ImPlotLineFlags_Shaded and ImPlotStairsFlags_Shaded

TODO.md

@@ -45,6 +45,8 @@ The list below represents a combination of high-priority work, nice-to-have feat
 - first frame render delay might fix "fit pop" effect
 - move some code to new `implot_tools.cpp`
 - ColormapSlider (see metrics)
+- FillAlpha should not affect markers?
+- fix mouse text for time axes
 
 ## Optimizations
 

implot.h

@@ -84,6 +84,7 @@ typedef int ImPlotLegendFlags;        // -> enum ImPlotLegendFlags_
 typedef int ImPlotMouseTextFlags;     // -> enum ImPlotMouseTextFlags_
 typedef int ImPlotDragToolFlags;      // -> ImPlotDragToolFlags_
 typedef int ImPlotColormapScaleFlags; // -> ImPlotColormapScaleFlags_
+
 typedef int ImPlotItemFlags;          // -> ImPlotItemFlags_
 typedef int ImPlotLineFlags;          // -> ImPlotLineFlags_
 typedef int ImPlotScatterFlags;       // -> ImPlotScatterFlags
@@ -163,7 +164,7 @@ enum ImPlotAxisFlags_ {
     ImPlotAxisFlags_AuxDefault    = ImPlotAxisFlags_NoGridLines | ImPlotAxisFlags_Opposite
 };
 
-// Options for subplots (see BeginSubplot).
+// Options for subplots (see BeginSubplot)
 enum ImPlotSubplotFlags_ {
     ImPlotSubplotFlags_None        = 0,       // default
     ImPlotSubplotFlags_NoTitle     = 1 << 0,  // the subplot title will not be displayed (titles are also hidden if preceeded by double hashes, e.g. "##MySubplot")
@@ -229,6 +230,7 @@ enum ImPlotLineFlags_ {
     ImPlotLineFlags_Loop        = 1 << 11, // the last and first point will be connected to form a closed loop
     ImPlotLineFlags_SkipNaN     = 1 << 12, // NaNs values will be skipped instead of rendered as missing data
     ImPlotLineFlags_NoClip      = 1 << 13, // markers (if displayed) on the edge of a plot will not be clipped
+    ImPlotLineFlags_Shaded      = 1 << 14, // a filled region between the line and horizontal origin will be rendered; use PlotShaded for more advanced cases
 };
 
 // Flags for PlotScatter
@@ -240,7 +242,8 @@ enum ImPlotScatterFlags_ {
 // Flags for PlotStairs
 enum ImPlotStairsFlags_ {
     ImPlotStairsFlags_None     = 0,       // default
-    ImPlotStairsFlags_PreStep  = 1 << 10 // the y value is continued constantly to the left from every x position, i.e. the interval (x[i-1], x[i]] has the value y[i]
+    ImPlotStairsFlags_PreStep  = 1 << 10, // the y value is continued constantly to the left from every x position, i.e. the interval (x[i-1], x[i]] has the value y[i]
+    ImPlotStairsFlags_Shaded   = 1 << 11  // a filled region between the stairs and horizontal origin will be rendered; use PlotShaded for more advanced cases
 };
 
 // Flags for PlotShaded (placeholder)

implot_demo.cpp

@@ -295,7 +295,7 @@ void Demo_LinePlots() {
         xs2[i] = i * 1/19.0f;
         ys2[i] = xs2[i] * xs2[i];
     }
-    if (ImPlot::BeginPlot("Line Plot")) {
+    if (ImPlot::BeginPlot("Line Plots")) {
         ImPlot::SetupAxes("x","y");
         ImPlot::PlotLine("f(x)", xs1, ys1, 1001);
         ImPlot::SetNextMarkerStyle(ImPlotMarker_Circle);
@@ -419,6 +419,8 @@ void Demo_StairstepPlots() {
         ys1[i] = 0.75f + 0.2f * sinf(10 * i * 0.05f);
         ys2[i] = 0.25f + 0.2f * sinf(10 * i * 0.05f);
     }
+    static ImPlotStairsFlags flags = 0;
+    CHECKBOX_FLAG(flags, ImPlotStairsFlags_Shaded);
     if (ImPlot::BeginPlot("Stairstep Plot")) {
         ImPlot::SetupAxes("x","f(x)");
         ImPlot::SetupAxesLimits(0,1,0,1);
@@ -429,9 +431,11 @@ void Demo_StairstepPlots() {
         ImPlot::PopStyleColor();
 
