ChartDC.h

#pragma once
/*
  AWind.h - Arduino window library support for Color TFT LCD Boards
  Copyright (C)2015 Andrei Degtiarev. All right reserved
  

  You can always find the latest version of the library at 
  https://github.com/AndreiDegtiarev/AWind


  This library is free software; you can redistribute it and/or
  modify it under the terms of the CC BY-NC-SA 3.0 license.
  Please see the included documents for further information.

  Commercial use of this library requires you to buy a license that
  will allow commercial use. This includes using the library,
  modified or not, as a tool to sell products.

  The license applies to all part of the library including the 
  examples and tools supplied with the library.
*/
class ChartDC
{
    float _last_y;
    float _scale_x;
    float _scale_y;
    float _offset_x;
    float _offset_y;
    float _min_y;
    float _max_y;
    int   _dc_start_x;
    int   _dc_start_y;
public:
    static const float AutoMin;
    static const float AutoMax;
    ChartDC()
    {
        _scale_x=1;
        _scale_y=1;
        _offset_x=0;
        _offset_y=0;
        _dc_start_x=0;
        _dc_start_y=0;
        _min_y=0;
        _max_y=0;
    }
    float calcScaling(int length,float &min_val,float &max_val)
    {
        if(min_val == max_val)
        {
            if(min_val == 0)
            {
                min_val=-1;
                max_val=1;
            }
            else if(min_val<0)
                max_val = 0;
            else if(min_val>0)
                min_val = 0;
        }
        return length/(max_val-min_val);
    }
    void setScalingX(int dc_offset,int length,float min_val,float max_val)
    {
        _scale_x=calcScaling(length,min_val,max_val);
        _offset_x=min_val;
        _dc_start_x=dc_offset;
        /*Log::Number("Set scale x scale: ",_scale_x);
        Log::Number(" offset: ",_offset_x);
        Log::Number(" min: ",min_val);
        Log::Number(" max: ",max_val,true);*/
    }
    void setScalingY(int dc_offset,int length,float min_val,float max_val)
    {
        _scale_y=calcScaling(length,min_val,max_val);
        _offset_y=min_val;
        /*Log::Number("Set scale y scale: ",_scale_y);
        Log::Number(" offset: ",_offset_y);
        Log::Number(" min: ",min_val);
        Log::Number(" max: ",max_val,true);*/
        _dc_start_y=dc_offset;
        _min_y=min_val;
        _max_y=max_val;
    }
    float MinY()
    {
        return _min_y;
    }
    float MaxY()
    {
        return _max_y;
    }
    float LCtoDC_x(float x)
    {
        return _dc_start_x+(x-_offset_x)*_scale_x;
    }
    float LCtoDC_y(float y)
    {
        return _dc_start_y-(y-_offset_y)*_scale_y;
    }
    void MoveTo(DC *dc,float x,float y)
    {
        _last_y=y;
        dc->MoveTo(LCtoDC_x(x),LCtoDC_y(y));
        //Log::Number("Move to x: ",x);
        //Log::Number(" y: ",y,true);
    }
    void LineTo(DC *dc,float x,float y)
    {
        if(y<_min_y || y> _max_y || _last_y<_min_y || _last_y> _max_y)
            dc->MoveTo(LCtoDC_x(x),LCtoDC_y(y));
        else
            dc->LineTo(LCtoDC_x(x),LCtoDC_y(y));
        _last_y=y;
        //Log::Number(" min_y: ",_min_y);
        //Log::Number(" max_y: ",_max_y,true);

        /*Log::Number("Line: ",_last_x);
        Log::Number(" ",_last_y);
        Log::Number(" ",new_x);
        Log::Number(" ",new_y,"");
        Log::Number(" lc: ",x);
        Log::Number(",",y,true);*/
    }
};
const float ChartDC::AutoMin = 1e-8;
const float ChartDC::AutoMax = 1e8;