I am attempting to make a dynamic image with PHP, and I can't find out how to set partial transparency. It is very easy to make things either solid or fully transparent, but I have been unable to do this.
Assuming you're creating your image with the imagecreatetruecolor function and that you're outputting the image as a PNG file....
You need to call the following methods to specify that the image must be generated as a 24-bit PNG before calling imagepng:
imagesavealpha($im, true);
Note that Internet Explorer 6 doesn't support 24-bit PNG files without the use of a CSS filter applied to the img tag.
Check out the documentation for imagecolorallicatealpha() There they create a transparent color circle.
Related
I am using Imagick to product images from massive pdf files. I also want those images with RGB or sRGB color mode so Internet Explorer can display the images correctly.
I have tried
$im = new imagick($fileName.'[0]');
//$im->setImageColorspace(Imagick::COLORSPACE_SRGB); //try this already
// $im->setImageColorSpace(1); //try this already
$im->setResolution(300,300);
$im->setImageFormat('jpeg');
$im->writeImage($imageFile);
$im->clear();
$im->destroy();
I did get images but the color is way off with setImageColorspace and setImageColorSpace methods. (ex: color is inverted.)
If I comment out those methods, the images look right but some of them are not RGB mode and create problems in Internet Explorer.
I really need the RGB color mode on the images. Are there anyways to do it? Thanks so much!
You seem to encounter a problem with CMYK pdfs. Have you tried converting them to PNG? PNG -contrary to jpeg - only encodes RGB so the images will in any case be in the correct colorspace.
You might also want to have a look at ghostscript (the engine behind imagemagicks PDF conversion) and it's --UseCIE switch.
I wrote a php-wrapper to ghostscript which you can find at github that you might find usefull when you want to use ghostscript.
I am making an avatar script from scratch and am having some problems. I got transparency working, and multi-image support for heads, bodies, shirts, etc.
Anyhow, I want to be able to generate specific sizes of the avatar within the PHP script. At this time, I have the variable $baseImage, which is an image generated using the GD script below:
$baseImage = imagecreatefrompng($startAsset);
imagealphablending($baseImage, true);
imagesavealpha($baseImage, true);
... combine all images into $base here
header("Content-type: image/png");
imagepng($baseImage);
The size of the image this generates is 350x550 (pixels) and I want to be able to get a smaller size.
I've done research but cannot find a working solution. What built-in PHP GD functions can resize this, retain transparency, and keep the great quality/colors?
There is no way to change the size of an image resource directly. Instead, you need to create a new image of the desired size and use imagecopyresampled to copy from the fullsize image to the resized one.
Whenever a user uploads a photo using my script, WideImage converts it to JPEG. However, I just noticed that if I upload a PNG picture, with a transparent background, it makes it black instead.
Is there any way to make this white instead?
This is how i save the image:
$img->resizeDown('500', null)->saveToFile('annonce_billeder/'.$bnavn.'.jpeg', 70);
Edit
I looked through the API and I don't see anything for setting the BG color on resizeDown or changing the alpha channel on the PNG before resizeDown... I do however, think that you can use the merge method to merge the PNG with a white background image. Take a look at the API for that function, essentially the PNG image would be the "watermark".
http://wideimage.sourceforge.net/wp-content/current/doc/WideImage/WideImage_Image.html#methodmerge
Posting some code might help... you might be able to use this method
$white = $image->allocateColor(255, 255, 255);
I am looking to add a background to images that users upload that are not square. So if they upload a tall and skinny photo I want to add a white background to the sides of the image to make the resulting image have an aspect ratio of 1:1. Is this possible using PHP or javascript?
You can use the GD library for what, with a library called Wideimage it's a breeze:
$image = WideImage::load('img_form_field_name');
$size = max($image->getHeight(), $image->getWidth());
$white = $image->allocateColor(255, 255, 255);
$image->resizeCanvas($size, $size, 'center', 'center', $white);
See the documentation and examples, many functions can even be tested interactively.
The GD library is the most commonly used image manipulation package. It's a set of functions often installed with PHP which handle image manipulation.
What you'll want to do is either scale and crop your image to a specific aspect ratio so that you place your image on a square canvas and cut off whatever does fit or
You'll want to simply resize your image to a fixed aspect ratio and place it on a square canvas with whitespace around it.
Either way, this tutorial should point you in the right direction
http://return-true.com/2009/02/making-cropping-thumbnails-square-using-php-gd/
Yep you'll want to look into either the GD library or ImageMagik. There are plenty of tutorials available for this task.
Functions like imagecreatetruecolor() etc will allow you to create a new image, and then stack the uploaded image on top of it and save it as a new file.
Yes.
http://www.php.net/manual/en/refs.utilspec.image.php
I have a small Minecraft server where people can upload their skins. Minecraft skins are small png images. Is it possible to convert this png image to another png image via PHP (e.g. GD library)?
I have made this image to help me explain what I am trying to do:
Yes, it's possible. You'd need multiple imagecopy commands to pull out sections of the skin image and paste it into the proper spots in the "output" image.
Basic order of operations would be:
$input = imagecreatefrompng('skin.png');
$output = imagecreatetruecolor(800, 600); // whatever the dimensions should be.
imagecopy($output, $input, 0,0, 10,20, 50,60);
imagecopy(...);
...
...
The first copy command is saying "take a 50x60 section of the input image, starting at coordinates 10x20, and paste it into the destination image in the top left corner".
The actual sequence/coordinates/sizes will be up to you to figure out.
If you're not doing a 1:1 copy of the image and are doing resizing, then you'll want imagecopyresampled() instead.
Here is the PHP manual for creating images from png :
http://php.net/manual/en/function.imagecreatefrompng.php
Here is a simple tutorial :
http://www.phptutorial.info/?imagecreatefrompng
You can do this with CSS
Here is a tutorial: http://www.w3schools.com/css/css_image_sprites.asp