M-M-M/software/apps/M&MStudioBV/fscale.rtf

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\f0\fs24 \cf0 /* fscale\
 Floating Point Autoscale Function V0.1\
 Paul Badger 2007\
 Modified from code by Greg Shakar\
\
 This function will scale one set of floating point numbers (range) to another set of floating point numbers (range)\
 It has a "curve" parameter so that it can be made to favor either the end of the output. (Logarithmic mapping)\
\
 It takes 6 parameters\
\
 originalMin - the minimum value of the original range - this MUST be less than origninalMax\
 originalMax - the maximum value of the original range - this MUST be greater than orginalMin\
\
 newBegin - the end of the new range which maps to orginalMin - it can be smaller, or larger, than newEnd, to facilitate inverting the ranges\
 newEnd - the end of the new range which maps to originalMax  - it can be larger, or smaller, than newBegin, to facilitate inverting the ranges\
\
 inputValue - the variable for input that will mapped to the given ranges, this variable is constrained to originaMin <= inputValue <= originalMax\
 curve - curve is the curve which can be made to favor either end of the output scale in the mapping. Parameters are from -10 to 10 with 0 being\
          a linear mapping (which basically takes curve out of the equation)\
\
 To understand the curve parameter do something like this: \
\
 void loop()\{\
  for ( j=0; j < 200; j++)\{\
    scaledResult = fscale( 0, 200, 0, 200, j, -1.5);\
\
    Serial.print(j, DEC);  \
    Serial.print("    ");  \
    Serial.println(scaledResult, DEC); \
  \}  \
\}\
\
And try some different values for the curve function - remember 0 is a neutral, linear mapping\
\
To understand the inverting ranges, do something like this:\
\
 void loop()\{\
  for ( j=0; j < 200; j++)\{\
    scaledResult = fscale( 0, 200, 200, 0, j, 0);\
\
    //  Serial.print lines as above\
\
  \}  \
\}\
\
*/\
\
\
#include <math.h>\
\
int j;\
float scaledResult; \
\
void setup() \{\
  Serial.begin(9600);\
\}\
\
void loop()\{\
  for ( j=0; j < 200; j++)\{\
    scaledResult = fscale( 0, 200, 0, 200, j, -1.5);\
\
    Serial.print(j, DEC);  \
    Serial.print("    ");  \
    Serial.println(scaledResult , DEC); \
  \}  \
\}\
\
float fscale( float originalMin, float originalMax, float newBegin, float\
newEnd, float inputValue, float curve)\{\
\
  float OriginalRange = 0;\
  float NewRange = 0;\
  float zeroRefCurVal = 0;\
  float normalizedCurVal = 0;\
  float rangedValue = 0;\
  boolean invFlag = 0;\
\
\
  // condition curve parameter\
  // limit range\
\
  if (curve > 10) curve = 10;\
  if (curve < -10) curve = -10;\
\
  curve = (curve * -.1) ; // - invert and scale - this seems more intuitive - postive numbers give more weight to high end on output \
  curve = pow(10, curve); // convert linear scale into lograthimic exponent for other pow function\
\
  /*\
   Serial.println(curve * 100, DEC);   // multply by 100 to preserve resolution  \
   Serial.println(); \
   */\
\
  // Check for out of range inputValues\
  if (inputValue < originalMin) \{\
    inputValue = originalMin;\
  \}\
  if (inputValue > originalMax) \{\
    inputValue = originalMax;\
  \}\
\
  // Zero Refference the values\
  OriginalRange = originalMax - originalMin;\
\
  if (newEnd > newBegin)\{ \
    NewRange = newEnd - newBegin;\
  \}\
  else\
  \{\
    NewRange = newBegin - newEnd; \
    invFlag = 1;\
  \}\
\
  zeroRefCurVal = inputValue - originalMin;\
  normalizedCurVal  =  zeroRefCurVal / OriginalRange;   // normalize to 0 - 1 float\
\
  /*\
  Serial.print(OriginalRange, DEC);  \
   Serial.print("   ");  \
   Serial.print(NewRange, DEC);  \
   Serial.print("   ");  \
   Serial.println(zeroRefCurVal, DEC);  \
   Serial.println();  \
   */\
\
  // Check for originalMin > originalMax  - the math for all other cases i.e. negative numbers seems to work out fine \
  if (originalMin > originalMax ) \{\
    return 0;\
  \}\
\
  if (invFlag == 0)\{\
    rangedValue =  (pow(normalizedCurVal, curve) * NewRange) + newBegin;\
\
  \}\
  else     // invert the ranges\
  \{   \
    rangedValue =  newBegin - (pow(normalizedCurVal, curve) * NewRange); \
  \}\
\
  return rangedValue;\
\}\
}