finish refactoring implot for v0.5

README.md

@@ -40,7 +40,7 @@ ImPlot is an immediate mode plotting widget for [Dear ImGui](https://github.com/
 
 ## Usage
 
-The API is used just like any other ImGui `BeginX`/`EndX` pair. First, start a plotting context with `ImPlot::BeginPlot()`. Next, plot as many items as you want with the provided `PlotX` functions (e.g. `PlotLine()`, `PlotBars()`, `PlotErrorBars()`, etc). Finally, wrap things up with a call to `ImPlot::EndPlot()`. That's it! 
+The API is used just like any other ImGui `BeginX`/`EndX` pair. First, start a new plot with `ImPlot::BeginPlot()`. Next, plot as many items as you want with the provided `PlotX` functions (e.g. `PlotLine()`, `PlotBars()`, `PlotErrorBars()`, etc). Finally, wrap things up with a call to `ImPlot::EndPlot()`. That's it!
 
 ```cpp
 if (ImPlot::BeginPlot("My Plot")) {
@@ -55,11 +55,22 @@ Consult `implot_demo.cpp` for a comprehensive example of ImPlot's features.
 
 ## Integration
 
-Just add `implot.h`, `implot.cpp`, and optionally `implot_demo.cpp` to your sources. This assumes you already have an ImGui-ready environment. If not, consider trying [mahi-gui](https://github.com/mahilab/mahi-gui), which bundles ImGui, ImPlot, and several other packages for you.
+1) Add `implot.h`, `implot_internal.h`, `implot.cpp`, `implot_items.cpp` and optionally `implot_demo.cpp` to your sources.
+2) Create and destroy an `ImPlotContext` wherever you create your `ImGuiContext`:
+
+```cpp
+ImGui::CreateContext();
+ImPlot::CreateContext();
+...
+ImPlot::DestroyContext();
+ImGui::DestroyContext();
+```
+
+Of course, this assumes you already have an ImGui-ready environment. If not, consider trying [mahi-gui](https://github.com/mahilab/mahi-gui), which bundles ImGui, ImPlot, and several other packages for you.
 
 ## Special Notes
 
-- If you experience data truncation and/or visual glitches, it is **HIGHLY** recommended that you either: 
+- If you experience data truncation and/or visual glitches, it is **HIGHLY** recommended that you EITHER:
     1) Handle the `ImGuiBackendFlags_RendererHasVtxOffset` flag in your renderer when using 16-bit indices (the official OpenGL3 renderer supports this) and use an ImGui version with patch [imgui@f6120f8](https://github.com/ocornut/imgui/commit/f6120f8e16eefcdb37b63974e6915a3dd35414be).
     2) Enable 32-bit indices by uncommenting `#define ImDrawIdx unsigned int` in your `imconfig.h` file.
 - By default, no anti-aliasing is done on line plots for performance reasons. If you use 4x MSAA, then you likely won't even notice. However, you can re-enable AA with the `ImPlotFlags_AntiAliased` flag.

implot.h

@@ -25,12 +25,14 @@
 #pragma once
 #include "imgui.h"
 
+#define IMPLOT_VERSION "0.5 WIP"
+
 //-----------------------------------------------------------------------------
-// Forward declarations and basic types
+// Forward Declarations and Basic Types
 //-----------------------------------------------------------------------------
 
 // Forward declarations
-struct ImPlotContext;  // ImPlot context (opaque struct)
+struct ImPlotContext;          // ImPlot context (opaque struct, see implot_internal.h)
 
 // Enums/Flags
 typedef int ImPlotFlags;       // -> enum ImPlotFlags_
@@ -149,16 +151,15 @@ struct ImPlotPoint {
 struct ImPlotRange {
     double Min, Max;
     ImPlotRange();
-    bool Contains(double value) const;
+    bool Contains(double value) const { return value >= Min && value <= Max; };
-    double Size() const;
+    double Size() const               { return Max - Min; };
 };
 
 // Combination of two ranges for X and Y axes.
