PHP 7.1.0 Released

Funções da GD

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User Contributed Notes 9 notes

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8
shd at earthling dot net
10 years ago
If you happen to need a way to output a Windows BMP file (e.g. when using the PEAR ExcelWriter), feel free to use the following code:

<?php
function imagebmp ($im, $fn = false)
{
    if (!
$im) return false;
           
    if (
$fn === false) $fn = 'php://output';
   
$f = fopen ($fn, "w");
    if (!
$f) return false;
           
   
//Image dimensions
   
$biWidth = imagesx ($im);
   
$biHeight = imagesy ($im);
   
$biBPLine = $biWidth * 3;
   
$biStride = ($biBPLine + 3) & ~3;
   
$biSizeImage = $biStride * $biHeight;
   
$bfOffBits = 54;
   
$bfSize = $bfOffBits + $biSizeImage;
           
   
//BITMAPFILEHEADER
   
fwrite ($f, 'BM', 2);
   
fwrite ($f, pack ('VvvV', $bfSize, 0, 0, $bfOffBits));
           
   
//BITMAPINFO (BITMAPINFOHEADER)
   
fwrite ($f, pack ('VVVvvVVVVVV', 40, $biWidth, $biHeight, 1, 24, 0, $biSizeImage, 0, 0, 0, 0));
           
   
$numpad = $biStride - $biBPLine;
    for (
$y = $biHeight - 1; $y >= 0; --$y)
    {
        for (
$x = 0; $x < $biWidth; ++$x)
        {
           
$col = imagecolorat ($im, $x, $y);
           
fwrite ($f, pack ('V', $col), 3);
        }
        for (
$i = 0; $i < $numpad; ++$i)
           
fwrite ($f, pack ('C', 0));
    }
   
fclose ($f);
    return
true;
}
?>

It works the same way as regular imagejpeg/imagepng do and only supports GD2.0 true colour bitmaps (which is what's required by ExcelWriter).
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7
michal-ok at o2 dot pl
11 years ago
The image sharpen function (by Alex R. Austin) provided below seems to be very resource hungry and I couldn't make it work on two different servers - trying to sharpen a 413 x 413 image I ended up with "Fatal error: Allowed memory size of 8388608 bytes exhausted" or "Internal Server Error" or the script terminated without notice. Because I had no priviliges to change the default memory limit on these servers I started looking for other sharpen functions. I have come across a php Unsharp Mask function which works like a charm on both of the servers I dealt with. It can be found at http://vikjavev.no/hovudsida/umtestside.php.
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5
ingo at jache dot de
5 years ago
I know this might look somewhat superfluous to others, but i once came across a situation where i needed a *strong* blur on an image without having ImageMagick installed. Executing the convolution-filter several times on the same image is awfully slow and still doesn't give a good blur.

The function below accepts a truecolor-image and a blur-factor between 0.0 and 1.0. Beware: It's still quite slow.

<?php

   
function blurImage($srcimg,$blur)
    {
       
$blur = $blur*$blur;
       
$blur = max(0,min(1,$blur));
   
       
$srcw = imagesx($srcimg);
       
$srch = imagesy($srcimg);
       
       
$dstimg = imagecreatetruecolor($srcw,$srch);
   
       
$f1a = $blur;
       
$f1b = 1.0 - $blur;

   
       
$cr = 0; $cg = 0; $cb = 0;
       
$nr = 0; $ng = 0; $nb = 0;

       
$rgb = imagecolorat($srcimg,0,0);
       
$or = ($rgb >> 16) & 0xFF;
       
$og = ($rgb >> 8) & 0xFF;
       
$ob = ($rgb) & 0xFF;

       
//-------------------------------------------------
        // first line is a special case
        //-------------------------------------------------
       
$x = $srcw;
       
$y = $srch-1;
        while (
$x--)
        {
           
//horizontal blurren
           
$rgb = imagecolorat($srcimg,$x,$y);
           
