PHP 5.4.33 Released

imageline

(PHP 4, PHP 5)

imagelineDraw a line

Opis

bool imageline ( resource $image , int $x1 , int $y1 , int $x2 , int $y2 , int $color )

Draws a line between the two given points.

Parametry

obraz

Zasób obrazu, zwrócony przez jedną z funkcji tworzących obrazy, taką jak imagecreatetruecolor().

x1

x-coordinate for first point.

y1

y-coordinate for first point.

x2

x-coordinate for second point.

y2

y-coordinate for second point.

color

The line color. A color identifier created with imagecolorallocate().

Zwracane wartości

Zwraca TRUE w przypadku powodzenia, FALSE w przypadku błędu.

Przykłady

Przykład #1 Drawing a thick line

<?php

function imagelinethick($image$x1$y1$x2$y2$color$thick 1)
{
    
/* this way it works well only for orthogonal lines
    imagesetthickness($image, $thick);
    return imageline($image, $x1, $y1, $x2, $y2, $color);
    */
    
if ($thick == 1) {
        return 
imageline($image$x1$y1$x2$y2$color);
    }
    
$t $thick 0.5;
    if (
$x1 == $x2 || $y1 == $y2) {
        return 
imagefilledrectangle($imageround(min($x1$x2) - $t), round(min($y1$y2) - $t), round(max($x1$x2) + $t), round(max($y1$y2) + $t), $color);
    }
    
$k = ($y2 $y1) / ($x2 $x1); //y = kx + q
    
$a $t sqrt(pow($k2));
    
$points = array(
        
round($x1 - (1+$k)*$a), round($y1 + (1-$k)*$a),
        
round($x1 - (1-$k)*$a), round($y1 - (1+$k)*$a),
        
round($x2 + (1+$k)*$a), round($y2 - (1-$k)*$a),
        
round($x2 + (1-$k)*$a), round($y2 + (1+$k)*$a),
    );
    
imagefilledpolygon($image$points4$color);
    return 
imagepolygon($image$points4$color);
}

?>

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User Contributed Notes 30 notes

up
2
kramesch_NOSPAM_ at _nospam_idsolutions dot at
12 years ago
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;                
    }
  }
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0
Nils
2 years ago
A quick function using imageline that I wrote so i could specify a starting point, angle and length of vector.

Thought other people might find this useful.

<?php
$size
= 600;
$img = imagecreatetruecolor($size, $size);

$white = imagecolorallocate($img, 255, 255, 255);
$black = imagecolorallocate($img, 0, 0, 0);

imagefilledrectangle($img,0,0,$size,$size,$white);

function
Vector($palette,$startx,$starty,$angle,$length,$colour){
   
$angle = deg2rad($angle);
   
$endx = $startx+cos($angle)*$length;
   
$endy = $starty-sin($angle)*$length;
    return(
imageline($palette,$startx,$starty,$endx,$endy,$colour));
}

Vector($img,$size/2,$size/2,30,200,$black);

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

?>

For this script angles work in a anti-clockwise direction (modify + and - in function to change start of 0 degrees and also direction of angle calculated)
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0
Anonymous
3 years ago
The most bold-line-functions i found have problems with lines in a certian direction (they draw smaller lines with some angles). To do a real bold line just use this function:

<?php
function imageBoldLine($resource, $x1, $y1, $x2, $y2, $Color, $BoldNess=2, $func='imageLine')
{
$center = round($BoldNess/2);
for(
$i=0;$i<$BoldNess;$i++)

 
$a = $center-$i; if($a<0){$a -= $a;}
  for(
$j=0;$j<$BoldNess;$j++)
  {
  
$b = $center-$j; if($b<0){$b -= $b;}
  
$c = sqrt($a*$a + $b*$b);
   if(
$c<=$BoldNess)
   {
   
$func($resource, $x1 +$i, $y1+$j, $x2 +$i, $y2+$j, $Color);
   }
  }
}        
}
?>
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0
sbm007 at gmail dot com
4 years ago
Here is a analog clock representation of the system time along with digits for hours and little dots for minutes/seconds:

<?php
$img
= imagecreatetruecolor(450, 450);

