php中文手册

目录搜索

文字

imagecopy

(PHP 4, PHP 5, PHP 7)

imagecopy — 拷贝图像的一部分

说明

bool imagecopy ( resource $dst_im , resource $src_im , int $dst_x , int $dst_y , int $src_x , int $src_y , int $src_w , int $src_h )

将 src_im 图像中坐标从 src_x，src_y 开始，宽度为 src_w，高度为 src_h 的一部分拷贝到 dst_im 图像中坐标为 dst_x 和 dst_y 的位置上。

用户评论:

[#1] petr dot biza at gmail dot com [2010-05-11 07:23:00]

There is function to crop blank edges from image.

<?php function imageCrop($image, $background = false, $padding = 0) { if($background) $background = imagecolorallocate($image, 255, 255, 255); $top = imageSY($image); $left = imageSX($image); $bottom = 0; $right = 0; for ($x = 0 ; $x < imagesx($image) ; $x++) { for ($y = 0 ; $y < imagesy($image) ; $y++) { // if there match if(imagecolorat($image, $x, $y) != $background) { if($x < $left) $left = $x; if($x > $right) $right = $x; if($y > $bottom) $bottom = $y; if($y < $top) $top = $y; } } } $right++; $bottom++; // create new image with padding $img = imagecreatetruecolor($right-$left+$padding*2,$bottom-$top+$padding*2); // fill the background imagefill($img, 0, 0, $background); // copy imagecopy($img, $image, $padding, $padding, $left, $top, $right-$left, $bottom-$top); // destroy old image cursor imagedestroy($image); return $img; } ?>

[#2] latin4567 at gmail dot com [2009-09-22 19:29:55]

I have created a PHP function which performs the standard 9-Slice scaling technique. This is extremely useful for thumbnail shadow scaling, and anything involving skinning. Feel free to pick apart and use

Note: instead of specifying margins, my 9-slicing routine uses a centered-rectangle concept... as input you provide the image (as a resource), the x and y coords of the rectangle, and the width and height of the rectangle.

The $src_im parameter should be an image resource. This script was written for 9-slicing translucent PNG images, and has only been tested with translucent PNG images, however it should work with other image types (possibly requiring some modification)

so if your source image was 400 x 400, you needed a 24 pixel margin on all sides, and your target size was 800 x 500, you would use the following parameters:

<?php $im = NineSlice($im, 24, 24, 352, 352, 800, 500) ?>

<?php function NineSlice($src_im, $rect_x, $rect_y, $rect_w, $rect_h, $target_w, $target_h) { $src_w = imagesx($src_im); $src_h = imagesy($src_im); $im = CreateBlankPNG($target_w, $target_h); imagealphablending($im,true); $left_w = $rect_x; $right_w = $src_w - ($rect_x + $rect_w); $left_src_y = ceil($rect_h / 2) - 1 + $rect_y; $right_src_y = $left_src_y; $left_src_x = 0; $right_src_x = $left_w + $rect_w; $top_src_x = ceil($rect_w / 2) - 1 + $rect_x; $bottom_src_x = $top_src_x; $bottom_src_y = $rect_y + $rect_h; $bottom_h = $src_h - $bottom_src_y; $left_tile = CreateBlankPNG($left_w, 1); imagecopy($left_tile, $src_im, 0, 0, 0, $left_src_y, $left_w, 1); $right_tile = CreateBlankPNG($right_w, 1); imagecopy($right_tile, $src_im, 0, 0, $right_src_x, $right_src_y, $right_w, 1); $top_tile = CreateBlankPNG(1, $rect_y); imagecopy($top_tile, $src_im, 0, 0, $top_src_x, 0, 1, $rect_y); $bottom_tile = CreateBlankPNG(1, $bottom_h); imagecopy($bottom_tile, $src_im, 0, 0, $bottom_src_x, $bottom_src_y, 1, $bottom_h); $inner_tile = CreateBlankPNG(4, 4); imagecopy($inner_tile, $src_im, 0, 0, ceil($src_w / 2) - 1, ceil($src_h / 2) - 1, 4, 4); imagecopy($im, $src_im, 0, 0, 0, 0, $left_w, $rect_y); imagecopy($im, $src_im, 0, $target_h - $bottom_h, 0, $bottom_src_y, $rect_x, $bottom_h); imagecopy($im, $src_im, $target_w - $right_w, 0, $right_src_x, 0, $right_w, $rect_y); imagecopy($im, $src_im, $target_w - $right_w, $target_h - $bottom_h, $src_w - $right_w, $bottom_src_y, $right_w, $bottom_h); imagesettile($im, $top_tile); imagefilledrectangle($im, $left_w, 0, $target_w - $right_w - 1, $rect_y, IMG_COLOR_TILED); imagesettile($im, $left_tile); imagefilledrectangle($im, 0, $rect_y, $left_w, $target_h - $bottom_h - 1, IMG_COLOR_TILED); $right_side = CreateBlankPNG($right_w, $target_h - $rect_y - $bottom_h); imagesettile($right_side, $right_tile); imagefilledrectangle($right_side, 0, 0, $right_w, $target_h - $rect_y - $bottom_h, IMG_COLOR_TILED); imagecopy($im, $right_side, $target_w - $right_w, $rect_y, 0, 0, $right_w, $target_h - $rect_y - $bottom_h); $bottom_side = CreateBlankPNG($target_w - $right_w - $left_w, $bottom_h); imagesettile($bottom_side, $bottom_tile); imagefilledrectangle($bottom_side, 0, 0, $target_w - $right_w - $left_w, $bottom_h, IMG_COLOR_TILED); imagecopy($im, $bottom_side, $right_w, $target_h - $bottom_h, 0, 0, $target_w - $right_w - $left_w, $bottom_h); imagedestroy($left_tile); imagedestroy($right_tile); imagedestroy($top_tile); imagedestroy($bottom_tile); imagedestroy($inner_tile); imagedestroy($right_side); imagedestroy($bottom_side); return $im; } function CreateBlankPNG($w, $h) { $im = imagecreatetruecolor($w, $h); imagesavealpha($im, true); $transparent = imagecolorallocatealpha($im, 0, 0, 0, 127); imagefill($im, 0, 0, $transparent); return $im; } ?>

[#3] Chad Allard [2009-07-06 12:20:19]

Regarding the image_flip function discussed in the notes here, don't forget to support transparency.

AFTER:

$imgdest = imagecreatetruecolor($width, $height);

ADD:

imagealphablending($imgdest, false);
imagesavealpha($imgdest, true);

In another post here it mentioned you didn't have to use the imagesavealpha function, but I found without it the background transparency can turn the background canvas black.

[#4] etienne at escott dot info [2009-07-03 02:16:45]

This is based on the Skew function from designerkamal at gmail dot com.

This is a function for skewing images in PHP with anti-aliasing. It works with alpha PNG images.

Warning: the bigger the image you skew, the longer it will take to process. It's about 3 times longer than without anti-aliasing.