$cr = ($rgb >> 16) & 0xFF;
           
$cg = ($rgb >> 8) & 0xFF;
           
$cb = ($rgb) & 0xFF;
   
           
$nr = ($cr * $f1a) + ($or * $f1b);
           
$ng = ($cg * $f1a) + ($og * $f1b);
           
$nb = ($cb * $f1a) + ($ob * $f1b);   

           
$or = $nr;
           
$og = $ng;
           
$ob = $nb;
           
           
imagesetpixel($dstimg,$x,$y,($nr << 16) | ($ng << 8) | ($nb));
        }
       
//-------------------------------------------------

        //-------------------------------------------------
        // now process the entire picture
        //-------------------------------------------------
       
$y = $srch-1;
        while (
$y--)
        {

           
$rgb = imagecolorat($srcimg,0,$y);
           
$or = ($rgb >> 16) & 0xFF;
           
$og = ($rgb >> 8) & 0xFF;
           
$ob = ($rgb) & 0xFF;

           
$x = $srcw;
            while (
$x--)
            {
               
//horizontal
               
$rgb = imagecolorat($srcimg,$x,$y);
               
$cr = ($rgb >> 16) & 0xFF;
               
$cg = ($rgb >> 8) & 0xFF;
               
$cb = ($rgb) & 0xFF;
               
               
$nr = ($cr * $f1a) + ($or * $f1b);
               
$ng = ($cg * $f1a) + ($og * $f1b);
               
$nb = ($cb * $f1a) + ($ob * $f1b);   
   
               
$or = $nr;
               
$og = $ng;
               
$ob = $nb;
               
               
               
//vertical
               
$rgb = imagecolorat($dstimg,$x,$y+1);
               
$vr = ($rgb >> 16) & 0xFF;
               
$vg = ($rgb >> 8) & 0xFF;
               
$vb = ($rgb) & 0xFF;
               
               
$nr = ($nr * $f1a) + ($vr * $f1b);
               
$ng = ($ng * $f1a) + ($vg * $f1b);
               
$nb = ($nb * $f1a) + ($vb * $f1b);   
   
               
$vr = $nr;
               
$vg = $ng;
               
$vb = $nb;
               
               
imagesetpixel($dstimg,$x,$y,($nr << 16) | ($ng << 8) | ($nb));
            }
       
        }
       
//-------------------------------------------------
       
return $dstimg;       

    }

   
   
$srcimg = imagecreatefromjpeg("test.jpg");
   
$dstimg = blurImage($srcimg,0.2);

   
header('Content-type: image/jpeg');
    echo(
imagejpeg($dstimg) );
    exit();
   
   
?>
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5
felipensp at gmail dot com
10 years ago
Representation decimal of a color in hexadecimal for use on functions of library GD.

<?php

   
// Representation hexadecimal
   
$var = '#FFFFFF';

    function
getRgbFromGd($color_hex) {

        return
array_map('hexdec', explode('|', wordwrap(substr($color_hex, 1), 2, '|', 1)));

    }
   
   
print_r(getRgbFromGd($var));

   
// Output: Array ( [0] => 255 [1] => 255 [2] => 255 )

?>
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4
jeff at lushmedia dot com
13 years ago
I wrote an online overview of the image functions that people might find useful. In addition to a general overview of the various function categories and code samples, I have included many interactive examples of the functions, allowing viewers to experiment with the parameters, and seeing the results in real time. The presentation is located at New York PHP
http://www.nyphp.org/content/presentations/GDintro/
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2
mpyw
26 days ago
This is an example of black-and-white imagebmp() implementation.

