I'm trying to batch scale a load of xpm images to double pixel size. I can do this using ImageMagick like this:
convert infile.xpm -sample 200% outfile.xpm
However, the symbolic colour names are lost.
In the original input, the colour entries are as follows:
". c #007EBF s active_hilight_1",
"+ c #0A5E89 s active_color_1",
"# c #143D52 s active_shadow_1",
In the up-scaled version:
" c #143D52",
". c #0A5E89",
"X c #007EBF",
The colour names changed, which is fine, but as you can see the s <symbolic-name> suffixes are stripped.
Does anyone know a quick way to do this using ImageMagick or a similar (open-source) utility?
Thanks
EDIT: Seems ImageMagick can't due this due to a bug, but does anyone know any other tool which may be able to do this?
mogrify -sample 200% *.xpm
^ This works as long as you have a new (post 2019-09-02) version of ImageMagick with the xpm output bug fixed, as described here:
https://github.com/ImageMagick/ImageMagick/issues/1684
Today's master branch, for example, passes symbolic colour names through properly.
Related
I am using CUPS with the printer driver which use "application/vnd.cups-raster 10 rastertopj" and i am trying to get the look of dither 4x4 print/output but i am clueless where to change the setting for choosing different dithering/halftoning pattern..
i also contacted the cups and they said dithering is done by the driver and also told that If the driver is Ghostscript-based you may be able to change the dither as you’d like, and yes this is indeed Ghostscript-based printer driver/filter cause when i open .PPD file i see *Product: "(ESP Ghostscript)".
Can you please guide me on how or where to change the dither of the printer filter/driver?
Edited:
this is the halftone output its printing: https://imgur.com/a/18hkC1H or https://imgur.com/download/7pTksX4
this is the output i am looking for: https://imgur.com/a/KZTQrkp or https://imgur.com/download/5FnpKEM
Thankyou
Ghostscript supports the full range of halftoning defined in the PostScript Language Reference Manual. It also has its own stochastic screening code.
To change the screening, you put the relevant commands in the PostScript file. If you are starting with a PostScript program, then that's where you put the screening. Otherwise you'll have to inject it into the PostScript, which is where you modify the PPD file.
I can't tell you how to do that (because its a CUPS thing, not Ghostscript), nor can I tell you what the PostScript you need is (because I have no idea what the screen you want looks like), you'll have to experiment to match the output you want (note that halftoning is not the same as dithering). Worst case you can use a type 3 halftone dictionary which should produce something similar to what you want, at the cost of needing a lot of data to set it up.
<<
/HalftoneType 1
/Frequency 37
/Angle 45
/SpotFunction {180 mul cos
exch 180 mul cos
add 2 div}
>> sethalftone
For what its worth, the above is a type 1 halftone dictionary defining a round spot shape and with what I beleive are 'reasonable' values for a 300 dpi monochrome output device.
As to how you get that into the PostScript that Cups sends to Ghostscript, or onto the Ghostscript command line, I can't tell you.
I want to print a bitmap logo file with ESC POS command ESC*.
Following is the link for technical documentation of the command.
https://reference.epson-biz.com/modules/ref_escpos/index.php?content_id=88
According to me, the printer requires the image data in the form of 1s and 0s. So, it prints a dot, with the occurrence of 1 and blank, with the occurrence of 0.
But I am not able to figure out how to send multi line bit image data with the help of above command, since the command accepts only the image data in the horizontal direction. Please help me with the problem.
ESC * is one of several "bit image" commands in ESC/POS. It accepts "column format" data, which can only represent a single line of either 8 or 24 pixels. So there are two good options here.
Print multiple lines using ESC *
It sounds like you are able to print one line, so I will assume that the data format itself is not an issue.
You can print multiple lines by simply repeating the command to print the extra lines, separated by line breaks \n. This requires chopping up the image, and padding it with whitespace so that it is a multiple of 8 or 24 pixels in height (again, due to the format).
Because of line spacing, you need to issue a command to change the size of line feeds during the image print, then another command to reset them at the end.
I use ESC 3 0x10 for 16-unit line feeds (bytes 0x1b 0x33 0x10) and ESC 2 (bytes 0x1b 0x32) to reset.
Example of column format bit image printing in Python using ESC *
Example of column format bit image printing in PHP using ESC *
This method of printing has excellent compatibility with old printers, but you can get some thin horizontal lines in the output.
Print the entire image with GS v 0
This bit image command accepts the different "raster format" data. I make use of the fact that the blob in this format is identical to the binary data in the widely implemented PBM bitmap format (specifically the binary data in files with the P4 header).
The height of the image will be limited by your print buffer size, but could go up to 65535 pixels. The width must be divisible by 8 because of the representation.
Example of raster format bit image printing in Python using VS v 0
Example of raster format bit image printing in PHP using GS v 0
Side note: These snippets the actual prototypes of the image processing code that now appears in the popular open source escpos-php and python-escpos libraries. Using an existing library has a number of benefits, and you should consider it if it's an option.
