so i have an image that is originally 1696x1696. i want to use a php file to MIME a png file. what i want the php to do is crop the original file and produce a quarter of the image. Later i plan to use $_GET variables to return which quadrant i want, but for testing/debugging, im just aiming to get the top left quadrant.
here's the code:
Header("Content-type:image/png");
$newImg =imagecreatefrompng('test.png');
//manually entered half height and width
$img=imagecreatetruecolor(848,848);
//here is where the bugs keep flawing the image
imagecopyresampled($img,$newImg,0,0,0,0,1696,1696,1696,1696);
imagepng($img);
imagedestroy($img);
this will produce the image (top, left) like it's supposed to, however it adds several smaller resampled images on top of it. no matter how i toy with it, i cant get it right. i've also tried imagecopy() and cant get it right as well. looked up tutorials and i cant seem to find on that helps.
Your code looks fine. The only thing I would change is to use imagecopyresized() instead of imagecopyresampled() in this use case.
Header("Content-type:image/png");
$source = imagecreatefrompng('images/test.png');
// manually entered half height and width
$thumb = imagecreatetruecolor(848,848);
imagecopyresized($thumb, $source, 0, 0, 0, 0, 1696, 1696, 1696, 1696);
imagepng($thumb);
imagedestroy($thumb);
I am guessing that earlier in your tests, you were overwriting your original image. That would explain the...
however it adds several smaller resampled images on top of it...
...part of your experience. Each time you ran the code, you picked up the previously modified file.
ok, so after enough headbanging and hair-tearing out, i decided to just go back to photoshop and overwrite the .png with my original .psd. starting to get somewhere now. i got my quadrant without all the ridiculousness. when i get a better understanding, i might come back and explain where i kept going wrong
Related
I have a straightforward PHP script (php version 7+) that I run to resize images to a smaller dimension around 1200px wide ...
I use imagecreatefromjpeg and imagecopyresampled method and the save new file with imagejpeg # 88% compression.
I and ran over 100 images through it and most images worked out great, except for a few stubborn images that results to BLACK square image.
I tried imagecopyresized and played with different new dimensions but it just didnt work. I even tried outputting the ob stream from these tests at the point of resizing instead of saving to file (no compressions applied) and i can confirm that the moment the image was resized, it is already black square.
On the images that produces black square the result is false.
I did verify mime type IMAGETYPE_JPEG of file, regardless of file extension, before running the code.
Now, I tried running the same files thru imagescale instead
$new_img = imagescale($img, $new_width, $new_height, IMG_SINC );
and that worked.
Now I prefer to use the previous method for better more crispier output so I've been trying to get it to work :(
Why is this happening? I searched stack for similar issues but they are describing a issues that completely didnt work on any images, not my case, where only a select few images had issues.
I am dealing with JPG only, but is it possible that the jpg file is just named with extension ".jpg" but actually a png, bmp, or something else? Will that cause issues?
I'm stuck, and i hope you guys can help.
Thank you
Most images resized nicely
We are processing nearly 20M existing images (not files), all of which have been converted to the raw PNG data. Each image is always 640x480, and we want them all to be saved as square 640x640 files, with the original image on the top of the larger canvas, leaving the additional lower 160px for descriptive text to be added.
Our PNG data being retrieved is like this:
data:image/png;base64,iVBORw0 ... kJggg==
I've seen lots of posts and examples showing work with resizing, transparencies, colors, etc., but cannot determine where to start creating a new empty 640x640 "canvas" with existing PNG data.
If this is a duplicate question, I'd be happy to delete it if I can get some direction on how to begin. Without knowing the basics to get started, googling things like "image create png canvas" hasn't been helpful. Clearly, image processing is new to me, so apologize if I'm not being clear enough. Thanks in advance.
This should work for you:
$imgData = 'data:image/png;base64,iVBORw0 ... kJggg==';
$img = imagecreatefromstring(base64_decode(preg_replace('#^data:image/\w+;base64,#i', '', $imgData)));
$targetImage = imagecreatetruecolor(640, 640);
imagecopyresampled($targetImage, $img, 0, 0, 0, 0, 640, 480, 640, 480);
imagepng($targetImage, $yourPath);
Of course you might want to add some checks, background color etc. but I think you will be ready to start with this.
this is my first question and I'm planning to hang around in this forum. I'm very new to programming since I'm studying but I'm making great progress. So, with this in mind I'll try to be as detailed as possible.