<?php

/**
* Output a black-and-white BMP image to either the browser or a file.
*
* @param resource $image
*            An image resource, returned by one of the image creation functions,
*            such as imagecreatetruecolor().
*
* @param string|null $to
*            The path or an open stream resource
*            (which is automatically being closed after this function returns)
*            to save the file to.
*            If not set or NULL, the raw image stream will be outputted directly.
*
* @param float $threshold
*            The number in the range of 0.0 to 1.0.
*            Brighter for larger, or darker for smaller.
*
* @return bool Returns TRUE on success or FALSE on failure.
*
*/
function imagebwbmp($image, $to = null, $threshold = 0.5)
{
    if (
func_num_args() < 1) {
       
$fmt = "imagebwbmp() expects a least 1 parameters, %d given";
       
trigger_error(sprintf($fmt, func_num_args()), E_USER_WARNING);
        return;
    }
    if (!
is_resource($image)) {
       
$fmt = "imagebwbmp() expects parameter 1 to be resource, %s given";
       
trigger_error(sprintf($fmt, gettype($image)), E_USER_WARNING);
        return;
    }
    if (!
is_numeric($threshold)) {
       
$fmt = "imagebwbmp() expects parameter 3 to be float, %s given";
       
trigger_error(sprintf($fmt, gettype($threshold)), E_USER_WARNING);
        return;
    }

    if (
get_resource_type($image) !== 'gd') {
       
$msg = "imagebwbmp(): supplied resource is not a valid gd resource";
       
trigger_error($msg, E_USER_WARNING);
        return
false;
    }
    switch (
true) {
        case
$to === null:
            break;
        case
is_resource($to) && get_resource_type($to) === 'stream':
        case
is_string($to) && $to = fopen($to, 'wb'):
            if (
preg_match('/[waxc+]/', stream_get_meta_data($to)['mode'])) {
                break;
            }
        default:
           
$msg = "imagebwbmp(): Invalid 2nd parameter, it must a writable filename or a writable stream";
           
trigger_error($msg, E_USER_WARNING);
            return
false;
    }

    if (
$to === null) {
       
$to = fopen('php://output', 'wb');
    }

   
$biWidth = imagesx($image);
   
$biHeight = imagesy($image);
   
$biSizeImage = ((int)ceil($biWidth / 32) * 32 / 8 * $biHeight);
   
$bfOffBits = 54 + 4 * 2; // Use two colors (black and white)
   
$bfSize = $bfOffBits + $biSizeImage;
   
   
fwrite($to, 'BM');
   
fwrite($to, pack('VvvV', $bfSize, 0, 0, $bfOffBits));
   
fwrite($to, pack('VVVvvVVVVVV', 40, $biWidth, $biHeight, 1, 1, 0, $biSizeImage, 0, 0, 0, 0));
   
fwrite($to, "\xff\xff\xff\x00"); // white
   
fwrite($to, "\x00\x00\x00\x00"); // black
   
   
for ($y = $biHeight - 1; $y >= 0; --$y) {
       
$byte = 0;
        for (
$x = 0; $x < $biWidth; ++$x) {
           
$rgb = imagecolorsforindex($image, imagecolorat($image, $x, $y));
           
$value = (0.299 * $rgb['red'] + 0.587 * $rgb['green'] + 0.114 * $rgb['blue']) / 0xff;
           
$color = (int)($value > $threshold);
           
$byte = ($byte << 1) | $color;
            if (
$x % 8 === 7) {
               
fwrite($to, pack('C', $byte));
               
$byte = 0;
            }
        }
        if (
$x % 8) {
           
fwrite($to, pack('C', $byte << (8 - $x % 8)));
        }
        if (
$x % 32) {
           
fwrite($to, str_repeat("\x00", (int)((32 - $x % 32) / 8)));
        }
    }

    return
true;
}
?>
up
4
chuckstudios at gmail dot com
8 years ago
I wrote a simple function to convert an image resource to PGM (portable graymap) in order to feed it to an OCR program. It works just like the rest of the image output functions, and will convert to grayscale for you:

