imageline

add a note User Contributed Notes

pb_2001 at haefft dot de
05-Mar-2006 06:41


This is a function to make a dotted line. It accepts (it actually requires) 7 parameters and returns 1 if everything went OK and 0 if there was a problem.



int imagelinedotted ( resource im, int x1, int y1, int x2, int y2, int dist, int col )



imagelinedotted() draws a line from x1, y1 to x2, y2 (top left is 0, 0) in image im of colour col where dist defines the distance (measured in pixels) between one dot and another.



<?php

function imagelinedotted ($im, $x1, $y1, $x2, $y2, $dist, $col) {

    $transp = imagecolortransparent ($im);

    

    $style = array ($col);

    

    for ($i=0; $i<$dist; $i++) {

        array_push($style, $transp);        // Generate style array - loop needed for customisable distance between the dots

    }

    

    imagesetstyle ($im, $style);

    return (integer) imageline ($im, $x1, $y1, $x2, $y2, IMG_COLOR_STYLED);

    imagesetstyle ($im, array($col));        // Reset style - just in case...

}

?>

fatpratmatt at gmail dot com
31-Jan-2006 03:43


Here is a function which draws lines that cross at a specific point [It may need some tweaking]:



<?php

// Image Cross by Matt Evans

// $im - image resource

// $x - x coordinate where the lines should cross

// $y - y coordinate where the lines should cross

// $size - the length of each line

// $colour - the colour of the cross



function imagecross($im, $x, $y, $size = 5, $colour) {

imageline($im, $x+$size/2, $y+$size/2, $x-$size/2, $y-$size/2, $colour);

imageline($im, $x-$size/2, $y+$size, $x+$size/2, $y-$size, $colour);

}



// Example

imagecross($im, 50, 50, 5, $crosscolour);

?>

21-Oct-2005 10:30


imageline coordinate variables are documented as int ,  a value in decimal format will be truncated.



This may be useful when, for example, applying a non-integer scaling factor in generating an image.



Care should be taken to ensure this does not create significant errors that affect the quality of the image. For example :



<?php

$x=0.00000000001;$y=100;

imageline($img,0,0,0,$y+$x);

imageline($img,0,0,0,$y-$x);

?>



the first line will be straight , the second will have a step. Use round() where appropriate.

meid at gmx dot at
08-Sep-2005 01:39


Some simple code to draw lines with specific thickness using "imagefilledpolygon". Useful if your gdlib does not support "imagesetthickness". 



<?

function dickelinie($img,$start_x,$start_y,$end_x,$end_y,$color,$thickness) 

{

    $angle=(atan2(($start_y - $end_y),($end_x - $start_x))); 



    $dist_x=$thickness*(sin($angle));

    $dist_y=$thickness*(cos($angle));

    

    $p1x=ceil(($start_x + $dist_x));

    $p1y=ceil(($start_y + $dist_y));

    $p2x=ceil(($end_x + $dist_x));

    $p2y=ceil(($end_y + $dist_y));

    $p3x=ceil(($end_x - $dist_x));

    $p3y=ceil(($end_y - $dist_y));

    $p4x=ceil(($start_x - $dist_x));

    $p4y=ceil(($start_y - $dist_y));

    

    $array=array(0=>$p1x,$p1y,$p2x,$p2y,$p3x,$p3y,$p4x,$p4y);

    imagefilledpolygon ( $img, $array, (count($array)/2), $color );

}

// Example:

header ("Content-type: image/jpeg");

$img = ImageCreate (210, 210) or die("Cannot Initialize new GD image stream ");

$backgroundcolor = ImageColorAllocate ($img, 255, 255, 255);

$orange = ImageColorAllocate($img, 252, 102, 4);

dickelinie($img, 10, 10, 10, 200,$orange,2);

dickelinie($img, 10, 200, 200, 10,$orange,2);    

dickelinie($img, 200, 10, 200, 200,$orange,2);

imagejpeg($img);   

ImageDestroy($img);



?>

d [AT] sprid [DOT] de
06-Sep-2005 06:12


Here my function do clear all problems. With this, you can draw firstly smooth lines (basic code adapted from code_couturier at graffiti dot net, with some performance changes). The special is, you can define the alpha-value of the line (0 = normal smooth line, 127 = fully transparent). Change whatever you want to make it better, but post your results ;) 



<?php

/**

 * function imageSmoothAlphaLine() - version 1.0

 * Draws a smooth line with alpha-functionality

 *

 * @param   ident    the image to draw on

 * @param   integer  x1

 * @param   integer  y1

 * @param   integer  x2

 * @param   integer  y2

 * @param   integer  red (0 to 255)

 * @param   integer  green (0 to 255)

 * @param   integer  blue (0 to 255)

 * @param   integer  alpha (0 to 127)

 *

 * @access  public

 *

 * @author  DASPRiD <d@sprid.de>

 */

function imageSmoothAlphaLine ($image, $x1, $y1, $x2, $y2, $r, $g, $b, $alpha=0) {

