prototyping tooltip support

implot.cpp

@@ -2842,6 +2842,83 @@ bool DragPoint(const char* id, double* x, double* y, bool show_label, const ImVe
     return dragging;
 }
 
+//-----------------------------------------------------------------------------
+// TOOLTIPS
+//-----------------------------------------------------------------------------
+
+template <typename T>
+T GetClosest(T val1, T val2, T target) { 
+    if (target - val1 >= val2 - target) 
+        return val2; 
+    else
+        return val1; 
+} 
+
+template <typename T>
+int FindClosestIdx(const T* arr, int n, T target) { 
+    if (target <= arr[0]) 
+        return 0; 
+    if (target >= arr[n - 1]) 
+        return n - 1;   
+    int i = 0, j = n, mid = 0; 
+    while (i < j) { 
+        mid = (i + j) / 2;   
+        if (arr[mid] == target) 
+            return mid;  
+        if (target < arr[mid]) {
+            if (mid > 0 && target > arr[mid - 1]) 
+                return (target - arr[mid - 1] >= arr[mid] - target) ? mid : mid - 1;
+            j = mid; 
+        }   
+        else { 
+            if (mid < n - 1 && target < arr[mid + 1]) 
+                return (target - arr[mid] >= arr[mid+1] - target) ? mid + 1 : mid;
+            i = mid + 1;  
+        } 
+    }   
+    return mid; 
+} 
+
+// bool BeginTooltip(const double* xs_mono, const double* ys, int* idx_out = NULL);
+
+
+bool BeginTooltipX(const double* xs_mono, const double* ys, int count, int* idx_out) {
+    if (ImPlot::IsPlotHovered()) {
+        double mouse_x   = ImPlot::GetPlotMousePos().x;
+        if (mouse_x < (double)xs_mono[0] || mouse_x > (double)xs_mono[count-1])
+            return false;
+        const int idx = FindClosestIdx(xs_mono, count, mouse_x);
+        PushPlotClipRect();
+        ImVec2 pos = PlotToPixels(xs_mono[idx], ys[idx]);
+        ImVec4 col = GetLastItemColor();
+        GetPlotDrawList()->AddCircleFilled(pos, 6, ImGui::ColorConvertFloat4ToU32(col));
+        PopPlotClipRect();
+        if (idx_out == NULL) {
+            ImGui::BeginTooltip();
+            ImGui::PushStyleColor(ImGuiCol_Text, col);
+            ImGui::Text("%.3f,%.3f",xs_mono[idx], ys[idx]);
+            ImGui::PopStyleColor();
+            ImGui::EndTooltip();
+        }
+        else {
+            *idx_out = idx;
+        }
+        return true;
+    }
+    return false;
+}
+
+void EndTooltip() {
+
+}
+
+// bool BeginTooltipY(const double* xs, const double* ys_mono, int* idx_out = NULL);
+
+
+//-----------------------------------------------------------------------------
+// LEGEND UTILS
+//-----------------------------------------------------------------------------
+
 void SetLegendLocation(ImPlotLocation location, ImPlotOrientation orientation, bool outside) {
     ImPlotContext& gp = *GImPlot;
     IM_ASSERT_USER_ERROR(gp.CurrentPlot != NULL, "SetLegendLocation() needs to be called between BeginPlot() and EndPlot()!");

implot.h

@@ -531,6 +531,17 @@ IMPLOT_API bool DragLineY(const char* id, double* y_value, bool show_label = tru
 // Shows a draggable point at x,y. #col defaults to ImGuiCol_Text.
 IMPLOT_API bool DragPoint(const char* id, double* x, double* y, bool show_label = true, const ImVec4& col = IMPLOT_AUTO_COL, float radius = 4);
 
+// Facilitates adding hover tooltips to plots. If #idx_out is NULL, a default tooltip will be rendered. Otherwise, the value will be set to the hovered idx, 
+// and it becomes YOUR responsibility to render tooltip information using regular ImGui functions. You MUST make a matching call to EndTooltip if these
+// functions return true!
+IMPLOT_API bool BeginTooltip(const double* xs_mono, const double* ys, int count, int* idx_out = NULL);
+// This variant is optimized to search along monotonically increasing x values (this is the one you want for time-series plots).
+IMPLOT_API bool BeginTooltipX(const double* xs_mono, const double* ys, int count, int* idx_out = NULL);
+// This variant is optimized to search along monotonically increasing y values.
+IMPLOT_API bool BeginTooltipY(const double* xs, const double* ys_mono, int count, int* idx_out = NULL);
+// Only call EndTooltip if BeginTooltip returns true! e.g. if (BeginTooltipX(...)) { ... EndTooltip(); } 
+IMPLOT_API void EndTooltip();
+
 //-----------------------------------------------------------------------------
 // Legend Utils and Tools
 //-----------------------------------------------------------------------------

implot_demo.cpp

@@ -233,10 +233,10 @@ void ShowDemoWindow(bool* p_open) {
     }
     //-------------------------------------------------------------------------
     if (ImGui::CollapsingHeader("Line Plots")) {
-        static float xs1[1001], ys1[1001];
+        static double xs1[1001], ys1[1001];
         for (int i = 0; i < 1001; ++i) {
             xs1[i] = i * 0.001f;
-            ys1[i] = 0.5f + 0.5f * sinf(50 * (xs1[i] + (float)DEMO_TIME / 10));
+            ys1[i] = 0.5 + 0.5 * sin(50 * (xs1[i] + (double)DEMO_TIME / 10));
         }
         static double xs2[11], ys2[11];
         for (int i = 0; i < 11; ++i) {
@@ -246,8 +246,12 @@ void ShowDemoWindow(bool* p_open) {
         ImGui::BulletText("Anti-aliasing can be enabled from the plot's context menu (see Help).");
         if (ImPlot::BeginPlot("Line Plot", "x", "f(x)")) {
             ImPlot::PlotLine("sin(x)", xs1, ys1, 1001);
+            if (ImPlot::BeginTooltipX(xs1,ys1,1001)) 
+                ImPlot::EndTooltip();
             ImPlot::SetNextMarkerStyle(ImPlotMarker_Circle);
             ImPlot::PlotLine("x^2", xs2, ys2, 11);
+            if (ImPlot::BeginTooltipX(xs2,ys2,11)) 
+                ImPlot::EndTooltip();
             ImPlot::EndPlot();
         }
     }
@@ -314,7 +318,7 @@ void ShowDemoWindow(bool* p_open) {
     //-------------------------------------------------------------------------
     if (ImGui::CollapsingHeader("Scatter Plots")) {
         srand(0);
-        static float xs1[100], ys1[100];
+        static double xs1[100], ys1[100];
         for (int i = 0; i < 100; ++i) {
             xs1[i] = i * 0.01f;
             ys1[i] = xs1[i] + 0.1f * ((float)rand() / (float)RAND_MAX);
@@ -327,6 +331,8 @@ void ShowDemoWindow(bool* p_open) {
 
         if (ImPlot::BeginPlot("Scatter Plot", NULL, NULL)) {
             ImPlot::PlotScatter("Data 1", xs1, ys1, 100);
+            if (ImPlot::BeginTooltipX(xs1,ys1,100)) 
+                ImPlot::EndTooltip();
             ImPlot::PushStyleVar(ImPlotStyleVar_FillAlpha, 0.25f);
             ImPlot::SetNextMarkerStyle(ImPlotMarker_Square, 6, ImVec4(0,1,0,0.5f), IMPLOT_AUTO, ImVec4(0,1,0,1));
             ImPlot::PlotScatter("Data 2", xs2, ys2, 50);