Feat: PlotPolygon

implot.h

@@ -95,6 +95,7 @@ typedef int ImPlotItemFlags;          // -> ImPlotItemFlags_
 typedef int ImPlotLineFlags;          // -> ImPlotLineFlags_
 typedef int ImPlotScatterFlags;       // -> ImPlotScatterFlags
 typedef int ImPlotBubblesFlags;       // -> ImPlotBubblesFlags
+typedef int ImPlotPolygonFlags;       // -> ImPlotPolygonFlags_
 typedef int ImPlotStairsFlags;        // -> ImPlotStairsFlags_
 typedef int ImPlotShadedFlags;        // -> ImPlotShadedFlags_
 typedef int ImPlotBarsFlags;          // -> ImPlotBarsFlags_
@@ -271,6 +272,12 @@ enum ImPlotBubblesFlags_ {
   ImPlotBubblesFlags_None = 0, // default
 };
 
+// Flags for PlotPolygon. Used by setting ImPlotSpec::Flags.
+enum ImPlotPolygonFlags_ {
+  ImPlotPolygonFlags_None     = 0,       // default (closed, convex polygon)
+  ImPlotPolygonFlags_Concave  = 1 << 10, // use concave polygon filling (slower but supports concave shapes)
+};
+
 // Flags for PlotStairs. Used by setting ImPlotSpec::Flags.
 enum ImPlotStairsFlags_ {
     ImPlotStairsFlags_None     = 0,       // default
@@ -960,6 +967,9 @@ IMPLOT_API void PlotScatterG(const char* label_id, ImPlotGetter getter, void* da
 IMPLOT_TMP void PlotBubbles(const char* label_id, const T* values, const T* szs, int count, double xscale=1, double xstart=0, const ImPlotSpec& spec=ImPlotSpec());
 IMPLOT_TMP void PlotBubbles(const char* label_id, const T* xs, const T* ys, const T* szs, int count, const ImPlotSpec& spec=ImPlotSpec());
 
+// Plots a polygon. Points are specified in counter-clockwise order. If concave, make sure to set the Concave flag.
+IMPLOT_TMP void PlotPolygon(const char* label_id, const T* xs, const T* ys, int count, const ImPlotSpec& spec=ImPlotSpec());
+
 // Plots a a stairstep graph. The y value is continued constantly to the right from every x position, i.e. the interval [x[i], x[i+1]) has the value y[i]
 IMPLOT_TMP void PlotStairs(const char* label_id, const T* values, int count, double xscale=1, double xstart=0, const ImPlotSpec& spec=ImPlotSpec());
 IMPLOT_TMP void PlotStairs(const char* label_id, const T* xs, const T* ys, int count, const ImPlotSpec& spec=ImPlotSpec());
@@ -1193,18 +1203,18 @@ IMPLOT_API void PushStyleVar(ImPlotStyleVar idx, int val);
 IMPLOT_API void PushStyleVar(ImPlotStyleVar idx, const ImVec2& val);
 // Undo temporary style variable modification(s). Undo multiple pushes at once by increasing count.
 IMPLOT_API void PopStyleVar(int count = 1);
-    
+
 // Gets the last item primary color (i.e. its legend icon color)
 IMPLOT_API ImVec4 GetLastItemColor();
 
 // Returns the null terminated string name for an ImPlotCol.
 IMPLOT_API const char* GetStyleColorName(ImPlotCol idx);
 // Returns the null terminated string name for an ImPlotMarker.
 IMPLOT_API const char* GetMarkerName(ImPlotMarker idx);
-    
+
 // Returns the next marker and advances the marker for the current plot. You need to call this between Begin/EndPlot!
 IMPLOT_API ImPlotMarker NextMarker();
-    
+
 //-----------------------------------------------------------------------------
 // [SECTION] Colormaps
 //-----------------------------------------------------------------------------
@@ -1274,7 +1284,7 @@ IMPLOT_API void BustColorCache(const char* plot_title_id = nullptr);
 //-----------------------------------------------------------------------------
 // [SECTION] Input Mapping
 //-----------------------------------------------------------------------------
-    
+
 // Provides access to input mapping structure for permanent modifications to controls for pan, select, etc.
 IMPLOT_API ImPlotInputMap& GetInputMap();
 

implot_demo.cpp

@@ -437,7 +437,7 @@ void Demo_ScatterPlots() {
 //-----------------------------------------------------------------------------
 
 void Demo_BubblePlots() {
-    IMGUI_DEMO_MARKER("Demo_BubblePlots");
+    IMGUI_DEMO_MARKER("Plots/Bubble Plots");
     srand(0);
     static float xs[20], ys1[20], ys2[20], szs1[20], szs2[20];
     for (int i = 0; i < 20; ++i) {
@@ -460,6 +460,49 @@ void Demo_BubblePlots() {
 
