Add SetupAxisTicks for configuring custom ticks

implot3d.cpp

@@ -597,6 +597,11 @@ void RenderGrid(ImDrawList* draw_list, const ImPlot3DPlot& plot, const ImPlot3DP
 
                 // Compute position along u
                 float t_u = (tick.PlotPos - axis_u.Range.Min) / (axis_u.Range.Max - axis_u.Range.Min);
+
+                // Skip ticks that are out of range
+                if (t_u < 0.0f || t_u > 1.0f)
+                    continue;
+
                 ImPlot3DPoint p_start = p0 + u_vec * t_u;
                 ImPlot3DPoint p_end = p3 + u_vec * t_u;
 
@@ -618,6 +623,11 @@ void RenderGrid(ImDrawList* draw_list, const ImPlot3DPlot& plot, const ImPlot3DP
 
                 // Compute position along v
                 float t_v = (tick.PlotPos - axis_v.Range.Min) / (axis_v.Range.Max - axis_v.Range.Min);
+
+                // Skip ticks that are out of range
+                if (t_v < 0.0f || t_v > 1.0f)
+                    continue;
+
                 ImPlot3DPoint p_start = p0 + v_vec * t_v;
                 ImPlot3DPoint p_end = p1 + v_vec * t_v;
 
@@ -720,6 +730,9 @@ void RenderTickMarks(ImDrawList* draw_list, const ImPlot3DPlot& plot, const ImPl
             const ImPlot3DTick& tick = axis.Ticker.Ticks[t];
             float v = (tick.PlotPos - axis.Range.Min) / (axis.Range.Max - axis.Range.Min);
 
+            // Skip ticks that are out of range
+            if (v < 0.0f || v > 1.0f)
+                continue;
             ImPlot3DPoint tick_pos_ndc = PlotToNDC(axis_start + axis_dir * (v * axis_len));
 
             // Half tick on each side of the axis line
@@ -811,6 +824,10 @@ void RenderTickLabels(ImDrawList* draw_list, const ImPlot3DPlot& plot, const ImP
 
             // Compute position along the axis
             float t_axis = (tick.PlotPos - axis.Range.Min) / (axis.Range.Max - axis.Range.Min);
+
+            // Skip ticks that are out of range
+            if (t_axis < 0.0f || t_axis > 1.0f)
+                continue;
             ImPlot3DPoint tick_pos = axis_start + axis_dir * t_axis;
 
             // Convert to pixel coordinates
@@ -1114,6 +1131,15 @@ void Locator_Default(ImPlot3DTicker& ticker, const ImPlot3DRange& range, float p
     }
 }
 
+void AddTicksCustom(const double* values, const char* const labels[], int n, ImPlot3DTicker& ticker, ImPlot3DFormatter formatter, void* data) {
+    for (int i = 0; i < n; ++i) {
+        if (labels != nullptr)
+            ticker.AddTick(values[i], false, true, labels[i]);
+        else
+            ticker.AddTick(values[i], false, true, formatter, data);
+    }
+}
+
 //------------------------------------------------------------------------------
 // [SECTION] Context Menus
 //------------------------------------------------------------------------------
@@ -1338,6 +1364,11 @@ bool BeginPlot(const char* title_id, const ImVec2& size, ImPlot3DFlags flags) {
     // Reset legend
     plot.Items.Legend.Reset();
 
+    // Reset axes
+    for (int i = 0; i < ImAxis3D_COUNT; ++i) {
+        plot.Axes[i].Reset();
+    }
+
     // Push frame rect clipping
     ImGui::PushClipRect(plot.FrameRect.Min, plot.FrameRect.Max, true);
     plot.DrawList._Flags = window->DrawList->Flags;
@@ -1471,6 +1502,31 @@ void SetupAxisFormat(ImAxis3D idx, ImPlot3DFormatter formatter, void* data) {
     axis.FormatterData = data;
 }
 