$white = imagecolorallocate($img, 255, 255, 255);
$red = imagecolorallocate($img, 255, 0, 0);
$black = imagecolorallocate($img, 0, 0, 0);
$grey = imagecolorallocate($img, 211, 211, 211);

imagefill($img, 0, 0, $white);
imagearc($img, 224, 224, 400, 400, 0, 0, $black);
imagefilledarc($img, 224, 224, 15, 15, 0, 0, $black, IMG_ARC_PIE);

for (
$zz = 0; $zz < 60; $zz++) {
   
$digitCoords['x'][] = 175 * cos(deg2rad(($zz-10) * (360/60))) + 224;
   
$digitCoords['y'][] = 175 * sin(deg2rad(($zz-10) * (360/60))) + 224;
}

for (
$zz = 0; $zz < 60; $zz++) {
    if (
$zz % 5 == 0)
       
imagestring($img, 5, $digitCoords['x'][$zz] - 4, $digitCoords['y'][$zz] - 6, ($zz/5) + 1, $black);
    else
       
imagefilledarc($img, $digitCoords['x'][$zz], $digitCoords['y'][$zz], 3, 3, 0, 0, $grey, IMG_ARC_PIE);
}

$seconds = date('s');
$minutes = date('i') + ($seconds/60);
$hours = date('h') + ($minutes/60);

$r_sec = 175;
$r_min = 175;
$r_hr = 125;

$x_sec = $r_sec * cos(deg2rad(($seconds-15) * (360/60))) + 224;
$y_sec = $r_sec * sin(deg2rad(($seconds-15) * (360/60))) + 224;

$x_min = $r_min * cos(deg2rad(($minutes-15) * (360/60))) + 224;
$y_min = $r_min * sin(deg2rad(($minutes-15) * (360/60))) + 224;

$x_hr = $r_hr * cos(deg2rad(($hours-3) * (360/12))) + 224;
$y_hr = $r_hr * sin(deg2rad(($hours-3) * (360/12))) + 224;

imageline($img, 224, 224, $x_sec, $y_sec, $red);
imagesetthickness($img, 3);
imageline($img, 224, 224, $x_min, $y_min, $black);
imagesetthickness($img, 5);
imageline($img, 224, 224, $x_hr, $y_hr, $black);

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

imagedestroy($img);
?>
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0
Anonymous
5 years ago
Here's another way of modifying likavcan's code to display filled arrows. This makes use of imagefilledpolygon(...) instead of recursive function calls.

<?php
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);
   
imagefilledpolygon($im, array($x2, $y2, $x3, $y3, $x4, $y4), 3, $color);
}
?>
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0
ca dot ddy at gmx dot de
5 years ago
I've modified the Arrow function of likavcan.

This arrowFunction draws the arrow filled :

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

    if(
$alength > 1 )
       
arrow( $im, $x1, $y1, $x2, $y2, $alength - 1, $awidth - 1, $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);

}
?>
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0
keksnicoh
5 years ago
Little function I made to draw faaaaat lines...

<?php
/**
* imageBoldLine function
* this function allows you to draw faaaat lines.
*
* To keep the function a bit more flexible, it's possible to change the function which draw the lines
* @param resource $resource
* @param int $x1
* @param int $y1
* @param int $x2
* @param int $y2
* @param int $Color
* @param int $BoldNess (1 = thin, 2=bold, 1000 = extreme fat)
* @param string $func Functionname. Notice that the function must got the same signature.
* @return void
* @author Nicolas 'keksnicoh' Heimann <www.salamipla.net>
* @date nov08
* <code><?php
* imageBoldLine($res, 0, 0, 100, 100, $col, 5);
* ?></code>
*/
function imageBoldLine($resource, $x1, $y1, $x2, $y2, $Color, $BoldNess=2, $func='imageLine')
{
   
$x1 -= ($buf=ceil(($BoldNess-1) /2));
   
$x2 -= $buf;
    for(
$i=0;$i < $BoldNess;++$i)
       
$func($resource, $x1 +$i, $y1, $x2 +$i, $y2, $Color);
}
?>
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0
huirong dot jin at gmail dot com
6 years ago
An example to draw Lissajous Curve (http://en.wikipedia.org/wiki/Lissajous_curve):
x = a1 * cos(t/T1);
y = a2 * sin(t/T2);

You can easily modify the codes to create your own oscilloscope application!