 //-----------------------------------------------------------------------------
 
+void Demo_PolygonPlots() {
+    IMGUI_DEMO_MARKER("Plots/Polygon Plots");
+    // Triangle (convex)
+    static float tri_xs[3] = {0.5f, 1.0f, 0.0f};
+    static float tri_ys[3] = {1.0f, 0.0f, 0.0f};
+
+    // Pentagon (convex)
+    static float pent_xs[5], pent_ys[5];
+    for (int i = 0; i < 5; ++i) {
+        float angle = (float)i * 2.0f * 3.14159f / 5.0f - 3.14159f / 2.0f;
+        pent_xs[i] = 3.0f + 0.8f * cosf(angle);
+        pent_ys[i] = 0.5f + 0.8f * sinf(angle);
+    }
+
+    // Star (concave), counter-clockwise
+    static float star_xs[10], star_ys[10];
+    for (int i = 0; i < 10; ++i) {
+        float angle = (float)i * 2.0f * 3.14159f / 10.0f - 3.14159f / 2.0f;
+        float radius = (i % 2 == 0) ? 0.8f : 0.3f;
+        star_xs[i] = 5.5f + radius * cosf(angle);
+        star_ys[i] = 0.5f + radius * sinf(angle);
+    }
+
+    if (ImPlot::BeginPlot("Polygon Plot", ImVec2(-1,0), ImPlotFlags_Equal)) {
+        ImPlot::PlotPolygon("Triangle", tri_xs, tri_ys, 3, {
+            ImPlotProp_FillAlpha, 0.5f,
+        });
+        ImPlot::PlotPolygon("Pentagon", pent_xs, pent_ys, 5, {
+            ImPlotProp_FillAlpha, 0.5f,
+            ImPlotProp_FillColor, ImVec4(0,1,0,1),
+        });
+        ImPlot::PlotPolygon("Star (Concave)", star_xs, star_ys, 10, {
+            ImPlotProp_FillAlpha, 0.5f,
+            ImPlotProp_FillColor, ImVec4(1,1,0,1),
+            ImPlotProp_Flags, ImPlotPolygonFlags_Concave,
+        });
+
+        ImPlot::EndPlot();
+    }
+}
+
+//-----------------------------------------------------------------------------
+
 void Demo_StairstepPlots() {
     IMGUI_DEMO_MARKER("Plots/Stairstep Plots");
     static float ys1[21], ys2[21];
@@ -2440,6 +2483,7 @@ void ShowDemoWindow(bool* p_open) {
             DemoHeader("Shaded Plots##", Demo_ShadedPlots);
             DemoHeader("Scatter Plots", Demo_ScatterPlots);
             DemoHeader("Bubble Plots", Demo_BubblePlots);
+            DemoHeader("Polygon Plots", Demo_PolygonPlots);
             DemoHeader("Realtime Plots", Demo_RealtimePlots);
             DemoHeader("Stairstep Plots", Demo_StairstepPlots);
             DemoHeader("Bar Plots", Demo_BarPlots);

implot_items.cpp

@@ -1701,7 +1701,6 @@ struct RendererCircleLine : RendererBase {
     mutable ImVec2 UV1;
 };
 
