question: public void prepareMatrixValuePx ( float xChartMin , float deltaX , float deltaY , float yChartMin ) { float scaleX = ( float ) ( mViewPortHandler . contentWidth ( ) / deltaX ) ; float scaleY = ( float ) ( mViewPortHandler . contentHeight ( ) / deltaY ) ; if ( Float . isInfinite ( scaleX ) ) { scaleX = 0 ; } if ( Float . isInfinite ( scaleY ) ) { scaleY = 0 ; } mMatrixValueToPx . reset ( ) ; mMatrixValueToPx . postTranslate ( - xChartMin , - yChartMin ) ; mMatrixValueToPx . postScale ( scaleX , - scaleY ) ; }
target:  Prepares the matrix that transforms values to pixels. Calculates the scale factors from the charts size and offsets.