anchor point prototype

implot.cpp

@@ -2486,11 +2486,11 @@ ImPlotLimits GetPlotQuery(int y_axis_in) {
 bool HorizontalGuide(const char* id, double* value, const ImVec4& col, float thickness) {
     ImPlotContext& gp = *GImPlot;
     IM_ASSERT_USER_ERROR(gp.CurrentPlot != NULL, "HorizontalGuide() needs to be called between BeginPlot() and EndPlot()!");
-    const float grab_size = ImMax(6.0f, thickness);
+    const float grab_size = ImMax(5.0f, thickness);
     float xl = gp.BB_Plot.Min.x;
     float xr = gp.BB_Plot.Max.x;
     float y  = IM_ROUND(PlotToPixels(0, *value).y);
-    const bool outside = (y < gp.BB_Plot.Min.y - grab_size / 2 || y > gp.BB_Plot.Max.y + grab_size / 2);
+    const bool outside = y < (gp.BB_Plot.Min.y - grab_size / 2) || y > (gp.BB_Plot.Max.y + grab_size / 2);
     if (outside)
         return false;
 
@@ -2546,11 +2546,11 @@ bool HorizontalGuide(const char* id, double* value, const ImVec4& col, float thi
 bool VerticalGuide(const char* id, double* value, const ImVec4& col, float thickness) {
     ImPlotContext& gp = *GImPlot;
     IM_ASSERT_USER_ERROR(gp.CurrentPlot != NULL, "VerticalGuide() needs to be called between BeginPlot() and EndPlot()!");
-    const float grab_size = ImMax(6.0f, thickness);
+    const float grab_size = ImMax(5.0f, thickness);
     float yt = gp.BB_Plot.Min.y;
     float yb = gp.BB_Plot.Max.y;
     float x  = IM_ROUND(PlotToPixels(*value,0).x);
-    const bool outside = (x < gp.BB_Plot.Min.x - grab_size / 2 || x > gp.BB_Plot.Max.x + grab_size / 2);
+    const bool outside = x < (gp.BB_Plot.Min.x - grab_size / 2) || x > (gp.BB_Plot.Max.x + grab_size / 2);
     if (outside)
         return false;
 
@@ -2596,6 +2596,55 @@ bool VerticalGuide(const char* id, double* value, const ImVec4& col, float thick
     return dragging;
 }
 
+bool AnchorPoint(const char* id, double* x, double* y, const ImVec4& col, float radius) {
+    ImPlotContext& gp = *GImPlot;
+    IM_ASSERT_USER_ERROR(gp.CurrentPlot != NULL, "AnchorPoint() needs to be called between BeginPlot() and EndPlot()!");
+    const float grab_size = ImMax(5.0f, 2*radius);
+    const bool outside = !GetPlotLimits().Contains(*x,*y);
+    if (outside)
+        return false;
+
+    ImVec4 color = IsColorAuto(col) ? ImGui::GetStyleColorVec4(ImGuiCol_Text) : col;
+    ImU32 col32 = ImGui::ColorConvertFloat4ToU32(color);
+    ImDrawList& DrawList = *GetPlotDrawList();
+
+    ImVec2 pos = PlotToPixels(*x,*y);
+
+    PushPlotClipRect();
+    DrawList.AddCircleFilled(pos, radius, col32);
+    PopPlotClipRect();
+
+    int yax = GetCurrentYAxis();
+    ImVec2 old_cursor_pos = ImGui::GetCursorScreenPos();
+    ImVec2 new_cursor_pos = ImVec2(pos - ImVec2(grab_size,grab_size)*0.5f);
+    ImGui::SetItemAllowOverlap();
+    ImGui::SetCursorScreenPos(new_cursor_pos);
+    ImGui::InvisibleButton(id, ImVec2(grab_size, grab_size));
+    ImGui::SetCursorScreenPos(old_cursor_pos);
+    if (ImGui::IsItemHovered() || ImGui::IsItemActive()) {
+        ImGui::SetMouseCursor(ImGuiMouseCursor_ResizeAll);
+        // double range_x = gp.XTicks.Size > 1 ? (gp.XTicks.Ticks[1].PlotPos - gp.XTicks.Ticks[0].PlotPos) : gp.CurrentPlot->XAxis.Range.Size();
+        // char buf[32];
+        // snprintf(buf, 32, "%s = %.*f", id, Precision(range_x), *value);
+        // ImVec2 size = ImGui::CalcTextSize(buf);
+        // const int pad = 2;
+        // PushPlotClipRect();
+        // DrawList.AddRectFilled(ImVec2(x - size.x/2 - pad, yb - size.y - 2*pad), ImVec2(x + pad + size.x/2, yb), col32);
+        // DrawList.AddText(ImVec2(x - size.x/2, yb - size.y - pad), CalcTextColor(color), buf);
+        // PopPlotClipRect();
+    }
+
+    bool dragging = false;
+    if (ImGui::IsItemActive() && ImGui::IsMouseDragging(0)) {
+        *x = ImPlot::GetPlotMousePos().x;
+        *y = ImPlot::GetPlotMousePos().y;
+        *x = ImClamp(*x, gp.X.Axis->Range.Min, gp.X.Axis->Range.Max);
+        *y = ImClamp(*y, gp.Y[yax].Axis->Range.Min, gp.Y[yax].Axis->Range.Max);
+        dragging = true;
+    }
+    return dragging;
+}
+
 bool IsLegendEntryHovered(const char* label_id) {
     ImPlotContext& gp = *GImPlot;
     IM_ASSERT_USER_ERROR(gp.CurrentPlot != NULL, "IsPlotItemHighlight() needs to be called between BeginPlot() and EndPlot()!");

implot.h

@@ -453,11 +453,6 @@ IMPLOT_API ImPlotPoint GetPlotMousePos(int y_axis = IMPLOT_AUTO);
 // Returns the current plot axis range. A negative y_axis uses the current value of SetPlotYAxis (0 initially).
 IMPLOT_API ImPlotLimits GetPlotLimits(int y_axis = IMPLOT_AUTO);
 