  $icr = $r;

  $icg = $g;

  $icb = $b;

  $dcol = imagecolorallocatealpha($image, $icr, $icg, $icb, $alpha);

  

  if ($y1 == $y2 || $x1 == $x2) 

    imageline($image, $x1, $y2, $x1, $y2, $dcol);

  else {

    $m = ($y2 - $y1) / ($x2 - $x1);

    $b = $y1 - $m * $x1;



    if (abs ($m) <2) {

      $x = min($x1, $x2);

      $endx = max($x1, $x2) + 1;



      while ($x < $endx) {

        $y = $m * $x + $b;

        $ya = ($y == floor($y) ? 1: $y - floor($y));

        $yb = ceil($y) - $y;

   

        $trgb = ImageColorAt($image, $x, floor($y));

        $tcr = ($trgb >> 16) & 0xFF;

        $tcg = ($trgb >> 8) & 0xFF;

        $tcb = $trgb & 0xFF;

        imagesetpixel($image, $x, floor($y), imagecolorallocatealpha($image, ($tcr * $ya + $icr * $yb), ($tcg * $ya + $icg * $yb), ($tcb * $ya + $icb * $yb), $alpha));

  

        $trgb = ImageColorAt($image, $x, ceil($y));

        $tcr = ($trgb >> 16) & 0xFF;

        $tcg = ($trgb >> 8) & 0xFF;

        $tcb = $trgb & 0xFF;

        imagesetpixel($image, $x, ceil($y), imagecolorallocatealpha($image, ($tcr * $yb + $icr * $ya), ($tcg * $yb + $icg * $ya), ($tcb * $yb + $icb * $ya), $alpha));

  

        $x++;

      }

    } else {

      $y = min($y1, $y2);

      $endy = max($y1, $y2) + 1;



      while ($y < $endy) {

        $x = ($y - $b) / $m;

        $xa = ($x == floor($x) ? 1: $x - floor($x));

        $xb = ceil($x) - $x;

  

        $trgb = ImageColorAt($image, floor($x), $y);

        $tcr = ($trgb >> 16) & 0xFF;

        $tcg = ($trgb >> 8) & 0xFF;

        $tcb = $trgb & 0xFF;

        imagesetpixel($image, floor($x), $y, imagecolorallocatealpha($image, ($tcr * $xa + $icr * $xb), ($tcg * $xa + $icg * $xb), ($tcb * $xa + $icb * $xb), $alpha));

  

        $trgb = ImageColorAt($image, ceil($x), $y);

        $tcr = ($trgb >> 16) & 0xFF;

        $tcg = ($trgb >> 8) & 0xFF;

        $tcb = $trgb & 0xFF;

        imagesetpixel ($image, ceil($x), $y, imagecolorallocatealpha($image, ($tcr * $xb + $icr * $xa), ($tcg * $xb + $icg * $xa), ($tcb * $xb + $icb * $xa), $alpha));

  

        $y ++;

      }

    }

  }

} // end of 'imageSmoothAlphaLine()' function

?>

Tyron
03-May-2005 02:50


// Here's a function for drawing a rotated gradient Rectangle (based on a previous note)



// Create An Image 255x255

$img = ImageCreateTrueColor(255, 255);



GradientRect($img,50,50,80,80,30);



ImagePng($img,"test.png");

ImageDestroy($img);

echo "<br><img src=\"test.png\">";



function GradientRect($img, $x1, $y1, $x2, $y2, $wdt) {

  $alpha = atan2($y2-$y1,$x2-$x1);

  $real_wdt = $wdt*sin($alpha);

  $real_hgt = $wdt*cos($alpha);

  echo "real wdt:".$real_wdt;

  echo "<br>real hgt:".$real_hgt;

  echo "<br>angle: ".($angle*180/pi());

  $plotD = 0;

  $i=0; 



  $dy = $real_hgt/$wdt;

  $dx = $real_wdt/$wdt;

  $drgb= 256/$wdt;

  while($i++ < $wdt) {

    // Draw a line and move it down and make it lighter to get the gradient effect

    ImageLine($img, $x1-$i*$dx, $y1+$i*$dy, $x2-$i*$dx, $y2+$i*$dy, ImageColorAllocate($img, $i*$drgb, 0, 0));

    ImageLine($img, $x1-$i*$dx+1, $y1+$i*$dy, $x2-$i*$dx+1, $y2+$i*$dy, ImageColorAllocate($img, $i*$drgb, 0, 0));



  }

}

ajreading at classixshop dot com
23-Apr-2005 10:28


<?php

// An easy bit of code showing how you can use the ImageLine() function to create gradients



// Create An Image 255x255

$img = ImageCreateTrueColor(255, 255);



$plotD = 0;

while($plotD < 256)

{

    // Draw a line and move it down and make it lighter to get the gradient effect

    ImageLine($img, 0, $plotD , 255, $plotD, ImageColorAllocate($img, $plotD, $plotD, $plotD));

    $plotD++;

}

Header("Content-type: image/png");

ImagePng($img);

ImageDestroy($img);

?>

eviloverlord at gmail dot com
27-Jan-2005 11:50


This code is used to draw a board of hexagons (for games, classes, etc.)