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

$T1 = 20;
$T2 = 30;

$myImage = @imagecreatetruecolor(640, 480)
      or die(
"Cannot Initialize new GD image stream");
$text_color = imagecolorallocate($myImage, 255, 255, 224);
$poly_color = imagecolorallocate($myImage, 124, 120, 224);

//calculate x-value and y-value point by point
$points = array();
for (
$i=0; $i<1000; $i=$i+1)
{
   
//define curve's function
   
$x = 310*cos($i/$T1); //define x-value
   
$y = 230*sin($i/$T2);//define y-value
   
    //move the coordinate, append a point's x-value and y-value
   
$points[] = 320+$x; //x-value
   
$points[] = 240-$y//y-value
}

//count points
$totalPoints = count($points)/2;

//drawing title
$title = "Final Plot ($totalPoints points)";
imagestring($myImage, 3, 5, 5$title, $text_color);

/** drawing points one by one, notice if there
* are 10 points, we need to draw 9 lines:
* 1) point 0 to 1;
* 2) point 1 to 2;
* ...
* ...
* 9) point 8 to 9;
*/
for ($i=0; $i<$totalPoints-1; $i++)
{
   
imageLine($myImage, $points[2*$i], $points[1+2*$i], $points[2+2*$i], $points[3+2*$i], $poly_color);   
}

//finalizing
imagepng($myImage);
imagedestroy($myImage);
?>
up
0
huirong dot jin at gmail dot com
6 years ago
An example to draw Amplitude Modulation curve: y = c * sin (x/a) * sin (x/b) . You can easily modify the codes to create your own oscilloscope application!

<?php
header
("Content-type: image/png");
$myImage = @imagecreatetruecolor(640, 480)
      or die(
"Cannot Initialize new GD image stream");
$text_color = imagecolorallocate($myImage, 255, 255, 224);
$poly_color = imagecolorallocate($myImage, 124, 120, 224);

//calculate x-value and y-value point by point
$points = array();
for (
$i=1; $i<640; $i=$i+1)
{
   
//define curve's function
   
$x = $i; //define x-value, which is $i itself
   
$y = 150*sin($x/80)*sin($x/5);//define y-value
   
    //append a point's x-value and y-value
   
$points[] = $x; //x-value
   
$points[] = 240-$y//y-value
}

//count points
$totalPoints = count($points)/2;

//drawing title
$title = "Final Plot ($totalPoints points)";
imagestring($myImage, 3, 5, 5$title, $text_color);

/** drawing points one by one, notice if there
* are 10 points, we need to draw 9 lines:
* 1) point 0 to 1;
* 2) point 1 to 2;
* ...
* ...
* 9) point 8 to 9;
*/
for ($i=0; $i<$totalPoints-1; $i++)
{
   
imageLine($myImage, $points[2*$i], $points[1+2*$i], $points[2+2*$i], $points[3+2*$i], $poly_color);   
}

//finalizing
imagepng($myImage);
imagedestroy($myImage);
?>
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0
admin at xpmail dot net
7 years ago
example of a Simple grid...
bool imagegrid ( resource $image, int $width, int $Height, int $size, mixed $color )

<?php
Header
("Content-type: image/png");
$Width=450;
$Height=450;

$img = ImageCreateTrueColor($Width, $Height);

$bg = imagecolorallocate($img, 255, 255, 255);
imagefill($img, 0, 0, $bg);

$grid = imagecolorallocate($img, 225, 245, 249);

imagesetstyle($img, array($bg, $grid));
imagegrid($img, $Width, $Height, 10, IMG_COLOR_STYLED);
//makegrid($img, $Width, $Height, 10, $grid);

ImagePNG($img);
ImageDestroy($img);

function
imagegrid($image, $w, $h, $s, $color)
{
    for(
$iw=1; $iw<$w/$s; $iw++){imageline($image, $iw*$s, 0, $iw*$s, $w, $color);}
    for(
$ih=1; $ih<$h/$s; $ih++){imageline($image, 0, $ih*$s, $w, $ih*$s, $color);}
}
?>
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0
Jonathan W.
7 years ago
I've modified the previous entry for drawing on a polar coordinate system to better represent angles based on a 360º whole circle bearing.

