Demo: Custom Rendering: better demonstrate PathArcTo(), PathBezierQuadraticCurveTo(), PathBezierCubicCurveTo(), PathStroke(), PathFillConvex() functions.

ago%!(EXTRA string=1 year) · 198c38f0b1
parent 3b6d924acd
commit 198c38f0b1
3 changed files with 36 additions and 6 deletions
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@ -55,6 +55,8 @@ Other changes:
  drawn too low, particularly visible with tables that have no scrolling. (#6917)
 - ProgressBar: Fixed a minor tesselation issue when rendering rounded progress bars,
  where in some situations the rounded section wouldn't follow regular tesselation rules.
+- Demo: Custom Rendering: better demonstrate PathArcTo(), PathBezierQuadraticCurveTo(),
+  PathBezierCubicCurveTo(), PathStroke(), PathFillConvex() functions.


 -----------------------------------------------------------------------
--- a/imgui.h
+++ b/imgui.h
@ -2765,7 +2765,8 @@ struct ImDrawList
    IMGUI_API void  AddImageRounded(ImTextureID user_texture_id, const ImVec2& p_min, const ImVec2& p_max, const ImVec2& uv_min, const ImVec2& uv_max, ImU32 col, float rounding, ImDrawFlags flags = 0);

    // Stateful path API, add points then finish with PathFillConvex() or PathStroke()
-    // - Filled shapes must always use clockwise winding order. The anti-aliasing fringe depends on it. Counter-clockwise shapes will have "inward" anti-aliasing.
+    // - Important: filled shapes must always use clockwise winding order! The anti-aliasing fringe depends on it. Counter-clockwise shapes will have "inward" anti-aliasing.
+    //   so e.g. 'PathArcTo(center, radius, PI * -0.5f, PI)' is ok, whereas 'PathArcTo(center, radius, PI, PI * -0.5f)' won't have correct anti-aliasing when followed by PathFillConvex().
    inline    void  PathClear()                                                 { _Path.Size = 0; }
    inline    void  PathLineTo(const ImVec2& pos)                               { _Path.push_back(pos); }
    inline    void  PathLineToMergeDuplicate(const ImVec2& pos)                 { if (_Path.Size == 0 || memcmp(&_Path.Data[_Path.Size - 1], &pos, 8) != 0) _Path.push_back(pos); }
--- a/imgui_demo.cpp
+++ b/imgui_demo.cpp
@ -8030,6 +8030,9 @@ static void ShowExampleAppCustomRendering(bool* p_open)
            const float rounding = sz / 5.0f;
            const int circle_segments = circle_segments_override ? circle_segments_override_v : 0;
            const int curve_segments = curve_segments_override ? curve_segments_override_v : 0;
+            const ImVec2 cp3[3] = { ImVec2(0.0f, sz * 0.6f), ImVec2(sz * 0.5f, -sz * 0.4f), ImVec2(sz, sz) }; // Control points for curves
+            const ImVec2 cp4[4] = { ImVec2(0.0f, 0.0f), ImVec2(sz * 1.3f, sz * 0.3f), ImVec2(sz - sz * 1.3f, sz - sz * 0.3f), ImVec2(sz, sz) };
+
            float x = p.x + 4.0f;
            float y = p.y + 4.0f;
            for (int n = 0; n < 2; n++)
@ -8048,17 +8051,23 @@ static void ShowExampleAppCustomRendering(bool* p_open)
                draw_list->AddLine(ImVec2(x, y), ImVec2(x, y + sz), col, th);                                       x += spacing;       // Vertical line (note: drawing a filled rectangle will be faster!)
                draw_list->AddLine(ImVec2(x, y), ImVec2(x + sz, y + sz), col, th);                                  x += sz + spacing;  // Diagonal line

+                // Path
+                draw_list->PathArcTo(ImVec2(x + sz*0.5f, y + sz*0.5f), sz*0.5f, 3.141592f, 3.141592f * -0.5f);
+                draw_list->PathStroke(col, ImDrawFlags_None, th);
+                x += sz + spacing;
+
                // Quadratic Bezier Curve (3 control points)
-                ImVec2 cp3[3] = { ImVec2(x, y + sz * 0.6f), ImVec2(x + sz * 0.5f, y - sz * 0.4f), ImVec2(x + sz, y + sz) };
-                draw_list->AddBezierQuadratic(cp3[0], cp3[1], cp3[2], col, th, curve_segments); x += sz + spacing;
+                draw_list->AddBezierQuadratic(ImVec2(x + cp3[0].x, y + cp3[0].y), ImVec2(x + cp3[1].x, y + cp3[1].y), ImVec2(x + cp3[2].x, y + cp3[2].y), col, th, curve_segments);
+                x += sz + spacing;

