PHP image processing function examples and PHP verification code-PHP Tutorial-php.cn

//Prepare canvas
$im = imagecreatetruecolor(500, 300);
//Prepare paint
$black = imagecolorallocate( $im, 0, 0, 0);
$white = imagecolorallocate($im, 255, 255, 255);
//The background is filled with Black
imagefill($im,0,0, $black);
//Draw a rectangle and fill it with white
imagefilledellipse($im, 258, 151, 200, 200, $white );
//Output to the browser or save it
header("content-type:image/png");
//Output the image
imagepng($im);
// Close the canvas
imagedestroy($im);
?>

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php image processing function 1. Mathematical functions 2. Image processing function

Math functions: 1,max(); 2,min(); 3. mt_rand(); randomly pick a number

echomt_rand(1,5);
?>

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mt_rand randomly picks a value

//Randomly pick a value from an array
$arr = array("a","b","c","d","e ");
$rkey = mt_rand(0,count($arr)-1);
echo $arr[$rkey];
?> ;

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4.ceil(); ceiling 5.floor(); 6.round(); rounding

echo ceil(2.4);//3
echo floor(2.4);//2
echo round(2.4);//2
echo round(2.6 );//3
?>

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6.pi(); //π takes pi

echo(pi());
echo M_PI;
?>

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image processing function usage scenarios 1.Verification code 2.Zoom 3.Crop 4. Watermark

Five steps to create an image in PHP 1. Prepare the canvas 2. Prepare paint 3. Draw images or text on the canvas 4. Output the final image or Caocun final image 5. Release canvas resources

Example:

//1. Prepare canvas
$im = imagecreatetruecolor(500,300);
//2. Prepare paint
$black = imagecolorallocate($im, 0, 0 , 0);
$white = imagecolorallocate($im, 255, 255, 255);
//3. Draw images or text on the canvas
//If the background is not filled, the default It's black
imageellipse($im,258,151,200,200,$white);
//4. Output the final image or save the final image
header("content-type:image/png");
imagepng($im);
//5. Release canvas resources
imagedestroy($im);
?>

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Draw the image: imagefill(); imagesetpixel();//draw pixels imageline();//Draw line imagerectangle();//Draw a rectangle imagepolygon();//Draw a polygon imageellipse();//Draw an ellipse imageare(); draw an arc imagechar();//Draw a character horizontally imagestring();//Draw a line of string horizontally

Example:

//Draw lines
//1. Prepare canvas
$im = imagecreatetruecolor(500,300);
//2. Prepare paint
$black = imagecolorallocate($ im, 0, 0, 0);
$white = imagecolorallocate($im, 255, 255, 255);
//3. Draw images or text on the canvas
//If The background is not filled, the default is black
imageline($im,0,0,500,300,$white);
imageline($im,0,300,500,0,$white);
imageline($im,0,150,500,150,$white);
imageline( $im,250,0,250,300,$white);
//4. Output the final image or save the final image
header("content-type:image/png");
imagepng($ im);
//5. Release canvas resources
imagedestroy($im);
?>

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Example:

//Add interferon
//1. Prepare canvas
$im = imagecreatetruecolor(500,300);
//2. Prepare paint
$black = imagecolorallocate( $im, 0, 0, 0);
$white = imagecolorallocate($im, 255, 255, 255);
//3. Draw images or text on the canvas
// Generate random points
for ($i=0; $i < 1000; $i++) {
imagesetpixel($im,mt_rand(0,500),mt_rand(0,300),$white) ;
}
//Generate random lines
for ($j=0; $j < 100; $j++) {
imageline($ im, mt_rand(0,500), mt_rand(0,300), mt_rand(0,500), mt_rand(0,300), $white);
}//4. Output the final image or save the final image
header("content-type:image/png ");
imagepng($im);
//5. Release canvas resources
imagedestroy($im);
?>

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Example:

//Draw a rectangle:
//1. Prepare the canvas
$im = imagecreatetruecolor(500,300);
//2. Prepare the paint
$black = imagecolorallocate( $im, 0, 0, 0);
$white = imagecolorallocate($im, 255, 255, 255);
//3. Draw an image or text on the canvas
imagerectangle( $im, 20, 20, 480, 280, $white);//
imagefilledrectangle($im, 20, 20, 480, 280, $white);//Filling
// 4. Output the final image or save the final image
header("content-type:image/png");
imagepng($im);
//5. Release canvas resources
imagedestroy($im);
?> < ;/p>

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Example:

//imagepolygon draw polygon_draw triangle
//1. Prepare canvas
$im = imagecreatetruecolor(500,300);
//2. Prepare paint
$black = imagecolorallocate($im, 0, 0, 0);
$white = imagecolorallocate($im, 255, 255, 255);
//3. Draw images or text on the canvas
$arr = array(
250,20,
60,240,
440,240
);
imagepolygon($im, $arr, 3, $white);
//4. Output final image or save the final image
header("content-type:image/png");
imagepng($im);
//5. Release canvas resources
imagedestroy($im);
?>