         ImPlot::SetNextMarkerStyle(ImPlotMarker_Circle);
-        ImPlot::PlotStairs("Post Step (default)", ys1, 21, 0.05f);
+        ImPlot::SetNextFillStyle(IMPLOT_AUTO_COL, 0.25f);
+        ImPlot::PlotStairs("Post Step (default)", ys1, 21, 0.05f, 0, flags);
         ImPlot::SetNextMarkerStyle(ImPlotMarker_Circle);
-        ImPlot::PlotStairs("Pre Step", ys2, 21, 0.05f, 0, ImPlotStairsFlags_PreStep);
+        ImPlot::SetNextFillStyle(IMPLOT_AUTO_COL, 0.25f);
+        ImPlot::PlotStairs("Pre Step", ys2, 21, 0.05f, 0, flags|ImPlotStairsFlags_PreStep);
 
         ImPlot::EndPlot();
     }
@@ -1202,7 +1206,7 @@ void Demo_AxisConstraints() {
 //-----------------------------------------------------------------------------
 
 void Demo_EqualAxes() {
-    ImGui::BulletText("Equal constraint applies to axis pairs (e.g ImAxis_X1/Y1, ImAxis_X2/Y2");
+    ImGui::BulletText("Equal constraint applies to axis pairs (e.g ImAxis_X1/Y1, ImAxis_X2/Y2)");
     static double xs1[360], ys1[360];
     for (int i = 0; i < 360; ++i) {
         double angle = i * 2 * PI / 359.0;
@@ -2289,12 +2293,9 @@ void Sparkline(const char* id, const float* values, int count, float min_v, floa
     if (ImPlot::BeginPlot(id,size,ImPlotFlags_CanvasOnly|ImPlotFlags_NoChild)) {
         ImPlot::SetupAxes(0,0,ImPlotAxisFlags_NoDecorations,ImPlotAxisFlags_NoDecorations);
         ImPlot::SetupAxesLimits(0, count - 1, min_v, max_v, ImGuiCond_Always);
-        ImPlot::PushStyleColor(ImPlotCol_Line, col);
+        ImPlot::SetNextLineStyle(col);
-        ImPlot::PlotLine(id, values, count, 1, 0, 0, offset);
+        ImPlot::SetNextFillStyle(col, 0.25);
-        ImPlot::PushStyleVar(ImPlotStyleVar_FillAlpha, 0.25f);
+        ImPlot::PlotLine(id, values, count, 1, 0, ImPlotLineFlags_Shaded, offset);
-        ImPlot::PlotShaded(id, values, count, 0, 1, 0, 0, offset);
-        ImPlot::PopStyleVar();
-        ImPlot::PopStyleColor();
         ImPlot::EndPlot();
     }
     ImPlot::PopStyleVar();

implot_items.cpp

@@ -1159,6 +1159,72 @@ struct RendererStairsPost : RendererBase {
     mutable ImVec2 UV;
 };
 
