Image transparency not preserved when merging two images in PHP - php

When using examples from other posts to try and merge one PNG that has transparent parts on it with another non-transparent PNG, the foreground PNGs transparency is lost and defaults to white.
The code so far:
$width = 349;
$height = 250;
$base_image = imagecreatefrompng($_GET['bg']);
$top_image = imagecreatefrompng($_GET['fg']);
$merged_image = "merged.png";
imagesavealpha($top_image, true);
imagealphablending($top_image, true);
imagecopy($base_image, $top_image, 0, 0, 0, 0, $width, $height);
imagepng($base_image, $merged_image);
Can anyone suggest where I may be going wrong?
Coming out like this
Should look like this

Copy from Can PNG image transparency be preserved when using PHP's GDlib imagecopyresampled?
Codes should be like this:
imagesavealpha($base_image, true);
imagealphablending($base_image, false);

$image = imagecreatefrompng($_GET['bg']);
$frame = imagecreatefrompng($_GET['fg']);
imagealphablending($frame,true);
imagecopymerge($image, $frame, 0, 0, 0, 0, 0, 100, 100);
# Save the image to a file
imagepng($image, 'file-xyz.png');

Related

Remove transparent space from a png image while merging with another png image using PHP GD

I am merging two png images in my php code using php-gd. The images are getting merged, however the problem is that there is extra transparent space in the image which I want to remove.
Here is my php code.
<?php
$image1Url = "/home/sunpure-refined-sunflower-oil-v-5-ltr-1.png";
$image2Url = "/home/hypercity-every-day-sooji-rawa-v-1-kg-6.png";
$dest = imagecreatefrompng($image1Url);
$src = imagecreatefrompng($image2Url);
$offset2x = imagesx($src);
$offset3x = imagesx($dest);
$temp = imagecreatetruecolor($offset2x + $offset3x, 140);
$background = imagecolorallocate($temp, 0, 0, 0);
imagecolortransparent($temp, $background);
imagecopymerge($temp, $src, 0, 0, 0, 0, 180, 180, 100); //have to play with these numbers for it to work for you, etc.
imagecopymerge($temp, $dest, $offset2x-50, 0, 0, 0, 180, 180, 100);
header('Content-Type: image/png');
imagepng($temp, "/home/myImage.png");
imagedestroy($dest);
imagedestroy($src);
In the rightmost image, I was trying to remove the space between them , but due to transparent space, its not happening.

Placing Transparent Image to Another non-transparent image

How can I place a transparent image to a background image using PHP?
I have here my code:
$width = 400;
$height = 400;
$base_image = imagecreatefrompng("img/frame1.png");
$top_image = imagecreatefrompng("randyorton.png");
$merged_image = "merged.png";
imagealphablending($base_image, true);
imagesavealpha($base_image, true);
imagealphablending($top_image, true);
imagesavealpha($top_image, true);
imagecopy($base_image, $top_image, 10080, 10080, 0, 0, $width, $height);
imagecopy($base_image, $top_image, 80, 80, 0, 0, $width, $height);
header('Content-Type: image/png');
imagepng($base_image, $merged_image);
What's wrong with this? The image I am creating now has a black background on it.
Please see this picture for reference:
Am I making sense?
Thanks!
I get it. I have a big width and height for the top image. I just get the size of the top image and pass it on the imagecopy function. :D

What’s wrong with this PNG Transparent image generator? The background is Black

First: I want to create a PNG image and draw a shape inside it.
Second: Overlap the first PNG on another image (for example a jpg image)
The problem is: When I create the first PNG with a shape inside (the background is not transparent and is dark) so this make a black overlap on second image.
How can I fix it?
I don’t work so much with images function so I got trouble.
Notes: I need to create the first transparent PNG and then overlap it on second image. I don’t want to create shape directly on second image.
And The Code:
<?php
define('EXAMPLE_TMP_SERVERPATH', '');
define('EXAMPLE_TMP_URLRELPATH', '');
$tempDir = EXAMPLE_TMP_SERVERPATH;
$fileName = 'test3img.png';
$imgW = 125;
$imgH = 125;
# First
$base_image = imagecreatetruecolor($imgW, $imgH);
$black = imagecolorallocate($base_image, 0, 0, 0);
imagecolortransparent($base_image, $black);
$col[0] = imagecolortransparent($base_image, $black);
imagealphablending($base_image, true);
imagesavealpha($base_image, true);
imagefill($base_image, 0, 0, $col[0]);
imagefilledrectangle($base_image, 4, 4, 50, 25, 255);
imagepng($base_image, $tempDir.$fileName);
# First2
$target_image = imagecreatetruecolor($imgW*5, $imgH*5);
$black2 = imagecolorallocatealpha($base_image, 0, 0, 0, 127);
imagecolortransparent($target_image, $black2);
imagecopyresized($target_image, $base_image, 0, 0, 0, 0,$imgW, $imgH, $imgW, $imgH);
imagedestroy($base_image);
imagepng($target_image, $tempDir.$fileName);
imagedestroy($target_image);
# First2
# Second
$dest = imagecreatefromjpeg('../avatar.jpg');
$src = imagecreatefrompng(EXAMPLE_TMP_URLRELPATH.$fileName);
imagealphablending($dest, true);
imagesavealpha($dest, true);
imagealphablending($src, true);
imagecopyresampled(
$dest,
$src,
0,0,
0,0,
200, 200,
125, 125
);
imagepng($dest, EXAMPLE_TMP_URLRELPATH.'_m.jpeg');
imagedestroy($dest);
imagedestroy($src);
?>
Need to add the alpha channel too:
Alpha Channel