-// Returns true if the current plot is being queried.
-IMPLOT_API bool IsPlotQueried();
-// Returns the current plot query bounds.
-IMPLOT_API ImPlotLimits GetPlotQuery(int y_axis = IMPLOT_AUTO);
-
 //-----------------------------------------------------------------------------
 // Plot Tools
 //-----------------------------------------------------------------------------
@@ -466,6 +461,13 @@ IMPLOT_API ImPlotLimits GetPlotQuery(int y_axis = IMPLOT_AUTO);
 IMPLOT_API bool HorizontalGuide(const char* id, double* y_value, const ImVec4& col = IMPLOT_AUTO_COL, float thickness = 1);
 // Shows a draggable vertical guide line. #col defaults to ImGuiCol_Text.
 IMPLOT_API bool VerticalGuide(const char* id, double* x_value, const ImVec4& col = IMPLOT_AUTO_COL, float thickness = 1);
+// Shows a draggable anchor point. #col defaults to ImGuiCol_Text.
+IMPLOT_API bool AnchorPoint(const char* id, double* x, double* y, const ImVec4& col = IMPLOT_AUTO_COL, float radius = 5);
+
+// Returns true if the current plot is being queried. Query must be enabled with ImPlotFlags_Query.
+IMPLOT_API bool IsPlotQueried();
+// Returns the current plot query bounds. Query must be enabled with ImPlotFlags_Query.
+IMPLOT_API ImPlotLimits GetPlotQuery(int y_axis = IMPLOT_AUTO);
 
 //-----------------------------------------------------------------------------
 // Legend Utils and Tools

implot_demo.cpp

@@ -805,7 +805,7 @@ void ShowDemoWindow(bool* p_open) {
         }
     }
     //-------------------------------------------------------------------------
-    if (ImGui::CollapsingHeader("Guide Lines")) {
+    if (ImGui::CollapsingHeader("Guides and Anchors")) {
         ImGui::BulletText("Click and drag the horizontal and vertical guide lines.");
         static double x1 = 0.2;
         static double x2 = 0.8;
@@ -829,6 +829,36 @@ void ShowDemoWindow(bool* p_open) {
             ImPlot::PlotLine("Why Not?", xs, ys, 1000);
             ImPlot::EndPlot();
         }
+        ImGui::BulletText("Click and drag the anchor points.");
+        ImPlotAxisFlags flags = ImPlotAxisFlags_NoTickLabels | ImPlotAxisFlags_NoTickMarks;
+        ImPlot::SetNextPlotLimits(0,1,0,1,ImGuiCond_Always);
+        if (ImPlot::BeginPlot("##Bezier",0,0,ImVec2(-1,0),ImPlotFlags_CanvasOnly|ImPlotFlags_NoChild,flags,flags)) {
+            static ImPlotPoint P[] = {ImPlotPoint(0,0), ImPlotPoint(0.2,0.4),  ImPlotPoint(0.8,0.6),  ImPlotPoint(1,1)};
+            static ImPlotPoint B[100];
+            for (int i = 0; i < 100; ++i) {
+                double t  = i / 99.0;
+                double u  = 1 - t;
+                double w1 = u*u*u;
+                double w2 = 3*u*u*t;
+                double w3 = 3*u*t*t;
+                double w4 = t*t*t;
+                B[i] = ImPlotPoint(w1*P[0].x + w2*P[1].x + w3*P[2].x + w4*P[3].x, w1*P[0].y + w2*P[1].y + w3*P[2].y + w4*P[3].y);
+            }
+            static ImVec4 gray = ImVec4(0.5f,0.5f,0.5f,1.0f);
+            ImPlot::SetNextFillStyle(ImVec4(0,1,0,0.25f));
+            ImPlot::PlotShaded("##bez",&B[0].x, &B[0].y, 100, 0, 0, sizeof(ImPlotPoint));
+            ImPlot::SetNextLineStyle(ImVec4(0,1,0,1), 2);
+            ImPlot::PlotLine("##bez",&B[0].x, &B[0].y, 100, 0, sizeof(ImPlotPoint));
+            ImPlot::SetNextLineStyle(gray, 2);
+            ImPlot::PlotLine("##h1",&P[0].x, &P[0].y, 2, 0, sizeof(ImPlotPoint));
+            ImPlot::SetNextLineStyle(gray, 2);
+            ImPlot::PlotLine("##h2",&P[2].x, &P[2].y, 2, 0, sizeof(ImPlotPoint));
+            ImPlot::AnchorPoint("P0",&P[0].x,&P[0].y,gray);
+            ImPlot::AnchorPoint("P1",&P[1].x,&P[1].y,gray);        
+            ImPlot::AnchorPoint("P2",&P[2].x,&P[2].y,gray);
+            ImPlot::AnchorPoint("P3",&P[3].x,&P[3].y,gray);       
+            ImPlot::EndPlot();
+        }
     }
     //-------------------------------------------------------------------------
     if (ImGui::CollapsingHeader("Drag and Drop")) {