+template <class _Getter>
+struct RendererStairsPreShaded : RendererBase {
+    RendererStairsPreShaded(const _Getter& getter, ImU32 col) :
+        RendererBase(getter.Count - 1, 6, 4),
+        Getter(getter),
+        Col(col)
+    {
+        P1 = this->Transformer(Getter(0));
+        Y0 = this->Transformer(ImPlotPoint(0,0)).y;
+    }
+    void Init(ImDrawList& draw_list) const {
+        UV = draw_list._Data->TexUvWhitePixel;
+    }
+    IMPLOT_INLINE bool Render(ImDrawList& draw_list, const ImRect& cull_rect, int prim) const {
+        ImVec2 P2 = this->Transformer(Getter(prim + 1));
+        ImVec2 PMin(ImMin(P1.x, P2.x), ImMin(Y0, P2.y));
+        ImVec2 PMax(ImMax(P1.x, P2.x), ImMax(Y0, P2.y));
+        if (!cull_rect.Overlaps(ImRect(PMin, PMax))) {
+            P1 = P2;
+            return false;
+        }
+        PrimRectFill(draw_list, PMin, PMax, Col, UV);
+        P1 = P2;
+        return true;
+    }
+    const _Getter& Getter;
+    const ImU32 Col;
+    float Y0;
+    mutable ImVec2 P1;
+    mutable ImVec2 UV;
+};
+
+template <class _Getter>
+struct RendererStairsPostShaded : RendererBase {
+    RendererStairsPostShaded(const _Getter& getter, ImU32 col) :
+        RendererBase(getter.Count - 1, 6, 4),
+        Getter(getter),
+        Col(col)
+    {
+        P1 = this->Transformer(Getter(0));
+        Y0 = this->Transformer(ImPlotPoint(0,0)).y;
+    }
+    void Init(ImDrawList& draw_list) const {
+        UV = draw_list._Data->TexUvWhitePixel;
+    }
+    IMPLOT_INLINE bool Render(ImDrawList& draw_list, const ImRect& cull_rect, int prim) const {
+        ImVec2 P2 = this->Transformer(Getter(prim + 1));
+        ImVec2 PMin(ImMin(P1.x, P2.x), ImMin(P1.y, Y0));
+        ImVec2 PMax(ImMax(P1.x, P2.x), ImMax(P1.y, Y0));
+        if (!cull_rect.Overlaps(ImRect(PMin, PMax))) {
+            P1 = P2;
+            return false;
+        }
+        PrimRectFill(draw_list, PMin, PMax, Col, UV);
+        P1 = P2;
+        return true;
+    }
+    const _Getter& Getter;
+    const ImU32 Col;
+    float Y0;
+    mutable ImVec2 P1;
+    mutable ImVec2 UV;
+};
+
+
+
 template <class _Getter1, class _Getter2>
 struct RendererShaded : RendererBase {
     RendererShaded(const _Getter1& getter1, const _Getter2& getter2, ImU32 col) :
@@ -1462,20 +1528,26 @@ void RenderMarkers(const _Getter& getter, ImPlotMarker marker, float size, bool
 // [SECTION] PlotLine
 //-----------------------------------------------------------------------------
 
