2D Line Plot (fully working)

<?
//---------------------
//class plot2D - 3/1/01
//version 0.5          
//By Nelson Rothermel  
//[email protected] 
//---------------------

class plot2D {
 var $img, $imgWidth, $imgHeight, $fontSize, $fontWidth, $fontHeight, $cBack, $acPlot, $maxCatLen, $aItems, $maxVal, $numItems, $maxNumItems, $maxLinesDesc, $numberY, $cBlack, $cGrid;
 var $graphX, $graphY, $graphWidth, $graphHeight;
 var $titleString, $titleFontSize, $cTitle, $titleWidth, $titleHeight;
 var $xDesc, $yDesc, $xDescLength, $yDescLength;
 function plot2D($width=640, $height=480, $fontSize=2, $red=0xFF, $green=0xFF, $blue=0xFF) {
  $this->img = imageCreate($width, $height);
  $this->imgWidth = $width-10;
  $this->imgHeight = $height;
  $this->cBack = imageColorAllocate($this->img, $red, $green, $blue);
  $this->cBlack = imageColorAllocate($this->img, 0, 0, 0);
  $this->cNavy = imageColorAllocate($this->img, 0x00, 0x00, 0x80);
  $this->fontSize = $fontSize;
  $this->fontWidth = imageFontWidth($fontSize);
  $this->fontHeight = imageFontHeight($fontSize);
  $this->graphX = 0;
  $this->graphY = 0;
  $this->graphWidth = $this->imgWidth;
  $this->graphHeight = $this->imgHeight;
  $this->setGrid();
 }
 
 function setTitle($title, $fontSize=3, $red=0x00, $green=0x00, $blue=0x00) {
  $this->titleString = $title;
  $this->titleFontSize = $fontSize;
  $this->cTitle = imageColorAllocate($this->img, $red, $green, $blue);
  $this->titleWidth = imageFontWidth($fontSize) * strLen($title);
  $this->titleHeight = imageFontHeight($fontSize);
  $this->graphY = $this->graphY + ($this->titleHeight + 2);
  $this->graphHeight = $this->graphHeight - ($this->titleHeight + 2);
 }
 
 function setDescription($x, $y="") {
  if ($x) {
   $this->xDesc = $x;
   $this->xDescLength = $this->fontWidth * strLen($x);
   $this->graphHeight = $this->graphHeight - ($this->fontHeight + 2);
  }
  
  if ($y) {
   $this->yDesc = $y;
   $this->yDescLength = $this->fontWidth * strLen($y);
   $this->graphX = $this->graphX + ($this->fontHeight + 2);
   $this->graphWidth = $this->graphWidth - ($this->fontHeight + 2);
  }
 }
 
 function setGrid($number=5, $red=0xCC, $green=0xCC, $blue=0xCC) { //Horizontal grid
  $this->cGrid = imageColorAllocate($this->img, $red, $green, $blue);
  $this->numberY = $number;
 }
 
 function addCategory($description, $red, $green, $blue) {
  $this->acPlot[$description] = imageColorAllocate($this->img, $red, $green, $blue);
  if (strLen($description) > $this->maxCatLen)
   $this->maxCatLen = strLen($description);
 }
 
 function categoryExists($description) {
  if (isSet($this->acPlot[$description])) {
   return true;
  } else {
   return false;
  }
 }
 
 function addItem($category, $description, $value) {
  $this->aItems[$category][$description] = $value;
  $this->checkItem($category, $description, $this->aItems[$category][$description]);
 }
 
 function incrementItem($category, $description, $value) {
  if (!isSet($this->aItems[$category][$description]))
   $this->addItem($category, $description, $value);
  $this->aItems[$category][$description] = $this->aItems[$category][$description] + $value;
  $this->checkItem($category, $description, $this->aItems[$category][$description]);
 }
 
 function checkItem($category, $description, $value) {
  if ($value > $this->maxVal)
   $this->maxVal = $value;
  $this->numItems[$category]++;
  if ($this->numItems[$category] > $this->maxNumItems)
   $this->maxNumItems = $this->numItems[$category];
  if (sizeOf(explode("n", $description)) > $this->maxLinesDesc)
   $this->maxLinesDesc = sizeOf(explode("n", $description));
 }
 