<?php // $img: handle of an image // $skew_val: level of skew to apply (0 being none, 1 being 45??) function imageskewantialiased($img, $skew_val) { $width = imagesx($img); $height = imagesy($img); $height2 = $height + ($width * $skew_val); // See below for definition of imagecreatealpha $imgdest = imagecreatealpha($width, $height2); // Process the image for($x = 0, $level = 0; $x < $width - 1; $x++) { $floor = floor($level); // To go faster, some lines are being copied at once if ($level == $floor) imagecopy($imgdest, $img, $x, $level, $x, 0, 1, $height - 1); else { $temp = $level - $floor; // The first pixel of the line // We get the color then apply a fade on it depending on the level $color1 = imagecolorsforindex($img, imagecolorat($img, $x, 0)); $alpha = $color1['alpha'] + ($temp * 127); if ($alpha < 127) { $color = imagecolorallocatealpha($imgdest, $color1['red'], $color1['green'], $color1['blue'], $alpha); imagesetpixel($imgdest, $x, $floor, $color); } // The rest of the line for($y = 1; $y < $height - 1; $y++) { // Merge this pixel and the upper one $color2 = imagecolorsforindex($img, imagecolorat($img, $x, $y)); $alpha = ($color1['alpha'] * $temp) + ($color2['alpha'] * (1 - $temp)); if ($alpha < 127) { $red = ($color1['red'] * $temp) + ($color2['red'] * (1 - $temp)); $green = ($color1['green'] * $temp) + ($color2['green'] * (1 - $temp)); $blue = ($color1['blue'] * $temp) + ($color2['blue'] * (1 - $temp)); $color = imagecolorallocatealpha($imgdest, $red, $green, $blue, $alpha); imagesetpixel($imgdest, $x, $floor + $y, $color); } $color1 = $color2; } // The last pixel of the line $color1 = imagecolorsforindex($img, imagecolorat($img, $x, $height - 1)); $alpha = $color1['alpha'] + ((1 - $temp) * 127); if ($alpha < 127) { $color = imagecolorallocatealpha($imgdest, $color1['red'], $color1['green'], $color1['blue'], $alpha); imagesetpixel($imgdest, $x, $floor + $height - 1, $color); } } // The line is finished, the next line will be lower $level += $skew_val; } // Finished processing, return the skewed image return $imgdest; } // Creates a new image of the size specified with a blank background (transparent) function imagecreatealpha($width, $height) { // Create a normal image and apply required settings $img = imagecreatetruecolor($width, $height); imagealphablending($img, false); imagesavealpha($img, true); // Apply the transparent background $trans = imagecolorallocatealpha($img, 0, 0, 0, 127); for ($x = 0; $x < $width; $x++) { for ($y = 0; $y < $height; $y++) { imagesetpixel($img, $x, $y, $trans); } } return $img; } // Here's an example of how to use it imagepng(imageskewantialiased(imagecreatefrompng('test.png'), 0.15), 'skew.png'); ?>

[#5] John Conde [2009-05-27 07:55:26]

Simple and basic image cropping:

<?php // Original image $filename = 'someimage.jpg'; // Get dimensions of the original image list($current_width, $current_height) = getimagesize($filename); // The x and y coordinates on the original image where we // will begin cropping the image $left = 50; $top = 50; // This will be the final size of the image (e.g. how many pixels // left and down we will be going) $crop_width = 200; $crop_height = 200; // Resample the image $canvas = imagecreatetruecolor($crop_width, $crop_height); $current_image = imagecreatefromjpeg($filename); imagecopy($canvas, $current_image, 0, 0, $left, $top, $current_width, $current_height); imagejpeg($canvas, $filename, 100); ?>

[#6] webmaster at plumage dot nl [2009-03-18 04:38:22]

I have a few remarks om the mirror-function:
The cases horizontal and vertical are switched.
1 = vertical and 2 = horizontal.
When I used it there appeared a black lining of 1 pixel on the side or on the top of the picture.
To remove it the function becomes as follows:

<?php function ImageFlip ( $imgsrc, $mode ) { $width = imagesx ( $imgsrc ); $height = imagesy ( $imgsrc ); $src_x = 0; $src_y = 0; $src_width = $width; $src_height = $height; switch ( $mode ) { case '1': //vertical $src_y = $height -1; $src_height = -$height; break; case '2': //horizontal $src_x = $width -1; $src_width = -$width; break; case '3': //both $src_x = $width -1; $src_y = $height -1; $src_width = -$width; $src_height = -$height; break; default: return $imgsrc; } $imgdest = imagecreatetruecolor ( $width, $height ); if ( imagecopyresampled ( $imgdest, $imgsrc, 0, 0, $src_x, $src_y , $width, $height, $src_width, $src_height ) ) { return $imgdest; } return $imgsrc; } ?>

[#7] xafford [2008-09-27 05:53:57]

concerning the previous post of Borszczuk and the function to mirror images:

There?s a way better (and faster) method for this task with imagecopyresampled.

<?php define ( 'IMAGE_FLIP_HORIZONTAL', 1 ); define ( 'IMAGE_FLIP_VERTICAL', 2 ); define ( 'IMAGE_FLIP_BOTH', 3 ); function ImageFlip ( $imgsrc, $mode ) { $width = imagesx ( $imgsrc ); $height = imagesy ( $imgsrc ); $src_x = 0; $src_y = 0; $src_width = $width; $src_height = $height; switch ( (int) $mode ) { case IMAGE_FLIP_HORIZONTAL: $src_y = $height; $src_height = -$height; break; case IMAGE_FLIP_VERTICAL: $src_x = $width; $src_width = -$width; break; case IMAGE_FLIP_BOTH: $src_x = $width; $src_y = $height; $src_width = -$width; $src_height = -$height; break; default: return $imgsrc; } $imgdest = imagecreatetruecolor ( $width, $height ); if ( imagecopyresampled ( $imgdest, $imgsrc, 0, 0, $src_x, $src_y, $width, $height, $src_width, $src_height ) ) { return $imgdest; } return $imgsrc; } ?>