Applying text to png transparency issue PHP

I am trying to write text onto a png, however when I do it puts a dark border around it, I am not sure why.
The original image:
The processed image:
Code:
// Load the image
$im = imagecreatefrompng("admin/public/images/map/order/wally.png");
// If there's an error, gtfo
if(!$im) {
die("");
}
$textColor = imagecolorallocate($im, 68, 68, 68);
$width = imagesx($im);
$height = imagesy($im);
$fontSize = 5;
$text = "AC";
// Calculate the left position of the text
$leftTextPos = ($width - imagefontwidth($fontSize)*strlen($text)) / 2;
// Write the string
imagestring($im, $fontSize, $leftTextPos, $height-28, $text, $textColor);
// Output the image
header('Content-type: image/png');
imagepng($im);
imagedestroy($im);
I've had this issue several times, let me find the answer...
Ok, found something:
imagesavealpha($im, true);
imagealphablending($im, true);
Write that before imagepng.
Yes, saving with alpha is important but loading it is important as well. Your PNG image might have transparency but it is good practice to account for that as well.
You'd need to create true color image, set alpha color and then draw your loaded image with text over it. So something like this:
// create true color image
$img = imagecreatetruecolor($width, $height);
$transparent_color = imagecolorallocatealpha($img, 255, 255, 255, 0);
imagealphablending($img, false);
imagefillrectangle($img, 0, 0, $width, $height, $transparent_color);
imagealphablending($img, true);
// draw previously loaded PNG image
imagecopy($img, $loaded_img, 0, 0, 0, 0, $width, $height);
// draw your text
// save the whole thing
imagesavealpha($img, true);
imagepng($img, $file);

Background transperancy in imagerotate()

Since last 2 days, I was trying to add transperancy to the background after rotating an image using imagerotate() PHP-GD function.
But, to my great disappointment, it's not working at all.
It's just giving out a black background behind it.
Here's my code -
$patchImageS = 'image.png'; // the image to be patched over the final bg
$patchImage = imagecreatefrompng($patchImageS); // resource of image to be patched
$patchImage = imagerotate($patchImage, 23, 0, 0);
imagepng($patchImage,'tt.png');
I tried to change the parameters being passed in function to
imagerotate($patchImage, 23, 5, 0);
imagerotate($patchImage, 23, 0, 5);
Any help would be highly appreciated.
After a number of 99% finished answers, here's the solution I've found:
// Create, or create from image, a PNG canvas
$png = imagecreatetruecolor($width, $height);
// Preserve transparency
imagesavealpha($png , true);
$pngTransparency = imagecolorallocatealpha($png , 0, 0, 0, 127);
imagefill($png , 0, 0, $pngTransparency);
// Rotate the canvas including the required transparent "color"
$png = imagerotate($png, $rotationAmount, $pngTransparency);
// Set your appropriate header
header('Content-Type: image/png');
// Render canvas to the browser
imagepng($png);
// Clean up
imagedestroy($png);
The key here is to include your imagecolorallocatealpha() in your imagerotate() call...
look for imagesavealpha() in the php-documentation - i think this is what you are looking for.
EDIT: here's an example:
$png = imagecreatefrompng('./alphachannel_example.png');
// Do required operations
$png = imagerotate($png, 23, 0, 0);
// Turn off alpha blending and set alpha flag
imagealphablending($png, false);
imagesavealpha($png, true);
// Output image to browser
header('Content-Type: image/png');
imagepng($png);
imagedestroy($png);
For anyone having problems with imagecopyresampled or imagerotate with black bars on background, I have found a code example here:
https://qna.habr.com/q/646622#answer_1417035
// get image sizes (X,Y)
$wx = imagesx($imageW);
$wy = imagesy($imageW);
// create a new image from the sizes on transparent canvas
$new = imagecreatetruecolor($wx, $wy);
$transparent = imagecolorallocatealpha($new, 0, 0, 0, 127);
$rotate = imagerotate($imageW, 280, $transparent);
imagealphablending($rotate, true);
imagesavealpha($rotate, true);
// get the newest image X and Y
$ix = imagesx($rotate);
$iy = imagesy($rotate);
//copy the image to the canvas
imagecopyresampled($destImg, $rotate, 940, 2050, 0, 0, $ix, $iy, $ix, $iy);

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