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Example to draw a 3D pie chart

//1. Prepare canvas
$im = imagecreatetruecolor(500,300);
//2. Prepare paint
$black = imagecolorallocate($im, 0, 0 , 0);
$red = imagecolorallocate($im, 255, 0, 0);
$grayred = imagecolorallocate($im, 255, 100, 100);
$green = imagecolorallocate($im, 0, 255, 0 );
$blue = imagecolorallocate($im, 0, 0, 255);
$gray = imagecolorallocate($im, 200, 200, 200);
$white = imagecolorallocate($im, 255, 255, 255);
//3. Draw images or text on the canvas
for ($i=0; $i < 10; $i++) {
imagefilledarc($im, 250, 150+$ i, 200, 200, 0, 70, $gray,IMG_ARC_PIE);
imagefilledarc($im, 250, 150+$i, 200, 200, 70, 190, $grayred,IMG_ARC_PIE);
imagefilledarc($im, 250
}
imagefilledarc($im, 250, 150, 200, 200, 0, 70, $white,IMG_ARC_PIE);
imagefilledarc($im, 250, 150, 200, 200, 70, 190, $red,IMG_ARC_PIE);
imagefilledarc($im, 250, 150, 200, 200, 190, 270, $green,IMG_ARC_PIE);
imagefilledarc($im, 250, 150, 200, 200, 270, 360, $blue ,IMG_ARC_PIE);
//4. Output the final image or save the final image
header("content-type:image/png");
imagepng($im);
//5 .Release canvas resources
imagedestroy($im);
?>

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Example:

//Write text:
//1. Prepare canvas
$im = imagecreatetruecolor(500,300);
//2. Prepare paint
$black = imagecolorallocate( $im, 0, 0, 0);
$red = imagecolorallocate($im, 255, 0, 0);
$grayred = imagecolorallocate($im, 255, 100, 100);
$green = imagecolorallocate($im , 0, 255, 0);
$blue = imagecolorallocate($im, 0, 0, 255);
$gray = imagecolorallocate($im, 200, 200, 200);
$white = imagecolorallocate($im, 255 , 255, 255);
//3. Draw images or text on the canvas
$str= "PHP is very much";
imagestring($im, 5, 260, 160, $str, $green);
//4. Output the final image or save the final image
header("content-type:image/png") ;
imagepng($im);
//5. Release canvas resources
imagedestroy($im);
?>

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Example:

//Write a single character:
//1. Prepare canvas
$im = imagecreatetruecolor(500,300);
//2. Prepare paint
$black = imagecolorallocate ($im, 0, 0, 0);
$red = imagecolorallocate($im, 255, 0, 0);
$grayred = imagecolorallocate($im, 255, 100, 100);
$green = imagecolorallocate($ im, 0, 255, 0);
$blue = imagecolorallocate($im, 0, 0, 255);
$gray = imagecolorallocate($im, 200, 200, 200);
$white = imagecolorallocate($im, 255, 255, 255);
//3. Draw images or text on the canvas
$str= "P";
imagechar($im, 5, 260, 160, $str, $green);
//4. Output the final image or save the final image
header("content-type:image/png");
imagepng($im);
//5. Release canvas resources
imagedestroy($im);
?>

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Example,

//Write on the picture
//1. Prepare the canvas
$im = imagecreatetruecolor(500,300);
//2. Prepare the paint
$black = imagecolorallocate ($im, 0, 0, 0);
$red = imagecolorallocate($im, 255, 0, 0);
$grayred = imagecolorallocate($im, 255, 100, 100);
$green = imagecolorallocate($ im, 0, 255, 0);
$blue = imagecolorallocate($im, 0, 0, 255);
$gray = imagecolorallocate($im, 200, 200, 200);
$white = imagecolorallocate($im, 255, 255, 255);
//3. Draw images or text on the canvas
$str= "junzaivip";
$file = " E:/PHP/fonts/SIMYOU.TTF";
// $file = "fonts/SIMYOU.TTF";
imagettftext($im, 50, 0, 100, 200, $ green, $file, $str);
//4. Output the final image or save the final image
header("content-type:image/png");
imagepng($im) ;
//5. Release canvas resources
imagedestroy($im);
?>

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PHP verification code design

//Prepare canvas
$im = imagecreatetruecolor(100,50);
//Prepare paint
$black = imagecolorallocate($im, 0, 0, 0 );
$gray = imagecolorallocate($im, 200, 200, 200);
//Fill the background
imagefill($im, 0, 0, $gray);
//Text coordinates
$x = (100-4*20)/2 + 6;
$y = (50-20)/2 + 20;
//Draw images or text on the canvas
//Connect three arrays
$strarr = array_merge(range(1, 9),range(a, z),range(A , Z));
//Shuffle the array
shuffle($strarr);
//array_slice: Take the first few digits of the array
// Join turns the array into a string, and uses the first variable as the delimiter
$str = join('',array_slice($strarr, 0,4));
$file = "E:/PHP/fonts/msyh.ttf";
// $file = "fonts/msyh.ttf";
imagettftext($im, 20, 0, $x, $ y, $black, $file, $str);
//Output the final image or save the final image
header("content-type:image/png");
imagepng($im );
//Release canvas resources
imagedestroy($im);
?>

