imagecopymergegray

(PHP 4 >= 4.0.6, PHP 5, PHP 7, PHP 8)

imagecopymergegray — Copiar y fusionar parte de una imagen con escala de grises

Descripción

imagecopymergegray(
    resource $dst_im,
    resource $src_im,
    int $dst_x,
    int $dst_y,
    int $src_x,
    int $src_y,
    int $src_w,
    int $src_h,
    int $pct
): bool

imagecopymergegray() copia una parte de src_im en dst_im comenzando en las coodenadas x,y src_x, src_y con un ancho de src_w y un alto de src_h. La porción definida será copiada en las coordenadas x,y dst_x y dst_y.

Esta función es idéntica a imagecopymerge() excepto que en la fusión preserva el tono del origen convirtiendo los píxeles de destino en escala de grises antes de la operación de copia.

Parámetros

dst_im: Recurso de tipo enlace a la imagen de destino.
src_im: Recurso de tipo enlace a la imagen original.
dst_x: Coordenada x del punto de destino.
dst_y: Coordenada y del punto de destino.
src_x: Coordenada x del punto de origen.
src_y: Coordenada y del punto de origen.
src_w: Ancho original.
src_h: Altura original.
pct: src_im será cambiado a escala de grises según pct, donde 0 es totalmente escala de grises y 100 es sin cambios. Cuando pct = 100 esta función se comporta de forma idéntica a imagecopy() para imágenes de paleta, excepto para ignorar componentes alfa, mientras que implementa transparencia alfa para imágenes de color verdadero.

Valores devueltos

Devuelve true en caso de éxito o false en caso de error.

Ejemplos

Ejemplo #1 Uso de imagecopymergegray()

<?php
// Crear instancias de imágenes
$destino = imagecreatefromgif('php.gif');
$origen = imagecreatefromgif('php.gif');

// Copiar y fusionar - Gris = 20%
imagecopymergegray($destino, $origen, 10, 10, 0, 0, 100, 47, 20);

// Imprimir y liberar memoria
header('Content-Type: image/gif');
imagegif($destino);

imagedestroy($destino);
imagedestroy($origen);
?>

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User Contributed Notes 8 notes

down

amezghal at msn dot com ¶

16 years ago

gray effect :)
<?php
header('content-type:image/png');
$url_img = 'my_image.png';
$img = imagecreatefrompng($url_img);
$x = imagesx($img);
$y = imagesy($img);
$gray_img = imagecreatetruecolor($x, $y);
imagecolorallocate($gray_img, 0, 0, 0);
for ($i = 0; $i < $x; $i++) {
  for ($j = 0; $j < $y; $j++) {
    $rgb = imagecolorat($img, $i, $j);
    $r = ($rgb >> 16) & 0xFF;
    $g = ($rgb >> 8) & 0xFF;
    $b = $rgb & 0xFF;
     //for gray mode $r = $g = $b
    $color = max(array($r, $g, $b));
    $gray_color = imagecolorexact($new_img, $color, $color,   $color);
     imagesetpixel($gray_img, $i, $j, $gray_color);
   }
}
?>

down

Mark Barba ¶

19 years ago

//  Using the same code I found here on php.net, 
// I was able to figure out how to convert GIF (or any other
// format GD supports) to CIP format.  CIP is the image
// format for Cisco IP Phones...  7905/7940 and 7960 
// models...  Hope someone finds this useful and make it 
// better...  

