ruler.hh

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#pragma once
 
#include <array>
#include <memory>
 
#include <gtk/gtk.h>
 
#include "rulerstrategies.hh"
 
class Ruler
{
 
public:
  using Ptr = std::shared_ptr<Ruler>;
 
  enum Orientation
  {
    HORIZONTAL,
    VERTICAL
  };
 
  static Ptr create(Orientation orientation, GtkWidget* drawArea);
 
  ~Ruler();
  Ruler(const Ruler&) = delete;
  Ruler(Ruler&&) = delete;
  Ruler operator=(const Ruler&) = delete;
  Ruler operator=(Ruler&&) = delete;
 
  void setRange(double lower, double upper);
 
private:
  GtkWidget* drawingArea{};
 
  static constexpr double DEFAULT_LOWER{0};
  static constexpr double DEFAULT_UPPER{10};
 
  constexpr static std::array<int, 2> SUBTICK_SEGMENTS{5, 2};
 
  // The range to be displayed.
  double lowerLimit{DEFAULT_LOWER};
  double upperLimit{DEFAULT_UPPER};
 
  // The allocated width and height for the drawing area widget.
  int width{};
  int height{};
 
  int majorInterval{1};
 
  int majorTickSpacing{};
 
  // ==== DRAWING PROPERTIES ====
 
  RulerDrawStrategy::Ptr drawStrategy;
 
  static constexpr int MIN_SPACE_SUBTICKS{5};
 
  static constexpr double FONT_SIZE{11};
 
  static constexpr double LABEL_OFFSET{4};
 
  static constexpr double LABEL_ALIGN{0.7};
 
  static constexpr double LINE_MULTIPLIER{0.6};
 
  GdkRGBA lineColor{0, 0, 0, 1};
 
  static constexpr double LINE_WIDTH{1};
 
  static constexpr double MAJOR_TICK_LENGTH{0.8};
 
  Ruler(RulerDrawStrategy::Ptr strategy, GtkWidget* drawingArea);
 
  static gboolean drawCallback(GtkWidget* widget, cairo_t* cr, gpointer data);
 
  void draw(GtkWidget* widget, cairo_t* cr);
 
  static void sizeAllocateCallback(GtkWidget* widget, GdkRectangle* allocation, gpointer data);
 
  void updateAllocatedSize(int newWidth, int newHeight);
 
  void updateMajorTickInterval();
 
  void drawTicks(cairo_t* cr, double lower, double upper, double lineLength);
 
  void drawSingleTick(cairo_t* cr, double linePosition, double lineLength, bool drawLabel, const std::string& label);
 
  void drawSubTicks(cairo_t* cr, double lower, double upper, int depth, double lineLength);
};
 
class RulerCalculations
{
private:
  constexpr static std::array<int, 4> VALID_INTERVALS{1, 5, 10, 25};
 
public:
  static constexpr int MIN_SPACE_MAJORTICKS{80};
 
  static int calculateInterval(double lower, double upper, double allocatedSize);
 
  static int intervalPixelSpacing(double interval, double lower, double upper, double allocatedSize);
 
  static int firstTick(double lower, int interval);
 
  static double scaleToRange(double x, double src_lower, double src_upper, double dest_lower, double dest_upper);
};