                // Cubic Bezier Curve (4 control points)
-                ImVec2 cp4[4] = { ImVec2(x, y), ImVec2(x + sz * 1.3f, y + sz * 0.3f), ImVec2(x + sz - sz * 1.3f, y + sz - sz * 0.3f), ImVec2(x + sz, y + sz) };
-                draw_list->AddBezierCubic(cp4[0], cp4[1], cp4[2], cp4[3], col, th, curve_segments);
+                draw_list->AddBezierCubic(ImVec2(x + cp4[0].x, y + cp4[0].y), ImVec2(x + cp4[1].x, y + cp4[1].y), ImVec2(x + cp4[2].x, y + cp4[2].y), ImVec2(x + cp4[3].x, y + cp4[3].y), col, th, curve_segments);

                x = p.x + 4;
                y += sz + spacing;
            }
+
+            // Filled shapes
            draw_list->AddNgonFilled(ImVec2(x + sz * 0.5f, y + sz * 0.5f), sz * 0.5f, col, ngon_sides);             x += sz + spacing;  // N-gon
            draw_list->AddCircleFilled(ImVec2(x + sz * 0.5f, y + sz * 0.5f), sz * 0.5f, col, circle_segments);      x += sz + spacing;  // Circle
            draw_list->AddEllipseFilled(ImVec2(x + sz * 0.5f, y + sz * 0.5f), sz * 0.5f, sz * 0.3f, col, -0.3f, circle_segments); x += sz + spacing;// Ellipse
@ -8070,9 +8079,27 @@ static void ShowExampleAppCustomRendering(bool* p_open)
            draw_list->AddRectFilled(ImVec2(x, y), ImVec2(x + sz, y + thickness), col);                             x += sz + spacing;  // Horizontal line (faster than AddLine, but only handle integer thickness)
            draw_list->AddRectFilled(ImVec2(x, y), ImVec2(x + thickness, y + sz), col);                             x += spacing * 2.0f;// Vertical line (faster than AddLine, but only handle integer thickness)
            draw_list->AddRectFilled(ImVec2(x, y), ImVec2(x + 1, y + 1), col);                                      x += sz;            // Pixel (faster than AddLine)
+
+            // Path
+            draw_list->PathArcTo(ImVec2(x + sz * 0.5f, y + sz * 0.5f), sz * 0.5f, 3.141592f * -0.5f, 3.141592f);
+            draw_list->PathFillConvex(col);
+            x += sz + spacing;
+
+            // Quadratic Bezier Curve (3 control points)
+            draw_list->PathLineTo(ImVec2(x + cp3[0].x, y + cp3[0].y));
+            draw_list->PathBezierQuadraticCurveTo(ImVec2(x + cp3[1].x, y + cp3[1].y), ImVec2(x + cp3[2].x, y + cp3[2].y), curve_segments);
+            draw_list->PathFillConvex(col);
+            x += sz + spacing;
+
+            // Cubic Bezier Curve (4 control points): this is concave so not drawing it yet
+            //draw_list->PathLineTo(ImVec2(x + cp4[0].x, y + cp4[0].y));
+            //draw_list->PathBezierCubicCurveTo(ImVec2(x + cp4[1].x, y + cp4[1].y), ImVec2(x + cp4[2].x, y + cp4[2].y), ImVec2(x + cp4[3].x, y + cp4[3].y), curve_segments);
+            //draw_list->PathFillConvex(col);
+            //x += sz + spacing;
+
            draw_list->AddRectFilledMultiColor(ImVec2(x, y), ImVec2(x + sz, y + sz), IM_COL32(0, 0, 0, 255), IM_COL32(255, 0, 0, 255), IM_COL32(255, 255, 0, 255), IM_COL32(0, 255, 0, 255));

-            ImGui::Dummy(ImVec2((sz + spacing) * 11.2f, (sz + spacing) * 3.0f));
+            ImGui::Dummy(ImVec2((sz + spacing) * 12.2f, (sz + spacing) * 3.0f));
            ImGui::PopItemWidth();
            ImGui::EndTabItem();
        }