I like to do this with PythonMagick:
composite -dissolve 40 over.png base.png new.png
I have tried:
import PythonMagick
base = PythonMagick.Image("base.png")
over = PythonMagick.Image("over.png")
base.composite(over,0,0,PythonMagick.CompositeOperator.DissolveCompositeOp)
base.write("some.png")
That works fine, but how can I specify the dissolve value?
Thanks in advance
Thomas
Based on your other question, I would recommend staying with PIL since PythonMagick seems to be inactive. I also looked into Magick++'s documentation, but it fails to mention how to specify extra options for composite. I would stay away from these libraries, and instead use the direct CLI provided by ImageMagick.
Related
Does anybody knows how to create/apply grunge or vintage-worn filters? I'm creating an iOS app to apply filters to photos, just for fun and to learn more about CIImage. Now, I'm using Core-Image to apply CIGaussianBlur, CIGloom, and the like through commands such as ciFilter.setValue(value, forKey:key) and corresponding commands.
So far, core image filters such as blur, color adjustment, sharpen , stylize work OK. But I'd like to learn how to apply one of those grunge, vintage-worn effects available in other photo editing apps, something like this:
Does anybody knows how to create/apply those kind of filters?
Thanks!!!
You have two options.
(1) Use "canned" filters in a chain. If the output of one filter is the input of the next, code things that way. It won't waste any resources until you actually call for output.
(2) Write your own kernel code. It can be a color kernel that mutates a single pixel independently, a warp kernel that checks the values of a pixel and it's surrounding ones to generate the output pixel, or a general kernel that isn't optimized like the last two. Either way, you can use GLSL pretty much for the code (it's pretty much C language for the GPU).
Okay, there's a third option - a combination of the two above options. Also, in iOS 11 and above, you can write kernels using Metal 2.
I am using JsPdf to generate pdf from multiple images, the issue is that I get the same image generated in all pdf files. any idea please.
I had a similar problem when using multiple canvases to generate multi-page PDF document, I was originally using the default format (PNG), so after several hours going through my code I decided to change the format to JPEG, what do you know, the problem went away. Here is the call:
doc.addImage(canvas.toDataURL("image/jpeg"), "JPEG", 0, 0, canvas.width, canvas.height);
Have a look at the parameter list of addImage():
jsPDFAPI.addImage = function(imageData, format, x, y, w, h, alias, compression, rotation)
If you add multiple different images but somehow set alias to the same for all, jsPDF will reuse the first of those images. This is intended behaviour and reduces the output size.
I recommend to always set alias to something unique for unique images. If alias is not set, jsPDF will calculate a hash and for large images, this can be quite expensive.
[Edit, as I can't comment directly to marwen web's answer below:
addImage() has no option split, so I don not know what you mean. Perhaps you can give an example in case other users have the same problem?]
thank you for your answer, actually the problem was caused by an option added in the call of the function, it is caused by the option "split".i use the PNG format withount any problem.
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'm working with openCV and I'm a newbie in this field. I'm researching about Camshift. I want to extend this method by using multiple histograms. It means when tracking an object has many than one apperance (ex: rubik cube with six apperance), if we use only one histogram, Camshift will most likely fail.
I know calcHist function in openCV (http://docs.opencv.org/modules/imgproc/doc/histograms.html#calchist) has a parameter is "accumulate", but I don't know how to use and when to use (apply for camshiftdemo.cpp in opencv samples folder). This function can help me solve this problem? Or I have to use difference solution?
I have an idea, that is: create an array histogram for object, for every appearance condition that strongly varies in color, we pre-compute and store all to this array. But when we compute new histogram? It means that the pre-condition to start compute new histogram is what?
And what happend if I have to track multiple object has same color?
Everybody please help me. Thank you so much!
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.