Summary 8 : PHP Graphics, Image Processing
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1. 선 그리기

   boolean imageline(integer image, integer start_x, integer start_y, integer end_x,
        integer end_y, integer color)

<?php
   header("Content-type: image/gif");
   $image=imagecreate(200,200);
   $colorWhite=imagecolorallocate($image,255,255,255);
   $colorMagenta=imagecolorallocate($image,255,0,255);
   imagefill($image,0,0,$colorWhite);
   imageline($image,50,60,150,160,$colorMagenta);
   imageline($image,150,60,50,160,$colorMagenta);
   imagegif($image);
?>


2. 원 그리기

   boolean imagearc(integer image, integer center_x, integer center_y,
        integer width, integer height, integer start, integer end, integer color)
     // 호(arc) 그림

<?php
   header("Content-type: image/gif");
   $image=imagecreate(200,200);
   $colorWhite=imagecolorallocate($image,255,255,255);
   $colorMagenta=imagecolorallocate($image,255,0,255);
   imagefill($image,0,0,$colorWhite);
   imagearc($image,100,100,80,80,0,360,$colorMagenta);
   imagegif($image);
?>

<?php
   header("Content-type: image/gif");
   $image=imagecreate(200,200);
   $colorWhite=imagecolorallocate($image,255,255,255);
   $colorMagenta=imagecolorallocate($image,255,0,255);
   $colorBlue=imagecolorallocate($image,0,0,255);
   imagefill($image,0,0,$colorWhite);
   imagearc($image,100,100,100,100,0,360,$colorMagenta);
   imagearc($image,100,100,70,70,0,80,$colorBlue);
   imagegif($image);
?>

  * 채워진 원 그리기

   boolean imagefilledarc ( resource $image , int $cx , int $cy , int $width ,
          int $height , int $start , int $end , int $color , int $style )

   $style : A bitwise OR of the following possibilities: 

   1. IMG_ARC_PIE 
   2. IMG_ARC_CHORD 
   3. IMG_ARC_NOFILL 
   4. IMG_ARC_EDGED 

<?php
   header("Content-type: image/gif");
   $image=imagecreate(200,200);
   $colorWhite=imagecolorallocate($image,255,255,255);
   $colorMagenta=imagecolorallocate($image,255,0,255);
   imagefill($image,0,0,$colorWhite);
   imagefilledarc($image,100,100,80,80,0,360,$colorMagenta,IMG_ARC_PIE);
   imagegif($image);
?>

  * 여러개의 채워진 동심원 그리기
<?php
  header("Content-type: image/gif");
  $image=imagecreate(500,500);
  $c[0] = imagecolorallocate($image,255,255,255);
  imagefill($image,0,0,$c[0]);
  $c[1] = imagecolorallocate($image,255,0,0);
  $c[2] = imagecolorallocate($image,0,255,0);
  $c[3] = imagecolorallocate($image,0,0,255);
  $c[4] = imagecolorallocate($image,255,255,0);
  $c[5] = imagecolorallocate($image,255,0,255);
  $c[6] = imagecolorallocate($image,0,255,255);
  $c[7] = imagecolorallocate($image,0,0,0);
  for($i=6;$i>0;$i--) {
    $s = $i*80;
    imagefilledarc($image,250,250,$s,$s,0,360,$c[$i],
       IMG_ARC_PIE);
  }
  imagegif($image);
?>


3. 사각형 그리기

   imagerectangle(integer image, integer top_left_x, integer top_left_y, integer
       bottom_right_x, integer bottom_right_y, integer color)
     // 직사각형

<?php // image rectangle
  header("Content-type: image/gif");
  $size = 300;
  $im=imagecreate($size,$size);
  $wh = imagecolorallocate($im,255,255,255);
  $black = imagecolorallocate($im,0,0,0);
  imagefill($im,0,0,$wh);
  imagerectangle($im,70,70,230,230,$black);
  imagegif($im);
?>

  * 채워진 사각형(여러개 동심)

   imagefilledrectangle(integer image, integer top_left_x, integer top_left_y,
           integer bottom_right_x, integer bottom_right_y, integer color)
     //  색으로 채워진 직사각형