[#8] Cory Gagliardi [2008-07-08 11:40:13]

Here is some simple code for resizing an uploaded image and inserting a watermark (from a 24-bit PNG) on the bottom right of it. In this case, the water mark was a diagnol band that said "SOLD" across it. The code that verifies the uploaded image is the correct type has been omitted:

<?PHP //Load and resize the image $uploaded = imagecreatefromjpeg($_FILES['file']['tmp_name']); $image = imagecreatetruecolor(IMAGE_WIDTH, IMAGE_HEIGHT); imagecopyresampled($image, $uploaded, 0, 0, 0, 0, IMAGE_WIDTH, IMAGE_HEIGHT, imagesx($uploaded), imagesy($uploaded)); imagealphablending($image,true); //allows us to apply a 24-bit watermark over $image //Load the sold watermark $sold_band = imagecreatefrompng('../images/sold_band.png'); imagealphablending($sold_band,true); //Apply watermark and save $image = image_overlap($image, $sold_band); imagecopy($image,$sold_band,IMAGE_WIDTH - SOLD_WIDTH,IMAGE_HEIGHT - SOLD_HEIGHT,0,0,SOLD_WIDTH,SOLD_HEIGHT); $success = imagejpeg($image,'../images/sold/'.$id.'.jpg',85); imagedestroy($image); imagedestroy($uploaded); imagedestroy($sold_band); ?>

[#9] matrebatre [2008-02-02 05:22:00]

I had the same problem as Jeff, but his solution didn't work for me. I made this script, and it seems to work:

<?php $img = imagecreatefromgif('in.gif'); $w = imagesx($img); $h = imagesy($img); $trans = imagecolortransparent($img); if($trans >= 0) { $rgb = imagecolorsforindex($img, $trans); $oldimg = $img; $img = imagecreatetruecolor($w,$h); $color = imagecolorallocate($img,$rgb['red'],$rgb['green'],$rgb['blue']); imagefilledrectangle($img,0,0,$w,$h,$color); imagecopy($img,$oldimg,0,0,0,0,$w,$h); } imagegif($img,'out.gif'); ?>

[#10] Jeff [2007-02-22 15:27:34]

I came across the problem of having a page where any image could be uploaded, then I would need to work with it as a true color image with transparency. The problem came with palette images with transparency (e.g. GIF images), the transparent parts changed to black (no matter what color was actually representing transparent) when I used imagecopy to convert the image to true color.

To convert an image to true color with the transparency as well, the following code works (assuming $img is your image resource):

<?php //Convert $img to truecolor $w = imagesx($img); $h = imagesy($img); if (!imageistruecolor($img)) { $original_transparency = imagecolortransparent($img); //we have a transparent color if ($original_transparency >= 0) { //get the actual transparent color $rgb = imagecolorsforindex($img, $original_transparency); $original_transparency = ($rgb['red'] << 16) | ($rgb['green'] << 8) | $rgb['blue']; //change the transparent color to black, since transparent goes to black anyways (no way to remove transparency in GIF) imagecolortransparent($img, imagecolorallocate($img, 0, 0, 0)); } //create truecolor image and transfer $truecolor = imagecreatetruecolor($w, $h); imagealphablending($img, false); imagesavealpha($img, true); imagecopy($truecolor, $img, 0, 0, 0, 0, $w, $h); imagedestroy($img); $img = $truecolor; //remake transparency (if there was transparency) if ($original_transparency >= 0) { imagealphablending($img, false); imagesavealpha($img, true); for ($x = 0; $x < $w; $x++) for ($y = 0; $y < $h; $y++) if (imagecolorat($img, $x, $y) == $original_transparency) imagesetpixel($img, $x, $y, 127 << 24); } } ?>

And now $img is a true color image resource

[#11] john at mccarthy dot net [2007-01-17 05:37:22]

Here is an upgrade of that cool wave function: Double the size of the image, wave it, then resample it down again. This makes even nicer, anti aliased waves.