<?php

function imagepolarline($image,$x1,$y1,$length,$angle,$color)
{
   
$x2 = $x1 + sin( deg2rad($angle) ) * $length;
   
$y2 = $y1 + cos( deg2rad($angle+180) ) * $length;

   
imageline($image,$x1,$y1,$x2,$y2,$color);
}

?>
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0
pb_2001 at haefft dot de
8 years ago
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...
}
?>
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0
fatpratmatt at gmail dot com
8 years ago
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);
?>
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0
Anonymous
8 years ago
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.
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meid at gmx dot at
9 years ago
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);

?>
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d [AT] sprid [DOT] de
9 years ago
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
?>
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Tyron
9 years ago
// 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));

  }
}
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ajreading at classixshop dot com
9 years ago
<?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);
?>
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eviloverlord at gmail dot com
9 years ago
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);
?>
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likavcan at NOSPAN sturak nospan dot sk
10 years ago
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);

}
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Lionel Van Bemten
10 years ago
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);
?>
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ruturaj_v at yahoo dot com
10 years ago
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);

?>
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yl at sota dot ch
10 years ago
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");
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XxXoldsaltXxX at hotmail dot com
10 years ago
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
?>
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mueller at inf dot ufsc dot br
10 years ago
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);
?>
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code_couturier at graffiti dot net
10 years ago
# 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
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0
code_couturier at graffiti dot net
10 years ago
# 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);
  }
}

}
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0
nanobot at chipx86 dot com
11 years ago
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.
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0
darren at php4hosting dot com
13 years ago
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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-1
allenn at hot dot ee
4 years ago
Function drawing of a line by a brush uses midpoint circle algorithm..., if dullness I agree to remove :)))

<?php
//function drawLine(resource$image,int $x0,int $y0,int $x1,int $y1,int $lineWidth,int $color)
function drawLine($image,$x0, $y0,$x1, $y1,$radius,$color)
{
 
$f = 1 - $radius;
 
$ddF_x= 1;
 
$ddF_y = -2 * $radius;
 
$x= 0;
 
$y = $radius;
   
imageline($image,$x0, $y0 + $radius,$x1, $y1 + $radius,$color);
    
imageline($image,$x0, $y0 - $radius,$x1, $y1 - $radius,$color);
   
imageline($image,$x0 + $radius, $y0,$x1 + $radius, $y1,$color);
   
imageline($image,$x0 - $radius, $y0,$x1 - $radius, $y1,$color);

  while(
$x< $y)
  {
    if(
$f >= 0)
    {
     
$y--;
     
$ddF_y += 2;
     
$f += $ddF_y;
    }
   
$x++;
   
$ddF_x+= 2;
   
$f += $ddF_x;
   
imageline($image,$x0 + $x, $y0 + $y,$x1 + $x, $y1+ $y,$color);
      
imageline($image,$x0 - $x, $y0 + $y,$x1 - $x, $y1 + $y,$color);
      
imageline($image,$x0 + $x, $y0 - $y,$x1 + $x, $y1 - $y,$color);
      
imageline($image,$x0 - $x, $y0 - $y,$x1 - $x, $y1 - $y,$color);
      
imageline($image,$x0 + $y, $y0 + $x,$x1 + $y, $y1 + $x,$color);
      
imageline($image,$x0 - $y, $y0 + $x,$x1 - $y, $y1 + $x,$color);
      
imageline($image,$x0 + $y, $y0 - $x,$x1 + $y, $y1 - $x,$color);
      
imageline($image,$x0 - $y, $y0 - $x,$x1 - $y, $y1 - $x,$color);

  }
}
header ('Content-type: image/png');
$img = imagecreatetruecolor(600,600);
$col = imagecolorallocate($img,0,255,252);
//use the function
rasterCircle($img,50, 50,540,540,40,$col);
imagepng($img);
imagedestroy($img);
?>
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