How do I efficiently compress a PNG? In my case, the images are small grayscale images with transparency.
Currently I'm playing with this:
// ...
$im->setImageFormat('png');
$im->setImageColorspace(\Imagick::COLORSPACE_GRAY);
$im->setImageCompression(\Imagick::COMPRESSION_LZW);
$im->setImageCompressionQuality(9);
$im->stripImage();
$im->writeImage($url_t);
As Imagick doesn't offer COMPRESSION_PNG, I've tried LZW but there's almost no change in the filesize (usually it's even bigger than before).
If I open the image in GIMP and simply save it, the filesize gets drastically reduced (e.g. 11,341 B --> 3,763 B or 11,057 B --> 3,538).
What is the correct way of saving a compressed PNG with Imagick?
Have a look at the first part of this answer:
Convert multipage PDF to PNG and back (Linux)
It explains the meaning + syntax of ImageMagick's -quality setting for PNGs.
I'm definitely not sure if it is correct way to save PNG, but my way is:
$im->setImageCompression(\Imagick::COMPRESSION_UNDEFINED);
$im->setImageCompressionQuality(0);
This gives me perfect quality of the image and file size very similar to PS6 saved 'Save for Web'. Sometimes even smaller sizes!
Related
I'm trying to convert and resize eps files into jpg. I use php imagick for this.
After converting the quality is very bad.
my eps you can download here:
https://www.file-upload.net/download-14285439/icon.eps.html
my jpg-img
i use this code:
if ( extension_loaded('imagick') ) {
$imagePath = 'icon.eps';
$imagick = new Imagick();
$imagick->setResolution(300, 300);
$imagick->setColorspace(Imagick::COLORSPACE_SRGB);
$imagick->readImage($imagePath);
$imagick->resizeImage(0, 1000, Imagick::FILTER_LANCZOS, 1);
$imagick->setImageResolution(72, 72);
$imagick->setImageCompressionQuality(70);
$imagick->setImageCompression(\Imagick::COMPRESSION_JPEG);
$imagick->setCompressionQuality(70);
$imagick->setImageFormat('jpeg');
$imagick->writeImage('test.jpg');
} else {
echo 'not found';
}
same result with this settings without resize/only convert, but the quality is still bad:
if ( extension_loaded('imagick') ) {
$imagePath = 'icon.eps';
$imagick = new Imagick();
$imagick->setResolution(300, 300);
$imagick->setColorspace(Imagick::COLORSPACE_SRGB);
$imagick->readImage($imagePath);
$imagick->setImageFormat('jpeg');
$imagick->writeImage('test.jpg');
} else {
echo 'not found';
}
i use this version with php 7.2.33:
phpinfo
What is wrong?
As you obviously know ImageMagick uses Ghostscript to render EPS files to JPEG. I would suggest that, rather than use ImageMagick you use Ghostscript directly. This will give you more control over the process than using ImageMagick and will mean that you can post the Ghostscript command line instead of an IM one.
I'm afraid that I have no idea what ImageMagick sends to Ghostscript which makes it rather difficult to offer any suggestions.
In addition you really need to be much more explicit about your problem. What do you actually mean by 'the quality is very bad'. Is this purely subjective or is there some objective criteria you are using ?
The image you've posted doesn't look much like what I see, but since I don't know what command is being used to drive Ghostscript, it may simply be that I am not reproducing your setup exactly.
First note; the nature of your EPS is not really suitable for JPEG compression. JPEG performs best when applied to smoothly varying images, like photographs (JPEG = Joint Photographic Expert Group), it does not work well with large areas of flat colour with sharp edges (which is exactly what you have here), the high frequency component of the sharp edges gives rise to 'ringing' or 'fringing' effects.
When using Ghostscript directly it is possible to alter the JPEG quality. Setting -dJPEGQ=100 will produce the highest quality, trading off the compression (ie the output file will be larger).
In addition your EPS gives its BoundingBox as 20x20 points. So that's 20/72 inch in each dimension. Even at 300 dpi that's going to result in an image which is 84x84 pixels. Pretty small. At 72 dpi you'll get an image which is 20x20 pixels,
It looks to me like you have rendered the EPS at 72 dpi with the default JPEGQ value, the 'poor quality' appears to be nothing more than the well known artefacts produced by JPEG compression. Using that setup with Ghostscript produces something not entirely unlike your posted image (though without the sharp edged corner artefacts). Setting JPEGQ to 100 produces something more sensible. The file produced by the default settings is 3,564 bytes, while the higher quality file is 4,485 bytes.
If it were me I would render to a TIFF file at a decent resolution, say 1200 dpi to give an image 333x333 pixels. Then load that into ImageMagick and resize it to your desired dimensions. Finally export as a JPEG if you require it that way for some reason.
here's a comparison of the output from Ghostscript. On the left is a JPEG produced at 1200 dpi, in the middle is the default quality rendering at 72 dpi and on the right the 72 dpi rendering with JPEGQ set to 100.
I have an eps. I want to make an jpg out of it. I tried everything, but the quality is too bad.
I think imagick takes the original size of the file, makes an jpg, and then makes it bigger without any compression. The problem is, the generated image of the eps is in bad quality, and the bigger image is totally bad.
Here are some configurations I tried:
$imagick = new \Imagick();
$imagick->readImage($imagePath);
$imagick->flattenImages();
$imagick->resizeImage(1024, 0, \Imagick::FILTER_LANCZOS, 1);
$imagick->setImageResolution(300, 300);
$imagick->setImageCompressionQuality(100);
$imagick->setImageCompression(\Imagick::COMPRESSION_JPEG);
$imagick->setCompressionQuality(100);
$imagick->setImageFormat('jpeg');
$imagick->writeImage($new_imagePath);
Can anyone help me with this? I don't get it.
