display part of image

@ariellOct 09.2008 — #The following code is nothing special, but when you watch it carefully, you immediately get a glimpse how to handle the GD functions mentioned by scragar. In the example, you'll certainly need to replace image names (and pathes), but once you got that straight, you can play around with calling the code directly from a browser window. This script does all the stuff, such as copying, resizing, blending, bla, bla, bla...

[code=php]
 <?php	//	/_tools/xic/overlay/tab_lines_partofbg.php
 
  $imgpath		=	'../../../img/bg/';
 
  //	image usage name
  $usagename		=	'bg';		//	background
  if (@$_GET['un'])
   $usagename	=	$_GET['un'];
 
  //	corename for image
  $corename		=	'ovl';		//	overlay
  if (@$_GET['cn'])
   $corename	=	$_GET['cn'];
 
  //	spectrum name
  $specname		=	'tab';		//	table
  if (@$_GET['sn'])
   $specname	=	$_GET['sn'];
 
  //	source image dimensions, X1
  $startXOverlay	=	200;	//	relative to X1(sizeX)
  if (@$_GET['sox'])
   $startXOverlay = $_GET['sox'];
 
  //	source image dimensions, Y1
  $startYOverlay	=	5;	//	relative to Y1(sizeY)
  if (@$_GET['soy'])
   $startYOverlay = $_GET['soy'];
 
  //	new image dimensions, X1
  $sizeX			=	640;
  if (@$_GET['w'])
   $sizeX = $_GET['w'];
 
  //	new image dimensions, Y1
  $sizeY			=	350;
  if (@$_GET['h'])
   $sizeY = $_GET['h'];
 
  //	figutive "level" to qualify a number 
  //		(to define the distance between vertical lines in the grid)
  $units			=	0;
  if (@$_GET['u'])
   $units = $_GET['u'];
 
  //	transparancy 
  $opacity		=	70;	//	0 = 100% opaque, 127 = 100% transaparent
  if (@$_GET['o'])
   $opacity = $_GET['o'];
 
  //	color
  $RGB	=	array(127,127,192);
 
  if (@$_GET['rgb'])							{
   $t = explode('-', $_GET['rgb']);
   for ($i=0; $i < count($t); $i++)
   $RGB[$i] = $t[$i];
  }	//	RGB passed 
 
  $bgFile	=	'bg_cspace3_blended.png';
  if (@$_GET['bgfile'])
   $bgFile	=	$_GET['bgfile'];
 
  //	generate an appropriate file name
  //	@TODO define rules
  $newfile		=	$imgpath.'.'.$usagename.'.'.$corename.'.'.$specname.'-'; //	corepart of ilename
  $newfile		.=	'sox_'.$startXOverlay.'.soy_'.$startYOverlay.'.w_'.$sizeX.'.h_'.$sizeY.'.u_'.$units.'.o_'.$opacity;
  $newfile		.=	'.png'; 
 
  //	create canvas
  $img			=	imagecreatetruecolor($sizeX,$sizeY);
  imageantialias($img, true);
  imagealphablending($img, true);
 
  //	bg image (underneath overlay)
  $bgFile			=	$imgpath.$bgFile;
  $bgImage		=	imagecreatefrompng($bgFile);
  $dim			=	getimagesize($bgFile);
  //	calculate prospective remainings
  //		total width BG image - space between start and OVERLAY start - overlay total width
  $sizeXRemaining	=	($dim[0] - $startXOverlay - $sizeX); 
  //		total height BG image - space between start and OVERLAY start - overlay total height
  $sizeYRemaining	=	($dim[1] - $startYOverlay - $sizeY); 
 
 
  //	copy PART of image read from file onto destination image (the blend)
  imagecopyresized(
   /*destination image*/		$img,
   /*source image*/			$bgImage,
   /*destination coords*/		0, 0, 
   /*source STARTING coords*/	$startXOverlay, $startYOverlay,
   /*destination lengths*/		$sizeX, $sizeY,
   /*source lengths*/			$sizeX, $sizeY
  );
 
  //	draw the blueish areas ion the background image
  //		one for the chart, one for the title
  $background	=	imagecolorallocatealpha(
   /*resource image*/	$img, 
   /*R*/				$RGB[0], 
   /*G*/				$RGB[1], 
   /*B*/				$RGB[2], 
   /*alpha*/			$opacity
  );
 
  //	the actual tab
  imagefilledrectangle(
   /*resource image*/ 			$img, 
   /*coords*/ 					20, 20, 
   ($sizeX - 20), ($sizeY - 20), 
   /*(background-)color*/ 		$background
  );
 
  if ($units > 0)																					{	//	grid 
   //	the grid...
   //	color every second line black, the others grey
 
   //	define a color for "ONE" and "THEOTHER"
   $linecolor1		=	imagecolorallocate($img, 149, 160, 151);
   $linecolor2		=	imagecolorallocate($img, 138, 138, 138);
 
   //	get some cushion rules for our table
   //	figutive maximum on a 100 percent basis
   //	NOTE: UNITS stands for a picture line, thus 1/1000 px 
   $maxValue		=	8000;			//	NORMAL (LINES) TABLE 
   //$maxValue		=	($sizeY*1000);	//	RASTERED BG (-ONLY) TABLE, the more units, the more rastered
 
   for ($i=$units; $i < $maxValue; $i += $units)							{
 
   $x1		=	40;
   /*
   *	the more space you need UNDER the table lines, but WITHIN the image,
   * 	the more you need to increase $y1, i.e.:
   *  	$y1		=	( ($sizeY - 120 - ( ($i / $maxValue) * ($sizeY - 160) ) ) );
   * 	... and you have pleanty of space for a BOLD explanation on what you show on the image,
   * 	for instance, a GRAPH
   */
 
   $y1		=	( ($sizeY - 80 - ( ($i / $maxValue) * ($sizeY - 120) ) ) );
   $x2		=	($sizeX - 40);
   $y2		=	$y1;			//	take ($sizeY-40) and you have a falling gradiant!
 
   //	draw a graphical LINE
   imageline(
   /*resource image*/ 	$img, 
   /*coords*/ 			$x1, $y1, $x2, $y2,
   /*color*/ 			($i % (2 * $units)) == 0 ? $linecolor1 : $linecolor2
   );
   }	//	all units
  }	//	grid
 
  //	flush to browser
  header('Content-type: image/png');
 
  if (@$_GET['file'] != '')					{	//	supposed to be written to disk 
   if (@$_GET['file']=== '1')			{	//	use pre-formed name 
   $filename	=	$newfile;
   }	//	use pre-formed name
   else 								{	//	use passed name
   $filename 	= $imgpath.$_GET['file'].'.png';
   }	//	use passed name
   imagepng($img, $filename, 7, NULL);
  }	//	supposed to be written to disk 
 
  imagepng($img);
 
 ?>
 [/code]

P.S. This is tailored for *.png, but it's easy to change that, just see imageXXX functions in GD...

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display part of image

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