-template <typename Getter>
+template <typename _Getter>
-void PlotLineEx(const char* label_id, const Getter& getter, ImPlotLineFlags flags) {
+void PlotLineEx(const char* label_id, const _Getter& getter, ImPlotLineFlags flags) {
-    if (BeginItemEx(label_id, Fitter1<Getter>(getter), flags, ImPlotCol_Line)) {
+    if (BeginItemEx(label_id, Fitter1<_Getter>(getter), flags, ImPlotCol_Line)) {
         const ImPlotNextItemData& s = GetItemData();
-        if (getter.Count > 1 && s.RenderLine) {
+        if (getter.Count > 1) {
+            if (ImHasFlag(flags, ImPlotLineFlags_Shaded) && s.RenderFill) {
+                const ImU32 col_fill = ImGui::GetColorU32(s.Colors[ImPlotCol_Fill]);
+                GetterOverrideY<_Getter> getter2(getter, 0);
+                RenderPrimitives2<RendererShaded>(getter,getter2,col_fill);
+            }
+            if (s.RenderLine) {
                 const ImU32 col_line = ImGui::GetColorU32(s.Colors[ImPlotCol_Line]);
                 if (ImHasFlag(flags,ImPlotLineFlags_Segments)) {
                     RenderPrimitives1<RendererLineSegments1>(getter,col_line,s.LineWeight);
                 }
                 else if (ImHasFlag(flags, ImPlotLineFlags_Loop)) {
                     if (ImHasFlag(flags, ImPlotLineFlags_SkipNaN))
-                    RenderPrimitives1<RendererLineStripSkip>(GetterLoop<Getter>(getter),col_line,s.LineWeight);
+                        RenderPrimitives1<RendererLineStripSkip>(GetterLoop<_Getter>(getter),col_line,s.LineWeight);
                     else
-                    RenderPrimitives1<RendererLineStrip>(GetterLoop<Getter>(getter),col_line,s.LineWeight);
+                        RenderPrimitives1<RendererLineStrip>(GetterLoop<_Getter>(getter),col_line,s.LineWeight);
                 }
                 else {
                     if (ImHasFlag(flags, ImPlotLineFlags_SkipNaN))
@@ -1484,6 +1556,7 @@ void PlotLineEx(const char* label_id, const Getter& getter, ImPlotLineFlags flag
                         RenderPrimitives1<RendererLineStrip>(getter,col_line,s.LineWeight);
                 }
             }
+        }
         // render markers
         if (s.Marker != ImPlotMarker_None) {
             if (ImHasFlag(flags, ImPlotLineFlags_NoClip)) {
@@ -1492,7 +1565,7 @@ void PlotLineEx(const char* label_id, const Getter& getter, ImPlotLineFlags flag
             }
             const ImU32 col_line = ImGui::GetColorU32(s.Colors[ImPlotCol_MarkerOutline]);
             const ImU32 col_fill = ImGui::GetColorU32(s.Colors[ImPlotCol_MarkerFill]);
-            RenderMarkers<Getter>(getter, s.Marker, s.MarkerSize, s.RenderMarkerFill, col_fill, s.RenderMarkerLine, col_line, s.MarkerWeight);
+            RenderMarkers<_Getter>(getter, s.Marker, s.MarkerSize, s.RenderMarkerFill, col_fill, s.RenderMarkerLine, col_line, s.MarkerWeight);
         }
         EndItem();
     }
@@ -1518,7 +1591,7 @@ template IMPLOT_API void PlotLine<double>(const char* label_id, const double* va
 template <typename T>
 void PlotLine(const char* label_id, const T* xs, const T* ys, int count, ImPlotLineFlags flags, int offset, int stride) {
     GetterXY<IndexerIdx<T>,IndexerIdx<T>> getter(IndexerIdx<T>(xs,count,offset,stride),IndexerIdx<T>(ys,count,offset,stride),count);
-    return PlotLineEx(label_id, getter, flags);
+    PlotLineEx(label_id, getter, flags);
 }
 
 template IMPLOT_API void PlotLine<ImS8>(const char* label_id, const ImS8* xs, const ImS8* ys, int count, ImPlotLineFlags flags, int offset, int stride);
@@ -1535,7 +1608,7 @@ template IMPLOT_API void PlotLine<double>(const char* label_id, const double* xs
 // custom
 void PlotLineG(const char* label_id, ImPlotGetter getter_func, void* data, int count, ImPlotLineFlags flags) {
     GetterFuncPtr getter(getter_func,data, count);
-    return PlotLineEx(label_id, getter, flags);
+    PlotLineEx(label_id, getter, flags);
 }
 
 //-----------------------------------------------------------------------------
@@ -1608,13 +1681,22 @@ template <typename Getter>
 void PlotStairsEx(const char* label_id, const Getter& getter, ImPlotStairsFlags flags) {
     if (BeginItemEx(label_id, Fitter1<Getter>(getter), flags, ImPlotCol_Line)) {
         const ImPlotNextItemData& s = GetItemData();
-        if (getter.Count > 1 && s.RenderLine) {
+        if (getter.Count > 1 ) {
+            if (s.RenderFill && ImHasFlag(flags,ImPlotStairsFlags_Shaded)) {
+                const ImU32 col_fill = ImGui::GetColorU32(s.Colors[ImPlotCol_Fill]);
+                if (ImHasFlag(flags, ImPlotStairsFlags_PreStep))
+                    RenderPrimitives1<RendererStairsPreShaded>(getter,col_fill);
+                else
+                    RenderPrimitives1<RendererStairsPostShaded>(getter,col_fill);
+            }
+            if (s.RenderLine) {
                 const ImU32 col_line = ImGui::GetColorU32(s.Colors[ImPlotCol_Line]);
                 if (ImHasFlag(flags, ImPlotStairsFlags_PreStep))
                     RenderPrimitives1<RendererStairsPre>(getter,col_line,s.LineWeight);
                 else
                     RenderPrimitives1<RendererStairsPost>(getter,col_line,s.LineWeight);
             }
+        }
         // render markers
         if (s.Marker != ImPlotMarker_None) {
             PopPlotClipRect();