 function destroy() {
  imageDestroy($this->img);
 }
 
 function printGraph($filename = 0) {
  $this->graphHeight = $this->graphHeight - (($this->maxLinesDesc + 1) * ($this->fontHeight + 2)); //Adjust for bottom values
  $this->graphX = $this->graphX + ($this->fontWidth * strLen($this->maxVal) + 2); //Adjust left margin for values
  $this->graphWidth = $this->graphWidth - ($this->fontWidth * strLen($this->maxVal) + 2) - (($this->maxCatLen * $this->fontWidth) + 17) - (strLen($this->maxVal) * $this->fontWidth); //+17 = Adjust right margin for category descriptions
  imageRectangle($this->img, $this->graphX, $this->graphY, $this->graphX + $this->graphWidth, $this->graphY + $this->graphHeight, $this->cBlack); //Box
  if ($this->titleString)
   imageString($this->img, $this->titleFontSize, $this->graphX + ($this->graphWidth / 2) - ($this->titleWidth / 2), 0, $this->titleString, $this->cTitle);
  if ($this->xDesc)
   imageString($this->img, $this->fontSize, $this->graphX + ($this->graphWidth / 2) - ($this->xDescLength / 2), $this->graphY + $this->graphHeight + (($this->maxLinesDesc + 1) * ($this->fontHeight + 2)), $this->xDesc, $this->cBlack);
  if ($this->yDesc)
   imageStringUp($this->img, $this->fontSize, 0, ($this->graphY + ($this->graphHeight / 2)) + ($this->xDescLength / 2), $this->yDesc, $this->cBlack);
  
  for ($i = 0; $i <= $this->numberY; $i++) { //Grid
    $yPos = $this->graphY + $i * ($this->graphHeight / ($this->numberY + 1));
   if ($i)
    imageLine($this->img, $this->graphX+1, $yPos, $this->graphX + $this->graphWidth - 1, $yPos, $this->cGrid);
   $yVal = floor($this->maxVal - (($this->maxVal / ($this->numberY + 1)) * $i) + .5);
   imageString($this->img, $this->fontSize, $this->graphX - 3 - ($this->fontWidth * strLen($yVal)), $yPos - ($this->fontHeight / 2), $yVal, $this->cNavy);
  }
  
  imageString($this->img, $this->fontSize, $this->graphX - 3 - $this->fontWidth, $this->graphY + $this->graphHeight - ($this->fontHeight / 2), "0", $this->cNavy);
  
  $c = 0;
  while (list($cDesc, $cColor) = each($this->acPlot)) { //Loop through categories
   $s=0;
   while (list($sKey, $sVal) = each($this->aItems[$cDesc])) { //Loop through items
    $sum[$cDesc] += $sVal; //Sum up values for each category
    $xPos = ($this->graphX + 4) + ((($this->graphWidth - 10) / ($this->maxNumItems - 1)) * $s);
    $yPos = $this->graphY + ($this->graphHeight - floor((($sVal / $this->maxVal) * $this->graphHeight) + .5));
    imageRectangle($this->img, $xPos - 2, $yPos - 2, $xPos + 2, $yPos + 2, $cColor);
    if ($s)
     imageLine($this->img, $prevX, $prevY, $xPos, $yPos, $cColor);

    $aValues = explode("n", $sKey);
    for ($i = 0; $i < sizeOf($aValues); $i++) {
     imageString($this->img, $this->fontSize, $xPos - ((strLen($aValues[$i]) * $this->fontWidth) / 2), $this->graphY + $this->graphHeight + 2 + ($i * ($this->fontHeight + 2)), $aValues[$i], $this->cNavy); //Bottom values
    }
    $prevX = $xPos;
    $prevY = $yPos;
    $s++;
   }
   $boxX = $this->graphX + $this->graphWidth + 5;
   $boxY = $this->graphY + 10 + ($c * 15);
   imageFilledRectangle($this->img, $boxX, $boxY, $boxX + 10, $boxY + 10, $cColor);
   imageRectangle($this->img, $boxX, $boxY, $boxX + 10, $boxY + 10, $this->cBlack);
   imageString($this->img, $this->fontSize, $boxX + 14, ($boxY + 5) - ($this->fontHeight / 2), $cDesc."=".$sum[$cDesc], $cColor);
   $c++;
  }
  if ($filename) {
   imagePNG($this->img, "$filename.png");
  } else {
   imagePNG($this->img);
  }
 }
}


//Example -- comment this out if you want to use the class on other pages.
header ("Content-type: image/png");  #Line added to ensure image displays correctly in browser

$plot = new plot2D();
$plot->setTitle("John's spending habits");
$plot->setDescription("Days of the week", "Dollars spent");
$plot->setGrid();
$plot->addCategory("Food", 0xCC, 0x00, 0x00);
 $plot->addItem("Food", "sunn12/1", 152);
 $plot->addItem("Food", "monn12/2", 76);
 $plot->addItem("Food", "tuesn12/3", 81);
$plot->addCategory("Candy", 0x00, 0xCC, 0x00);
 $plot->addItem("Candy", "sunn12/1", 51);
 $plot->addItem("Candy", "monn12/2", 127);
 $plot->addItem("Candy", "tuesn12/3", 45);
$plot->printGraph();
$plot->destroy();
?>