<?php

//Draws a hexagonal board



// User-defined values

$maxTiles = 7;                    //The number of tiles at the center (widest part) of the board

$minTiles = 4;                    //The number of tiles at the edges of the board

$side = 30;                        //The length of the sides of the tiles in pixels

$bgColor = array(0, 0, 0);        //The background color in RGB format

$fgColor = array(255, 255, 255);//The foreground color in RGB format



//Calculated values

$widthInTiles = range($maxTiles, $minTiles);            //In our example: 7, 6, 5, 4

$rowsInTiles = count($widthInTiles)*2-1;                //the total number of rows on our board

$xSide = $side*sin(deg2rad(60));                        //the length of the x-part of the angled sides

$ySide = $side*sin(deg2rad(30));                        //the length of the y-part of the angled sides

$boardWidth = $xSide*$widthInTiles[0]*2;                //The entire width of the board

$boardHeight = $rowsInTiles*($side + $ySide) + $ySide;    //The entire height of the board



// create a blank image and allocate the foreground, background colors

$image = imagecreate($boardWidth, $boardHeight);

$bg = imagecolorallocate($image, $bgColor[0], $bgColor[1], $bgColor[2]);

$fg = imagecolorallocate($image, $fgColor[0], $fgColor[1], $fgColor[2]);



// draw the board

$row = 0;

foreach($widthInTiles as $tiles)

{

    for ($i = 0; $i < $tiles+1; $i++)

    {

        $x1 = $row*$xSide + $i*$xSide*2;

        $y1 = $boardHeight/2;

        $y1Dif = ($side/2) + $row*($side+$ySide);



        $x2 = $x1 + $xSide;

        $y2 = $y1;

        $y2Dif = $ySide;



        $x3 = $x2 + $xSide;



        if ($i < $tiles)

        {

            imageline($image, $x1, $y1 - $y1Dif, $x2, $y2 - $y1Dif - $y2Dif, $fg);

            imageline($image,  $x1, $y1 + $y1Dif, $x2, $y2 + $y1Dif + $y2Dif, $fg);

            imageline($image, $x2, $y2 - $y1Dif - $y2Dif, $x3, $y1 - $y1Dif, $fg);

            imageline($image, $x2, $y2 + $y1Dif + $y2Dif, $x3, $y1 + $y1Dif, $fg);

        }

                

        imageline($image, $x1, $y1 - $y1Dif, $x1, $y1 - $y1Dif + $side, $fg);            

        imageline($image, $x1, $y1 + $y1Dif, $x1, $y1 + $y1Dif - $side, $fg);            

    }

    $row++;

}



// output the picture

header("Content-type: image/png");

imagepng($image);

imagedestroy($image);

?>

likavcan at NOSPAN sturak nospan dot sk
06-Jun-2004 06:56


This function draws arrow.



function arrow($im, $x1, $y1, $x2, $y2, $alength, $awidth, $color) {



    $distance = sqrt(pow($x1 - $x2, 2) + pow($y1 - $y2, 2));



    $dx = $x2 + ($x1 - $x2) * $alength / $distance;

    $dy = $y2 + ($y1 - $y2) * $alength / $distance;



    $k = $awidth / $alength;



    $x2o = $x2 - $dx;

    $y2o = $dy - $y2;



    $x3 = $y2o * $k + $dx;

    $y3 = $x2o * $k + $dy;



    $x4 = $dx - $y2o * $k;

    $y4 = $dy - $x2o * $k;



    imageline($im, $x1, $y1, $dx, $dy, $color);

    imageline($im, $x3, $y3, $x4, $y4, $color);

    imageline($im, $x3, $y3, $x2, $y2, $color);

    imageline($im, $x2, $y2, $x4, $y4, $color);



}

Lionel Van Bemten
23-May-2004 06:41


here is a code to draw a "degraded" ... :

<?

header("Content-type : image/jpeg");



$image = @ImageCreate(200, 100)

  or die ("Erreur de cration de l'image");



$lignes_colorees = 1;

$couleur_fond = ImageColorAllocate($image, 255, 255, 255);



$rouge_depart = 100;

$vert_depart = 255;

$bleu_depart = 0;



$rouge_fin = 0;

$vert_fin = 100;

$bleu_fin = 0;



$lignes = 100; //nb de lignes de l'image



$vert_diff = $vert_fin - $vert_depart;

$vert1 = $vert_diff / $lignes;



$bleu_diff = $bleu_fin - $bleu_depart;

$bleu1 = $bleu_diff / $lignes;



$rouge_diff = $rouge_fin - $rouge_depart;

$rouge1 = $rouge_diff / $lignes;



while ($lignes_colorees <= 100)