<?php
  header("Content-type: image/gif");
  $size = 500;
  $n = 8;
  $image=imagecreate($size,$size);
  $c[0] = imagecolorallocate($image,255,255,255);
  imagefill($image,0,0,$c[0]);
  $c[1] = imagecolorallocate($image,255,0,0);
  $c[2] = imagecolorallocate($image,0,255,0);
  $c[3] = imagecolorallocate($image,0,0,255);
  $c[4] = imagecolorallocate($image,255,255,0);
  $c[5] = imagecolorallocate($image,255,0,255);
  $c[6] = imagecolorallocate($image,255,255,0);
  $c[7] = imagecolorallocate($image,0,255,255);
  $c[8] = imagecolorallocate($image,0,0,0);
  $cc = $size/2;
  $rs = intval($size/$n);
  for($i=$n; $i>0; $i--) {
    $s = $cc - $i*$rs/2;
    $e = $cc + $i*$rs/2;
    imagefilledrectangle($image,$s,$s,$e,$e,$c[$i]);
  }
  imagegif($image);
?>


4. 색 채우기

   boolean imagefill(integer image, integer x, integer y, integer color)
     // 지정된 색으로 채우기


<?php // image collored rectangles
// look at the difference between imagefill & imagefilledrectangle
  header("Content-type: image/gif");
  $size = 300;
  $im=imagecreate($size,$size);
  $wh = imagecolorallocate($im,255,255,255);
  $re = imagecolorallocate($im,255,0,0);
  $ye = imagecolorallocate($im,255,255,0);
  $bl = imagecolorallocate($im,0,0,255);
  $gr = imagecolorallocate($im,0,255,0);
  $black = imagecolorallocate($im,0,0,0);
  imagefill($im,0,0,$wh);
  imagerectangle($im,0,0,299,299,$black);
  imagefilledrectangle($im,30,30,$size-30,$size-30,$bl);
  imagerectangle($im,90,90,210,210,$black);
  imagefill($im,150,150,$gr);
  imagerectangle($im,150,170,230,230,$black);
  imagefill($im,151,195,$re);
  imagefilledrectangle($im,15,50,160,130,$ye);
  imagegif($im);
?>


5. 문자(글자)열 넣기

   boolean imagestring(integer image, integer font, integer x, integer y, string text, integer color)
     // 문자열 넣기

<?php
  header("Content-type: image/gif");
  $size = 500;
  $n = 8;
  $image=imagecreate($size,$size);
  $c[0] = imagecolorallocate($image,255,255,255);
  imagefill($image,0,0,$c[0]);
  $c[1] = imagecolorallocate($image,255,0,0);
  $c[2] = imagecolorallocate($image,0,255,0);
  $c[3] = imagecolorallocate($image,0,0,255);
  $c[4] = imagecolorallocate($image,255,255,0);
  $c[5] = imagecolorallocate($image,255,0,255);
  $c[6] = imagecolorallocate($image,255,255,0);
  $c[7] = imagecolorallocate($image,0,255,255);
  $c[8] = imagecolorallocate($image,0,0,0);
  $cc = $size/2;
  $rs = intval($size/$n);
  for($i=$n; $i>0; $i--) {
    $s = $cc - $i*$rs/2;
    $e = $cc + $i*$rs/2;
    imagefilledrectangle($image,$s,$s,$e,$e,$c[$i]);
  }
  imagestring($image,5,5,5,"Computer Science",$c[0]);
  
  imagegif($image);
?>

<?php //ipimg.php
$img_number = imagecreate(140,25);
$backcolor = imagecolorallocate($img_number,255,255,255);
$textcolor = imagecolorallocate($img_number,50,104,28);

imagefill($img_number,0,0,$backcolor);
$number = "IP - $_SERVER[REMOTE_ADDR]";

Imagestring($img_number,3,0,5,$number,$textcolor);

header("Content-type: image/jpeg");
imagejpeg($img_number);
?>


6. 다각형 그리기

   boolean imagepolygon(integer image, array points, integer number, integer color)
     //	다각형 그리기

   boolean imagefilledpolygon(integer image, array points, integer number, integer color)
     //	채워진 다각형


7. 지정된 그림으로부터 이미지 불러오기, 편집

   지정된 크기의 이미지 생성, 아래는 그림으로부터 생성.

   integer imagecreatefromjpeg(string filename)

   integer imagecreatefromgif(string filename)

   integer imagecreatefrompng(string filename)


8. Truefont 이용

   array imagettfbbox ( float $size , float $angle , string $fontfile , string $text )
   This function calculates and returns the bounding box in pixels for a TrueType text. 

size : The font size. Depending on your version of GD, this should be specified as the pixel size (GD1) or point size (GD2). 

angle :
Angle in degrees in which text will be measured. 

fontfile : The name of the TrueType font file (can be a URL). Depending on which version of the GD library that PHP is using, it may attempt to search for files that do not begin with a leading '/' by appending '.ttf' to the filename and searching along a library-defined font path. 

text : The string to be measured. 