 struct ImPlotLimits {
     ImPlotRange X, Y;
-    ImPlotLimits();
+    bool Contains(const ImPlotPoint& p) const { return Contains(p.x, p.y); }
-    bool Contains(const ImPlotPoint& p) const;
+    bool Contains(double x, double y) const   { return X.Contains(x) && Y.Contains(y); }
-    bool Contains(double x, double y) const;
 };
 
 // Plot style structure
@@ -193,9 +194,8 @@ struct ImPlotInputMap {
     ImPlotInputMap();
 };
 
-
 //-----------------------------------------------------------------------------
-// ImPlot end-user API
+// ImPlot End-User API
 //-----------------------------------------------------------------------------
 
 namespace ImPlot {
@@ -385,6 +385,7 @@ void SetNextPlotLimitsY(double y_min, double y_max, ImGuiCond cond = ImGuiCond_O
 // Set the X axis ticks and optionally the labels for the next plot.
 void SetNextPlotTicksX(const double* values, int n_ticks, const char** labels = NULL, bool show_default = false);
 void SetNextPlotTicksX(double x_min, double x_max, int n_ticks, const char** labels = NULL, bool show_default = false);
+
 // Set the Y axis ticks and optionally the labels for the next plot.
 void SetNextPlotTicksY(const double* values, int n_ticks, const char** labels = NULL, bool show_default = false, int y_axis = 0);
 void SetNextPlotTicksY(double y_min, double y_max, int n_ticks, const char** labels = NULL, bool show_default = false, int y_axis = 0);
@@ -399,8 +400,11 @@ ImVec2 GetPlotSize();
 
 // Convert pixels to a position in the current plot's coordinate system. A negative y_axis uses the current value of SetPlotYAxis (0 initially).
 ImPlotPoint PixelsToPlot(const ImVec2& pix, int y_axis = -1);
+ImPlotPoint PixelsToPlot(float x, float y, int y_axis = -1);
+
 // Convert a position in the current plot's coordinate system to pixels. A negative y_axis uses the current value of SetPlotYAxis (0 initially).
 ImVec2 PlotToPixels(const ImPlotPoint& plt, int y_axis = -1);
+ImVec2 PlotToPixels(double x, double y, int y_axis = -1);
 
 // Renders a vertical color scale using the current color map
 void ShowColormapScale(double scale_min, double scale_max, float height);

implot_internal.h

@@ -0,0 +1,447 @@
+// MIT License
+
+// Copyright (c) 2020 Evan Pezent
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+// ImPlot v0.5 WIP
+
+// You may use this file to debug, understand or extend ImPlot features but we don't provide any guarantee of forward compatibility!
+
+//-----------------------------------------------------------------------------
+// [SECTION] Header mess
+//-----------------------------------------------------------------------------
+
+#pragma once
+
+#ifndef IMGUI_DEFINE_MATH_OPERATORS
+#define IMGUI_DEFINE_MATH_OPERATORS
+#endif
+
+#include "imgui_internal.h"
+
+#ifndef IMPLOT_VERSION
+#error Must include implot.h before implot_internal.h
+#endif
+
+//-----------------------------------------------------------------------------
+// [SECTION] Forward declarations
+//-----------------------------------------------------------------------------
+
+struct ImPlotTick;
+struct ImPlotAxis;
+struct ImPlotAxisState;
+struct ImPlotAxisColor;
+struct ImPlotItem;
+struct ImPlotState;
+struct ImPlotNextPlotData;
+
+//-----------------------------------------------------------------------------
+// [SECTION] Context pointer
+//-----------------------------------------------------------------------------
+
+extern ImPlotContext* GImPlot; // Current implicit context pointer
+
+//-----------------------------------------------------------------------------
+// [SECTION] Macros
+//-----------------------------------------------------------------------------
+
+// The maximum number of supported y-axes (DO NOT CHANGE THIS)
+#define MAX_Y_AXES 3
+
+//-----------------------------------------------------------------------------
+// [SECTION] Generic helpers
+//-----------------------------------------------------------------------------
+
+// Computes the common (base-10) logarithm
+static inline float  ImLog10(float x)  { return log10f(x); }
+static inline double ImLog10(double x) { return log10(x);  }
+
+// Returns true if a flag is set
+template <typename TSet, typename TFlag>
+inline bool ImHasFlag(TSet set, TFlag flag) { return (set & flag) == flag; }
+
+// Flips a flag in a flagset
+template <typename TSet, typename TFlag>
+inline void ImFlipFlag(TSet& set, TFlag flag) { ImHasFlag(set, flag) ? set &= ~flag : set |= flag; }
+
+// Linearly remaps x from [x0 x1] to [y0 y1].