{

    $rouge2 = $lignes_colorees * $rouge1;    $rouge3 = $rouge_depart + $rouge2;

    $rouge = round($rouge3);

    

    $vert2 = $lignes_colorees * $vert1;

    $vert3 = $vert_depart + $vert2;

    $vert = round($vert2);

    

    $bleu2 = $lignes_colorees * $bleu1;

    $bleu3 = $bleu_depart + $bleu2;

    $bleu = round($bleu2);

    

    $y1 = $lignes_colorees;

    $y2 = $lignes_colorees;

    $x1 = 1;    $x2 = 200;

    

    $couleur = ImageColorAllocate($image, $rouge, $vert, $bleu);

    //dessine la ligne

    ImageLine($image, $x1, $y1, $x2, $y2, $couleur);    $lignes_colorees ++;

}



//dessine l'image

ImageJpeg($image);

?>

ruturaj_v at yahoo dot com
14-May-2004 11:48


here is a function that helps you create arrows...



<?php

function get_arrowheads ($x1, $y1, $x2, $y2, $arrhead, $arrang) {

    $debug = false;

    

    define("INFINITE", 'INFINITE');

    if (($x2-$x1)==0) {

        if ($y1 == 0) {

            $slope = 0;

        } else {

            $slope = INFINITE;

        }

    } else {

        $slope = -($y2-$y1)/($x2-$x1);

    }



    //$slope = number_format($slope, 2, '.','');

    if ($slope == 'INFINITE') {

        $ang = 90;

    } else {

        $ang = atan ($slope);

        $ang = ($ang * 180)/pi();

    }

    //$ang = number_format($ang, 2, '.', '');

    //echo ($ang);

    //exit;



    //convert the angle

    $arrang1 = ($ang - $arrang);

    $arrangdeg1 = ($ang - $arrang);

    //echo ($arrang1);exit;

    $arrang1 = ($arrang1*pi())/180;



    $arrang2 = ($ang + $arrang);

    $arrangdeg2 = ($ang + $arrang);

    $arrang2 = ($arrang2*pi())/180;

    //echo ($arrang1);



    $arx1 = (floor(cos($arrang1)*$arrhead));

    $ary1 = (floor(sin($arrang1)*$arrhead));

    $arx2 = (floor(cos($arrang2)*$arrhead));

    $ary2 = (floor(sin($arrang2)*$arrhead));

    if ($debug) {

        echo ("Values of arx1.. before add/sub</br>");

        echo ("$arx1,$ary1&nbsp;&nbsp;&nbsp;$arx2,$ary2</br>");

    }

    if ($ang==0) {

        if ($x2 > $x1) {

            $arx1 = $x2 - $arx1;    $ary1 = $y2 - $ary1;

            $arx2 = $x2 - $arx2;    $ary2 = $y2 - $ary2;

        } elseif ($x2 < $x1) {

            $arx1 = $x2 + $arx1;    $ary1 = $y2 - $ary1;

            $arx2 = $x2 + $arx2;    $ary2 = $y2 - $ary2;

        }

    }

    if ($ang > 0 && $ang < 90) {

        if (($x2 > $x1) && ($y2 < $y1)) {

            $arx1 = $x2 - $arx1;    $ary1 = $y2 + $ary1;

            $arx2 = $x2 - $arx2;    $ary2 = $y2 + $ary2;

        } elseif (($x2 < $x1) && ($y2 > $y1)) {

            $arx1 = $x2 + $arx1;    $ary1 = $y2 - $ary1;

            $arx2 = $x2 + $arx2;    $ary2 = $y2 - $ary2;

        }

    }

    if ($ang==90) {

        if (($y2 > $y1)) {

            $arx1 = $x2 - $arx1;    $ary1 = $y2 - $ary1;

            $arx2 = $x2 - $arx2;    $ary2 = $y2 - $ary2;

        } elseif (($y2 < $y1)) {

            $arx1 = $x2 - $arx1;    $ary1 = $y2 + $ary1;

            $arx2 = $x2 - $arx2;    $ary2 = $y2 + $ary2;

        }

    }

    if ($ang > -90 && $ang < 0) {

        if (($x2 > $x1) && ($y2 > $y1)) {

            $arx1 = $x2 - $arx1;    $ary1 = $y2 + $ary1;

            $arx2 = $x2 - $arx2;    $ary2 = $y2 + $ary2;

        } elseif (($x2 < $x1) && ($y2 < $y1)) {

            $arx1 = $x2 + $arx1;    $ary1 = $y2 - $ary1;

            $arx2 = $x2 + $arx2;    $ary2 = $y2 - $ary2;

        }

    }



    if ($debug) {

        echo ("Angle of line is (".$ang*180/pi().")</br>");

        echo ("Angle of line1 is $arrangdeg1</br>");

        echo ("Angle of line2 is $arrangdeg2</br>");

        echo ("$arx1,$ary1&nbsp;&nbsp;&nbsp;$x2,$y2</br>");

        echo ("$arx2,$ary2&nbsp;&nbsp;&nbsp;$x2,$y2");

        exit;

