<?php
//=======================================================================
// File:	JPGRAPH_IMGTRANS.PHP
// Description:	Extension for JpGraph to do some simple img transformations
// Created: 	2003-09-06
// Ver:		$Id: jpgraph_imgtrans.php 781 2006-10-08 08:07:47Z ljp $
//
// Copyright (c) Aditus Consulting. All rights reserved.
//========================================================================

//------------------------------------------------------------------------
// Class ImgTrans
// Perform some simple image transformations.
//------------------------------------------------------------------------
class ImgTrans
{
    private $gdImg=null;

    public function ImgTrans($aGdImg)
    {
        // Constructor
        $this->gdImg = $aGdImg;
    }

    // --------------------------------------------------------------------
    // _TransVert3D() and _TransHor3D() are helper methods to
    // Skew3D().
    // --------------------------------------------------------------------
    public function _TransVert3D($aGdImg, $aHorizon=100, $aSkewDist=120, $aDir=SKEW3D_DOWN, $aMinSize=true, $aFillColor='#FFFFFF', $aQuality=false, $aBorder=false, $aHorizonPos=0.5)
    {


    // Parameter check
        if ($aHorizonPos < 0 || $aHorizonPos > 1.0) {
            JpGraphError::RaiseL(9001);
            //("Value for image transformation out of bounds.\nVanishing point on horizon must be specified as a value between 0 and 1.");
        }

        $w = imagesx($aGdImg);
        $h = imagesy($aGdImg);

        // Create new image
        $ww = $w;
        if ($aMinSize) {
            $hh = ceil($h * $aHorizon / ($aSkewDist+$h));
        } else {
            $hh = $h;
        }
    
        $newgdh = imagecreatetruecolor($ww, $hh);
        $crgb = new RGB($newgdh);
        $fillColor = $crgb->Allocate($aFillColor);
        imagefilledrectangle($newgdh, 0, 0, $ww-1, $hh-1, $fillColor);

        if ($aBorder) {
            $colidx = $crgb->Allocate($aBorder);
            imagerectangle($newgdh, 0, 0, $ww-1, $hh-1, $colidx);
        }

        $mid = round($w * $aHorizonPos);
    
        $last=$h;
        for ($y=0; $y < $h; ++$y) {
            $yp = $h-$y-1;
            $yt = floor($yp * $aHorizon / ($aSkewDist + $yp));

            if (!$aQuality) {
                if ($last <= $yt) {
                    continue ;
                }
                $last = $yt;
            }

            for ($x=0; $x < $w; ++$x) {
                $xt = ($x-$mid) * $aSkewDist / ($aSkewDist + $yp);
                if ($aDir == SKEW3D_UP) {
                    $rgb = imagecolorat($aGdImg, $x, $h-$y-1);
                } else {
                    $rgb = imagecolorat($aGdImg, $x, $y);
                }
                $r = ($rgb >> 16) & 0xFF;
                $g = ($rgb >> 8) & 0xFF;
                $b = $rgb & 0xFF;
                $colidx = imagecolorallocate($newgdh, $r, $g, $b);
                $xt = round($xt+$mid);
                if ($aDir == SKEW3D_UP) {
                    $syt = $yt;
                } else {
                    $syt = $hh-$yt-1;
                }

                if (!empty($set[$yt])) {
                    $nrgb = imagecolorat($newgdh, $xt, $syt);
                    $nr = ($nrgb >> 16) & 0xFF;
                    $ng = ($nrgb >> 8) & 0xFF;
                    $nb = $nrgb & 0xFF;
                    $colidx = imagecolorallocate(
                        $newgdh,
                        floor(($r+$nr)/2),
                        floor(($g+$ng)/2),
                        floor(($b+$nb)/2)
                    );
                }

                imagesetpixel($newgdh, $xt, $syt, $colidx);
            }

            $set[$yt] = true;
        }

        return $newgdh;
    }

    // --------------------------------------------------------------------
    // _TransVert3D() and _TransHor3D() are helper methods to
    // Skew3D().
    // --------------------------------------------------------------------
    public function _TransHor3D($aGdImg, $aHorizon=100, $aSkewDist=120, $aDir=SKEW3D_LEFT, $aMinSize=true, $aFillColor='#FFFFFF', $aQuality=false, $aBorder=false, $aHorizonPos=0.5)
    {
        $w = imagesx($aGdImg);
        $h = imagesy($aGdImg);

        // Create new image
        $hh = $h;
        if ($aMinSize) {
            $ww = ceil($w * $aHorizon / ($aSkewDist+$w));
        } else {
            $ww = $w;
        }
    