-
 static const ImVec2 MARKER_FILL_CIRCLE[10]  = {ImVec2(1.0f, 0.0f), ImVec2(0.809017f, 0.58778524f),ImVec2(0.30901697f, 0.95105654f),ImVec2(-0.30901703f, 0.9510565f),ImVec2(-0.80901706f, 0.5877852f),ImVec2(-1.0f, 0.0f),ImVec2(-0.80901694f, -0.58778536f),ImVec2(-0.3090171f, -0.9510565f),ImVec2(0.30901712f, -0.9510565f),ImVec2(0.80901694f, -0.5877853f)};
 static const ImVec2 MARKER_FILL_SQUARE[4]   = {ImVec2(SQRT_1_2,SQRT_1_2), ImVec2(SQRT_1_2,-SQRT_1_2), ImVec2(-SQRT_1_2,-SQRT_1_2), ImVec2(-SQRT_1_2,SQRT_1_2)};
 static const ImVec2 MARKER_FILL_DIAMOND[4]  = {ImVec2(1, 0), ImVec2(0, -1), ImVec2(-1, 0), ImVec2(0, 1)};
@@ -1941,6 +1940,65 @@ void PlotBubbles(const char* label_id, const T* xs, const T* ys, const T* szs, i
 CALL_INSTANTIATE_FOR_NUMERIC_TYPES()
 #undef INSTANTIATE_MACRO
 
+//-----------------------------------------------------------------------------
+// [SECTION] PlotPolygon
+//-----------------------------------------------------------------------------
+
+template <typename Getter>
+void PlotPolygonEx(const char* label_id, const Getter& getter, const ImPlotSpec& spec) {
+    if (BeginItemEx(label_id, Fitter1<Getter>(getter), spec, spec.FillColor, spec.Marker)) {
+        if (getter.Count < 2) {
+            EndItem();
+            return;
+        }
+        const ImPlotNextItemData& s = GetItemData();
+        const bool is_concave = ImHasFlag(spec.Flags, ImPlotPolygonFlags_Concave);
+
+        ImDrawList& draw_list = *GetPlotDrawList();
+        const ImPlotAxis& x_axis = GetCurrentPlot()->Axes[GetCurrentPlot()->CurrentX];
+        const ImPlotAxis& y_axis = GetCurrentPlot()->Axes[GetCurrentPlot()->CurrentY];
+        Transformer2 transformer(x_axis, y_axis);
+
+        // Flip points to make sure they are in counter-clockwise order for correct filling when one axis is inverted
+        bool x_inv = ImHasFlag(x_axis.Flags, ImPlotAxisFlags_Invert);
+        bool y_inv = ImHasFlag(y_axis.Flags, ImPlotAxisFlags_Invert);
+        bool flip = !((x_inv ? 1 : 0) ^ (y_inv ? 1 : 0));
+
+        // Transform all points to screen space
+        ImVec2* points = (ImVec2*)IM_ALLOC(getter.Count * sizeof(ImVec2));
+        for (int i = 0; i < getter.Count; ++i) {
+            ImPlotPoint p = flip ? getter[getter.Count - 1 - i] : getter[i];
+            points[i] = transformer(p);
+        }
+
+        if (s.RenderFill && getter.Count >= 3) {
+            const ImU32 col_fill = ImGui::GetColorU32(s.Spec.FillColor);
+            if (is_concave)
+                draw_list.AddConcavePolyFilled(points, getter.Count, col_fill);
+            else
+                draw_list.AddConvexPolyFilled(points, getter.Count, col_fill);
+        }
+        if (s.RenderLine && getter.Count >= 2) {
+            const ImU32 col_line = ImGui::GetColorU32(s.Spec.LineColor);
+            draw_list.AddPolyline(points, getter.Count, col_line, ImDrawFlags_Closed, s.Spec.LineWeight);
+        }
+        IM_FREE(points);
+
+        EndItem();
+    }
+}
+
+template <typename T>
+void PlotPolygon(const char* label_id, const T* xs, const T* ys, int count, const ImPlotSpec& spec) {
+    GetterXY<IndexerIdx<T>,IndexerIdx<T>> getter(IndexerIdx<T>(xs,count,spec.Offset,Stride<T>(spec)),IndexerIdx<T>(ys,count,spec.Offset,Stride<T>(spec)),count);
+    return PlotPolygonEx(label_id, getter, spec);
+}
+
+#define INSTANTIATE_MACRO(T) \
+    template IMPLOT_API void PlotPolygon<T>(const char* label_id, const T* xs, const T* ys, int count, const ImPlotSpec& spec);
+CALL_INSTANTIATE_FOR_NUMERIC_TYPES()
+#undef INSTANTIATE_MACRO
+
 //-----------------------------------------------------------------------------
 // [SECTION] PlotStairs
 //-----------------------------------------------------------------------------