    }

    

    $array_arrows = array (

                    'x1' =>$arx1,

                    'y1' => $ary1,

                    'x2' => $arx2,

                    'y2' => $ary2

                    );

    return $array_arrows;



}



$x1 = 200; $y1 = 200;

$x2 = 400; $y2 = 100;

$arrhead = 15; //10px

$arrang = 10; //10 deg



$ar_arrws = get_arrowheads ($x1, $y1, $x2, $y2, $arrhead, $arrang);



$im  = imagecreate (400, 400); 

$w   = imagecolorallocate ($im, 255, 255, 255); 

$red = imagecolorallocate ($im, 255, 0, 0); 



//creates the base line

imageline ($im, $x1, $y1, $x2, $y2, $green);

imageline ($im, $x1+1, $x2+1, $y1+1, $y2+1, $red);

imageline ($im, $x2, $y2, $ar_arrws['x1'], $ar_arrws['y1'], $green);

imageline ($im, $x2, $y2, $ar_arrws['x2'], $ar_arrws['y2'], $green);



?>

yl at sota dot ch
15-Apr-2004 12:44


Simple function to create border for jpg-images:



function createImageBorder($imgName){



     $img     =  substr($imgName, 0, -4); // remove fileExtension

     $ext     = ".jpg";

     $quality = 95;

     $borderColor = 255;  // 255 = white

     

    /*

     a                         b

     +-------------------------+

     |                          

     |          IMAGE           

     |                          

     +-------------------------+

     c                         d   

    */

    

    $scr_img = imagecreatefromjpeg($img.$ext);

    $width   = imagesx($scr_img);

    $height  = imagesy($scr_img);

              

        // line a - b

        $abX  = 0;

        $abY  = 0;

        $abX1 = $width;

        $abY1 = 0;

        

        // line a - c

        $acX  = 0;

        $acY  = 0;

        $acX1 = 0;

        $acY1 = $height;

        

        // line b - d

        $bdX  = $width-1;

        $bdY  = 0;

        $bdX1 = $width-1;

        $bdY1 = $height;

        

        // line c - d

        $cdX  = 0;

        $cdY  = $height-1;

        $cdX1 = $width;

        $cdY1 = $height-1;

            

       // DRAW LINES    

        imageline($scr_img,$abX,$abY,$abX1,$abY1,$borderColor);

        imageline($scr_img,$acX,$acY,$acX1,$acY1,$borderColor);

        imageline($scr_img,$bdX,$bdY,$bdX1,$bdY1,$borderColor);

        imageline($scr_img,$cdX,$cdY,$cdX1,$cdY1,$borderColor);

        

      // create copy from image    

        imagejpeg($scr_img, $img."_border.jpg", $quality);

        imagedestroy($scr_img); 

  }

    

    createImageBorder("myfile.jpg");

XxXoldsaltXxX at hotmail dot com
15-Feb-2004 02:50


Script to draw a grid of lines, which make the entire side of the picture look like a quarter circle.. very cool :)

<?php

$img_disp = imagecreate(1000,1000);

$backcolor = imagecolorallocate($img_disp,0,0,0);

imagefill($img_disp,0,0,$backcolor);

$textcolor = imagecolorallocate($img_disp,255,0,0);

$x1 = 0;

$y1 = 0;

$x2 = 0;

$y2 = 1000;

for(;;){

$y1 = $y1 + 20;

$x2 = $x2 + 20;

imageline($img_disp,$x1,$y1,$x2,$y2,$textcolor);

if ($y1 == 1000){

break;

}

}

header("Content-type: image/png");

imagepng($img_disp); // Draw the image

imagedestroy($img_disp); // Delete the image from the server's memory

?>

mueller at inf dot ufsc dot br
06-Jan-2004 04:26


an algorithm to draw a bezier spline



<?php



$segmentos =30;

$x=array(0,10,80,30);

$y=array(0,10,40,50);



function bezier($p,$steps){

    $t = 1 / $steps;

    $temp = $t * $t;

    $ret = array();

    $f = $p[0];

    $fd = 3 * ($p[1] - $p[0]) * $t;

    $fdd_per_2=3*($p[0]-2*$p[1]+$p[2])*$temp;

    $fddd_per_2=3*(3*($p[1]-$p[2])+$p[3]-$p[0])*$temp*$t;

    $fddd = $fddd_per_2 + $fddd_per_2;

    $fdd = $fdd_per_2 + $fdd_per_2;

    $fddd_per_6 = $fddd_per_2 * (1.0 / 3);

    for ($loop=0; $loop<$steps; $loop++) {

        array_push($ret,$f);

        $f = $f + $fd + $fdd_per_2 + $fddd_per_6;

        $fd = $fd + $fdd + $fddd_per_2;