Report a bug Return Values
imagettfbbox() returns an array with 8 elements representing four points making the bounding box of the text on success and FALSE on error. key contents 
0 lower left corner, X position 
1 lower left corner, Y position 
2 lower right corner, X position 
3 lower right corner, Y position 
4 upper right corner, X position 
5 upper right corner, Y position 
6 upper left corner, X position 
7 upper left corner, Y position 

The points are relative to the text regardless of the angle, so "upper left" means in the top left-hand corner seeing the text horizontally. 

<?php
        header("Content-type: image/png");
        $image = imagecreate(200, 200);

        $size = 40;
        $angle = 30;
        $startX = 50;
        $startY = 100;

        // flood square with red
        $colorRed = imagecolorallocate($image, 0xFF, 0x00, 0x00);
        imagefill($image, 10, 10, $colorRed);

        $colorBlack = imagecolorallocate($image, 0, 0, 0);

        //get bounding box
        $Box = imagettfbbox($size, $angle, "GOTHIC.TTF", "PHP");

        //move bounding box to starting point (100,100)
        for($index = 0; $index < count($Box); $index += 2) {
                $Box[$index] += $startX;
                $Box[$index+1] += $startY;
//print("$Box[$index]  $Box[$index+1]");
        }

        //draw bounding box
        imagepolygon($image, $Box, count($Box)/2, $colorBlack);

        imagettftext($image, $size, $angle, 
                $startX, $startY, $colorBlack, 
                "GOTHIC.TTF", "PHP");

        imagepng($image);

?>


9. 이미지 회전 : 이미지를 주어진 각도 만큼 회전(시계방향)

   $newimage = imagerotate($image, $angle, $bgColour);

   $image=원본 이미지, $angle=회전 각도, $bgColour=배경색



10. 예제 프로그램

   http://jongp.com/php/gr
   http://info.skuniv.ac.kr/~jong/php/ex/gr

1) 정사각형 반복 그리기

<?php // image squares1b.php
// 
  header("Content-type: image/gif");
  $size = 300;
  $ns = 5; // the nuumber of squares
  $inc = $size / $ns; // increment size
  $im=imagecreate($size,$size);
  $wh = imagecolorallocate($im,255,255,255);
  $re = imagecolorallocate($im,255,0,0);
  $ye = imagecolorallocate($im,255,255,0);
  $bl = imagecolorallocate($im,0,0,255);
  $gr = imagecolorallocate($im,0,255,0);
  $black = imagecolorallocate($im,0,0,0);
  imagefill($im,0,0,$wh);
  for ($i=0; $i<$ns; $i++) {
    $p1 = $i * $inc;
    $p2 = $p1 + $inc;
    imagerectangle($im,$p1,$p1,$p2,$p2,$bl);
//    imagefilledrectangle($im,$p1,$p1,$p2,$p2,$bl);
  }
  imagerectangle($im,0,0,$size-1,$size-1,$black);
  imagegif($im);
?>

2) 색깔을 달리하여 정사각형 반복 그리기

<?php // image squares1e.php
// 
  header("Content-type: image/gif");
  $size = 300;
  $ns = 6; // the nuumber of squares
  $inc = $size / $ns; // increment size
  $im=imagecreate($size,$size);
  $c = array();
  $c[0] = imagecolorallocate($im,0,0,0);
  $c[1] = imagecolorallocate($im,255,255,255);
  $c[2] = imagecolorallocate($im,255,0,0);
  $c[3] = imagecolorallocate($im,255,255,0);
  $c[4] = imagecolorallocate($im,0,0,255);
  $c[5] = imagecolorallocate($im,0,255,0);
  imagefill($im,0,0,$c[1]);
  for ($i=0; $i<$ns; $i++) {
    for ($j=0; $j<$ns; $j++) {
      $p1x = $j * $inc;
      $p1y = $i * $inc;
      $p2x = $p1x + $inc;
      $p2y = $p1y + $inc;
      $cc = $c[($i+$j)%6];
      imagefilledrectangle($im,$p1x,$p1y,$p2x,$p2y,$cc);
    }
  }
  imagerectangle($im,0,0,$size-1,$size-1,$c[0]);
  imagegif($im);
?>