Ive been trying to make my own PNG reader in C and ive gotten to the point where it works normally but I want to try and expand its support. I noticed that while uncommon, interlaced png's do exist. Now, I want the goal of my reader simply to return an array of rgba values cooresponding to each pixel in top left to bottom right order. I would not be creating or displaying any pngs.
based on what i saw on the wikipedia for Adam7 Interlacing (the type pngs use) i would most have to add support for it by organizing the final array according to Adam7. However, when I reviewed the Interlacing and Progressive Display section of libpng (one of the sources i was using), it stated:
Note that, although I've described the method in terms of 8 × 8 tiles, pixels for any given pass are stored as complete rows, not as tiled groups. For example, the fifth pass consists of every other pixel in the entire third row of the image, followed by every other pixel in the seventh row, and so on.
This makes it seem as though the interlacing is meat for the program in which displays it to use, rather than the information itself being stored using the Adam7 Algorithm.
My question now is, If im not displaying the png, does interlacing matter? And if so, could someone provide an example of how to uninterlace the information? Because this aspect still confuses me.
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i was working on a program that will, depending on the input draw, shapes of different colors onto a bitmap file, it works fine if i just have to draw one shape, but if i for example take two or more shapes it just draws over the old picture and the old one gets lost but i need them to overlay to create more complex pictures. Is there a way when i am writing to a bitmap file to skip over parts i dont want to write over ? I also tryed making an array in which i would save all the pixel data, but that doesnt work if i take a bitmap of a size larger than 800x800, depending on the size of the type of the elements of the array. I am open for any suggestion and comment. Thank you in advance.
You need to draw the second shape using a transparent background, how you would do that is entirely up to you as you don't provide any information about what technology you are using.
I'm performing some geographical computations in a grid with squares (i.e. regions). I'm using Delphi, but the logic could probably be applied to C++ too. Let me first explain what I want to do.
The following image is a portion of my grid, which is represented by a two-dimensional array Square that denotes the centre point in each square, and the "movement through the layers":
The green square has an X and Y coordinate of 2, so that is Square[2,2]. The actual coordinates are stored in Square[2,2].Latitude and Square[2,2].Longitude as wel as extra information in e.g. Square[2,2].Info that I use for computations.
Now comes the purpose: I need to do some computations on the surrounding areas. How many of the surrounding areas can be called "neighbours", depends on how many "layers" I have defined. In the image above, I used two of these "layers". That means that when starting from the green cell, I go around it once (blue arrows) and then again in the second layer (red arrows).
Now comes the problem: if I would have started in Square[1,1] (green square) instead of Square[2,2] as in the image below, the second layer (in red) would try to access data on the left side and at the bottom that does not exist (i.e. in the "-1" column and row). See the image below. This problem occurs at all borders of course.
I probably can make exceptions with IF-statements for every scenario, but I was wondering if there are common programming "tricks" that can handle such situations where you try to access data does not exist.
For example, I imagine it would be very handy if I can follow the pattern of the arrows depicted in the first image to access all the neighbouring squares every single time, even if there are non-existing squares. So, looking at the first image, after Square[3,0] you'd go to something like Square[3,-1] etc. and then eventually come back into the "feasible" zone in Square[0,3].
To visit neighborhood, you can use some kind of BFS (breadth-first search).
But for sparse structure (like the last picture shows) it is worth to use some data structure to organize cells in a good way. Perhaps kd-tree is suitable - you add all existing cells in the tree and make range search around given cell to get other cells in its vicinity.
Also look at another spatial data structures (see list at the bottom of kd-tree page).
I am trying to build multiple arrays from a read textfile. The read text file comes out as a long column of numbers, and I am trying to split them in groups of three, building arrays until I am done running through the numbers. Here is the block diagram. I know you need a for loop to do this, but figuring out a way to utilize it is giving me lots of trouble.
You need the Reshape Array primitive. See image.
The attached image is a PNG VI snippet. Drag it out of your browser onto a block diagram to instantiate the code directly. This snippet works with LV 2015 and earlier (as noted in the image in the upper right corner). You can create snippets for future posts by selecting code on the block diagram and choosing "Edit >> Create VI Snippet From Selection".
I am new to WPF and c# as a whole. I have experience from programming language like PHP, HTML and Javascript so I was able to cope quickly.
I have a project that is used to print PINs and Serial Number on a card. Let say the card is A4 and on the paper there are 4 rows and 3 columns of printed cards.
My problem is, I dont really know how to generate the dynamic document and the approach to use. Since the content is not that I have to just make it available on the paper before hand, it has to be placed on a particular position on the paper. Inches calculation will strictly be adhered to.
The link below illustrates an explanation of what I am talking about with border exclusive. All I want to generate is the PIN and serial in this way on a specific paper size.
http://ecloudpack.com/grid.png
Dont get me wrong, speaking of flowDocuments, I think I can bring out something but I am faced with the challenge of precision of position on the paper and making sure the pagination is correct and making sure the margin as specified is what is generated.
I have a Monday deadline and I have been trying.
Is there anyone that can help.
I am using Silverlight (4) to create an application in (VS 2010). I utilized the ArcGIS API’s for Silverlight to generate the following scenario:
I buffered a polyline to a variable distance.
I then retrieve all but only those polygons that are overlapped by the buffer.
I then intersect the overlapped portions to separate them.
Attaining the separated overlapped portions, I was about to utilize the Area and perimeter service to retrieve the areas of the portions, but realized that this last step would be in the wind.
I have no problem coding the above scenario except; I now realize that step 4 would not be very useful at this point, since I have no way of sharing data between the separated overlapped portions to the original polygons. Imagine if you will; before I separated the overlapped portions from the polygons, they had data tied to them; such as valuationNumber and volume, but after the separation due to the intersection service, the separated portions seems blank with no data. My goal is to have a list highlighting the valuationNumber, volume, and the area of the separated portion.
Something like:
Valuation:
12345678
Volume:
1234/123
Area of Separation (M):
12
Any, and I mean any help would be appreciated.
[copied and pasted my comments from above due to laziness]
Well then, I would suppose I created a work around, I wonder if there is a right way out there though. Anyhow, I did the following: I created a Dictionary Object and populated it with the Attribute values of the original polygon just as they are created. Then, just as the overlapped portions are being created I assigned the attribute values from my Dictionary. So, now the values match up, and all binding works just fine. But hey, if anyone know a better way; I'm all eyes.
In fact, to make matters seem a bit better, I made an improvement on the work around. I create a class with the fields I wanted to be in both original and separated portions. Then added this class as the value parameter of my dictionary object I spoke of earlier, then followed the same procedure. Now I have all the fields being mapped to in XAML working nicely (for now).