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<?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,v 1.1 2004/06/15 10:13:19 jpm Exp $

//

// License:	This code is released under QPL

// Copyright (C) 2001,2002 Johan Persson

//========================================================================

*/

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( $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( $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]));

    }

    function GetMaxVal() {

	if( function_exists("bcpow") )

	    return round(bcpow(10,$this->scale[1],15),14);

	else

	    return round(pow(10,$this->scale[1]));

    }

    // 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;

	assert($max>0);

	$smin = floor(log10($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;

		    $this->maj_ticks_label[0]=$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->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]=$f($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->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;

		    $this->maj_ticks_label[0]=$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 ) {

		    $img->Line($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]=$f($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

		    $img->Line($xs,$pos,$xs,$a);

	    }

	}

	return true;

    }

} // Class

/* EOF */

?>