        $fdd = $fdd + $fddd;

        $fdd_per_2 = $fdd_per_2 + $fddd_per_2;

    }

    return $ret;

}



$by = bezier($y,$segmentos);

$bx = bezier($x,$segmentos);

header ("Content-type: image/jpeg");

$tam = 200;

$im = imagecreate($tam,$tam);

$background_color = imagecolorallocate ($im, 200, 200, 200);

$tc = imagecolorallocate ($im, 233, 14, 91);

for($i=0;$i<$segmentos-1;$i++)

    imageline($im,$bx[$i],$tam-$by[$i],$bx[$i+1],$tam-$by[$i+1],$tc);

imagejpeg($im); 

imagedestroy($im);

?>

code_couturier at graffiti dot net
18-Oct-2003 02:56


# antialiased draw_line function 1.1 (faster) 



# here is a drawLine() posted by nanobot at chipx86 dot com 

# on php.net and enhanced/optimized by myself :) 



# here are some changes i made: 

# 1. changed for true-color images (no index_var used) 

# 2. changed rgb extraction to logical shift 

# 3. reducing function call's



function drawQSLine ($image,$x1,$y1,$x2,$y2,$r,$g,$b) {

$icr=$r;

$icg=$g;

$icb=$b;

 $dcol = ImageColorAllocate ($image,$icr,$icg,$icb);

 if ($y1 == $y2) imageline ($image,$x1,$y1,$x2,$y1,$dcol);

 else if ($x1 == $x2) {  

   imageline ($image,$x1,$y1,$x1,$y2,$dcol); 

 } else {

 $m = ($y2 - $y1) / ($x2 - $x1);

 $b = $y1 - $m * $x1;



 if (abs ($m) <2) {



 $x = min ($x1,$x2);

 $endx = max ($x1,$x2)+1;



 while ($x < $endx) {

 $y=$m * $x + $b;

 $y == floor ($y) ? $ya = 1 : $ya = $y - floor ($y);

 $yb = ceil ($y) - $y;

 

 $trgb = ImageColorAt($image,$x,floor($y));

 $tcr = ($trgb >> 16) & 0xFF;

 $tcg = ($trgb >> 8) & 0xFF;

 $tcb = $trgb & 0xFF;

 imagesetpixel ($image,$x,floor ($y),imagecolorallocate ($image,($tcr * $ya + $icr * $yb),

($tcg * $ya + $icg * $yb),

($tcb * $ya + $icb * $yb)));



 $trgb = ImageColorAt($image,$x,ceil($y));

 $tcr = ($trgb >> 16) & 0xFF;

 $tcg = ($trgb >> 8) & 0xFF;

 $tcb = $trgb & 0xFF;

 imagesetpixel ($image,$x,ceil ($y),imagecolorallocate ($image,($tcr * $yb + $icr * $ya),

($tcg * $yb + $icg * $ya), 

($tcb * $yb + $icb * $ya)));



 $x ++;

 } # while_x_end

 } # if_end

 else { # else_abs_end



 $y = min ($y1,$y2);

 $endy = max ($y1,$y2)+1;



 while ($y < $endy) {

 $x=($y - $b) / $m;

 $x == floor ($x) ? $xa = 1 : $xa = $x - floor ($x);

 $xb = ceil ($x) - $x;



 $trgb = ImageColorAt($image,floor($x),$y);

 $tcr = ($trgb >> 16) & 0xFF;

 $tcg = ($trgb >> 8) & 0xFF;

 $tcb = $trgb & 0xFF;

 imagesetpixel ($image,floor ($x),$y,imagecolorallocate ($image,($tcr * $xa + $icr * $xb),

($tcg * $xa + $icg * $xb),

($tcb * $xa + $icb * $xb)));



 $trgb = ImageColorAt($image,ceil($x),$y);

 $tcr = ($trgb >> 16) & 0xFF;

 $tcg = ($trgb >> 8) & 0xFF;

 $tcb = $trgb & 0xFF;

 imagesetpixel ($image,ceil ($x),$y,imagecolorallocate ($image, ($tcr * $xb + $icr * $xa),

($tcg * $xb + $icg * $xa),

($tcb * $xb + $icb * $xa)));



 $y ++;

 }# while_y_end

 }# else_abs_end

 }# else_y=y_x=x_end 

}# drawOSLine_end

code_couturier at graffiti dot net
02-Oct-2003 12:33


# antialiased lines with true-type-fonts !?


# yip, it works - not very good - but faster


# (below 3 sec) than other routines (~7 sec)


# i saw here.





# the antialiased effect is minimal and only 


# at the top of the line - but, as better as


# nothing ;)





# here is a drawLine routine from Logan Gunthorpe 


# (logang at deltatee dot com) posted by nanobot at chipx86 dot com


# on php.net and enhanced/optimized by myself :)





function drawSoftLine ($image, $x1, $y1, $x2, $y2, $r,$g,$b) {





$fontfile="arial.ttf"; # the font for the dot


$str="" ; # the point_char for the dot


$size=12; # the point for the dot_size





 $color = ImageColorAllocate ($image, $r,$g,$b);





 if ($x2 == $x1) {


 $tmp = $x1; $x1 = $y1; $y1 = $tmp;


