // Channels // - Use to simulate layers. By switching channels to can render out-of-order (e.g. submit foreground primitives before background primitives) diff --git a/imgui_demo.cpp b/imgui_demo.cpp index 7ae60b2d..cd8d9dbd 100644 --- a/imgui_demo.cpp +++ b/imgui_demo.cpp @@ -1392,6 +1392,10 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref) { ImGui::Checkbox("Anti-aliased lines", &style.AntiAliasedLines); ImGui::Checkbox("Anti-aliased shapes", &style.AntiAliasedShapes); + ImGui::PushItemWidth(100); + ImGui::DragFloat("Curve Tessellation Tolerance", &style.CurveTessellationTol, 0.02f, 0.10f, FLT_MAX, NULL, 2.0f); + if (style.CurveTessellationTol < 0.0f) style.CurveTessellationTol = 0.10f; + ImGui::PopItemWidth(); ImGui::TreePop(); } diff --git a/imgui_draw.cpp b/imgui_draw.cpp index a4f6e4da..99430633 100644 --- a/imgui_draw.cpp +++ b/imgui_draw.cpp @@ -639,6 +639,56 @@ void ImDrawList::PathArcTo(const ImVec2& centre, float radius, float amin, float } } +static void PathBezierToCasteljau(ImVector* path, float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4, float tess_tol, int level) +{ + float dx = x4 - x1; + float dy = y4 - y1; + float d2 = ((x2 - x4) * dy - (y2 - y4) * dx); + float d3 = ((x3 - x4) * dy - (y3 - y4) * dx); + d2 = (d2 >= 0) ? d2 : -d2; + d3 = (d3 >= 0) ? d3 : -d3; + if ((d2+d3) * (d2+d3) < tess_tol * (dx*dx + dy*dy)) + { + path->push_back(ImVec2(x4, y4)); + } + else if (level < 10) + { + float x12 = (x1+x2)*0.5f, y12 = (y1+y2)*0.5f; + float x23 = (x2+x3)*0.5f, y23 = (y2+y3)*0.5f; + float x34 = (x3+x4)*0.5f, y34 = (y3+y4)*0.5f; + float x123 = (x12+x23)*0.5f, y123 = (y12+y23)*0.5f; + float x234 = (x23+x34)*0.5f, y234 = (y23+y34)*0.5f; + float x1234 = (x123+x234)*0.5f, y1234 = (y123+y234)*0.5f; + + PathBezierToCasteljau(path, x1,y1, x12,y12, x123,y123, x1234,y1234, tess_tol, level+1); + PathBezierToCasteljau(path, x1234,y1234, x234,y234, x34,y34, x4,y4, tess_tol, level+1); + } +} + +void ImDrawList::PathBezierTo(const ImVec2& p1, const ImVec2& p2, const ImVec2& p3, const ImVec2& p4, int num_segments) +{ + PathLineToMergeDuplicate(p1); + if (num_segments == 0) + { + // Auto-tessellated + PathBezierToCasteljau(&_Path, p1.x, p1.y, p2.x, p2.y, p3.x, p3.y, p4.x, p4.y, GImGui->Style.CurveTessellationTol, 0); + } + else + { + float t_step = 1.0f / (float)num_segments; + for (int i_step = 1; i_step <= num_segments; i_step++) + { + float t = t_step * i_step; + float u = 1.0f - t; + float w1 = u*u*u; + float w2 = 3*u*u*t; + float w3 = 3*u*t*t; + float w4 = t*t*t; + _Path.push_back(ImVec2(w1*p1.x + w2*p2.x + w3*p3.x + w4*p4.x, w1*p1.y + w2*p2.y + w3*p3.y + w4*p4.y)); + } + } +} + void ImDrawList::PathRect(const ImVec2& a, const ImVec2& b, float rounding, int rounding_corners) { float r = rounding;