I'm trying to write a PHP function to convert an SVG image without any antialiasing (so that the final PNG is blocky and contains only the colours specified in the SVG).
The command line equivalent is:
convert +antialias /path/to.svg /path/to.png
I'm assuming that I need to use PHP's Imagick::setOption method to pass in "+antialias", but the documentation is very sparse.
The following snippet will write a PNG file, but none of the options prevents antialiased pixels being rendered:
$image = new Imagick();
// None of these have any affect - output image is always antialiased.
$image->setOption('+antialias', true);
$image->setOption('-antialias', true);
$image->setOption('+antialias', 'true');
$image->setOption('-antialias', 'true');
$image->setOption('antialias', true);
$image->setOption('antialias', false);
$image->setOption('antialias', 'true');
$image->setOption('antialias', 'false');
$image->readImage('/path/to.svg');
$image->writeImage('/path/to.png');
Any help would be great, thanks.
That is not a good way to anti-alias a vector file such as SVG. The proper way in command line would be to set the desired density before reading the file and then resize back to compensate for a large magnification when using a large density. So for example
convert -density 288 image.svg -resize 25% image.png
Nominal density (default) is 72. So 288 = 72*4. Thus we resize afterwards by 1/4 = 25%, unless you want a larger output. Then resize by a larger value.
In PHP Imagick, you can create a new Imagick() instance. Then set the desired density. Then read the input SVG. Then resize. Then set the PNG format and save to disk. See setImageResolution for setting the density in Imagick. See https://www.php.net/manual/en/imagick.setimageresolution.php
I don't think what you want is possible, unfortunately. ImageMagick shells out to Inkscape to render SVGs, and Inkscape has no command-line option to disable antialiasing.
https://graphicdesign.stackexchange.com/questions/138075/export-svg-without-anti-aliasing-in-inkscape-1-0-by-command-line
You could render at high resolution and then do nearest-neighbour downsampling. It would reduce the visible antialiasing, but you would still get some colours not in the SVG file.
I am trying to convert an image with ImageMagick. I am cropping and resampling to 112 DPI:
convert myimg.jpg -crop 1024x683+0+0 -resize 100% -resample 112 downsample.jpg
A script runs through many images of varying DPI and downsamples them.
However, a particular file has gummed up the script. Somehow, the file has a DPI of 1 (?!?) So it ends up trying to sample it up to 112 from 1, and the attempt eats up all my RAM and hangs the script.
identify -verbose myimage.jpg
Image: myimage.jpg
Format: JPEG (Joint Photographic Experts Group JFIF format)
Class: DirectClass
Geometry: 1024x683+0+0
Resolution: 1x1
Print size: 1024x683
Is there an argument/flag I can use with ImageMagick to prevent this from happening, maybe something that tells it to only downsample?
Could your error be related to...
For formats which do not support an image resolution, the original resolution of the image must be specified via -density on the command line prior to specifying the resample resolution.
JPEG I know supports resolution but maybe its wrong in the EXIF header or somehow ambiguous / confused with embedded thumbnail (again, maybe the unit is assumed). I'd look more closely at the [-density] argument (http://www.imagemagick.org/script/command-line-options.php#density) and how it relates to resolution and density on certain formats.
As for getting your script working. Seems you might want to break the operations out into more individual actions? If you can't satisfy the convert with using -density I would look at testing for the case you know fails and just skipping. Could parse the results of identify or just the failure of the convert. You are executing these in shell calls from PHP yes?
I'm using PHP Imagick to convert PNG images generated in PhantomJS to TIF CMYK,
for print purposes I need a flat Black (cmyk - 0,0,0,100) - the conversion generates blacks like (cmyk - 58,49,44,89).
I'm converting the images using color profile (section of my code below) -> the code is based on Convert image from RGB to CMYK with Imagick
is it possible to force a flat black with Imagick ? do you know any other tools that might help ?
thanks,
if ($has_icc_profile === false) {
$icc_rgb = file_get_contents( '/srgb_profiles' . '/sRGB.icc');
$image->profileImage('icc', $icc_rgb);
unset($icc_rgb);
}
// then we add an CMYK profile
$icc_cmyk = file_get_contents( '/cmyk_profiles'.'/JapanColor2002Newspaper.icc');
$image->profileImage('icc', $icc_cmyk);
UPDATE :
after checking online I think I'm looking for a UCR en.wikipedia.org/wiki/Under_color_removal method for ImageMagick - I found that convert old versions supported under color removal
-undercolor <undercolor factor>x<black-generation factor>
control undercolor removal and black generation on CMYK images.
This option enables you to perform undercolor removal and black generation on CMYK images-- images to be printed on a four-color printing system. You can con- trol how much cyan, magenta, and yellow to remove from your image and how much black to add to it. The standard undercolor removal is 1.0x1.0. You'll frequently get better results, though, if the percentage of black you add to your image is slightly higher than the percentage of C, M, and Y you remove from it. For example you might try 0.5x0.7. (http://www.chemie.fu-berlin.de/chemnet/use/suppl/imagemagick/www/convert.html) -
apparently the option is not supported anymore, I'm interested if anyone knows if UCR is the solution I'm looking for and if anyone knows if it's supported or if I'm supposed to use a different method to get the same result.