+template <typename T>
+inline T ImRemap(T x, T x0, T x1, T y0, T y1) { return y0 + (x - x0) * (y1 - y0) / (x1 - x0); }
+
+// Returns always positive modulo (r != 0)
+inline int ImPosMod(int l, int r) { return (l % r + r) % r; }
+
+// Offset calculator helper
+template <int Count>
+struct ImOffsetCalculator {
+    ImOffsetCalculator(int* sizes) {
+        Offsets[0] = 0;
+        for (int i = 1; i < Count; ++i)
+            Offsets[i] = Offsets[i-1] + sizes[i-1];
+    }
+    int Offsets[Count];
+};
+
+// Character buffer writer helper
+struct ImBufferWriter
+{
+    char* const  Buffer;
+    size_t       Pos;
+    const size_t Size;
+
+    ImBufferWriter(char* buffer, size_t size) : Buffer(buffer), Pos(0), Size(size) {}
+
+    void Write(const char* fmt, ...) IM_FMTARGS(2) {
+        va_list argp;
+        va_start(argp, fmt);
+        const int written = ::vsnprintf(&Buffer[Pos], Size - Pos - 1, fmt, argp);
+        if (written > 0)
+          Pos += ImMin(size_t(written), Size-Pos-1);
+        va_end(argp);
+    }
+};
+
+//-----------------------------------------------------------------------------
+// [SECTION] ImPlot Structs
+//-----------------------------------------------------------------------------
+
+// Tick mark info
+struct ImPlotTick
+{
+    double PlotPos;
+    float  PixelPos;
+    ImVec2 Size;
+    int    TextOffset;
+    bool   Major;
+    bool   RenderLabel;
+    bool   Labeled;
+
+    ImPlotTick(double value, bool major, bool render_label = true) {
+        PlotPos     = value;
+        Major       = major;
+        RenderLabel = render_label;
+        Labeled     = false;
+    }
+};
+
+// Axis state information that must persist after EndPlot
+struct ImPlotAxis
+{
+    bool            Dragging;
+    bool            Hovered;
+    ImPlotRange     Range;
+    ImPlotAxisFlags Flags, PreviousFlags;
+    ImPlotAxis() {
+        Dragging  = false;
+        Hovered   = false;
+        Range.Min = 0;
+        Range.Max = 1;
+        Flags     = PreviousFlags = ImPlotAxisFlags_Default;
+    }
+};
+
+// Axis state information only needed between BeginPlot/EndPlot
+struct ImPlotAxisState
+{
+    ImPlotAxis* Axis;
+    bool        HasRange;
+    ImGuiCond   RangeCond;
+    bool        Present;
+    int         PresentSoFar;
+    bool        Invert;
+    bool        LockMin;
+    bool        LockMax;
+    bool        Lock;
+
+    ImPlotAxisState(ImPlotAxis& axis, bool has_range, ImGuiCond range_cond, bool present, int previous_present) :
+        Axis(&axis),
+        HasRange(has_range),
+        RangeCond(range_cond),
+        Present(present),
+        PresentSoFar(previous_present + (Present ? 1 : 0)),
+        Invert(ImHasFlag(Axis->Flags, ImPlotAxisFlags_Invert)),
+        LockMin(ImHasFlag(Axis->Flags, ImPlotAxisFlags_LockMin) || (HasRange && RangeCond == ImGuiCond_Always)),
+        LockMax(ImHasFlag(Axis->Flags, ImPlotAxisFlags_LockMax) || (HasRange && RangeCond == ImGuiCond_Always)),
+        Lock(!Present || ((LockMin && LockMax) || (HasRange && RangeCond == ImGuiCond_Always)))
+    {}
+
+    ImPlotAxisState() :
+        Axis(), HasRange(), RangeCond(), Present(), PresentSoFar(),Invert(),LockMin(), LockMax(), Lock()
+    {}
+};
+
+struct ImPlotAxisColor
+{
+    ImU32 Major, Minor, Txt;
+    ImPlotAxisColor() { Major = Minor = Txt = 0; }
+};
+
+// State information for Plot items
+struct ImPlotItem
+{
+    bool    Show;