 $tmp = $x2; $x2 = $y2; $y2 = $tmp;


 $swapx = true;


 }





 $m = (float)(( $y2 - $y1 ) / ( $x2 - $x1 ));


 $b = (float)($y1 - $m*$x1);





 $strx = min ( $x1 , $x2 );


 $endx = max ( $x1 , $x2 );


 $x=(int)0;





# the original loop was based on one for_loop


# with the if_swap inside. to speed up this loop


# i double it, to keep off the permanent if_call's. 





if (!$swapx) {


 for ($x = $strx; $x <= $endx; $x++) { 


   $y = (int)($m*$x + $b);  


   imagettftext($image, $size, 0, $x, $y, 


   $color, $fontfile,$str);


 }


} else {


 for ($x = $strx; $x <= $endx; $x++) { 


   $y = (int)($m*$x + $b);  


   imagettftext($image, $size, 0, $y, $x, 


   $color, $fontfile,$str);


  }


}





}

nanobot at chipx86 dot com
17-Jun-2003 08:28


Here is a function for making antialiased lines:



 function imagesmoothline ( $image , $x1 , $y1 , $x2 , $y2 , $color )

 {

  $colors = imagecolorsforindex ( $image , $color );

  if ( $x1 == $x2 )

  {

   imageline ( $image , $x1 , $y1 , $x2 , $y2 , $color ); // Vertical line

  }

  else

  {

   $m = ( $y2 - $y1 ) / ( $x2 - $x1 );

   $b = $y1 - $m * $x1;

   if ( abs ( $m ) <= 1 )

   {

    $x = min ( $x1 , $x2 );

    $endx = max ( $x1 , $x2 );

    while ( $x <= $endx )

    {

     $y = $m * $x + $b;

     $y == floor ( $y ) ? $ya = 1 : $ya = $y - floor ( $y );

     $yb = ceil ( $y ) - $y;

     $tempcolors = imagecolorsforindex ( $image , imagecolorat ( $image , $x , floor ( $y ) ) );

     $tempcolors['red'] = $tempcolors['red'] * $ya + $colors['red'] * $yb;

     $tempcolors['green'] = $tempcolors['green'] * $ya + $colors['green'] * $yb;

     $tempcolors['blue'] = $tempcolors['blue'] * $ya + $colors['blue'] * $yb;

     if ( imagecolorexact ( $image , $tempcolors['red'] , $tempcolors['green'] , $tempcolors['blue'] ) == -1 ) imagecolorallocate ( $image , $tempcolors['red'] , $tempcolors['green'] , $tempcolors['blue'] );

     imagesetpixel ( $image , $x , floor ( $y ) , imagecolorexact ( $image , $tempcolors['red'] , $tempcolors['green'] , $tempcolors['blue'] ) );

     $tempcolors = imagecolorsforindex ( $image , imagecolorat ( $image , $x , ceil ( $y ) ) );

     $tempcolors['red'] = $tempcolors['red'] * $yb + $colors['red'] * $ya;

      $tempcolors['green'] = $tempcolors['green'] * $yb + $colors['green'] * $ya;

     $tempcolors['blue'] = $tempcolors['blue'] * $yb + $colors['blue'] * $ya;

     if ( imagecolorexact ( $image , $tempcolors['red'] , $tempcolors['green'] , $tempcolors['blue'] ) == -1 ) imagecolorallocate ( $image , $tempcolors['red'] , $tempcolors['green'] , $tempcolors['blue'] );

     imagesetpixel ( $image , $x , ceil ( $y ) , imagecolorexact ( $image , $tempcolors['red'] , $tempcolors['green'] , $tempcolors['blue'] ) );

     $x ++;

    }

   }

   else

   {

    $y = min ( $y1 , $y2 );

    $endy = max ( $y1 , $y2 );

    while ( $y <= $endy )

    {

     $x = ( $y - $b ) / $m;

     $x == floor ( $x ) ? $xa = 1 : $xa = $x - floor ( $x );

     $xb = ceil ( $x ) - $x;

     $tempcolors = imagecolorsforindex ( $image , imagecolorat ( $image , floor ( $x ) , $y ) );

     $tempcolors['red'] = $tempcolors['red'] * $xa + $colors['red'] * $xb;

     $tempcolors['green'] = $tempcolors['green'] * $xa + $colors['green'] * $xb;

     $tempcolors['blue'] = $tempcolors['blue'] * $xa + $colors['blue'] * $xb;

     if ( imagecolorexact ( $image , $tempcolors['red'] , $tempcolors['green'] , $tempcolors['blue'] ) == -1 ) imagecolorallocate ( $image , $tempcolors['red'] , $tempcolors['green'] , $tempcolors['blue'] );

     imagesetpixel ( $image , floor ( $x ) , $y , imagecolorexact ( $image , $tempcolors['red'] , $tempcolors['green'] , $tempcolors['blue'] ) );