/////// GIF2CIP PHP code ///////

// Convert image in memory to grayscale
    $img_width  = imageSX($im2);
    $img_height = imageSY($im2);

   // convert to grayscale
   // note: this will NOT affect your original image, unless
   // originalFileName and destinationFileName are the same
   for ($y = 0; $y <$img_height; $y++) { 
       for ($x = 0; $x <$img_width; $x++) { 
           $rgb = imagecolorat($im2, $x, $y);
           $red  = ($rgb >> 16) & 0xFF;
           $green = ($rgb >> 8)  & 0xFF;
           $blue  = $rgb & 0xFF;

           $gray = round(.299*$red + .587*$green + .114*$blue);
           
           // shift gray level to the left
           $grayR = $gray << 16;  // R: red
           $grayG = $gray << 8;    // G: green
           $grayB = $gray;        // B: blue
           
           // OR operation to compute gray value
           $grayColor = $grayR | $grayG | $grayB;

           // set the pixel color
           imagesetpixel ($im2, $x, $y, $grayColor);
           imagecolorallocate ($im2, $gray, $gray, $gray);
       }
   }
/////////////////////////////////////////////////////////

    // Modifies palette to only 4-colors (CIP Images on 7905/7940 & 7960 is 2-bit color)
    ImageTrueColorToPalette2($im2,FALSE,4);

    // Basic header for CIP Image files...
    header ("Content-type: text/xml");
    echo "<CiscoIPPhoneImage> ";
    echo "<LocationX>-1</LocationX> ";
    echo "<LocationY>-1</LocationY> ";
    echo "<Width>132</Width> ";
    echo "<Height>65</Height> ";
    echo "<Depth>2</Depth> ";
    echo "<Data>";

// get image dimensions (almost same code as above)
   $img_width  = imageSX($im2);
   $img_height = imageSY($im2);

   // convert to grayscale
   // note: this will NOT affect your original image, unless
   // originalFileName and destinationFileName are the same
   for ($y = 0; $y <$img_height; $y++) { 
       for ($x = 0; $x+4 <$img_width; $x = $x+4) 
       { 
            for ($ix = 0; $ix < 4; $ix++)
            {
               $rgb = imagecolorat($im2, $x + $ix, $y);

               // I came up with this translation on my own
               // Some smart person is bound to perfect it
               if ($rgb=="2") {$rgb=0;$Gray1[$ix] = $rgb;continue;}
               if ($rgb=="0") {$rgb=2;$Gray1[$ix] = $rgb;continue;}
               if ($rgb=="1") {$rgb=1;$Gray1[$ix] = $rgb;continue;}
               if ($rgb=="3") {$rgb=3;$Gray1[$ix] = $rgb;continue;}
           }
                $gray1 = $Gray1[0];
                $gray2 = $Gray1[1] << 2;
                $gray3 = $Gray1[2] << 4;
                $gray4 = $Gray1[3] << 6;
                
                // Pack 4 pixels into a single byte for CIP images
                $grey = $gray1 | $gray2 | $gray3 | $gray4;

                // CIP image data is sent in HEX, strtoupper is not really needed.
                $code = strtoupper(dechex($grey)); 

                // My quick fix to padding single HEX values
                if (strlen($code)==1) $code = "0".$code;
                echo $code;
                
       }

   }
    echo "</Data>";
    echo "<Title>$myvar</Title> ";
    echo "<Prompt>$city</Prompt> ";
    echo "</CiscoIPPhoneImage>";
    exit;

down

switch251 at netcourrier dot com ¶

20 years ago

In addition to code_couturier too: his code will produce blue pictures, because the value he uses to set the pixel color (the code is incomplete: I first thought it should be $gray) is between 0 and 255, which corresponds to blue levels.

To convert the picture to grayscale, use the following code:

<?php
    // replace with your files
    $originalFileName    = "colorPicture.jpg";
    $destinationFileName = "bwPicture.jpg";
    
    // create a copy of the original image
    // works with jpg images
    // fell free to adapt to other formats ;)
    $fullPath = explode(".",$originalFileName);
    $lastIndex = sizeof($fullPath) - 1;
    $extension = $fullPath[$lastIndex];
    if (preg_match("/jpg|jpeg|JPG|JPEG/", $extension)){
        $sourceImage = imagecreatefromjpeg($originalFileName);
    }