I'm using wxMaxima 16.12.0 (Maxima 5.39.0) and when I try to print the output, I get overlapping text.
Here's an example (please, ignore the fact the the command couldn't be correct)
1st image
Sometimes happens also with print and printf (inside a block)
2nd image
printf(true, "Link ~d~%", i),
print("+------------------------------------------------+"),
3rd image
But outside a block
4th image
This makes all the output completely unreadable, and my program heavy relies on it. I think that in the 3rd image, the problem is that there is the 2 at the denominator is causing the "shrinking" of the output.
How can I solve it? Is it my problem or Maxima's?
OS: Mint 18 sarah
Kernel: x86_64 Linux 4.4.0-57-generic
DE: Cinnamon 3.0.7
P.S. I also noticed that sometimes, re-running previous commands could make "readable" the following, but that always happens random
EDIT1: I noticed that the last packages that I installed are
libwxbase3.0-dev
libwxgtk3.0-dev
libwxgtk3.0-0v5
libwxbase3.0-0v5
Could it be that there's some kind of conflict?
EDIT2: if I cut the command, the output is "reorganized" in a decent way
become
As BillThePlatypus requested, I'll answer so that everyone will have a quick solution.
In my case, just changing the font solved the problem (i.e. no more overlapping prints), so give it a try.
I'm trying to convert a tangent space normal map to a height/displacement map. For sure this will be not 100% accurate speaking in terms of "exact height" for each pixel. But the relative height from each pixel to the next is more than enough.
Available Algorithm + Info's:
http://www.cournia.com/devnull/n2h/n2h.pdf
Questions:
1. How to convert a normal-to-height map in Photoshop/Gimp? Is there a way using these tools? Beside; I don't wan't to use CrazyBump or any other Texture-Tools. This has to run via CL later on. A Photoshop solution is more or less just a pre-step to understand workflow a bit better.
If not possible with PS/Gimp; how to include the algorithm in an imagemagick process?
I've checked already Doom3:-Normal2Height; Crazybump & all other texture tools like Nvidia's PS-Plugin, xNormal, Awesomebump, SSBump, etc. I'd need this function working with Imagemagick.
Any help is very much welcome. Python preferable.
thx
There are a couple of possibilities for doing that with ImageMagick.
Firstly, you could implement your own process module. When running configure to install ImageMagick, you would then do:
./configure --with-modules=yes
Then, when you want to apply your bumpmap processing on the command-line, you would do:
convert input.png -process analyse <param1> <param2> result.png
Your processing needs to be written in C/C++ and the best description I know of is on Alan Gibson's webpages here.
Secondly, you could write your entire processing using Magick++ which is the C++ binding to ImageMagick. Best description I know of is here with sample code here.
I am doing image manipulation on the png images. I have the following problem. After saving an image with imwrite() function, the size of the image is increased. For example previously image is 847KB, after saving it becomes 1.20 MB. Here is a code. I just read an image and then save it, but the size is increased. I tried to set compression params but it doesn't help.
Mat image;
image = imread("5.png", -1);
vector<int> compression_params;
compression_params.push_back(CV_IMWRITE_PNG_COMPRESSION);
compression_params.push_back(9);
compression_params.push_back(0);
imwrite("output.png",image,compression_params);
What could be a problem? Any help please.
Thanks.
PNG has several options that influence the compression: deflate compression level (0-9), deflate strategy (HUFFMAN/FILTERED), and the choice (or strategy for dynamically chosing) for the internal prediction error filter (AVERAGE, PAETH...).
It seems OpenCV only lets you change the first one, and it hasn't a good default value for the second. So, it seems you must live with that.
Update: looking into the sources, it seems that compression strategy setting has been added (after complaints), but it isn't documented. I wonder if that source is released. Try to set the option CV_IMWRITE_PNG_STRATEGY with Z_FILTERED and see what happens
See the linked source code for more details about the params.
#Karmar, It's been many years since your last edit.
I had similar confuse to yours in June, 2021. And I found out sth which might benefit others like us.
PNG files seem to have this thing called mode. Here, let's focus only on three modes: RGB, P and L.
To quickly check an image's mode, you can use Python:
from PIL import Image
print(Image.open("5.png").mode)
Basically, when using P and L you are attributing 8 bits/pixel while RGB uses 3*8 bits/pixel.
For more detailed explanation, one can refer to this fine stackoverflow post: What is the difference between images in 'P' and 'L' mode in PIL?
Now, when we use OpenCV to open a PNG file, what we get will be an array of three channels, regardless which mode that
file was saved into. Three channels with data type uint8, that means when we imwrite this array into a file, no matter
how hard you compress it, it will be hard to beat the original file if it was saved in P or L mode.
I guess #Karmar might have already had this question solved. For future readers, check the mode of your own 5.png.