Rename IsPlotChanging to IsAxisRangeChanging and define PreviousRange in SetupFinish

Author: SamuMazzi

TODO.md

@@ -79,7 +79,8 @@ Ideally every `PlotX` function should use our faster rendering pipeline when it
 |PlotDummy|-|-|-|-|
 
 ## Completed
-- add `IsPlotChanging` to detect change in limits
+- add `IsAxisRangeChanging` to detect change in limits
+- add exploding to `PlotPieChart` (on legend hover)
 - make BeginPlot take fewer args:
 - make query a tool -> `DragRect`
 - rework DragLine/Point to use ButtonBehavior

implot.cpp

@@ -2135,8 +2135,6 @@ void SetupAxis(ImAxis idx, const char* label, ImPlotAxisFlags flags) {
     if (plot.JustCreated || flags != axis.PreviousFlags)
         axis.Flags = flags;
     axis.PreviousFlags = flags;
-    // cache previous range
-    axis.PreviousRange = ImPlotRange(axis.Range.Min, axis.Range.Max);
     // enable axis
     axis.Enabled = true;
     // set label
@@ -2632,6 +2630,11 @@ void SetupFinish() {
         }
     }
 
+    // cache previous ranges
+    for(int i = 0; i < ImAxis_COUNT; i++) {
+        plot.Axes[i].PreviousRange = ImPlotRange(plot.Axes[i].Range.Min, plot.Axes[i].Range.Max);
+    }
+
     // INPUT ------------------------------------------------------------------
     if (!ImHasFlag(plot.Flags, ImPlotFlags_NoInputs))
         UpdateInput(plot);
@@ -3741,14 +3744,14 @@ bool IsPlotHovered() {
     return gp.CurrentPlot->Hovered;
 }
 
-bool IsPlotChanging() {
+bool IsAxisRangeChanging(ImAxis axis) {
     ImPlotContext& gp = *GImPlot;
-    IM_ASSERT_USER_ERROR(gp.CurrentPlot != nullptr, "IsPlotChanging() needs to be called between BeginPlot() and EndPlot()!");
+    IM_ASSERT_USER_ERROR(gp.CurrentPlot != nullptr, "IsAxisRangeChanging() needs to be called between BeginPlot() and EndPlot()!");
     SetupLock();
     ImPlotPlot& plot = *gp.CurrentPlot;
-    bool differentX = plot.Axes[plot.CurrentX].Range.Min != plot.Axes[plot.CurrentX].PreviousRange.Min || plot.Axes[plot.CurrentX].Range.Max != plot.Axes[plot.CurrentX].PreviousRange.Max;
-    bool differentY = plot.Axes[plot.CurrentY].Range.Min != plot.Axes[plot.CurrentY].PreviousRange.Min || plot.Axes[plot.CurrentY].Range.Max != plot.Axes[plot.CurrentY].PreviousRange.Max;
-    return differentX || differentY;
+    bool isMinDifferent = plot.Axes[axis].Range.Min != plot.Axes[axis].PreviousRange.Min;
+    bool isMaxDifferent = plot.Axes[axis].Range.Max != plot.Axes[axis].PreviousRange.Max;
+    return isMinDifferent || isMaxDifferent;
 }
 
 bool IsAxisHovered(ImAxis axis) {

implot.h

@@ -982,8 +982,8 @@ IMPLOT_API ImPlotRect GetPlotLimits(ImAxis x_axis = IMPLOT_AUTO, ImAxis y_axis =
 
 // Returns true if the plot area in the current plot is hovered.
 IMPLOT_API bool IsPlotHovered();
-// Returns true if the limits of the current plot are changing.
-IMPLOT_API bool IsPlotChanging();
+// Returns true if the limits of the selected axis are changing.
+IMPLOT_API bool IsAxisRangeChanging(ImAxis axis);
 // Returns true if the axis label area in the current plot is hovered.
 IMPLOT_API bool IsAxisHovered(ImAxis axis);
 // Returns true if the bounding frame of a subplot is hovered.

implot_demo.cpp

@@ -2131,15 +2131,14 @@ void Demo_ColormapWidgets() {
 void Demo_PlotLimitsChanging() {
     unsigned int lin[10] = {8,8,9,7,8,8,8,9,7,8};
     unsigned int bar[10] = {1,2,5,3,4,1,2,5,3,4};
-    unsigned int dot[10] = {7,6,6,7,8,5,6,5,8,7};
 
     if (ImPlot::BeginPlot("##LimitsChanging")) {
         ImPlot::SetupAxes( "x-axis", "y-axis");
         ImPlot::SetupAxesLimits(-0.5f, 9.5f, 0, 10);
         ImPlot::PlotBars("Bars", bar, 10, 0.5f);
         ImPlot::PlotLine("Line", lin, 10);
-        bool is_changing = ImPlot::IsPlotChanging();
-        ImGui::Text("Axes are changing: %s", (is_changing ? "true" : "false"));
+        bool is_changing = ImPlot::IsAxisRangeChanging(ImAxis_X1);
+        ImGui::Text("Axis X1 is changing: %s", (is_changing ? "true" : "false"));
         ImPlot::EndPlot();
     }
 }