// So easy and nice!
function wave_region($img, $x, $y, $width, $height,$amplitude = 4.5,$period = 30)
{
    // Make a copy of the image twice the size
    $mult = 2;
    $img2 = imagecreatetruecolor($width * $mult, $height * $mult);
    imagecopyresampled ($img2,$img,0,0,$x,$y,$width * $mult,$height * $mult,$width, $height);

// Wave it
for ($i = 0;$i < ($width * $mult);$i += 2)
{
   imagecopy($img2,$img2,
       $x + $i - 2,$y + sin($i / $period) * $amplitude,    // dest
       $x + $i,$y,            // src
       2,($height * $mult));
}

// Resample it down again
imagecopyresampled ($img,$img2,$x,$y,0,0,$width, $height,$width * $mult,$height * $mult);
imagedestroy($img2);
}

To use it in a full image:
    wave_region ($oImage,0,0,imagesx($oImage),imagesy($oImage));

[#12] C. Jansen [2006-08-16 11:02:55]

While replying to a post in a support forum I noticed something odd about imagecopy(). The first snippet (should) create an image object, allocate a colour resource within that image, fill the background with the allocated colour and then copy another, cropped to fit, image onto it.

<?php // create a new image resource $temp = imagecreatetruecolor( $width, $height ); $white = imagecolorallocate( $temp, 255, 255, 255 ); //fill the background with white imagefill( $temp, 0, 0, $white ); //copy the image into new a resource imagecopy($temp, $this->Image, 0, 0, $crop_top, $crop_left, $width, $height); ?>

But this produces a black background. I noticed taking away the imagefill() call yields the same results. The solution was to call imagefill() after the imagecopy(). Thinking linearly I would have guessed this to cover the previously copied image in white but it doesn't. I guess GD uses a layer system? Is this correct?

<?php // create a new image resource $temp = imagecreatetruecolor( $width, $height ); $white = imagecolorallocate( $temp, 255, 255, 255 ); // copy image into new resource imagecopy( $temp, $this->Image, 0, 0, $crop_top, $crop_left, $width, $height ); //fill the background with white (not sure why it has to be in this order) imagefill( $temp, 0, 0, $white ); ?>

I am using php 5.1.4 with the bundled GD (2.0.28)

[#13] [2006-04-02 10:21:58]

Basic way to implement a "crop" feature : given an image (src), an offset (x, y) and a size (w, h).

crop.php :
<?php $w=$_GET['w']; $h=isset($_GET['h'])?$_GET['h']:$w; // h est facultatif, =w par d??faut $x=isset($_GET['x'])?$_GET['x']:0; // x est facultatif, 0 par d??faut $y=isset($_GET['y'])?$_GET['y']:0; // y est facultatif, 0 par d??faut $filename=$_GET['src']; header('Content-type: image/jpg'); header('Content-Disposition: attachment; filename='.$src); $image = imagecreatefromjpeg($filename); $crop = imagecreatetruecolor($w,$h); imagecopy ( $crop, $image, 0, 0, $x, $y, $w, $h ); imagejpeg($crop); ?>

Call it like this :

<img src="crop.php?x=10&y=20&w=30&h=40&src=photo.jpg">

[#14] admin at cvxdes dot com [2006-02-23 08:26:00]

I used this to watermark images. This is the function I wrote:

<?php function watermark($url,$logo){ $bwidth = imagesx($url); $bheight = imagesy($url); $lwidth = imagesx($logo); $lheight = imagesy($logo); $src_x = $bwidth - ($lwidth + 5); $src_y = $bheight - ($lheight + 5); ImageAlphaBlending($url, true); ImageCopy($url,$logo,$src_x,$src_y,0,0,$lwidth,$lheight); } ?>

Usage:
<?php //$current_image would be your image the watermark is overlayed onto. Make sure it's imagecreatefrom*** to work. watermark($current_image,$watermark_image); ?>

Hope this helps someone.