    // get image dimensions
    $img_width  = imageSX($sourceImage);
    $img_height = imageSY($sourceImage);

    // convert to grayscale
    // note: this will NOT affect your original image, unless
    // originalFileName and destinationFileName are the same
    for ($y = 0; $y <$img_height; $y++) { 
        for ($x = 0; $x <$img_width; $x++) { 
            $rgb = imagecolorat($sourceImage, $x, $y);
            $red   = ($rgb >> 16) & 0xFF;
            $green = ($rgb >> 8)  & 0xFF;
            $blue  = $rgb & 0xFF;

            $gray = round(.299*$red + .587*$green + .114*$blue);
            
            // shift gray level to the left
            $grayR = $gray << 16;   // R: red
            $grayG = $gray << 8;    // G: green
            $grayB = $gray;         // B: blue
            
            // OR operation to compute gray value
            $grayColor = $grayR | $grayG | $grayB;

            // set the pixel color
            imagesetpixel ($sourceImage, $x, $y, $grayColor);
            imagecolorallocate ($sourceImage, $gray, $gray, $gray);
        }
    }

    // copy pixel values to new file buffer
    $destinationImage = ImageCreateTrueColor($img_width, $img_height);
    imagecopy($destinationImage, $sourceImage, 0, 0, 0, 0, $img_width, $img_height);

    // create file on disk
    imagejpeg($destinationImage, $destinationFileName);
    
    // destroy temp image buffers
    imagedestroy($destinationImage);    
    imagedestroy($sourceImage);
?>

Copy-paste, replace the file names on the top and there you go (picture files must be in same folder as this script. If not, you will have to do your own file management).

down

mail at laeubi dot de ¶

21 years ago

This function don't work properly for me on trucolerimages (have not tried yet for other types) it jsut produce a part-grayscale image, and some color get mesed up.
I found a workaround here:
http://www.phpbuilder.com/columns/cash20030526.php3?page=2

[quote]
Advanced Image Editing Under the GD Library
Colorizing
Colorizing images is fairly easy to do. The easiest way to colorize an image is fairly simple to grasp. Create an image of the same dimensions and fill that image with the color you want to change it to. This new image is then placed on top of the older image, giving it a colorized look.

<?php 
function imagecolorize(&$im,&$col,$pct) { 
    // Get the image's width 
    $im_w = imagesx($im);  
    // Get the image's height 
    $im_h = imagesy($im);  
    // Set a pixel with the color, so we can get it easily 
    $setpixel = imagesetpixel($im,$im_w,0,$col);  
    // Get the color 
    $index = imagecolorat($im,$im_w,0);  
    // Find the color in the index 
    $rgb = imagecolorsforindex($im,$index);  
    // Get the red value 
    $r = $rgb["red"]; 
    // Get the green value 
    $g = $rgb["green"];  
    // Get the blue value 
    $b = $rgb["blue"];  
    // Create the layover 
    $layover = imagecreate($im_w,$im_h);  
    // Allocate the color on this image 
    $color = imagecolorallocate($layover,$r,$g,$b);  
    // Fill the image with the new color (this really isn't needed) 
    $fill = imagefill($layover,0,0,$color);  
    // Merge the layover on top of the older image 
    $merge = imagecopymerge($im,$layover,0,0,0,0,$im_w,$im_h,$pct); 
    imagedestroy($layover); // Destroy the layover 
} 
?> 

If we use a blue layover RGB(0,0,255), we get this result:
[/quote]

if you use black or gray, its not perfekt, but better than nothing ;)

down

szamil at ginf dot pl ¶

17 years ago

I've changed a little switch251's code and here we have sephia effect
<?php
   // replace with your files
    $originalFileName    = $filename;
    $destinationFileName = "2".$filename;
    