<?php
   
function imagepgm($image, $filename = null)
    {
       
$pgm = "P5 ".imagesx($image)." ".imagesy($image)." 255\n";
        for(
$y = 0; $y < imagesy($image); $y++)
        {
            for(
$x = 0; $x < imagesx($image); $x++)
            {
               
$colors = imagecolorsforindex($image, imagecolorat($image, $x, $y));
               
$pgm .= chr(0.3 * $colors["red"] + 0.59 * $colors["green"] + 0.11 * $colors["blue"]);
            }
        }
        if(
$filename != null)
        {
           
$fp = fopen($filename, "w");
           
fwrite($fp, $pgm);
           
fclose($fp);
        }
        else
        {
            return
$pgm;
        }
    }
?>
up
1
ph_corp at yahoo dot fr
8 years ago
<?php

/**
HSL/RGB conversion functions
very useful for a lot of applications
**/

function RBGtoHSL ( $R, $G, $B )
{

   
$var_R = ( $R / 255 );
   
$var_G = ( $G / 255 );
   
$var_B = ( $B / 255 );

   
$var_Min = min( $var_R, $var_G, $var_B )
   
$var_Max = max( $var_R, $var_G, $var_B )
   
$del_Max = $var_Max - $var_Min

    $L
= ( $var_Max + $var_Min ) / 2;

    if (
$del_Max == 0 )
    {
      
$H = 0
       $S
= 0
   
}
    else
    {
        if (
$L < 0.5 )
        {
           
$S = $del_Max / ( $var_Max + $var_Min );
        }
        else
        {
           
$S = $del_Max / ( 2 - $var_Max - $var_Min );
        }

       
$del_R = ( ( ( $var_Max - $var_R ) / 6 ) + ( $del_Max / 2 ) ) / $del_Max;
       
$del_G = ( ( ( $var_Max - $var_G ) / 6 ) + ( $del_Max / 2 ) ) / $del_Max;
       
$del_B = ( ( ( $var_Max - $var_B ) / 6 ) + ( $del_Max / 2 ) ) / $del_Max;

        if (
$var_R == $var_Max )
        {
           
$H = $del_B - $del_G;
        }
        else if (
$var_G == $var_Max )
        {
           
$H = ( 1 / 3 ) + $del_R - $del_B;
        }
        else if (
$var_B == $var_Max )
        {
           
$H = ( 2 / 3 ) + $del_G - $del_R;
        }

        if (
$H < 0 )
        {
           
$H += 1;
        }
        if (
$H > 1 )
        {
           
$H -= 1
       
}

    }

    return array(
$H, $S, $L );

}

function
HuetoRGB( $v1, $v2, $vH )
{
    if (
$vH < 0 )
    {
       
$vH += 1;
    }
    if (
$vH > 1 )
    {
       
$vH -= 1;
    }
    if ( (
6 * $vH ) < 1 )
    {
        return (
$v1 + ( $v2 - $v1 ) * 6 * $vH );
    }
    if ( (
2 * $vH ) < 1 )
    {
        return (
$v2 );
    }
    if ( (
3 * $vH ) < 2 )
    {
        return (
$v1 + ( $v2 - $v1 ) * ( ( 2 / 3 ) - $vH ) * 6 );
    }
    return (
$v1 )
}

function
HSLtoRGB ( $H, $S, $L )
{

    if (
$S == 0 )
    {
       
$R = $L * 255;
       
$G = $L * 255;
       
$B = $L * 255;
    }
    else
    {
        if (
$L < 0.5 )
        {
           
$var_2 = $L * ( 1 + $S );
        }
        else
        {
           
$var_2 = ( $L + $S ) - ( $S * $L );
        }

       
$var_1 = 2 * $L - $var_2;

       
$R = 255 * HuetoRGB( $var_1, $var_2, $H + ( 1 / 3 ) );
       
$G = 255 * HuetoRGB( $var_1, $var_2, $H );
       
$B = 255 * HuetoRGB( $var_1, $var_2, $H - ( 1 / 3 ) );
    }

    return array(
$R, $G, $B );

}

function
distance ( $R1, $G1, $B1, $R2, $G2, $B2 )
{
   
$result = sqrt ( ( $R1 - $R2 )*( $R1 - $R2 ) + ( $G1 - $G2 )*( $G1 - $G2 ) + ( $B1 - $B2 )*( $B1 - $B2 ) );
    return (
$result );
}

?>
up
1
delabahan at gmail dot com
12 days ago
This is an example of get high resolution images.