You'll need to set the image density/resolution before you read the Encapsulated PostScript file.
$imagick = new \Imagick();
$imagick->setResolution(100); // or 300
$imagick->readImage($imagePath);
Also note that, by nature, EPS is a vector format, and JPEG is a lossy raster format. Rendering at a low dpi, and resizing up to a given size will always result in poor quality. Either render at a high-dpi & downsample to a given size, or render at expected size & omit any resizing.
I am trying to convert a vector image formats .emf,.wmf to a high resolution sharp and crisp raster image .gif,jpg. (Usually this could be easily done in Illustrator). But i am unable to do this in PHP. I am trying the following code but the results are either blurry or distorted or even totally black.
<?php
$image = new Imagick("1.emf");
$image->resizeImage(1500,0,Imagick::FILTER_LANCZOS,1);
$image->setImageFormat('gif');
$image->setresolution(900, 900);
$image->writeImage("2.gif");
?>
We just needed to set the resolution before loading the image.
$image = new Imagick();
$image->setresolution(300, 300);
$image->readimage($filename);
$image->resizeImage(1500,0,Imagick::FILTER_LANCZOS,1);
$image->setImageFormat('jpg');
$image->writeImage("1.jpg");
This code will convert a vector to a sharp and crisp raster image. It works for all vector formats (svg, ai, emf, wmf, etc). If the jpg result is unexpectedly a black image, you need to change the image transparency to white (check this link). Another way to get around with transparency problem is by getting your PHP updated to 5.5 and by installing Imagick for that version. By doing so, it will not cause any problems with transparent images and the above code will just work fine.
For testing purposes you could change jpg to png because it supports transparency.
I'm using Imagick to compress images (JPEG mostly), but the results are quite random. For example, check out these results (aproximate numbers, and all JPEG):
1600kb -> 600kb (saved 1000kb)
1000kb -> 1200kb (wasted 200kb)
400kb -> 500kb (wasted 100kb)
Here's the code I used:
$image = new Imagick($path);
$image->stripImage(); // remove metadata, though Imagick adds its own, not sure why
$image->setImageCompressionQuality(0); // lossless compression
$image->writeImages($path, true); // writeImages instead of writeImage, in case it's a GIF
Image recompression will vary depending on the source image files. If the original image was carefully made with good software, ImageMagick might not be able to match it. Simple solution: compare the file sizes of the original and new versions, keep the smaller.
Also, note that the Compression Quality number means different things depending on the file type of the image. In particular, 0 means "worst quality, smallest size" for JPEG, but means "fast compression, not necessarily small" for PNG. See http://www.imagemagick.org/script/command-line-options.php#quality
I am trying to add round corners to a jpeg file, but the problem is that after adding round corners, I am getting a black background color. Somehow I am not able to change it to any other color (white, transparent, red). It just simply shows black background where the image has rounded corners.
The code that I am using is:
<?php
$image = new Imagick('example.jpg');
$image->setBackgroundColor("red");
$image->setImageFormat("jpg");
$image->roundCorners(575,575);
$image->writeImage("rounded.jpg");
header('Content-type: image/jpeg');
echo $image;
?>
I cannot use png as the jpeg files are huge, about 5 MB, so if I used png, the file size would go up to 26 MB, even though the png adds transparent round corners.
Also the IMagick version that i am using is:
ImageMagick 6.6.2-10 2010-06-29 Q16 http://www.imagemagick.org
Also the output(image generated) will get printed so I don't know if css will work over here.
Sorry, I am trying to actually create a new jpeg file with rounded corners from an already existing jpeg file that doesn't have round corners this is actually a photograph taken from a camera, so there are multiple/too many colors so I can't use gif as well.
Also my site will only just generate the round corner image then afterwards it will get downloaded using a FTP program by the admin of the site and then using a system software will get printed, so in short my website will not be printing the image but rather just generate it
Try this:
<?php
$input = 'example.jpg';
$size = getimagesize($input);
$background = new Imagick();
$background->newImage($size[0], $size[1], new ImagickPixel('red'));
$image = new Imagick($input);
$image->setImageFormat("png");
$image->roundCorners(575,575);
$image->compositeImage($background, imagick::COMPOSITE_DSTATOP, 0, 0);
$image->writeImage("rounded.jpg");
?>
I may get downvoted, but I say let css deal with the corners and take some load off of your server :)
CSS rounded corners.
JPG doesn't have a transparent color(s) (alpha channels) in its palette.
The output image must use either PNG or GIF (or another image format that supports alpha channels).
setImageBackgroundColor is another option if you want an opaque background.
EDIT
Your comment reminds me that you could try to use the command line; shell_exec() will run a command line argument from PHP. The command in the ImageMagick API you'll need to start with is convert example.jpg, and then you can pass flags with the various parameters you want.
Since ImageMagick is already installed, it will work right away. You may need to point your system PATH to the ImageMagick directory where all of the executables are.
There's plenty of questions and forums dedicated to rounded corners with this method so I'll leave that up to you.
Here's a helpful tip though - there is a silly confusion with the convert command, since Windows also has a convert.exe that is rarely used, but will confuse your command line, so make sure you're calling the right convert. ;) To test if it's working, try convert example.jpg example.gif (which should convert your example to a gif).
To get output from your command line, finish all commands with 2>&1 which will pipe cmd output back into PHP.