+void SetupAxisTicks(ImAxis3D idx, const double* values, int n_ticks, const char* const labels[], bool keep_default) {
+    ImPlot3DContext& gp = *GImPlot3D;
+    IM_ASSERT_USER_ERROR(gp.CurrentPlot != nullptr && !gp.CurrentPlot->SetupLocked,
+                         "Setup needs to be called after BeginPlot and before any setup locking functions (e.g. PlotX)!");
+    ImPlot3DPlot& plot = *gp.CurrentPlot;
+    ImPlot3DAxis& axis = plot.Axes[idx];
+    axis.ShowDefaultTicks = keep_default;
+    AddTicksCustom(values,
+                   labels,
+                   n_ticks,
+                   axis.Ticker,
+                   axis.Formatter ? axis.Formatter : Formatter_Default,
+                   (axis.Formatter && axis.FormatterData) ? axis.FormatterData : (void*)IMPLOT3D_LABEL_FORMAT);
+}
+
+void SetupAxisTicks(ImAxis3D idx, double v_min, double v_max, int n_ticks, const char* const labels[], bool keep_default) {
+    ImPlot3DContext& gp = *GImPlot3D;
+    IM_ASSERT_USER_ERROR(gp.CurrentPlot != nullptr && !gp.CurrentPlot->SetupLocked,
+                         "Setup needs to be called after BeginPlot and before any setup locking functions (e.g. PlotX)!");
+    n_ticks = n_ticks < 2 ? 2 : n_ticks;
+    ImVector<double> temp;
+    FillRange(temp, n_ticks, v_min, v_max);
+    SetupAxisTicks(idx, temp.Data, n_ticks, labels, keep_default);
+}
+
 void SetupAxes(const char* x_label, const char* y_label, const char* z_label, ImPlot3DAxisFlags x_flags, ImPlot3DAxisFlags y_flags, ImPlot3DAxisFlags z_flags) {
     SetupAxis(ImAxis3D_X, x_label, x_flags);
     SetupAxis(ImAxis3D_Y, y_label, y_flags);
@@ -2097,9 +2153,10 @@ void SetupLock() {
     // Compute ticks
     for (int i = 0; i < 3; i++) {
         ImPlot3DAxis& axis = plot.Axes[i];
-        axis.Ticker.Reset();
-        float pixels = plot.GetBoxZoom() * plot.BoxScale[i];
-        axis.Locator(axis.Ticker, axis.Range, pixels, axis.Formatter, axis.FormatterData);
+        if (axis.ShowDefaultTicks) {
+            float pixels = plot.GetBoxZoom() * plot.BoxScale[i];
+            axis.Locator(axis.Ticker, axis.Range, pixels, axis.Formatter, axis.FormatterData);
+        }
     }
 
     // Render title

implot3d.h

@@ -364,6 +364,12 @@ IMPLOT3D_API void SetupAxisLimits(ImAxis3D axis, double v_min, double v_max, ImP
 
 IMPLOT3D_API void SetupAxisFormat(ImAxis3D idx, ImPlot3DFormatter formatter, void* data = nullptr);
 
+// Sets an axis' ticks and optionally the labels. To keep the default ticks, set #keep_default=true
+IMPLOT3D_API void SetupAxisTicks(ImAxis3D axis, const double* values, int n_ticks, const char* const labels[] = nullptr, bool keep_default = false);
+
+// Sets an axis' ticks and optionally the labels for the next plot. To keep the default ticks, set #keep_default=true
+IMPLOT3D_API void SetupAxisTicks(ImAxis3D axis, double v_min, double v_max, int n_ticks, const char* const labels[] = nullptr, bool keep_default = false);
+
 // Sets the label and/or flags for primary X/Y/Z axes (shorthand for three calls to SetupAxis)
 IMPLOT3D_API void SetupAxes(const char* x_label, const char* y_label, const char* z_label, ImPlot3DAxisFlags x_flags = 0, ImPlot3DAxisFlags y_flags = 0, ImPlot3DAxisFlags z_flags = 0);
 