     $tempcolors = imagecolorsforindex ( $image , imagecolorat ( $image , ceil ( $x ) , $y ) );

     $tempcolors['red'] = $tempcolors['red'] * $xb + $colors['red'] * $xa;

     $tempcolors['green'] = $tempcolors['green'] * $xb + $colors['green'] * $xa;

     $tempcolors['blue'] = $tempcolors['blue'] * $xb + $colors['blue'] * $xa;

     if ( imagecolorexact ( $image , $tempcolors['red'] , $tempcolors['green'] , $tempcolors['blue'] ) == -1 ) imagecolorallocate ( $image , $tempcolors['red'] , $tempcolors['green'] , $tempcolors['blue'] );

     imagesetpixel ( $image , ceil ( $x ) , $y , imagecolorexact ( $image , $tempcolors['red'] , $tempcolors['green'] , $tempcolors['blue'] ) );

     $y ++;

    }

   }

  }

 }



EDITOR: My previous code contained bugs. Please use this one instead.

kramesch_NOSPAM_ at _nospam_idsolutions dot at
27-Feb-2002 05:44


Here is a simple code to draw a line with an arbitrary stroke. The parameter aStroke is treated as a cyclic boolean array where true equals "set a point"

e.g. $aDotStroke = array(true,false);



function ImageStrokeLine($im,$x1,$y1,$x2,$y2,$farbe, $aStroke)

  {

    $deltax = abs($x2 - $x1);        

    $deltay = abs($y2 - $y1);        

    $x = $x1;                       

    $y = $y1;                       

    

    if ($x2 >= $x1)                 

    {

      $xinc1 = 1;

      $xinc2 = 1;

    }

    else                          

    {

      $xinc1 = -1;

      $xinc2 = -1;

    }

    

    if ($y2 >= $y1)                 

    {

      $yinc1 = 1;

      $yinc2 = 1;

    }

    else                          

    {

      $yinc1 = -1;

      $yinc2 = -1;

    }

    

    if ($deltax >= $deltay)  

    {

      $xinc1 = 0;                 

      $yinc2 = 0;                 

      $den = $deltax;

      $num = $deltax / 2;

      $numadd = $deltay;

      $numpixels = $deltax; 

    }

    else                          

    {

      $xinc2 = 0;             

      $yinc1 = 0;             

      $den = $deltay;

      $num = $deltay / 2;

      $numadd = $deltax;

      $numpixels = $deltay; 

    }

    

    for ($curpixel = 0; $curpixel <= $numpixels; $curpixel++)

    {

      if ($iStrokeCount >= count($aStroke))

      {

        $iStrokeCount = 0;

      }

  

      if ($aStroke[$iStrokeCount++]) 

      {

        ImageSetPixel($im,$x, $y,$farbe);            

      }            

      $num += $numadd;            

      if ($num >= $den)             

      {

        $num -= $den;               

        $x += $xinc1;               

        $y += $yinc1;               

      }

      $x += $xinc2;                 

      $y += $yinc2;                 

    }

  }

darren at php4hosting dot com
29-Oct-2000 01:48


It does work (With a bit of editing)


save the following as graph.php (You dont need any directorys)





<?php 


Header("Content-type: image/png");


$picWidth=360*2; 


$picHeight=200; 


$pic=ImageCreate($picWidth+1,$picHeight+1); 


$cWhite=ImageColorAllocate($pic,255,255,255); 


ImageFilledRectangle($pic,0,0,$picWidth+1,$picHeight+1,$cWhite); 


$cRed=ImageColorAllocate($pic,255,0,0); 


$cBlue=ImageColorAllocate($pic,0,0,255); 


$curX=0; 


$curY=$picHeight; 


for($pt=0;$pt<$picWidth;$pt++){ 


$newX=$curX+1; 


$newY=($picHeight/2)+(cos(deg2rad($newX))*($picHeight/2)); 


ImageLine($pic,$curX,$curY,$newX,$newY,$cRed); 


$curX=$newX; 


$curY=$newY; 


} 


$curX=0; 


$curY=$picHeight/2; 


for($pt=0;$pt<$picWidth;$pt++){ 


$newX=$curX+1; 


$newY=($picHeight/2)+(sin(deg2rad($newX))*($picHeight/2)); 


ImageLine($pic,$curX,$curY,$newX,$newY,$cBlue); 


$curX=$newX; 


$curY=$newY; 


} 


$cBlack=ImageColorAllocate($pic,0,0,0); 


ImageLine($pic,0,0,0,$picHeight,$cBlack); 


ImageLine($pic,0,$picHeight/2,$picWidth,$picHeight/2,$cBlack); 


ImagePNG($pic); 


ImageDestroy($pic); 


?>

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