PHP image processing function examples and PHP verification code

//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);
?>

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);
?>

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];
?> ;

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
?>

6.pi(); //π takes pi

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

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);
?>

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);
?>

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; $i
imagesetpixel($im,mt_rand(0,500),mt_rand(0,300),$white) ;
}
//Generate random lines
for ($j=0; $j imageline($ 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);
?>

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>

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);
?>

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; $i imagefilledarc($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  p>
}
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);
?>