The project I am working with is about creating a png-image using GD PHP. The script recieves data, calculates image WIDTH/HEIGHT according to these. From this data I then print out pixels on the image in different spots. Everything works great, it displays the image and saves it on the server, there's nothing wrong with that. But when I run the script, it outputs the image to the browser. I don't want that. I just want the script to process the image and save it to the server. I have searched plenty but haven't found anything about it.
Code for creating the image: I have to remove some code though, but it's not needed to answer my question. I suspect it's something with the header and imagecreatetruecolor. This is all the data I can give.
<?php
//Some calculations before
// --- START: CREATE IMAGE ---
$png = imagecreatetruecolor($WIDTH, $HEIGHT);
imagesavealpha($png, true);
$trans_colour = imagecolorallocatealpha($png, 0, 0, 0, 127);
imagefill($png, 0, 0, $trans_colour);
//Here's just a loop to print pixels
header("Content-type: image/png");
imagepng($png);
save($png); //Function used for saving
//Erase from memory
imagedestroy($png);
?>
I have a script that handles/scales uploaded images. I noticed that some of the images come out significantly darkened, and through a process of elimination tracked the darkening back to this section of code:
$scaled = new IMagick();
$scaled->newPseudoImage($original->getImageWidth(), $original->getImageHeight(), 'xc:white');
$scaled->compositeImage($original, Imagick::COMPOSITE_DEFAULT, 0, 0);
$scaled->flattenImages();
What I'm doing here is trying to eliminate issues with transparent backgrounds in some images coming through as black when I convert to jpg.
Does anyone have any idea which part of this code is darkening the image and what a good way to fix it might be?
Edit: Still haven't figured out the heart of this issue, but I did find that I can avoid doing this to images that don't need it by wrapping it in:
if($original->getImageAlphaChannel()){
I have a site where users can upload images. I process these images directly and resize them into 5 additional formats using the CodeIgniter Image Manipulation class. I do this quite efficiently as follow:
I always resize from the previous format, instead of from the original
I resize using an image quality of 90% which about halves the file size of jpegs
The above way of doing things I implemented after advise I got from another question I asked. My test case is a 1.6MB JPEG in RGB mode with a high resolution of 3872 x 2592. For that image, which is kind of borderline case, the resize process in total takes about 2 secs, which is acceptable to me.
Now, only one challenge remains. I want the original file to be compressed using that 90% quality but without resizing it. The idea being that that file too will take half the file size. I figured I could simply resize it to its' current dimensions, but that doesn't seem to do anything to the file or its size. Here's my code, somewhat simplified:
$sourceimage = "test.jpg";
$resize_settings['image_library'] = 'gd2';
$resize_settings['source_image'] = $sourceimage;
$resize_settings['maintain_ratio'] = false;
$resize_settings['quality'] = '90%';
$this->load->library('image_lib', $resize_settings);
$resize_settings['width'] = $imagefile['width'];
$resize_settings['height'] = $imagefile['height'];
$resize_settings['new_image'] = $filename;
$this->image_lib->initialize($resize_settings);
$this->image_lib->resize();
The above code works fine for all formats except the original. I tried debugging into the CI class to see why nothing happens and I noticed that the script detects that the dimensions did not change. Next, it simply makes a copy of that file without processing it at all. I commented that piece of code to force it to resize but now still nothing happens.
Does anybody know how to compress an image (any image, not just jpegs) to 90% using the CI class without changing the dimensions?
I guess you could do something like this:
$original_size = getimagesize('/path/to/original.jpg');
And then set the following options like this:
$resize_settings['width'] = $original_size[0];
$resize_settings['height'] = $original_size[1];
Ok, so that doesn't work due to CI trying to be smart, the way I see it you've three possible options:
Rotate the Image by 360ยบ
Watermark the Image (with a 1x1 Transparent Image)
Do It Yourself
The DIY approach is really simple, I know you don't want to use "custom" functions but take a look:
ImageJPEG(ImageCreateFromString(file_get_contents('/path/to/original.jpg')), '/where/to/save/optimized.jpg', 90);
As you can see, it's even more simpler than using CI.
PS: The snippet above can open any type of image (GIF, PNG and JPEG) and it always saves the image as JPEG with 90% of quality, I believe this is what you're trying to archive.