<?php
/*=======================================================================
// File:        JPGRAPH_LOG.PHP
// Description: Log scale plot extension for JpGraph
// Created:     2001-01-08
// Author:      Johan Persson (johanp@aditus.nu)
// Ver:         $Id: jpgraph_log.php 56 2005-06-06 20:14:44Z ljp $
//
// Copyright (c) Aditus Consulting. All rights reserved.
//========================================================================
*/


DEFINE('LOGLABELS_PLAIN',0);
DEFINE('LOGLABELS_MAGNITUDE',1);

//===================================================
// CLASS LogScale
// Description: Logarithmic scale between world and screen
//===================================================
class LogScale extends LinearScale {
//---------------
// CONSTRUCTOR

    // Log scale is specified using the log of min and max
    function LogScale($min,$max,$type="y") {
        $this->LinearScale($min,$max,$type);
        $this->ticks = new LogTicks();
        $this->name = 'log';
    }

//----------------
// PUBLIC METHODS       

    // Translate between world and screen
    function Translate($a) {
        if( !is_numeric($a) ) {
            if( $a != '' && $a != '-' && $a != 'x' ) 
                JpGraphError::Raise('Your data contains non-numeric values.');
            return 1;
        }
        if( $a < 0 ) {
            JpGraphError::Raise("Negative data values can not be used in a log scale.");
            exit(1);
        }
        if( $a==0 ) $a=1;
        $a=log10($a);
        return ceil($this->off + ($a*1.0 - $this->scale[0]) * $this->scale_factor); 
    }

    // Relative translate (don't include offset) usefull when we just want
    // to know the relative position (in pixels) on the axis    
    function RelTranslate($a) {
        if( !is_numeric($a) ) {
            if( $a != '' && $a != '-' && $a != 'x' ) 
                JpGraphError::Raise('Your data contains non-numeric values.');
            return 1;
        }
        if( $a==0 ) $a=1;
        $a=log10($a);
        return round(($a*1.0 - $this->scale[0]) * $this->scale_factor); 
    }
                
    // Use bcpow() for increased precision
    function GetMinVal() {
        if( function_exists("bcpow") )
            return round(bcpow(10,$this->scale[0],15),14);
        else
            return round(pow(10,$this->scale[0]),14);
    }
        
    function GetMaxVal() {
        if( function_exists("bcpow") )
            return round(bcpow(10,$this->scale[1],15),14);
        else
            return round(pow(10,$this->scale[1]),14);
    }
        
    // Logarithmic autoscaling is much simplier since we just
    // set the min and max to logs of the min and max values.
    // Note that for log autoscale the "maxstep" the fourth argument
    // isn't used. This is just included to give the method the same
    // signature as the linear counterpart.
    function AutoScale(&$img,$min,$max,$dummy) {
        if( $min==0 ) $min=1;
        
        if( $max <= 0 ) {
            JpGraphError::Raise('Scale error for logarithmic scale. You have a problem with your data values. The max value must be greater than 0. It is mathematically impossible to have 0 in a logarithmic scale.');
        }
        $smin = floor(log10($min));
        $smax = ceil(log10($max));
        $this->Update($img,$smin,$smax);                                        
    }
//---------------
// PRIVATE METHODS      
} // Class

//===================================================
// CLASS LogTicks
// Description: 
//===================================================
class LogTicks extends Ticks{
    var $label_logtype=LOGLABELS_MAGNITUDE;
//---------------
// CONSTRUCTOR
    function LogTicks() {
    }
//---------------
// PUBLIC METHODS       
    function IsSpecified() {
        return true;
    }

    function SetLabelLogType($aType) {
        $this->label_logtype = $aType;
    }
        
    // For log scale it's meaningless to speak about a major step
    // We just return -1 to make the framework happy (specifically
    // StrokeLabels() )
    function GetMajor() {
        return -1;
    }

    function SetTextLabelStart($aStart) {
        JpGraphError::Raise('Specifying tick interval for a logarithmic scale is undefined. Remove any calls to SetTextLabelStart() or SetTextTickInterval() on the logarithmic scale.');
    }

    function SetXLabelOffset($dummy) {
        // For log scales we dont care about XLabel offset
    }

    // Draw ticks on image "img" using scale "scale". The axis absolute
    // position in the image is specified in pos, i.e. for an x-axis
    // it specifies the absolute y-coord and for Y-ticks it specified the
    // absolute x-position.
    function Stroke(&$img,&$scale,$pos) {
        $start = $scale->GetMinVal();
        $limit = $scale->GetMaxVal();
        $nextMajor = 10*$start;
        $step = $nextMajor / 10.0;
                