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php verification code design: This involves two pages: index.php & reg.php Description:

This verification code version only implements dynamic acquisition of verification images Compare the verification code on the front-end registration page with the verification code on the generated image The verification code is randomly composed of numbers, lowercase letters, and uppercase letters

index.php//Realize user registration

reg
User registration page
< td>

Name:

Password:

Verification code:

< ;/p>

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reg.php//Used to verify whether the verification code is correct

session_start();
// echo $_POST['username'];
// echo $_POST['password'];
$code = strtolower( $_POST['vcode']);
// echo $code;

// echo "

"; </li>
<li>// print_r( $_SESSION); </li>
<li>// echo "

$vstr = strtolower($_SESSION['vstr']);
if ($code==$vstr) {
//Realize page jump
echo "<script>location='http://www.xingzuo51.com'</script>";
}else{
echo "<script>alert(' Verification code input error')</script>";
//echo "Return to registration page";
echo "<script>location=' index.php'</script>";
}
?>

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auth.php is used to generate verification codes

//Open session, there cannot be any output before opening session
session_start();
$width = 50; //Verification code background width
$height = 26; //Verification code background high speed
$fonttype = 10; //Verification code font size
//Prepare canvas
$im = imagecreatetruecolor($width,$height);
//Prepare paint
$black = imagecolorallocate($im, 0, 0, 0);
$gray = imagecolorallocate($im, 200, 200, 200);
//Fill the background
imagefill($im, 0, 0, $gray);
//Text coordinates
$x = ($width-4*$fonttype)/2 +2;
$y = ($height-$fonttype)/2 + $fonttype;
//Draw images or text on the canvas
//Connect three arrays
$strarr = array_merge(range(1, 9),range(a, z),range(A, Z));
//Shuffle the array
shuffle($strarr);
($strarr, 0,4));
//Put $str into session to facilitate use on all pages
$_SESSION['vstr'] = $str;
$file = "E:/PHP/fonts/msyh.ttf";
// $file = "fonts/msyh.ttf";
imagettftext($ im, $fonttype, 0, $x, $y, $black, $file, $str);
//Output the final image or save the final image
header("content-type: image/png");
imagepng($im);
//Release canvas resources
imagedestroy($im);
?>
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php verification code design: Page jump: 1.php jump

$im = imagecreatefromjpeg("lyf.jpg");

$x = imagesx($im);
$y = imagesy($im);
echo $x . $y;
exit;
header("content-type:image/jpeg");
imagejpeg($im);
?>
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Method 2 to get the size of the image:

$imgfile = "lyf.jpg";

$imgarr = getimagesize($imgfile);

echo "

"; </li>
<li>print_r($imgarr); </li>
<li>echo "

exit;
echo $x . $y;
header("content-type:image/jpeg ");
imagejpeg($im);
?>
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Image zoom function:

$imgfile = "lyf.jpg";
//In order to get the width and height of the large image
$imgarr = getimagesize( $imgfile);
$maxw = $imgarr[0];
$maxh = $imgarr[1];
$maxt = $imgarr[2];
$maxm = $imgarr[ 'mime'];
//In order to turn large images into resources
$im = imagecreatefromjpeg("lyf.jpg");
//Small image resources
$minw = 100;
$minh = 400;
//Equal scaling
if (($minw/$maxw)> ;($minh/$maxh)) {
$rate = $minh/$maxh ;
}else{
$rate = $minw / $maxw ;
}
$minw = floor ($maxw * $rate);
$minh = floor($maxh * $rate);
$minim = imagecreatetruecolor($minw, $minh);
//Zoom the large image Into a small image
imagecopyresampled($minim, $im, 0, 0, 0, 0, $minw, $minh, $maxw, $maxh);
//Small image output
header ("content-type:{$maxm}");
//Determine the type
switch ($maxt) {
case 1:
$imageout = "imagegif";
break;
case 2:
$imageout = "imagejpeg";
break;
case 3:
$imageout = "imagepng";
break;
}
$imageout($minim);
$minfilename = "s_".$imgfile;
$imageout($minim,$minfilename);
// imagejpeg($im);
/ /Release resources
imagedestroy($maxim);
imagedestroy($minim);
?>

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Image cropping function: imagecopyresampled();

Image watermark function: imagecopy();

3, Crop

4, watermark

$maxim = imagecreatefromjpeg("lyf.jpg");
$minim = imagecreatefromjpeg("lyf.jpg");
$maxh = imagesy($maxim);
$minw = imagesx($minim);
$minh = imagesy($minim); < ;/p>
imagecopy($maxim, $minim, $maxw-$minw, $maxh-$minh, 0, 0, $minw, $minh);
header("content-type:image/jpeg");
imagejpeg($mamim);
?>

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PHP image processing function examples and PHP verification code

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