<?php
    # for reference on bands:
    # band01 = 1st sig digit 
    # band02 = 2nd sig digit
    # band03 = 3rd sig digit
    # band04 = multiplier
    # band05 = tolerance
    # band06 = tempCoeff
    #         _____________________________________
    # ________|__4_bands__|__5_bands__|__6_bands__|
    # band01  |_____X_____|_____X_____|_____X_____|
    # band02  |_____X_____|_____X_____|_____X_____|
    # band03  |___________|_____X_____|_____X_____|
    # band04  |_____X_____|_____X_____|_____X_____|
    # band05  |_____X_____|_____X_____|_____X_____|
    # band06  |___________|___________|_____X_____|
    
    header("Content-type: image/png");
    # based on the image width passed in, lets define some constants:
    #   image will be 1/4th as tall as wide;
    #   resistor will be 80% the image size, rounded rect with radius of corner = 1/4 resistor height
    #   stripe width will be width of resistor divided by 15
    $imageWidth = $_GET['size'];
    $numBands = $_GET['numBands'];
    $imageHeight = $imageWidth / 4;
    $txtHeight = $imageHeight / 2;
    $resWidth = ($imageWidth * 0.8);
    $resHeight = ($imageHeight * 0.8);
    $leadHeight = $resHeight / 8; 
    $leadY = ($imageHeight / 2) - ($leadHeight / 2);
    $resOffsetX = ($imageWidth - $resWidth) / 2;
    $resOffsetY = ($imageHeight - $resHeight) / 2;
    $resX1 = $resOffsetX;
    $resX2 = $imageWidth - $resOffsetX;
    $resY1 = $resOffsetY;
    $resY2 = $imageHeight - $resOffsetY;
    $resRad = $resHeight / 4;
    $resStripeWidth = $resWidth / ($numBands * 2.5); 
    $resStripTotWidths = $resStripeWidth * ( ($numBands * 2) - 1);
    $resStripeOffsetX = ($resWidth - $resStripTotWidths) / 2;
    $resStripeX1 = $resX1 +  $resStripeOffsetX;
    $resStripeX2 = $resStripeX1 + $resStripeWidth;
    $resStripeInc = $resStripeWidth * 2;
    $digit01 = $_GET['digit01'];
    $digit02 = $_GET['digit02'];
    $sigDigits = trim($digit01) . trim($digit02);
    if ($numBands > 4) {
      $digit03 = $_GET['digit03'];
      $sigDigits = trim($sigDigits) . trim($digit03);
    }
    $multiplier = $_GET['multiplier'];
    $totVal = $sigDigits * $multiplier;
    if ($totVal / 1000000 > 1) {
        $totVal = ($totVal / 1000000) . "M";
    } else if ($totVal / 1000 > 1 ) {
        $totVal = ($totVal / 1000) . "K";
    }
    $tolerance = $_GET['tolerance'];
    $outStr = $totVal . ", +/-" .  $tolerance . "%";
    if ($numBands > 5) {
        $tmpCoeff = $_GET['tmpCoeff'];
        $outStr = $outStr . ", " . $tmpCoeff . "PPM/C";  
    }
    #--------------------------------------- 
    $img_handle = imagecreatetruecolor($imageWidth,$imageHeight + $txtHeight);
    # define a font and get the biggest size that fits in our available space
    $dotFont = "images/OldSansBlack";
    $font_size = 33;
    do {
        $font_size--;
        $bbox=imagettfbbox ($font_size, 0, $dotFont, $outStr);
        $right_text = $bbox[2];    // right co-ordinate
        $left_text = $bbox[0];     // left co-ordinate
        $width_text = $right_text - $left_text;
        $height_text = abs($bbox[7] - $bbox[1]);
    } while ($height_text > $txtHeight || $width_text > $imageWidth );
    $textXOffset = ($imageWidth - $width_text) / 2;  
    # Define some colors
    $ResColor = ImageColorAllocate ($img_handle,255,255,205);
    $Black = ImageColorAllocate ($img_handle, 0,0,0);
    $Brown = ImageColorAllocate ($img_handle,105,50,50);
    $Red = ImageColorAllocate ($img_handle, 255,0,0);
    $Orange = ImageColorAllocate ($img_handle, 255,105,0);
    $Yellow = ImageColorAllocate ($img_handle,255,255,0);
    $Green = ImageColorAllocate ($img_handle, 50,205,50);
    $Blue = ImageColorAllocate ($img_handle, 105,105,255);
    $Violet = ImageColorAllocate ($img_handle, 255,105,255);
    $Grey = ImageColorAllocate ($img_handle, 145,145,145);
    $White = ImageColorAllocate ($img_handle, 255,255,255);
    $Silver = ImageColorAllocate ($img_handle, 205,205,205);
    $Gold = ImageColorAllocate ($img_handle, 205,155,50);
    $bandColors = array("0" => $Black, "1" => $Brown, "2" => $Red, "3" => $Orange, "4" => $Yellow, "5" => $Green, "6" => $Blue, "7" => $Violet, "8" => $Grey, "9" => $White);
    $multColors = array("0.01" => $Silver, "0.1" => $Gold, "1" => $Black, "10" => $Brown, "100" => $Red, "1000" => $Orange, "1K" => $Orange, "10K" => $Yellow, "100K" => $Green, "1000K" => $Blue, "1M" => $Blue );
    $tolColors = array("20" => $ResColor, "10" => $Silver, "5" => $Gold, "1" => $Brown, "2" => $Red); 
    $coeffColors = array("100" => $Brown, "50" => $Red, "15" => $Orange,"25" => $Yellow);
    $band01Color = $bandColors[$digit01];
    $band02Color = $bandColors[$digit02];
    if ($numBands > 4) {
        $band03Color = $bandColors[$digit03];
    }
    $band04Color = $multColors[$multiplier];
    $band05Color = $tolColors[$tolerance];
    if ($numBands > 5) {
        $band06Color = $coeffColors[$tmpCoeff];