[#15] designerkamal at gmail dot com [2006-02-09 11:38:04]

Skewing images in PHP...
<?php function Skew($src, $dest, $skew_val) { $imgsrc = imagecreatefromgif($src); $width = imagesx($imgsrc); $height = imagesy($imgsrc); $imgdest = imagecreatetruecolor($width, $height+($height*$skew_val)); $trans = imagecolorallocate($imgdest,0,0,0); $temp=0; for($x=0 ; $x<$width ; $x++) { for($y=0 ; $y<$height ; $y++) { imagecopy($imgdest, $imgsrc, $x, $y+$temp, $x, $y, 1, 1); imagecolortransparent($imgdest,$trans); } $temp+=$skew_val; } imagepng($imgdest, $dest); imagedestroy($imgsrc); imagedestroy($imgdest); } Skew("img.gif", "img2.png","1"); print "<img src='img.gif'>"; print "<br><br>"; print "<img src='img2.png'>"; ?>

[#16] ragnar_40k at hotmail dot com [2005-11-21 03:17:13]

Here a function to make holes into images:

// Set the alpha channel for a part of an image (it ignores the canvas alpha atm).
// $img_canvas - 32-bit true color image w/ alpha channel
// $img_mask - 8-bit gray scale image (white parts will be masked transparent in the canvas).
// This relies on the current pixel format:
// (high byte) -> (alpha channel} {red} {green} {blue} <- (low byte)
function mask($img_canvas, $img_mask, $dst_x, $dst_y)
{
   $old_blendmode = imagealphablending($img_canvas, FALSE);

   $width  = imagesx($img_mask);
   $heigth = imagesy($img_mask);

   $mask_x = 0;
   $x = $dst_y;
   while ($mask_x<$width)
   {
       $mask_y = 0;
       $y = $dst_y;
       while ($mask_y<$heigth)
       {
           imagesetpixel($img_canvas, $x, $y,
               ((imagecolorat($img_mask, $mask_x, $mask_y) >> 1) << 24) | (imagecolorat($img_canvas, $x, $y) & 0x00FFFFFF));

           ++$mask_y;
           ++$y;
       }
       ++$mask_x;
       ++$x;
   }

   imagealphablending($img_canvas, $old_blendmode);
}

[#17] johnny at netvor dot sk [2005-10-21 08:48:51]

simple image combination srcipt, ie. if u want to create one huuuge signature from more small ones

<?php // config -- $src = array ("http://www.google.com/images/logo_sm.gif", "http://sk2.php.net/images/php.gif"); $under = 0; // combine images underneath or not? // -- end of config $imgBuf = array (); $maxW=0; $maxH=0; foreach ($src as $link) { switch(substr ($link,strrpos ($link,".")+1)) { case 'png': $iTmp = imagecreatefrompng($link); break; case 'gif': $iTmp = imagecreatefromgif($link); break; case 'jpeg': case 'jpg': $iTmp = imagecreatefromjpeg($link); break; } if ($under) { $maxW=(imagesx($iTmp)>$maxW)?imagesx($iTmp):$maxW; $maxH+=imagesy($iTmp); } else { $maxW+=imagesx($iTmp); $maxH=(imagesy($iTmp)>$maxH)?imagesy($iTmp):$maxH; } array_push ($imgBuf,$iTmp); } $iOut = imagecreate ($maxW,$maxH) ; $pos=0; foreach ($imgBuf as $img) { if ($under) imagecopy ($iOut,$img,0,$pos,0,0,imagesx($img),imagesy($img)); else imagecopy ($iOut,$img,$pos,0,0,0,imagesx($img),imagesy($img)); $pos+= $under ? imagesy($img) : imagesx($img); imagedestroy ($img); } imagegif($iOut); ?>

[#18] sawaz [2005-07-03 04:45:21]

Just a little function that allows you to change the foreground color of a transparent gif or png.
It's supposed to use only two-color images, becouse it convert all the colors to the specified one.