+    bool    SeenThisFrame;
+    bool    Highlight;
+    ImVec4  Color;
+    int     NameOffset;
+    ImGuiID ID;
+
+    ImPlotItem() {
+        Show          = true;
+        SeenThisFrame = false;
+        Highlight     = false;
+        Color         = ImPlot::NextColormapColor();
+        NameOffset    = -1;
+        ID            = 0;
+    }
+
+    ~ImPlotItem() { ID = 0; }
+};
+
+// Holds Plot state information that must persist after EndPlot
+struct ImPlotState
+{
+    ImPool<ImPlotItem> Items;
+    ImRect             BB_Legend;
+    ImVec2             SelectStart;
+    bool               Selecting;
+    bool               Querying;
+    bool               Queried;
+    bool               DraggingQuery;
+    ImVec2             QueryStart;
+    ImRect             QueryRect;
+    ImPlotAxis         XAxis;
+    ImPlotAxis         YAxis[MAX_Y_AXES];
+    ImPlotFlags        Flags, PreviousFlags;
+    int                ColorIdx;
+    int                CurrentYAxis;
+
+    ImPlotState() {
+        Selecting    = Querying = Queried = DraggingQuery = false;
+        SelectStart  =  QueryStart = ImVec2(0,0);
+        Flags        = PreviousFlags = ImPlotFlags_Default;
+        ColorIdx     = 0;
+        CurrentYAxis = 0;
+    }
+};
+
+// Temporary data storage for upcoming plot
+struct ImPlotNextPlotData
+{
+    ImGuiCond   XRangeCond;
+    ImGuiCond   YRangeCond[MAX_Y_AXES];
+    ImPlotRange X;
+    ImPlotRange Y[MAX_Y_AXES];
+    bool        HasXRange;
+    bool        HasYRange[MAX_Y_AXES];
+    bool        ShowDefaultTicksX;
+    bool        ShowDefaultTicksY[MAX_Y_AXES];
+
+    ImPlotNextPlotData() {
+        HasXRange         = false;
+        ShowDefaultTicksX = true;
+        for (int i = 0; i < MAX_Y_AXES; ++i) {
+            HasYRange[i]         = false;
+            ShowDefaultTicksY[i] = true;
+        }
+    }
+};
+
+// Holds state information that must persist between calls to BeginPlot()/EndPlot()
+struct ImPlotContext {
+    // Plot States
+    ImPool<ImPlotState> Plots;
+    ImPlotState*        CurrentPlot;
+
+    // Legend
+    ImVector<int>   LegendIndices;
+    ImGuiTextBuffer LegendLabels;
+
+    // Bounding Boxes
+    ImRect BB_Frame;
+    ImRect BB_Canvas;
+    ImRect BB_Plot;
+
+    // Cached Colors
+    ImU32 Col_Frame;
+    ImU32 Col_Bg;
+    ImU32 Col_Border;
+    ImU32 Col_Txt;
+    ImU32 Col_TxtDis;
+    ImU32 Col_SlctBg;
+    ImU32 Col_SlctBd;
+    ImU32 Col_QryBg;
+    ImU32 Col_QryBd;
+
+    // Axis States
+    ImPlotAxisColor Col_X;
+    ImPlotAxisColor Col_Y[MAX_Y_AXES];
+    ImPlotAxisState X;
+    ImPlotAxisState Y[MAX_Y_AXES];
+
+    // Tick Marks and Labels
+    ImVector<ImPlotTick> XTicks;
+    ImVector<ImPlotTick> YTicks[MAX_Y_AXES];
+    ImGuiTextBuffer      XTickLabels;
+    ImGuiTextBuffer      YTickLabels[MAX_Y_AXES];
+    float                AxisLabelReference[MAX_Y_AXES];
+
+    // Transformations and Data Extents
+    ImRect      PixelRange[MAX_Y_AXES];
+    double      Mx;
+    double      My[MAX_Y_AXES];
+    double      LogDenX;
+    double      LogDenY[MAX_Y_AXES];
+    ImPlotRange ExtentsX;
+    ImPlotRange ExtentsY[MAX_Y_AXES];
+
+    // Data Fitting Flags
+    bool FitThisFrame;
+    bool FitX;
+    bool FitY[MAX_Y_AXES];
+
+    // Hover states
+    bool Hov_Frame;
+    bool Hov_Plot;
+
+    // Axis Rendering Flags
+    bool RenderX;
+    bool RenderY[MAX_Y_AXES];
+
+    // Axis Locking Flags