    }
    # Fill background with white...
    imagefilledrectangle($img_handle,0,0,$imageWidth,$imageHeight + $txtHeight,$White);
    # Draw the resistor 
    ImageRectangleWithRoundedCorners($img_handle, $resX1,$resY1,$resX2,$resY2,$resRad,$ResColor);
    # Draw the leads
    imagefilledrectangle($img_handle,0, $leadY, $resX1 ,$leadY + $leadHeight, $Black);
    imagefilledrectangle($img_handle, $resX2, $leadY, $imageWidth ,$leadY + $leadHeight, $Black);
    # stripe01 - 1st digit
    imagefilledrectangle($img_handle, $resStripeX1, $resY1, $resStripeX2, $resY2, $band01Color); 
    # stripe02 - 2nd digit
    $resStripeX1 = $resStripeX1 + $resStripeInc;
    $resStripeX2 = $resStripeX2 + $resStripeInc;
    imagefilledrectangle($img_handle, $resStripeX1, $resY1, $resStripeX2, $resY2, $band02Color);
    # stripe03 - 3rd digit
    if ($numBands > 4) {
        $resStripeX1 = $resStripeX1 + $resStripeInc;
        $resStripeX2 = $resStripeX2 + $resStripeInc;
        imagefilledrectangle($img_handle, $resStripeX1, $resY1, $resStripeX2, $resY2, $band03Color);
    }
    # stripe04 - multiplier
    $resStripeX1 = $resStripeX1 + $resStripeInc;
    $resStripeX2 = $resStripeX2 + $resStripeInc;
    imagefilledrectangle($img_handle, $resStripeX1, $resY1, $resStripeX2, $resY2, $band04Color);
    # stripe05 - tolerance
    $resStripeX1 = $resStripeX1 + $resStripeInc;
    $resStripeX2 = $resStripeX2 + $resStripeInc;
    imagefilledrectangle($img_handle, $resStripeX1, $resY1, $resStripeX2, $resY2, $band05Color);
    # stripe06 - temp coEff
    if ($numBands > 5) {
        $resStripeX1 = $resStripeX1 + $resStripeInc;
        $resStripeX2 = $resStripeX2 + $resStripeInc;
        imagefilledrectangle($img_handle, $resStripeX1, $resY1, $resStripeX2, $resY2, $band06Color);
    }
    # bottom Text
    imagettftext($img_handle, $font_size, 0 , $textXOffset, ($imageHeight + $txtHeight - 5) , $Black, $dotFont, $outStr);
    imagepng($img_handle);
    imagedestroy($img_handle);  

  function ImageRectangleWithRoundedCorners(&$im, $x1, $y1, $x2, $y2, $radius, $color) {
      // draw rectangle without corners
      imagefilledrectangle($im, $x1+$radius, $y1, $x2-$radius, $y2, $color);
      imagefilledrectangle($im, $x1, $y1+$radius, $x2, $y2-$radius, $color);
      // draw circled corners
      imagefilledellipse($im, $x1+$radius, $y1+$radius, $radius*2, $radius*2, $color);
      imagefilledellipse($im, $x2-$radius, $y1+$radius, $radius*2, $radius*2, $color);
      imagefilledellipse($im, $x1+$radius, $y2-$radius, $radius*2, $radius*2, $color);
      imagefilledellipse($im, $x2-$radius, $y2-$radius, $radius*2, $radius*2, $color);
  }
?>