implot3d_demo.cpp

@@ -565,6 +565,29 @@ void DemoBoxScale() {
     }
 }
 
+void DemoTickLabels() {
+    static bool custom_ticks = false;
+    static bool custom_labels = true;
+    ImGui::Checkbox("Show Custom Ticks", &custom_ticks);
+    if (custom_ticks) {
+        ImGui::SameLine();
+        ImGui::Checkbox("Show Custom Labels", &custom_labels);
+    }
+    const double pi = 3.14;
+    const char* pi_str[] = {"PI"};
+    static double letters_ticks[] = {0.0, 0.2, 0.4, 0.6, 0.8, 1.0};
+    static const char* letters_labels[] = {"A", "B", "C", "D", "E", "F"};
+    if (ImPlot3D::BeginPlot("##Ticks")) {
+        ImPlot3D::SetupAxesLimits(2, 5, 0, 1, 0, 1);
+        if (custom_ticks) {
+            ImPlot3D::SetupAxisTicks(ImAxis3D_X, &pi, 1, custom_labels ? pi_str : nullptr, true);
+            ImPlot3D::SetupAxisTicks(ImAxis3D_Y, letters_ticks, 6, custom_labels ? letters_labels : nullptr, false);
+            ImPlot3D::SetupAxisTicks(ImAxis3D_Z, 0, 1, 6, custom_labels ? letters_labels : nullptr, false);
+        }
+        ImPlot3D::EndPlot();
+    }
+}
+
 //-----------------------------------------------------------------------------
 // [SECTION] Custom
 //-----------------------------------------------------------------------------
@@ -753,6 +776,7 @@ void ShowDemoWindow(bool* p_open) {
         }
         if (ImGui::BeginTabItem("Axes")) {
             DemoHeader("Box Scale", DemoBoxScale);
+            DemoHeader("Tick Labels", DemoTickLabels);
             ImGui::EndTabItem();
         }
         if (ImGui::BeginTabItem("Custom")) {

implot3d_internal.h

@@ -97,6 +97,16 @@ static inline ImU32 ImMixU32(ImU32 a, ImU32 b, ImU32 s) {
 #endif
 }
 
+// Fills a buffer with n samples linear interpolated from vmin to vmax
+template <typename T>
+void FillRange(ImVector<T>& buffer, int n, T vmin, T vmax) {
+    buffer.resize(n);
+    T step = (vmax - vmin) / (n - 1);
+    for (int i = 0; i < n; ++i) {
+        buffer[i] = vmin + i * step;
+    }
+}
+
 } // namespace ImPlot3D
 
 //-----------------------------------------------------------------------------
@@ -435,6 +445,7 @@ struct ImPlot3DAxis {
     ImPlot3DFormatter Formatter;
     void* FormatterData;
     ImPlot3DLocator Locator;
+    bool ShowDefaultTicks;
     // Fit data
     bool FitThisFrame;
     ImPlot3DRange FitExtents;
@@ -452,6 +463,7 @@ struct ImPlot3DAxis {
         Formatter = nullptr;
         FormatterData = nullptr;
         Locator = nullptr;
+        ShowDefaultTicks = true;
         // Fit data
         FitThisFrame = true;
         FitExtents.Min = HUGE_VAL;
@@ -460,6 +472,16 @@ struct ImPlot3DAxis {
         Held = false;
     }
 
+    inline void Reset() {
+        Formatter = nullptr;
+        FormatterData = nullptr;
+        Locator = nullptr;
+        ShowDefaultTicks = true;
+        FitExtents.Min = HUGE_VAL;
+        FitExtents.Max = -HUGE_VAL;
+        Ticker.Reset();
+    }
+
     inline void SetRange(double v1, double v2) {
         Range.Min = (float)ImMin(v1, v2);
         Range.Max = (float)ImMax(v1, v2);