+    bool LockPlot;
+    bool ChildWindowMade;
+
+    // Style and Colormaps
+    ImPlotStyle             Style;
+    ImVector<ImGuiColorMod> ColorModifiers;
+    ImVector<ImGuiStyleMod> StyleModifiers;
+    ImVec4*                 Colormap;
+    int                     ColormapSize;
+
+    // Misc
+    int                VisibleItemCount;
+    int                DigitalPlotItemCnt;
+    int                DigitalPlotOffset;
+    ImPlotNextPlotData NextPlotData;
+    ImPlotInputMap     InputMap;
+    ImPlotPoint        LastMousePos[MAX_Y_AXES];
+};
+
+struct ImPlotAxisScale {
+    ImPlotAxisScale(int y_axis, float tx, float ty, float zoom_rate) {
+        ImPlotContext& gp = *GImPlot;
+        Min = ImPlot::PixelsToPlot(gp.BB_Plot.Min - gp.BB_Plot.GetSize() * ImVec2(tx * zoom_rate, ty * zoom_rate), y_axis);
+        Max = ImPlot::PixelsToPlot(gp.BB_Plot.Max + gp.BB_Plot.GetSize() * ImVec2((1 - tx) * zoom_rate, (1 - ty) * zoom_rate), y_axis);
+    }
+    ImPlotPoint Min, Max;
+};
+
+//-----------------------------------------------------------------------------
+// [SECTION] Internal API
+// No guarantee of forward compatibility here!
+//-----------------------------------------------------------------------------
+
+namespace ImPlot {
+
+// Initializes an ImPlotContext
+void Initialize(ImPlotContext* ctx);
+// Resets an ImPlot context for the next call to BeginPlot
+void Reset(ImPlotContext* ctx);
+// Gets a plot from the current ImPlotContext
+ImPlotState* GetPlot(const char* title);
+// Gets the current plot from the current ImPlotContext
+ImPlotState* GetCurrentPlot();
+// Updates pixel space to plot space transformation variables for the current plot
+void UpdateTransformCache();
+// Extends the current plots axes so that it encompasses point p
+void FitPoint(const ImPlotPoint& p);
+// Register or get an existing item from the current plot
+ImPlotItem* RegisterItem(const char* label_id);
+// Get the ith plot item from the current plot
+ImPlotItem* GetItem(int i);
+// Get a plot item from the current plot
+ImPlotItem* GetItem(const char* label_id);
+// Gets a plot item from a specific plot
+ImPlotItem* GetItem(const char* plot_title, const char* item_label_id);
+// Returns the number of entries in the current legend
+int GetLegendCount();
+// Gets the ith entry string for the current legend
+const char* GetLegendLabel(int i);
+// Populates a list of ImPlotTicks with automatically spaced ticks
+void  AddDefaultTicks(const ImPlotRange& range, int nMajor, int nMinor, bool logscale, ImVector<ImPlotTick> &out);
+// Populates a list of ImPlotTicks with custom spaced and labeled ticks
+void  AddCustomTicks(const double* values, const char** labels, int n, ImVector<ImPlotTick>& ticks, ImGuiTextBuffer& buffer);
+// Creates label information for a list of ImPlotTick
+void  LabelTicks(ImVector<ImPlotTick> &ticks, bool scientific, ImGuiTextBuffer& buffer);
+// Calculates the maximum width of a list of ImPlotTick
+float MaxTickLabelWidth(ImVector<ImPlotTick>& ticks);
+// Updates axis ticks, lins, and label colors
+void UpdateAxisColor(int axis_flag, ImPlotAxisColor* col);
+// Sets the colormap for a particular ImPlotContext
+void SetColormapEx(ImPlotColormap colormap, int samples, ImPlotContext* ctx);
+void SetColormapEx(const ImVec4* colors, int num_colors, ImPlotContext* ctx);
+// Draws vertical text. The position is the bottom left of the text rect.