It works with .gif or .png as source, but writes only .png

function ColorReplace( $url )
{
# The new color and its channels
$NEW_COLOR = "#FF66FF";
$r = 0+("0x".substr( $NEW_COLOR, 1, 2));
$g = 0+("0x".substr( $NEW_COLOR, 3, 2));
$b = 0+("0x".substr( $NEW_COLOR, 5, 2));

# I read the kind of file from the extension
$tmp = pathinfo($url);
$extension =$tmp['extension'];
if( $extension == 'png' ) $oldIm = @imagecreatefrompng( $url );
elseif( $extension == 'gif' ) $oldIm = @imagecreatefromgif( $url );

# I replace EACH color in the palette with the new one
for( $i=0; $i < imagecolorstotal( $oldIm ); $i++ )
imagecolorset( $oldIm, $i, $r,$g,$b );

# Output the file in png format : each color is now NEW COLOR
# but transparency is preserved !!
header("Content-type: image/png");
imagepng($oldIm);
imagedestroy($oldIm);
}

[#19] cod at crescentofdarkness dot cjb dot net [2004-12-20 09:45:42]

This function will put a truecolor png with transparency over a custom color backgorund.

The image will be gracefully blended with the background color using the alpha channel for each color.

In real world we'd just mix foreground and backgorund colors looking at their percentages (i.e. 20% of background + 80% of foreground)
Here we have to calculate this for each r, g and b value of each color, and we have to use 127 instead of 100, because alpha channel goes from 0 to 127.

Try it on a color-to-transparent gradient!

<?php function pngcolorizealpha($file, $color) { // first of all let's convert the background color $background = array( 'red' => hexdec(substr($color,0,2)), 'green' => hexdec(substr($color,2,2)), 'blue' => hexdec(substr($color,4,2)) ); $im1 = imagecreatefrompng($file) or die('Cannot Initialize new GD image stream'); $im2 = imagecreatetruecolor(imagesx($im1), imagesy($im1)); $col1 = imagecolorallocate($im2, $background['red'], $background['green'], $background['blue']); imagefill($im2,0,0,$col1); // for each color in the original png for ($i=0; $i< imagecolorstotal($im1); $i++) { // find r,g,b and alpha value $foreground = imagecolorsforindex($im1, $i); // blend fore and back colors using alpha value $r = (($foreground['red'] / 127) * (127 - $foreground['alpha'])) + (($background['red'] / 127)* $foreground['alpha']); $g = (($foreground['green'] / 127) * (127 - $foreground['alpha'])) + (($background['green'] / 127)* $foreground['alpha']); $b = (($foreground['blue'] / 127) * (127 - $foreground['alpha'])) + (($background['blue'] / 127)* $foreground['alpha']); // allocate this new color in the destination image imagecolorallocate($im2, $r,$g,$b); } imagecopy($im2, $im1, 0, 0, 0, 0, imagesx($im1), imagesy($im1)); header ("Content-type: image/png"); imagepng($im2); imagedestroy($im1); imagedestroy($im2); } ?>

[#20] RT [2004-05-09 03:09:35]

Although the following function doesn't use imagecopy(), I thought it might help in related tasks. Please see the code comments for details of it's operation. I made this function to assist in creating images using multiple "layers". For example if you wanted to dynamically create a logo image with seperate colors for say the logo itself and a glow around the logo, these steps would be followed:

-Using an image editor (like Photoshop), create a png-24 image with just the logo on a transparent background. The logo can be any color or multiple colors, but the final image created by this function will be of a single color.

-Create a similar image with just the glow (no logo)

-Create a background image

-Apply this colorize() function to the logo image and the glow image with your desired color for each.

-You can now use imagecopy() to merge all three into a single image ready for a browser.

Here's the code

<?php function colorize($src_path, $dest_path, $hex_color) { //get the png-24 image - it must have an alpha channel for this funciton to be effective $src = imagecreatefrompng($src_path); //get width $w = imagesx($src); //get height $h = imagesy($src); //create same size destination image $dest = imagecreatetruecolor($w, $h); //this must be set to false in order to be able to overwright the defualt black pixels of the background with our new //transparent pixels. Otherwise our new pixel would just be applied on top of the black. imagealphablending($dest, false); //get decimal components of the passed hex color $red = hexdec(substr($hex_color, 1, 2)); $green = hexdec(substr($hex_color, 3, 2)); $blue = hexdec(substr($hex_color, 5, 2)); for ($i = 0; $i < $h; $i++) { //this loop traverses each row in the image for ($j = 0; $j < $w; $j++) { //this loop traverses each pixel of each row //get the color & alpha info of the current pixel $retrieved_color = imagecolorat($src, $j, $i); //put this info into an array $rgba_array = imagecolorsforindex($src, $retrieved_color); //get the transparency of the pixel as a number from 0 (opaque) to 127 (transparent) $alpha = $rgba_array['alpha']; //allocate the color to paint. Note that we may continue to overwright this color since our image is not palleted $color_to_paint = imagecolorallocatealpha($dest, $red, $green, $blue, $alpha); //paint the pixel imagesetpixel($dest, $j, $i, $color_to_paint); } } //this allows the new transparency info to be saved with the image imagesavealpha($dest, true); //write the image to the destination file imagepng($dest, $dest_path); } ?>