<?php
/**
* Class name      : resizeImage
* Created by   : wang
* Description   : This class is to resize the image from original size to new size
*/
class resizeImage
{
    
/**
     * Function name : resize_img
     * Description   : This function is to resize image
     * @param          : $origimg variable is the original image
     * @param          : $newimg variable is the new image
     * @param          : $w variable is the width of image
     * @param          : $f variable is the height of image
     */
   
public  function resize_img($origimg,$newimg,$w,$h){
       
$info = getimagesize($origimg);
       
$mime   = $info['mime'];

       
// Make sure that the requested file is actually an image
       
if(substr($mime, 0, 6) != 'image/')
        {
           
header('HTTP/1.1 400 Bad Request');
            return
'Error: requested file is not an accepted type: ' .$origimg;
            exit();
        }

       
// Check they extention of image
       
$extension = image_type_to_extension($info[2]);
        if(
strtolower($extension) == '.png'){
           
$img = $this->resize_imagepng($origimg,$w, $h);
           
imagepng($img,$newimg);
           
imagedestroy($img);
        }elseif(
strtolower($extension) == '.jpeg'){
           
$img = $this->resize_imagejpeg($origimg, $w, $h);
           
imagejpeg($img, $newimg);
           
imagedestroy($img);
        }elseif(
strtolower($extension == '.gif')){
           
$img = $this->resize_imagegif($origimg, $w, $h);
           
imagegif($img,$newimg);
           
imagedestroy($img);
        }

    }
    
/**
     * End function name : resize_img
     */

     /**
     * Function name : resize_imagepng
     * Description   : This function is to resize png image
     * @param          : $file variable is the original image
     * @param          : $w variable is the width of image
     * @param          : $f variable is the height of image
     */
   
private function resize_imagepng($file, $w, $h) {
       list(
$width, $height) = getimagesize($file);
      
$src = imagecreatefrompng($file);
      
$dst = imagecreatetruecolor($w, $h);
      
imagecopyresampled($dst, $src, 0, 0, 0, 0, $w, $h, $width, $height);
       return
$dst;
    }
    
/**
     * End function name : resize_imagepng
     */

     /**
     * Function name : resize_imagejpeg
     * Description   : This function is to resize jpeg image
     * @param          : $file variable is the original image
     * @param          : $w variable is the width of image
     * @param          : $f variable is the height of image
     */
   
private function resize_imagejpeg($file, $w, $h) {
       list(
$width, $height) = getimagesize($file);
      
$src = imagecreatefromjpeg($file);
      
$dst = imagecreatetruecolor($w, $h);
      
imagecopyresampled($dst, $src, 0, 0, 0, 0, $w, $h, $width, $height);
       return
$dst;
    }
    
/**
     * End function name : resize_imagejpeg
     */

     /**
     * Function name : resize_imagegif
     * Description   : This function is to resize gif image
     * @param          : $file variable is the original image
     * @param          : $w variable is the width of image
     * @param          : $f variable is the height of image
     */
   
private function resize_imagegif($file, $w, $h) {
       list(
$width, $height) = getimagesize($file);
      
$src = imagecreatefromgif($file);
      
$dst = imagecreatetruecolor($w, $h);
      
imagecopyresampled($dst, $src, 0, 0, 0, 0, $w, $h, $width, $height);
       return
$dst;
    }
    
/**
     * End function name : resize_imagegif
     */
}
/**
* End class name : resizeImage
*/
?>
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