                
        $img->SetLineWeight($this->weight);                     
                
        if( $scale->type == "y" ) {
            // member direction specified if the ticks should be on
            // left or right side.
            $a=$pos + $this->direction*$this->GetMinTickAbsSize();
            $a2=$pos + $this->direction*$this->GetMajTickAbsSize();     
                        
            $count=1; 
            $this->maj_ticks_pos[0]=$scale->Translate($start);
            $this->maj_ticklabels_pos[0]=$scale->Translate($start);
            if( $this->supress_first )
                $this->maj_ticks_label[0]="";
            else {
                if( $this->label_formfunc != '' ) {
                    $f = $this->label_formfunc;
                    $this->maj_ticks_label[0]=call_user_func($f,$start);        
                }
                elseif( $this->label_logtype == LOGLABELS_PLAIN )
                    $this->maj_ticks_label[0]=$start;   
                else
                    $this->maj_ticks_label[0]='10^'.round(log10($start));
            }
            $i=1;
            for($y=$start; $y<=$limit; $y+=$step,++$count  ) {
                $ys=$scale->Translate($y);      
                $this->ticks_pos[]=$ys;
                $this->ticklabels_pos[]=$ys;
                if( $count % 10 == 0 ) {
                    if( !$this->supress_tickmarks ) {
                        if( $this->majcolor!="" ) {
                            $img->PushColor($this->majcolor);
                            $img->Line($pos,$ys,$a2,$ys);
                            $img->PopColor();
                        }
                        else
                            $img->Line($pos,$ys,$a2,$ys);
                    }

                    $this->maj_ticks_pos[$i]=$ys;
                    $this->maj_ticklabels_pos[$i]=$ys;
                    
                    if( $this->label_formfunc != '' ) {
                        $f = $this->label_formfunc;
                        $this->maj_ticks_label[$i]=call_user_func($f,$nextMajor);       
                    }
                    elseif( $this->label_logtype == 0 )
                        $this->maj_ticks_label[$i]=$nextMajor;  
                    else
                        $this->maj_ticks_label[$i]='10^'.round(log10($nextMajor));
                    ++$i;                                               
                    $nextMajor *= 10;
                    $step *= 10;        
                    $count=1;                           
                }
                else {
                    if( !$this->supress_tickmarks && !$this->supress_minor_tickmarks) {
                        if( $this->mincolor!="" ) $img->PushColor($this->mincolor);
                        $img->Line($pos,$ys,$a,$ys);            
                        if( $this->mincolor!="" ) $img->PopColor();
                    }
                }
            }           
        }
        else {
            $a=$pos - $this->direction*$this->GetMinTickAbsSize();
            $a2=$pos - $this->direction*$this->GetMajTickAbsSize();     
            $count=1; 
            $this->maj_ticks_pos[0]=$scale->Translate($start);
            $this->maj_ticklabels_pos[0]=$scale->Translate($start);
            if( $this->supress_first )
                $this->maj_ticks_label[0]="";
            else {
                if( $this->label_formfunc != '' ) {
                    $f = $this->label_formfunc;
                    $this->maj_ticks_label[0]=call_user_func($f,$start);        
                }
                elseif( $this->label_logtype == 0 )
                    $this->maj_ticks_label[0]=$start;   
                else
                    $this->maj_ticks_label[0]='10^'.round(log10($start));
            }
            $i=1;                       
            for($x=$start; $x<=$limit; $x+=$step,++$count  ) {
                $xs=$scale->Translate($x);      
                $this->ticks_pos[]=$xs;
                $this->ticklabels_pos[]=$xs;
                if( $count % 10 == 0 ) {
                    if( !$this->supress_tickmarks ) {
                        $img->Line($xs,$pos,$xs,$a2);
                    }
                    $this->maj_ticks_pos[$i]=$xs;
                    $this->maj_ticklabels_pos[$i]=$xs;

                    if( $this->label_formfunc != '' ) {
                        $f = $this->label_formfunc;
                        $this->maj_ticks_label[$i]=call_user_func($f,$nextMajor);       
                    }
                    elseif( $this->label_logtype == 0 )
                        $this->maj_ticks_label[$i]=$nextMajor;  
                    else
                        $this->maj_ticks_label[$i]='10^'.round(log10($nextMajor));
                    ++$i;
                    $nextMajor *= 10;
                    $step *= 10;        
                    $count=1;                           
                }
                else {
                    if( !$this->supress_tickmarks && !$this->supress_minor_tickmarks) {
                        $img->Line($xs,$pos,$xs,$a);            
                    }
                }
            }           
        }
        return true;
    }
} // Class
/* EOF */
?>