If you use ImageMagick's convert at the command line like this to generate a grayscale ramp, 1 pixel wide and 256 pixels tall, going from white to black and convert it to CMYK colorspace and then show it as text, you get what you want:
convert -size 1x256 'gradient:rgb(255,255,255)-rgb(0,0,0)' -colorspace cmyk txt:
# ImageMagick pixel enumeration: 1,256,65535,cmyk
0,0: (0%,0%,0%,0%) #0000000000000000 cmyk(0,0,0,0)
0,1: (0%,0%,0%,0.392157%) #0000000000000101 cmyk(0,0,0,1)
0,2: (0%,0%,0%,0.784314%) #0000000000000202 cmyk(0,0,0,2)
0,3: (0%,0%,0%,1.17647%) #0000000000000303 cmyk(0,0,0,3)
0,4: (0%,0%,0%,1.56863%) #0000000000000404 cmyk(0,0,0,4)
0,5: (0%,0%,0%,1.96078%) #0000000000000505 cmyk(0,0,0,5)
0,6: (0%,0%,0%,2.35294%) #0000000000000606 cmyk(0,0,0,6)
0,7: (0%,0%,0%,2.7451%) #0000000000000707 cmyk(0,0,0,7)
0,8: (0%,0%,0%,3.13725%) #0000000000000808 cmyk(0,0,0,8)
0,9: (0%,0%,0%,3.52941%) #0000000000000909 cmyk(0,0,0,9)
0,10: (0%,0%,0%,3.92157%) #0000000000000A0A cmyk(0,0,0,10)
...
...
0,249: (0%,0%,0%,97.6471%) #000000000000F9F9 cmyk(0,0,0,249)
0,250: (0%,0%,0%,98.0392%) #000000000000FAFA cmyk(0,0,0,250)
0,251: (0%,0%,0%,98.4314%) #000000000000FBFB cmyk(0,0,0,251)
0,252: (0%,0%,0%,98.8235%) #000000000000FCFC cmyk(0,0,0,252)
0,253: (0%,0%,0%,99.2157%) #000000000000FDFD cmyk(0,0,0,253)
0,254: (0%,0%,0%,99.6078%) #000000000000FEFE cmyk(0,0,0,254)
0,255: (0%,0%,0%,100%) #000000000000FFFF cmyk(0,0,0,255)
You must be doing something different - maybe this will help you work it out. I am guessing it is your ICC profiles but you can experiment with the above command.
If you just want to experiment with spot values, you can just have IM translate a single pixel like this:
convert -size 1x1 xc:#000000 -colorspace cmyk txt:
# ImageMagick pixel enumeration: 1,1,65535,cmyk
0,0: (0%,0%,0%,100%) #000000000000FFFF cmyk(0,0,0,255)
or maybe more simply like this:
convert -size 1x1 xc:#000000 -depth 8 -colorspace cmyk txt:
# ImageMagick pixel enumeration: 1,1,255,cmyk
0,0: (0,0,0,255) #000000FF cmyk(0,0,0,255)
Note the following though:
You must put profiles between input image and output image names on the command line.
If your image has no embedded profile, the first profile you give is applied to the input image and the second to the output image. If your input image does have a profile, the first profile you give is applied to the output image.
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.
I have a PHP application which needs to deal with incoming TIFF files. I have neither control nor knowledge over the colorspaces of this TIFFs and the application should store all incoming images as RGB JPEGs.
Problem is, incoming TIFF files are anything: CMYK, RGB, some sort of YCbCr wrapped in sRGB, and so on, and I need to convert them somehow to RGB JPEGs before saving.
I need some sort of a conversion function in PHP which uses IMagick extension which can get any binary TIFF data and convert it to proper RGB JPEG binary data. It needs to handle different colorspaces inside TIFF images correctly. Output format (RGB JPEG) stays the same for any input file.
The following obvious solution converts some CMYK TIFFs correctly, some CMYK TIFFs get inverted colors and YCbCr RGB TIFFs get totally corrupted by red overlay:
$converter = new IMagick();
$converter->setResourceLimit(6, 1);
$converter->readImageBlob($data);
if ($converter->getImageColorspace() != IMagick::COLORSPACE_RGB
&& $converter->getImageColorspace() != IMagick::COLORSPACE_GRAY
) {
$icc_rgb = file_get_contents('sRGB_v4_ICC_preference.icc');
$converter->profileImage('icc', $icc_rgb);
$converter->setImageColorspace(IMagick::COLORSPACE_RGB);
}
$converter->setImageFormat('jpeg');
$converter->setImageCompression(Imagick::COMPRESSION_JPEG);
$converter->setImageCompressionQuality(60);
$converter->resizeImage(1000, 1000, IMagick::FILTER_LANCZOS, 1, true);
$converter->stripImage();
$result = $converter->getImagesBlob();
This solution is taken from there: http://blog.rodneyrehm.de/archives/4-CMYK-Images-And-Browsers-And-ImageMagick.html Obviously, it doesn't work for all colorspaces, because it doesn't detect them reliably. As you can see, it even uses the sRGB_v4 ICC color profile downloaded from it's homepage.
Google finds me one particular solution to the red overlay problem (just one of the conversion screw-ups), but it's only for console and when you know beforehand that you deal with YCbCr images:
convert some.tif -set colorspace YCbCr -colorspace RGB some.jpg
I can live with passthru-ing convert and pass to convert all the magical switches needed, but I suppose I need to detect the source image's colorspace beforehand and call a identify | grep before every convert in an otherwise PHP application is an overkill.
I've experienced this same issue.
It also came up in the imagick forums and the correction was pushed into ImageMagick 6.8.0-4 .
So upgrading should solve this issue. I've upgraded to ImageMagick 6.8.1-9 and haven't encountered this since.