        $newgdh = imagecreatetruecolor($ww, $hh);
        $crgb = new RGB($newgdh);
        $fillColor = $crgb->Allocate($aFillColor);
        imagefilledrectangle($newgdh, 0, 0, $ww-1, $hh-1, $fillColor);

        if ($aBorder) {
            $colidx = $crgb->Allocate($aBorder);
            imagerectangle($newgdh, 0, 0, $ww-1, $hh-1, $colidx);
        }

        $mid = round($h * $aHorizonPos);

        $last = -1;
        for ($x=0; $x < $w-1; ++$x) {
            $xt = floor($x * $aHorizon / ($aSkewDist + $x));
            if (!$aQuality) {
                if ($last >= $xt) {
                    continue ;
                }
                $last = $xt;
            }

            for ($y=0; $y < $h; ++$y) {
                $yp = $h-$y-1;
                $yt = ($yp-$mid) * $aSkewDist / ($aSkewDist + $x);

                if ($aDir == SKEW3D_RIGHT) {
                    $rgb = imagecolorat($aGdImg, $w-$x-1, $y);
                } else {
                    $rgb = imagecolorat($aGdImg, $x, $y);
                }
                $r = ($rgb >> 16) & 0xFF;
                $g = ($rgb >> 8) & 0xFF;
                $b = $rgb & 0xFF;
                $colidx = imagecolorallocate($newgdh, $r, $g, $b);
                $yt = floor($hh-$yt-$mid-1);
                if ($aDir == SKEW3D_RIGHT) {
                    $sxt = $ww-$xt-1;
                } else {
                    $sxt = $xt ;
                }

                if (!empty($set[$xt])) {
                    $nrgb = imagecolorat($newgdh, $sxt, $yt);
                    $nr = ($nrgb >> 16) & 0xFF;
                    $ng = ($nrgb >> 8) & 0xFF;
                    $nb = $nrgb & 0xFF;
                    $colidx = imagecolorallocate(
                        $newgdh,
                        floor(($r+$nr)/2),
                        floor(($g+$ng)/2),
                        floor(($b+$nb)/2)
                    );
                }
                imagesetpixel($newgdh, $sxt, $yt, $colidx);
            }

            $set[$xt] = true;
        }

        return $newgdh;
    }

    // --------------------------------------------------------------------
    // Skew image for the apperance of a 3D effect
    // This transforms an image into a 3D-skewed version
    // of the image. The transformation is specified by giving the height
    // of the artificial horizon and specifying a "skew" factor which
    // is the distance on the horizon line between the point of
    // convergence and perspective line.
    //
    // The function returns the GD handle of the transformed image
    // leaving the original image untouched.
    //
    // Parameters:
    // * $aGdImg, GD handle to the image to be transformed
    // * $aHorizon, Distance to the horizon
    // * $aSkewDist, Distance from the horizon point of convergence
    //   on the horizon line to the perspective points. A larger
    //   value will fore-shorten the image more
    // * $aDir, parameter specifies type of convergence. This of this
    //   as the walls in a room you are looking at. This specifies if the
    //   image should be applied on the left,right,top or bottom walls.
    // * $aMinSize, true=make the new image just as big as needed,
    //   false = keep the image the same size as the original image
    // * $aFillColor, Background fill color in the image
    // * $aHiQuality, true=performa some interpolation that improves
    //   the image quality but at the expense of performace. Enabling
    //   high quality will have a dramatic effect on the time it takes
    //   to transform an image.
    // * $aBorder, if set to anything besides false this will draw a
    //   a border of the speciied color around the image
    // --------------------------------------------------------------------
    public function Skew3D($aHorizon=120, $aSkewDist=150, $aDir=SKEW3D_DOWN, $aHiQuality=false, $aMinSize=true, $aFillColor='#FFFFFF', $aBorder=false)
    {
        return $this->_Skew3D(
            $this->gdImg,
            $aHorizon,
            $aSkewDist,
            $aDir,
            $aHiQuality,
            $aMinSize,
            $aFillColor,
            $aBorder
        );
    }

    public function _Skew3D($aGdImg, $aHorizon=120, $aSkewDist=150, $aDir=SKEW3D_DOWN, $aHiQuality=false, $aMinSize=true, $aFillColor='#FFFFFF', $aBorder=false)
    {
        if ($aDir == SKEW3D_DOWN || $aDir == SKEW3D_UP) {
            return $this->_TransVert3D($aGdImg, $aHorizon, $aSkewDist, $aDir, $aMinSize, $aFillColor, $aHiQuality, $aBorder);
        } else {
            return $this->_TransHor3D($aGdImg, $aHorizon, $aSkewDist, $aDir, $aMinSize, $aFillColor, $aHiQuality, $aBorder);
        }
    }
}