[#21] matheus at slacklife dot com dot br [2003-09-12 16:24:28]

// Image Resize
function createthumb($IMAGE_SOURCE,$THUMB_X,$THUMB_Y,$OUTPUT_FILE){
  $BACKUP_FILE = $OUTPUT_FILE . "_backup.jpg";
  copy($IMAGE_SOURCE,$BACKUP_FILE);
  $IMAGE_PROPERTIES = GetImageSize($BACKUP_FILE);
  if (!$IMAGE_PROPERTIES[2] == 2) {
    return(0);
  } else {
    $SRC_IMAGE = ImageCreateFromJPEG($BACKUP_FILE);
    $SRC_X = ImageSX($SRC_IMAGE);
    $SRC_Y = ImageSY($SRC_IMAGE);
    if (($THUMB_Y == "0") && ($THUMB_X == "0")) {
      return(0);
    } elseif ($THUMB_Y == "0") {
      $SCALEX = $THUMB_X/($SRC_X-1);
      $THUMB_Y = $SRC_Y*$SCALEX;
    } elseif ($THUMB_X == "0") {
      $SCALEY = $THUMB_Y/($SRC_Y-1);
      $THUMB_X = $SRC_X*$SCALEY;
    }
    $THUMB_X = (int)($THUMB_X);
    $THUMB_Y = (int)($THUMB_Y);
    $DEST_IMAGE = imagecreatetruecolor($THUMB_X, $THUMB_Y);
    unlink($BACKUP_FILE);
    if (!imagecopyresized($DEST_IMAGE, $SRC_IMAGE, 0, 0, 0, 0, $THUMB_X, $THUMB_Y, $SRC_X, $SRC_Y)) {
      imagedestroy($SRC_IMAGE);
      imagedestroy($DEST_IMAGE);
      return(0);
    } else {
      imagedestroy($SRC_IMAGE);
      if (ImageJPEG($DEST_IMAGE,$OUTPUT_FILE)) {
        imagedestroy($DEST_IMAGE);
        return(1);
      }
      imagedestroy($DEST_IMAGE);
    }
    return(0);
  }

} # end createthumb

[#22] schdenis at telecom dot by [2003-05-02 03:02:40]

As you probably know 'gif' is a paletted image, that is why if you want to copy one 'gif' onto another 'gif' using ImageCopy you need to create a paletted destination image using (ImageCreate), not ImageCreateTrueColor.

[#23] mbostrom at paragee dot com [2002-11-30 12:56:26]

If you want to copy a non-rectangular (hence transparent) image onto a background (for example, a pawn onto a chessboard) do the following:

First, create the pawn image pawn.png in your favorite graphics program. Do NOT make the image transparent, instead, give it a distinct solid background color. You will flag this color as transpernt inside PHP, otherwise imagecopy will not honor the transparency.

Then:

$board = imagecreatefrompng ("board.png");
$pawn = imagecreatefrompng ("pawn.png");
imagecolortransparent ($pawn, imagecolorat ($pawn, 0, 0));
imagecopy ($board, $pawn, $x, $y, 0, 0, $pawnWidth, $pawnHeight);
imagedestroy ($pawn);

[#24] adam at shallimus dot com [2002-10-04 18:47:03]

One way 'round the even/odd image size problem would be to use bcdiv.

[#25] robert at scpallas dot com [2002-02-08 08:33:49]

If you are getting an error when using ImageCopy(), be sure that both images are of the same type - either True Color or Palette.
GD 1.x can copy images of different types, but with GD 2.0 this will cause an error.

sorry - forgot to fill in my email...
Note that ImageCreateFromJPEG always creates a True Color Image.
You can use ImageCreateTrueColor() instead of Image Create() to solve this problem.