+void AddTextVertical(ImDrawList *DrawList, const char *text, ImVec2 pos, ImU32 text_color);
+// Calculates the size of vertical text
+ImVec2 CalcTextSizeVertical(const char *text);
+// Returns white or black text given background color
+inline ImU32 CalcTextColor(const ImVec4& bg) { return (bg.x * 0.299 + bg.y * 0.587 + bg.z * 0.114) > 0.729 ? IM_COL32_BLACK : IM_COL32_WHITE; }
+// Rounds x to powers of 2,5 and 10 for generating axis labels
+// Taken from Graphics Gems 1 Chapter 11.2, "Nice Numbers for Graph Labels"
+double NiceNum(double x, bool round);
+// Turns NANs to 0s
+inline double ConstrainNan(double val) { return isnan(val) ? 0 : val; }
+// Turns infinity to floating point maximums
+inline double ConstrainInf(double val) { return val == HUGE_VAL ?  DBL_MAX : val == -HUGE_VAL ? - DBL_MAX : val; }
+// Turns numbers less than or equal to 0 to 0.001 (sort of arbitrary, is there a better way?)
+inline double ConstrainLog(double val) { return val <= 0 ? 0.001f : val; }
+// Returns true if val is NAN or INFINITY
+inline bool NanOrInf(double val) { return val == HUGE_VAL || val == -HUGE_VAL || isnan(val); }
+// Computes order of magnitude of double.
+inline int OrderOfMagnitude(double val) { return val == 0 ? 0 : (int)(floor(log10(fabs(val)))); }
+// Returns the precision required for a order of magnitude.
+inline int OrderToPrecision(int order) { return order > 0 ? 0 : 1 - order; }
+// Returns a floating point precision to use given a value
+inline int Precision(double val) { return OrderToPrecision(OrderOfMagnitude(val)); }
+// Returns the intersection point of two lines A and B (assumes they are not parallel!)
+inline ImVec2 Intersection(const ImVec2& a1, const ImVec2& a2, const ImVec2& b1, const ImVec2& b2) {
+    float v1 = (a1.x * a2.y - a1.y * a2.x);
+    float v2 = (b1.x * b2.y - b1.y * b2.x);
+    float v3 = ((a1.x - a2.x) * (b1.y - b2.y) - (a1.y - a2.y) * (b1.x - b2.x));
+    return ImVec2((v1 * (b1.x - b2.x) - v2 * (a1.x - a2.x)) / v3, (v1 * (b1.y - b2.y) - v2 * (a1.y - a2.y)) / v3);
+}
+// 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;
+    }
+}
+// Offsets and strides a data buffer
+template <typename T>
+inline T OffsetAndStride(const T* data, int idx, int count, int offset, int stride) {
+    idx = ImPosMod(offset + idx, count);
+    return *(const T*)(const void*)((const unsigned char*)data + (size_t)idx * stride);
+}
+
+} // namespace ImPlot