    // create a copy of the original image
    // works with jpg images
    // fell free to adapt to other formats ;)
    $fullPath = explode(".",$originalFileName);
    $lastIndex = sizeof($fullPath) - 1;
    $extension = $fullPath[$lastIndex];
    if (preg_match("/jpg|jpeg|JPG|JPEG/", $extension))
    {
        $sourceImage = imagecreatefromjpeg($originalFileName);
    }

    // get image dimensions
    $img_width  = imageSX($sourceImage);
    $img_height = imageSY($sourceImage);

    // convert to grayscale
    // note: this will NOT affect your original image, unless
    // originalFileName and destinationFileName are the same
    for ($y = 0; $y <$img_height; $y++) 
    { 
        for ($x = 0; $x <$img_width; $x++) 
        { 
            $rgb = imagecolorat($sourceImage, $x, $y);
            $red   = ($rgb >> 16) & 0xFF;
            $green = ($rgb >> 8)  & 0xFF;
            $blue  = $rgb & 0xFF;

          //sephia
            $red2 = min($red*.393 + $green*.769 + $blue*.189,255);
            $green2 = min($red*.349 + $green*.686 + $blue*.168,255);
            $blue2  = min($red*.272 + $green*.534 + $blue*.131,255);
            // shift gray level to the left
            
            $grayR = $red2 << 16;   // R: red
            $grayG = $green2 << 8 ;    // G: green
            $grayB = $blue2;         // B: blue
            
            // OR operation to compute gray value
            $grayColor = $grayR | $grayG | $grayB;

            
            // set the pixel color
            imagesetpixel ($sourceImage, $x, $y, $grayColor);
            imagecolorallocate ($sourceImage, $gray, $gray, $gray);
        }
    }

    // copy pixel values to new file buffer
    $destinationImage = ImageCreateTrueColor($img_width, $img_height);
    imagecopy($destinationImage, $sourceImage, 0, 0, 0, 0, $img_width, $img_height);

    // create file on disk
    imagejpeg($destinationImage, $destinationFileName);
    
    // destroy temp image buffers
    imagedestroy($destinationImage);    
    imagedestroy($sourceImage);
?>

down

annonymous at example dot com ¶

20 years ago

in addition to code_couturier - try this formula to calculate gray-value (luminance) in his "more exact" way:

$gray = round(.299*$red + .587*$green + .114*$blue);

down

code_couturier at graffiti dot net ¶

21 years ago

# very fast way to generate a grayscal-
# image from a true color image

#...

# --- quick grayscale image
for ($y = 0; $y <$img_height; $y++) { 
 for ($x = 0; $x <$img_width; $x++) { 

 # here we extract the green from 
 # the pixel at x,y , to use it as gray value
 $gray = (ImageColorAt($image, $x, $y) >> 8) & 0xFF;

 # a more exact way would be this:
 # $rgb = ImageColorAt($image, $x, $y);
 # $red = ($rgb >> 16) & 0xFF;
 # $green = (trgb >> 8) & 0xFF;
 # $blue = $rgb & 0xFF;
 # $gray = (int)(($red+$green+$blue)/4); 

 # and here we set the new pixel/color
  imagesetpixel ($image, $x, $y, 
  ImageColorAllocate ($image, $gray,$gray,$gray));
 }
}
 
# ...

down

-1

anonymous at domain dot com ¶

15 years ago

grayscale conversion is built-in with imagefilter(). 

<?php
     /* other code */

     $image = imagecreatefromjpeg('some.jpg');
     imagefilter($image, IMG_FILTER_GRAYSCALE);

     /* other code (ie save) */

     imagedestroy($image);

     /* other code */
?>

you could create the sepia effect by the following:

<?php
     /* other code */

     $image = imagecreatefromjpeg('some.jpg');
     imagefilter($image, IMG_FILTER_GRAYSCALE);
     imagefilter($image, IMG_FILTER_COLORIZE, 112, 66, 20);
     //Wikipedia RGB definition of sepia

     /* other code (ie save) */

     imagedestroy($image);

     /* other code */
?>

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